To estimate past temperatures, the research team looked at Arctic lake sediments and at previously published data of glacial ice cores and tree rings.
The team also examined a computer model of global climate based at the National Center for Atmospheric Research in Colorado.
Map of Global Warming Effects
Hungry Musk-Oxen, Caribou Could Help Warming Arctic
North Pole May Be Ice-Free for First Time This Summer
Miller and colleagues found that the wobble in Earth's tilt causes Arctic temperatures to drop by about 0.36 degree Fahrenheit (0.2 degree Celsius) every thousand years during a cooling phase.
But human-caused global warming overwhelmed that gradual cooling in the mid-1990s, shooting temperatures up by about 2.5 degrees Fahrenheit (1.4 degrees Celsius) over the course of a few decades.
In fact four of the five warmest decades in the past 2,000 years occurred after 1950, according to the study, which will be published tomorrow in the journal Science.
Ecologist Syndonia Bret-Harte said she has seen the effects of climate change firsthand during her research on the changing Alaskan tundra.
The new study "doesn't seem that surprising, but it's good to confirm what researchers were already thinking," said Bret-Harte, of the Institute of Arctic Biology at the University of Alaska, Fairbanks.
Global Warming Amplifiers
The effects of climate change are powerfully amplified in the Arctic, which has been heating up faster than anywhere else on Earth.
That's because Arctic temperatures are greatly impacted by melting from both summer sea ice and permafrost, or frozen soil, experts say.
Summer Arctic sea ice, which hit a record low in 2007, will probably have dissolved completely by 2030.
Without swaths of white ice to reflect sunlight back into the atmosphere, those rays will instead be absorbed into the darker oceans—speeding up the region's warming.
And melting permafrost is already starting to release carbon dioxide and methane, two potent greenhouse gases that have long been trapped underground.
"It's pretty straightforward that amplification will continue in the future. There will be direct impacts in the Arctic," study co-author Miller said.
"The big issue is, when you melt ice, the sea level rises—that's a global issue, and that has major impacts."
Bret-Harte agreed that the amplifying effects are "going to continue until summer sea ice is gone—there's no way to reverse the trend in the short term."
But that doesn't mean people shouldn't act, she said.
"Realistically we're looking at a warmer world, and there are two questions: How do we adapt to that as humans but [also] slow down the pace of [climate] change? The faster it is, the harder it is to adapt."
16 Aralık 2011 Cuma
Next Ice Age Delayed by Global Warming
Humans are putting the brakes on the next ice age, according to the most extensive study to date on Arctic climate change.
The Arctic may be warmer than it's been in the past 2,000 years—a trend that is reversing a natural cooling cycle dictated by a wobble in Earth's axis.
Map of Global Warming Effects
Hungry Musk-Oxen, Caribou Could Help Warming Arctic
North Pole May Be Ice-Free for First Time This Summer
Previously, researchers had looked at Arctic temperature data that went back just 400 years. (See photos of how climate change is transforming the Arctic.)
That research showed a temperature spike in the 20th century, but it was unclear whether human-caused greenhouse gas emissions or natural variability was the culprit, noted study co-author Gifford Miller of the Institute of Arctic and Alpine Research at the University of Colorado, Boulder.
By looking even farther back in time, Miller and colleagues' newest study reveals that the 20th century's abrupt warming may have in fact interrupted millennia of steady cooling.
It's "pretty clear that the most reasonable explanation for that reversal is due to increasing greenhouse gases," Miller said.
The researchers' computer climate models dovetails with field data such as sediment cores and tree rings, which "really … solidifies our understanding," he said.
Eventually Earth will slip again into the pattern of cyclical ice ages, Miller added, but it may be thousands of years before that happens.
Ice Age, Interrupted
Earth's angle toward the sun changes due to a natural 26,000-year-long wobble, which causes the planet to spin on is axis like an unstable top, so that a line drawn from the axis would trace a cone in the sky.
The wobble causes Earth to make its closest pass by the sun in different months over the long term. For the past 7,000 years, Earth has passed closest to the sun in January.
This means less sunlight has been hitting the Arctic during its summertime, so the region should be cooling.
The Arctic may be warmer than it's been in the past 2,000 years—a trend that is reversing a natural cooling cycle dictated by a wobble in Earth's axis.
Map of Global Warming Effects
Hungry Musk-Oxen, Caribou Could Help Warming Arctic
North Pole May Be Ice-Free for First Time This Summer
Previously, researchers had looked at Arctic temperature data that went back just 400 years. (See photos of how climate change is transforming the Arctic.)
That research showed a temperature spike in the 20th century, but it was unclear whether human-caused greenhouse gas emissions or natural variability was the culprit, noted study co-author Gifford Miller of the Institute of Arctic and Alpine Research at the University of Colorado, Boulder.
By looking even farther back in time, Miller and colleagues' newest study reveals that the 20th century's abrupt warming may have in fact interrupted millennia of steady cooling.
It's "pretty clear that the most reasonable explanation for that reversal is due to increasing greenhouse gases," Miller said.
The researchers' computer climate models dovetails with field data such as sediment cores and tree rings, which "really … solidifies our understanding," he said.
Eventually Earth will slip again into the pattern of cyclical ice ages, Miller added, but it may be thousands of years before that happens.
Ice Age, Interrupted
Earth's angle toward the sun changes due to a natural 26,000-year-long wobble, which causes the planet to spin on is axis like an unstable top, so that a line drawn from the axis would trace a cone in the sky.
The wobble causes Earth to make its closest pass by the sun in different months over the long term. For the past 7,000 years, Earth has passed closest to the sun in January.
This means less sunlight has been hitting the Arctic during its summertime, so the region should be cooling.
1 Aralık 2011 Perşembe
Global warming facts
Despite overwhelming scientific evidence, popular myths and misinformation abound. Here are some of the facts of what we know about global warming.
There is scientific consensus on the basic facts of global warming.
The most respected scientific bodies have stated unequivocally that global warming is occurring, and people are causing it. Read their statements
Scientists are certain that the Earth is warming.Y8,Y8,Y8,Y3
Scientists are certain the Earth has been warming for 100 years. Here's how they know
Human activity is causing the Earth to get warmer.friv
Only CO2 and other greenhouse gas emissions from human activities explain the observed warming now taking place on Earth How we know
The effects of warming can be seen today.
We can already see the effects of global warming in our world through disappearing habitat, shrinking arctic sea ice and extreme weather. Impacts we can see today
There is scientific consensus on the basic facts of global warming.
The most respected scientific bodies have stated unequivocally that global warming is occurring, and people are causing it. Read their statements
Scientists are certain that the Earth is warming.Y8,Y8,Y8,Y3
Scientists are certain the Earth has been warming for 100 years. Here's how they know
Human activity is causing the Earth to get warmer.friv
Only CO2 and other greenhouse gas emissions from human activities explain the observed warming now taking place on Earth How we know
The effects of warming can be seen today.
We can already see the effects of global warming in our world through disappearing habitat, shrinking arctic sea ice and extreme weather. Impacts we can see today
18 Kasım 2011 Cuma
What's Going to Happen?
What's Going to Happen?
A follow-up report by the IPCC released in April 2007 warned that global warming could lead to large-scale food and water shortages and have catastrophic effects on wildlife.
• Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by century's end, the IPCC's February 2007 report projects. Rises of just 4 inches (10 centimeters) could flood many South Seas islands and swamp large parts of Southeast Asia.
• Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world's population is concentrated in vulnerable coastal cities. In the U.S., Louisiana and Florida are especially at risk.
• Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water.
• Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world. The growth of deserts may also cause food shortages in many places.
• More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.
• The ocean's circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.
• At some point in the future, warming could become uncontrollable by creating a so-called positive feedback effect. Rising temperatures could release additional greenhouse gases by unlocking methane in permafrost and undersea deposits, freeing carbon trapped in sea ice, and causing increased evaporation of water.
What is Climategate?
In late November 2009, hackers unearthed hundreds of emails at the U.K.'s University of East Anglia that exposed private conversations among top-level British and U.S. climate scientists discussing whether certain data should be released to the public. [Do we know who the hackers were? Were they skeptics? Might be worth noting]
The email exchanges also refer to statistical tricks used to illustrate climate change? trends, and call climate skeptics idiots, according to the New York Times.
One such trick was used to create the well-known hockey-stick graph, which shows a sharp uptick in temperature increases during the 20th century. Former U.S vice president Al Gore relied heavily on the graph as evidence of human-caused climate change in the documentary An Inconvenient Truth.
The data used for this graph come from two sources: thermostat readings and tree-ring samples.
While thermostat readings have consistently shown a temperature rise over the past hundred years, tree-ring samples show temperature increases stalling around 1960.
On the hockey-stick graph, thermostat-only data is grafted onto data that incorporates both thermostat and tree-ring readings, essentially presenting a seamless picture of two different data sets, the hacked emails revealed.
But scientists argue that dropping the tree-ring data was no secret and has been written about in the scientific literature for years.
Climate change skeptics have heralded the emails as an attempt to fool the public, according to the Times.
Yet climate scientists maintain that these controversial points are small blips that are inevitable in scientific research, and that the evidence for human-induced climate change is much broader and still widely accepted.
A follow-up report by the IPCC released in April 2007 warned that global warming could lead to large-scale food and water shortages and have catastrophic effects on wildlife.
• Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by century's end, the IPCC's February 2007 report projects. Rises of just 4 inches (10 centimeters) could flood many South Seas islands and swamp large parts of Southeast Asia.
• Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world's population is concentrated in vulnerable coastal cities. In the U.S., Louisiana and Florida are especially at risk.
• Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water.
• Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world. The growth of deserts may also cause food shortages in many places.
• More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.
• The ocean's circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.
• At some point in the future, warming could become uncontrollable by creating a so-called positive feedback effect. Rising temperatures could release additional greenhouse gases by unlocking methane in permafrost and undersea deposits, freeing carbon trapped in sea ice, and causing increased evaporation of water.
What is Climategate?
In late November 2009, hackers unearthed hundreds of emails at the U.K.'s University of East Anglia that exposed private conversations among top-level British and U.S. climate scientists discussing whether certain data should be released to the public. [Do we know who the hackers were? Were they skeptics? Might be worth noting]
The email exchanges also refer to statistical tricks used to illustrate climate change? trends, and call climate skeptics idiots, according to the New York Times.
One such trick was used to create the well-known hockey-stick graph, which shows a sharp uptick in temperature increases during the 20th century. Former U.S vice president Al Gore relied heavily on the graph as evidence of human-caused climate change in the documentary An Inconvenient Truth.
The data used for this graph come from two sources: thermostat readings and tree-ring samples.
While thermostat readings have consistently shown a temperature rise over the past hundred years, tree-ring samples show temperature increases stalling around 1960.
On the hockey-stick graph, thermostat-only data is grafted onto data that incorporates both thermostat and tree-ring readings, essentially presenting a seamless picture of two different data sets, the hacked emails revealed.
But scientists argue that dropping the tree-ring data was no secret and has been written about in the scientific literature for years.
Climate change skeptics have heralded the emails as an attempt to fool the public, according to the Times.
Yet climate scientists maintain that these controversial points are small blips that are inevitable in scientific research, and that the evidence for human-induced climate change is much broader and still widely accepted.
A follow-up report by the IPCC released in April 2007 warned that global warming could lead to large-scale food and water shortages and have catastrophic effects on wildlife.
• Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by century's end, the IPCC's February 2007 report projects. Rises of just 4 inches (10 centimeters) could flood many South Seas islands and swamp large parts of Southeast Asia.
• Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world's population is concentrated in vulnerable coastal cities. In the U.S., Louisiana and Florida are especially at risk.
• Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water.
• Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world. The growth of deserts may also cause food shortages in many places.
• More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.
• The ocean's circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.
• At some point in the future, warming could become uncontrollable by creating a so-called positive feedback effect. Rising temperatures could release additional greenhouse gases by unlocking methane in permafrost and undersea deposits, freeing carbon trapped in sea ice, and causing increased evaporation of water.
What is Climategate?
In late November 2009, hackers unearthed hundreds of emails at the U.K.'s University of East Anglia that exposed private conversations among top-level British and U.S. climate scientists discussing whether certain data should be released to the public. [Do we know who the hackers were? Were they skeptics? Might be worth noting]
The email exchanges also refer to statistical tricks used to illustrate climate change? trends, and call climate skeptics idiots, according to the New York Times.
One such trick was used to create the well-known hockey-stick graph, which shows a sharp uptick in temperature increases during the 20th century. Former U.S vice president Al Gore relied heavily on the graph as evidence of human-caused climate change in the documentary An Inconvenient Truth.
The data used for this graph come from two sources: thermostat readings and tree-ring samples.
While thermostat readings have consistently shown a temperature rise over the past hundred years, tree-ring samples show temperature increases stalling around 1960.
On the hockey-stick graph, thermostat-only data is grafted onto data that incorporates both thermostat and tree-ring readings, essentially presenting a seamless picture of two different data sets, the hacked emails revealed.
But scientists argue that dropping the tree-ring data was no secret and has been written about in the scientific literature for years.
Climate change skeptics have heralded the emails as an attempt to fool the public, according to the Times.
Yet climate scientists maintain that these controversial points are small blips that are inevitable in scientific research, and that the evidence for human-induced climate change is much broader and still widely accepted.
A follow-up report by the IPCC released in April 2007 warned that global warming could lead to large-scale food and water shortages and have catastrophic effects on wildlife.
• Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by century's end, the IPCC's February 2007 report projects. Rises of just 4 inches (10 centimeters) could flood many South Seas islands and swamp large parts of Southeast Asia.
• Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world's population is concentrated in vulnerable coastal cities. In the U.S., Louisiana and Florida are especially at risk.
• Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water.
• Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world. The growth of deserts may also cause food shortages in many places.
• More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.
• The ocean's circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.
• At some point in the future, warming could become uncontrollable by creating a so-called positive feedback effect. Rising temperatures could release additional greenhouse gases by unlocking methane in permafrost and undersea deposits, freeing carbon trapped in sea ice, and causing increased evaporation of water.
What is Climategate?
In late November 2009, hackers unearthed hundreds of emails at the U.K.'s University of East Anglia that exposed private conversations among top-level British and U.S. climate scientists discussing whether certain data should be released to the public. [Do we know who the hackers were? Were they skeptics? Might be worth noting]
The email exchanges also refer to statistical tricks used to illustrate climate change? trends, and call climate skeptics idiots, according to the New York Times.
One such trick was used to create the well-known hockey-stick graph, which shows a sharp uptick in temperature increases during the 20th century. Former U.S vice president Al Gore relied heavily on the graph as evidence of human-caused climate change in the documentary An Inconvenient Truth.
The data used for this graph come from two sources: thermostat readings and tree-ring samples.
While thermostat readings have consistently shown a temperature rise over the past hundred years, tree-ring samples show temperature increases stalling around 1960.
On the hockey-stick graph, thermostat-only data is grafted onto data that incorporates both thermostat and tree-ring readings, essentially presenting a seamless picture of two different data sets, the hacked emails revealed.
But scientists argue that dropping the tree-ring data was no secret and has been written about in the scientific literature for years.
Climate change skeptics have heralded the emails as an attempt to fool the public, according to the Times.
Yet climate scientists maintain that these controversial points are small blips that are inevitable in scientific research, and that the evidence for human-induced climate change is much broader and still widely accepted.
Global Warming Fast Facts
Global warming, or climate change, is a subject that shows no sign of cooling down.
Here's the lowdown on why it's happening, what's causing it, and how it might change the planet.
Global Warming: How Hot? How Soon?
Global Warming Can Be Stopped, World Climate Experts Say
Global Warming Interactive: Learn About Its Causes and Effects
Is It Happening?
Yes. Earth is already showing many signs of worldwide climate change.
• Average temperatures have climbed 1.4 degrees Fahrenheit (0.8 degree Celsius) around the world since 1880, much of this in recent decades, according to NASA's Goddard Institute for Space Studies.
• The rate of warming is increasing. The 20th century's last two decades were the hottest in 400 years and possibly the warmest for several millennia, according to a number of climate studies. And the United Nations' Intergovernmental Panel on Climate Change (IPCC) reports that 11 of the past 12 years are among the dozen warmest since 1850.
• The Arctic is feeling the effects the most. Average temperatures in Alaska, western Canada, and eastern Russia have risen at twice the global average, according to the multinational Arctic Climate Impact Assessment report compiled between 2000 and 2004.
• Arctic ice is rapidly disappearing, and the region may have its first completely ice-free summer by 2040 or earlier. Polar bears and indigenous cultures are already suffering from the sea-ice loss.
• Glaciers and mountain snows are rapidly melting—for example, Montana's Glacier National Park now has only 27 glaciers, versus 150 in 1910. In the Northern Hemisphere, thaws also come a week earlier in spring and freezes begin a week later.
• Coral reefs, which are highly sensitive to small changes in water temperature, suffered the worst bleaching—or die-off in response to stress—ever recorded in 1998, with some areas seeing bleach rates of 70 percent. Experts expect these sorts of events to increase in frequency and intensity in the next 50 years as sea temperatures rise.
• An upsurge in the amount of extreme weather events, such as wildfires, heat waves, and strong tropical storms, is also attributed in part to climate change by some experts.
Here's the lowdown on why it's happening, what's causing it, and how it might change the planet.
Global Warming: How Hot? How Soon?
Global Warming Can Be Stopped, World Climate Experts Say
Global Warming Interactive: Learn About Its Causes and Effects
Is It Happening?
Yes. Earth is already showing many signs of worldwide climate change.
• Average temperatures have climbed 1.4 degrees Fahrenheit (0.8 degree Celsius) around the world since 1880, much of this in recent decades, according to NASA's Goddard Institute for Space Studies.
• The rate of warming is increasing. The 20th century's last two decades were the hottest in 400 years and possibly the warmest for several millennia, according to a number of climate studies. And the United Nations' Intergovernmental Panel on Climate Change (IPCC) reports that 11 of the past 12 years are among the dozen warmest since 1850.
• The Arctic is feeling the effects the most. Average temperatures in Alaska, western Canada, and eastern Russia have risen at twice the global average, according to the multinational Arctic Climate Impact Assessment report compiled between 2000 and 2004.
• Arctic ice is rapidly disappearing, and the region may have its first completely ice-free summer by 2040 or earlier. Polar bears and indigenous cultures are already suffering from the sea-ice loss.
• Glaciers and mountain snows are rapidly melting—for example, Montana's Glacier National Park now has only 27 glaciers, versus 150 in 1910. In the Northern Hemisphere, thaws also come a week earlier in spring and freezes begin a week later.
• Coral reefs, which are highly sensitive to small changes in water temperature, suffered the worst bleaching—or die-off in response to stress—ever recorded in 1998, with some areas seeing bleach rates of 70 percent. Experts expect these sorts of events to increase in frequency and intensity in the next 50 years as sea temperatures rise.
• An upsurge in the amount of extreme weather events, such as wildfires, heat waves, and strong tropical storms, is also attributed in part to climate change by some experts.
4 Kasım 2011 Cuma
Stopping global warming is risk management
Stopping global warming is risk management
The issue with stopping or reducing global warming is about risk and managing risk: Science still does not know the exact mechanism by which smoking and its associated chemicals causes cancer. What we do know is that smoking is the biggest risk factor in developing lung cancer. The more you smoke, the more your risk of getting lung cancer. Not everyone who smokes gets lung cancer, and not everyone who gets lung cancer has smoked.
Similarly with Climate Change (global warming), we are seeing that temperatures are rising at the same time that atmospheric greenhouse gas levels have gone off the charts over the last 650,000 years.
If the IPCC is right, and we don't do anything, we risk massive temperature increases that will lead to the loss of the great ice sheets of Greenland and Antarctica, resulting in a 20 foot increase in sea levels.That would take about 100 years if we do nothing. Almost all of the major population centers located on coasts (check out the % of Asia, Europe, and North American cities which would be affected.) Global warming causes huge costs if that is right.
If the IPCC is wrong, and we do everything we can to reduce new emissions of greenhouse gases, we would reduce the annual increase of global GDP by 0.12%. Since global GDP is growing around 3%, that is not a big cost.
This is exactly why people buy insurance. Most Americans will never have a fire. Only about 1% will ever have a house fire. However, most Americans buy fire insurance. Why? Managing risks. Science has told us the facts about global waming. It's up to us to manage the risks involved with global warming.
The issue with stopping or reducing global warming is about risk and managing risk: Science still does not know the exact mechanism by which smoking and its associated chemicals causes cancer. What we do know is that smoking is the biggest risk factor in developing lung cancer. The more you smoke, the more your risk of getting lung cancer. Not everyone who smokes gets lung cancer, and not everyone who gets lung cancer has smoked.
Similarly with Climate Change (global warming), we are seeing that temperatures are rising at the same time that atmospheric greenhouse gas levels have gone off the charts over the last 650,000 years.
If the IPCC is right, and we don't do anything, we risk massive temperature increases that will lead to the loss of the great ice sheets of Greenland and Antarctica, resulting in a 20 foot increase in sea levels.That would take about 100 years if we do nothing. Almost all of the major population centers located on coasts (check out the % of Asia, Europe, and North American cities which would be affected.) Global warming causes huge costs if that is right.
If the IPCC is wrong, and we do everything we can to reduce new emissions of greenhouse gases, we would reduce the annual increase of global GDP by 0.12%. Since global GDP is growing around 3%, that is not a big cost.
This is exactly why people buy insurance. Most Americans will never have a fire. Only about 1% will ever have a house fire. However, most Americans buy fire insurance. Why? Managing risks. Science has told us the facts about global waming. It's up to us to manage the risks involved with global warming.
Cause and effect for global warming
Cause of global warming
Almost 100% of the observed temperature increase over the last 50 years has been due to the increase in the atmosphere of greenhouse gas concentrations like water vapour, carbon dioxide (CO2), methane and ozone. Greenhouse gases are those gases that contribute to the greenhouse effect (see below). The largest contributing source of greenhouse gas is the burning of fossil fuels leading to the emission of carbon dioxide.
The greenhouse effect
When sunlight reaches Earth's surface some is absorbed and warms the earth and most of the rest is radiated back to the atmosphere at a longer wavelength than the sun light. Some of these longer wavelengths are absorbed by greenhouse gases in the atmosphere before they are lost to space. The absorption of this longwave radiant energy warms the atmosphere. These greenhouse gases act like a mirror and reflect back to the Earth some of the heat energy which would otherwise be lost to space. The reflecting back of heat energy by the atmosphere is called the "greenhouse effect".
The major natural greenhouse gases are water vapor, which causes about 36-70% of the greenhouse effect on Earth (not including clouds); carbon dioxide CO2, which causes 9-26%; methane, which causes 4-9%, and ozone, which causes 3-7%. It is not possible to state that a certain gas causes a certain percentage of the greenhouse effect, because the influences of the various gases are not additive. Other greenhouse gases include, but are not limited to, nitrous oxide, sulfur hexafluoride, hydrofluorocarbons, perfluorocarbons and chlorofluorocarbons.
Global warming causes by greenhouse effect
Greenhouse gases in the atmosphere (see above) act like a mirror and reflect back to the Earth a part of the heat radiation, which would otherwise be lost to space. The higher the concentration of green house gases like carbon dioxide in the atmosphere, the more heat energy is being reflected back to the Earth. The emission of carbon dioxide into the environment mainly from burning of fossil fuels (oil, gas, petrol, kerosene, etc.) has been increased dramatically over the past 50 years, see graph below.
Almost 100% of the observed temperature increase over the last 50 years has been due to the increase in the atmosphere of greenhouse gas concentrations like water vapour, carbon dioxide (CO2), methane and ozone. Greenhouse gases are those gases that contribute to the greenhouse effect (see below). The largest contributing source of greenhouse gas is the burning of fossil fuels leading to the emission of carbon dioxide.
The greenhouse effect
When sunlight reaches Earth's surface some is absorbed and warms the earth and most of the rest is radiated back to the atmosphere at a longer wavelength than the sun light. Some of these longer wavelengths are absorbed by greenhouse gases in the atmosphere before they are lost to space. The absorption of this longwave radiant energy warms the atmosphere. These greenhouse gases act like a mirror and reflect back to the Earth some of the heat energy which would otherwise be lost to space. The reflecting back of heat energy by the atmosphere is called the "greenhouse effect".
The major natural greenhouse gases are water vapor, which causes about 36-70% of the greenhouse effect on Earth (not including clouds); carbon dioxide CO2, which causes 9-26%; methane, which causes 4-9%, and ozone, which causes 3-7%. It is not possible to state that a certain gas causes a certain percentage of the greenhouse effect, because the influences of the various gases are not additive. Other greenhouse gases include, but are not limited to, nitrous oxide, sulfur hexafluoride, hydrofluorocarbons, perfluorocarbons and chlorofluorocarbons.
Global warming causes by greenhouse effect
Greenhouse gases in the atmosphere (see above) act like a mirror and reflect back to the Earth a part of the heat radiation, which would otherwise be lost to space. The higher the concentration of green house gases like carbon dioxide in the atmosphere, the more heat energy is being reflected back to the Earth. The emission of carbon dioxide into the environment mainly from burning of fossil fuels (oil, gas, petrol, kerosene, etc.) has been increased dramatically over the past 50 years, see graph below.
Global Warming is caused
Global Warming is caused by many things. The causes are split up into two groups, man-made or anthropogenic causes, and natural causes.
Natural Causes
Natural causes are causes created by nature. One natural cause is a release of methane gas from arctic tundra and wetlands. Methane is a greenhouse gas. A greenhouse gas is a gas that traps heat in the earth's atmosphere. Another natural cause is that the earth goes through a cycle of climate change. This climate change usually lasts about 40,000 years.
Man-made Causes
Man-made causes probably do the most damage. There are many man-made causes. Pollution is one of the biggest man-made problems. Pollution comes in many shapes and sizes. Burning fossil fuels is one thing that causes pollution. Fossil fuels are fuels made of organic matter such as coal, or oil. When fossil fuels are burned they give off a green house gas called CO2. Also mining coal and oil allows methane to escape. How does it escape? Methane is naturally in the ground. When coal or oil is mined you have to dig up the earth a little. When you dig up the fossil fuels you dig up the methane as well.
Another major man-made cause of Global Warming is population. More people means more food, and more methods of transportation, right? That means more methane because there will be more burning of fossil fuels, and more agriculture. Now your probably thinking, "Wait a minute, you said agriculture is going to be damaged by Global Warming, but now you're saying agriculture is going to help cause Global Warming?" Well, have you ever been in a barn filled with animals and you smell something terrible? You're smelling methane. Another source of methane is manure. Because more food is needed we have to raise food. Animals like cows are a source of food which means more manure and methane. Another problem with the increasing population is transportation. More people means more cars, and more cars means more pollution. Also, many people have more than one car.
OverpopulationSince CO2 contributes to global warming, the increase in population makes the problem worse because we breathe out CO2. Also, the trees that convert our CO2 to oxygen are being demolished because we're using the land that we cut the trees down from as property for our homes and buildings. We are not replacing the trees (an important part of our eco system), so we are constantly taking advantage of our natural resources and giving nothing back in return.
Natural Causes
Natural causes are causes created by nature. One natural cause is a release of methane gas from arctic tundra and wetlands. Methane is a greenhouse gas. A greenhouse gas is a gas that traps heat in the earth's atmosphere. Another natural cause is that the earth goes through a cycle of climate change. This climate change usually lasts about 40,000 years.
Man-made Causes
Man-made causes probably do the most damage. There are many man-made causes. Pollution is one of the biggest man-made problems. Pollution comes in many shapes and sizes. Burning fossil fuels is one thing that causes pollution. Fossil fuels are fuels made of organic matter such as coal, or oil. When fossil fuels are burned they give off a green house gas called CO2. Also mining coal and oil allows methane to escape. How does it escape? Methane is naturally in the ground. When coal or oil is mined you have to dig up the earth a little. When you dig up the fossil fuels you dig up the methane as well.
Another major man-made cause of Global Warming is population. More people means more food, and more methods of transportation, right? That means more methane because there will be more burning of fossil fuels, and more agriculture. Now your probably thinking, "Wait a minute, you said agriculture is going to be damaged by Global Warming, but now you're saying agriculture is going to help cause Global Warming?" Well, have you ever been in a barn filled with animals and you smell something terrible? You're smelling methane. Another source of methane is manure. Because more food is needed we have to raise food. Animals like cows are a source of food which means more manure and methane. Another problem with the increasing population is transportation. More people means more cars, and more cars means more pollution. Also, many people have more than one car.
OverpopulationSince CO2 contributes to global warming, the increase in population makes the problem worse because we breathe out CO2. Also, the trees that convert our CO2 to oxygen are being demolished because we're using the land that we cut the trees down from as property for our homes and buildings. We are not replacing the trees (an important part of our eco system), so we are constantly taking advantage of our natural resources and giving nothing back in return.
20 Ekim 2011 Perşembe
Human Fingerprints
Earth's surface has undergone unprecedented warming over the last century, particularly over the last two decades. Astonishingly, every single year since 1992 is in the current list of the 20 warmest years on record.[1,2] The natural patterns of climate have been altered. Like detectives, science sleuths seek the answer to "Whodunnit?" — are humans part of the cause? To answer this question, patterns observed by meteorologists and oceanographers are compared with patterns developed using sophisticated models of Earth's atmosphere and ocean. By matching the observed and modeled patterns, scientists can now positively identify the "human fingerprints" associated with the changes. The fingerprints that humans have left on Earth's climate are turning up in a diverse range of records and can be seen in the ocean, in the atmosphere, and at the surface.
Because most global warming emissions remain in the atmosphere for decades or centuries, the energy choices we make today greatly influence the climate our children and grandchildren inherit. We have the technology to increase energy efficiency, significantly reduce these emissions from our energy and land use, and secure a high quality of life for future generations. We must act now to reduce dangerous consequences.
In its 2001 report, the Intergovernmental Panel on Climate Change stated, "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities." [3] Carbon dioxide from fossil fuel burning and land clearing has been accumulating in the atmosphere, where it acts like a blanket keeping Earth warm and heating up the surface, ocean, and atmosphere. As a result, current levels of carbon dioxide in the atmosphere are higher than at any time during the last 650,000 years. [4,5,6]
Background: Driving the Climate ("Forcing")
Climate is influenced by many factors, both natural and human. [7] Things that increase temperature, such as increases in heat-trapping emissions from cars and power plants or an increase in the amount of radiation the sun emits, are examples of "positive" forcings or drivers. Volcanic events and some types of human-made pollution, both of which inject sunlight-reflecting aerosols into the atmosphere, lower temperature and are examples of "negative" forcings or drivers. Natural climate drivers include the sun's energy output, aerosols from volcanic activity, and changes in snow and ice cover. Human climate drivers include heat-trapping emissions from cars and power plants, aerosols from pollution, and soot particles.
Much as the Air Force develops computer programs to simulate aircraft flight under different conditions, climate scientists develop computer programs to simulate global climate changes under different conditions. These programs use our knowledge of physical, chemical, and biological processes that occur within Earth's atmosphere and oceans and on its land surfaces. Mathematical models allow scientists to simulate the behavior of complex systems such as climate and explore how these systems respond to natural and human factors.
Fingerprint 1: The Ocean Layers Warm
The world's oceans have absorbed about 20 times as much heat as the atmosphere over the past half-century, leading to higher temperatures not only in surface waters but also in water 1,500 feet below the surface. [8,9] The measured increases in water temperature lie well outside the bounds of natural climate variation.
Fingerprint 2: The Atmosphere Shifts
Recent research shows that human activities have lifted the boundary of Earth's lower atmosphere. Known as the troposphere (from the Greek tropos, which means "turning"), this lowest layer of the atmosphere contains Earth's weather. The stable layer above is called the stratosphere. The boundary that separates the two layers, the tropopause, is as high as nine miles above the equator and as low as five miles above the poles. In an astounding development, a 2003 study showed that this tropopause has shifted upward over the last two decades by more than 900 feet. [10] The rising tropopause marks another human fingerprint on Earth's climate.
In their search for clues, scientists compared two natural drivers of climate (solar changes and volcanic aerosols) and three human drivers of climate (heat-trapping emissions, aerosol pollution, and ozone depletion), altering these one at a time in their sophisticated models. Changes in the sun during the twentieth century have warmed both the troposphere and stratosphere. But human activities have increased heat-trapping emissions and decreased stratospheric ozone. This has led to the troposphere warming more because the increase in heat-trapping emissions is trapping more of Earth's outgoing heat. The stratosphere has cooled more because there is less ozone to absorb incoming sunlight to heat up the stratosphere. Both these effects combine to shift the boundary upward. Over the period 1979-1999, a study shows that human-induced changes in heat-trapping emissions and ozone account for more than 80 percent of the rise in tropopause height. [10] This is yet another example of how science detectives are quantifying the impact of human activities on climate.
Fingerprint 3: The Surface Heats Up
Measurements show that global average temperature has risen by 1.4 degrees Fahrenheit in the last 100 years, with most of that happening in the last three decades. [1,2] By comparing Earth's temperature over that last century with models comparing climate drivers, a study showed that, from 1950 to the present, most of the warming was caused by heat-trapping emissions from human activities [3]. In fact, heat-trapping emissions are driving the climate about three times more strongly now than they were in 1950. The spatial pattern of where this warming is occurring around the globe indicates human-induced causes. Even accounting for the occasional short-lived cooling from volcanic events and moderate levels of cooling from aerosol pollution as well as minor fluctuations in the sun's output in the last 30 years, heat-trapping emissions far outweigh any other current climate driver. Once again, our scientific fingerprinting identifies human activities as the main driver of our warming climate.
Human Causes, Human Solutions
The identification of humans as the main driver of global warming helps us understand how and why our climate is changing, and it clearly defines the problem as one that is within our power to address. Because of past emissions, we cannot avoid some level of warming from the heat-trapping emissions already present in the atmosphere, some of which (such as carbon dioxide and nitrous oxide) last for 100 years or more. However, with aggressive emission reductions as well as flexibility in adapting to those changes we cannot avoid, we have a small window in which to avoid truly dangerous warming and provide future generations with a sustainable world. This will require immediate and sustained action to reduce our heat-trapping emissions through increased energy efficiency, expanding our use of renewable energy, and slowing deforestation (among other solutions).
Melanie Fitzpatrick (Earth and Space Sciences and Atmospheric Sciences at the University of Washington and UCS consultant) prepared this summary with input from Brenda Ekwurzel (Union of Concerned Scientists) and reviews by Philip Mote (Climate Impacts Group at the University of Washington and Washington's state climatologist), Richard Gammon (Chemistry, Oceanography, and Atmospheric Sciences at the University of Washington) and Peter Frumhoff (Union of Concerned Scientists). (c)2006 Union of Concerned Scientists
References
1. U.S. National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies. 2006. Global temperature trends: 2005 summation. New York, NY. Online at http://data.giss.nasa.gov/gistemp/2005.
2. U.S. National Oceanic and Atmospheric Administration (NOAA) National Climate Data Center. 2006. Climate of 2005 - annual report. Asheville, NC. Online at http://www.ncdc.noaa.gov/oa/climate/research/2005/ann/global.html.
3. Intergovernmental Panel on Climate Change. 2001. Climate change 2001: The scientific basis. Cambridge, UK: Cambridge University Press.
4. EPICA. 2004. Eight glacial cycles from an Antarctic ice core. Nature 429:623-628.
5. Petit, J.R., J. Jouzel, D. Raynaud, N.I. Barkov, J.-M. Barnola, I. Basile, M. Bender, J. Chappellaz, M. Davis, G. Delaygue, M. Delmotte, V.M. Kotlyakov, M. Legrand, V.Y. Lipenkov, C. Lorius, L. Pépin, C. Ritz, E. Saltzman, and M. Stievenard. 1999. Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature 399:429-436.
6. Siegenthaler, U., T.F. Stocker, E. Monnin, D. Lüthi, J. Schwander, B. Stauffer, D. Raynaud, J.-M. Barnola, H. Fischer, V. Masson-Delmotte, and J. Jouzel. 2005. Stable carbon cycle-climate relationship during the late Pleistocene. Science 310:1313-1316.
7. Hansen, J., L. Nazarenko, R. Ruedy, M. Sato, J. Willis, A. Del Genio, D. Koch, A. Lacis, K. Lo, S. Menon, T. Novakov, J. Perlwitz, G. Russell, G.A. Schmidt, and N. Tausnev. 2005. Earth's energy imbalance: Confirmation and implications. Science 308:1431-1435.
8. Barnett, T.P., D.W. Pierce, K.M. AchutaRao, P.J. Gleckler, B.D. Santer, J.M. Gregory, and W.M. Washington. 2005. Penetration of human-induced warming into the world's oceans. Science 309:284-287.
9. Levitus, S., J. Antonov, and T. Boyer. 2005. Warming of the world ocean, 1955-2003. Geophysical Research Letters 32. Online at http://www.agu.org (doi:10.1029/2004GL021592).
10. Santer, B.D., M.F. Wehner, T.M.L. Wigley, R. Sausen, G.A. Meehl, K.E. Taylor, C. Ammann, J. Arblaster, W.M. Washington, J.S. Boyle, and W. Bruggemann. 2003. Contribution of anthropogenic and natural forcing to recent
Because most global warming emissions remain in the atmosphere for decades or centuries, the energy choices we make today greatly influence the climate our children and grandchildren inherit. We have the technology to increase energy efficiency, significantly reduce these emissions from our energy and land use, and secure a high quality of life for future generations. We must act now to reduce dangerous consequences.
In its 2001 report, the Intergovernmental Panel on Climate Change stated, "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities." [3] Carbon dioxide from fossil fuel burning and land clearing has been accumulating in the atmosphere, where it acts like a blanket keeping Earth warm and heating up the surface, ocean, and atmosphere. As a result, current levels of carbon dioxide in the atmosphere are higher than at any time during the last 650,000 years. [4,5,6]
Background: Driving the Climate ("Forcing")
Climate is influenced by many factors, both natural and human. [7] Things that increase temperature, such as increases in heat-trapping emissions from cars and power plants or an increase in the amount of radiation the sun emits, are examples of "positive" forcings or drivers. Volcanic events and some types of human-made pollution, both of which inject sunlight-reflecting aerosols into the atmosphere, lower temperature and are examples of "negative" forcings or drivers. Natural climate drivers include the sun's energy output, aerosols from volcanic activity, and changes in snow and ice cover. Human climate drivers include heat-trapping emissions from cars and power plants, aerosols from pollution, and soot particles.
Much as the Air Force develops computer programs to simulate aircraft flight under different conditions, climate scientists develop computer programs to simulate global climate changes under different conditions. These programs use our knowledge of physical, chemical, and biological processes that occur within Earth's atmosphere and oceans and on its land surfaces. Mathematical models allow scientists to simulate the behavior of complex systems such as climate and explore how these systems respond to natural and human factors.
Fingerprint 1: The Ocean Layers Warm
The world's oceans have absorbed about 20 times as much heat as the atmosphere over the past half-century, leading to higher temperatures not only in surface waters but also in water 1,500 feet below the surface. [8,9] The measured increases in water temperature lie well outside the bounds of natural climate variation.
Fingerprint 2: The Atmosphere Shifts
Recent research shows that human activities have lifted the boundary of Earth's lower atmosphere. Known as the troposphere (from the Greek tropos, which means "turning"), this lowest layer of the atmosphere contains Earth's weather. The stable layer above is called the stratosphere. The boundary that separates the two layers, the tropopause, is as high as nine miles above the equator and as low as five miles above the poles. In an astounding development, a 2003 study showed that this tropopause has shifted upward over the last two decades by more than 900 feet. [10] The rising tropopause marks another human fingerprint on Earth's climate.
In their search for clues, scientists compared two natural drivers of climate (solar changes and volcanic aerosols) and three human drivers of climate (heat-trapping emissions, aerosol pollution, and ozone depletion), altering these one at a time in their sophisticated models. Changes in the sun during the twentieth century have warmed both the troposphere and stratosphere. But human activities have increased heat-trapping emissions and decreased stratospheric ozone. This has led to the troposphere warming more because the increase in heat-trapping emissions is trapping more of Earth's outgoing heat. The stratosphere has cooled more because there is less ozone to absorb incoming sunlight to heat up the stratosphere. Both these effects combine to shift the boundary upward. Over the period 1979-1999, a study shows that human-induced changes in heat-trapping emissions and ozone account for more than 80 percent of the rise in tropopause height. [10] This is yet another example of how science detectives are quantifying the impact of human activities on climate.
Fingerprint 3: The Surface Heats Up
Measurements show that global average temperature has risen by 1.4 degrees Fahrenheit in the last 100 years, with most of that happening in the last three decades. [1,2] By comparing Earth's temperature over that last century with models comparing climate drivers, a study showed that, from 1950 to the present, most of the warming was caused by heat-trapping emissions from human activities [3]. In fact, heat-trapping emissions are driving the climate about three times more strongly now than they were in 1950. The spatial pattern of where this warming is occurring around the globe indicates human-induced causes. Even accounting for the occasional short-lived cooling from volcanic events and moderate levels of cooling from aerosol pollution as well as minor fluctuations in the sun's output in the last 30 years, heat-trapping emissions far outweigh any other current climate driver. Once again, our scientific fingerprinting identifies human activities as the main driver of our warming climate.
Human Causes, Human Solutions
The identification of humans as the main driver of global warming helps us understand how and why our climate is changing, and it clearly defines the problem as one that is within our power to address. Because of past emissions, we cannot avoid some level of warming from the heat-trapping emissions already present in the atmosphere, some of which (such as carbon dioxide and nitrous oxide) last for 100 years or more. However, with aggressive emission reductions as well as flexibility in adapting to those changes we cannot avoid, we have a small window in which to avoid truly dangerous warming and provide future generations with a sustainable world. This will require immediate and sustained action to reduce our heat-trapping emissions through increased energy efficiency, expanding our use of renewable energy, and slowing deforestation (among other solutions).
Melanie Fitzpatrick (Earth and Space Sciences and Atmospheric Sciences at the University of Washington and UCS consultant) prepared this summary with input from Brenda Ekwurzel (Union of Concerned Scientists) and reviews by Philip Mote (Climate Impacts Group at the University of Washington and Washington's state climatologist), Richard Gammon (Chemistry, Oceanography, and Atmospheric Sciences at the University of Washington) and Peter Frumhoff (Union of Concerned Scientists). (c)2006 Union of Concerned Scientists
References
1. U.S. National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies. 2006. Global temperature trends: 2005 summation. New York, NY. Online at http://data.giss.nasa.gov/gistemp/2005.
2. U.S. National Oceanic and Atmospheric Administration (NOAA) National Climate Data Center. 2006. Climate of 2005 - annual report. Asheville, NC. Online at http://www.ncdc.noaa.gov/oa/climate/research/2005/ann/global.html.
3. Intergovernmental Panel on Climate Change. 2001. Climate change 2001: The scientific basis. Cambridge, UK: Cambridge University Press.
4. EPICA. 2004. Eight glacial cycles from an Antarctic ice core. Nature 429:623-628.
5. Petit, J.R., J. Jouzel, D. Raynaud, N.I. Barkov, J.-M. Barnola, I. Basile, M. Bender, J. Chappellaz, M. Davis, G. Delaygue, M. Delmotte, V.M. Kotlyakov, M. Legrand, V.Y. Lipenkov, C. Lorius, L. Pépin, C. Ritz, E. Saltzman, and M. Stievenard. 1999. Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature 399:429-436.
6. Siegenthaler, U., T.F. Stocker, E. Monnin, D. Lüthi, J. Schwander, B. Stauffer, D. Raynaud, J.-M. Barnola, H. Fischer, V. Masson-Delmotte, and J. Jouzel. 2005. Stable carbon cycle-climate relationship during the late Pleistocene. Science 310:1313-1316.
7. Hansen, J., L. Nazarenko, R. Ruedy, M. Sato, J. Willis, A. Del Genio, D. Koch, A. Lacis, K. Lo, S. Menon, T. Novakov, J. Perlwitz, G. Russell, G.A. Schmidt, and N. Tausnev. 2005. Earth's energy imbalance: Confirmation and implications. Science 308:1431-1435.
8. Barnett, T.P., D.W. Pierce, K.M. AchutaRao, P.J. Gleckler, B.D. Santer, J.M. Gregory, and W.M. Washington. 2005. Penetration of human-induced warming into the world's oceans. Science 309:284-287.
9. Levitus, S., J. Antonov, and T. Boyer. 2005. Warming of the world ocean, 1955-2003. Geophysical Research Letters 32. Online at http://www.agu.org (doi:10.1029/2004GL021592).
10. Santer, B.D., M.F. Wehner, T.M.L. Wigley, R. Sausen, G.A. Meehl, K.E. Taylor, C. Ammann, J. Arblaster, W.M. Washington, J.S. Boyle, and W. Bruggemann. 2003. Contribution of anthropogenic and natural forcing to recent
14 Ekim 2011 Cuma
The Greenhouse Effect
Anyone who has either spent time in a greenhouse for plants or simply gotten into a car on a hot summer day has personally experienced the greenhouse effect. Heat enters an enclosed area and then reflects back and forth building upon itself. While the ambient temperature outside might be 85 degrees Fahrenheit, inside an automobile the temperature easily zooms upward to 130F. Simply put, the greenhouse effect is what happens when heat is trapped in one way or another and then increases as more heat radiation is added.
This is fine if you are an orchid or other tropical plant. But living things, including people, require set parameters of climate. When we discuss the greenhouse effect as regarding global warming we place the effect into a specific environment. That is the Earth’s atmosphere. When referencing the Earth, our entire planet becomes the interior of an automobile in the heat of summer. The Earth of course does not have a metal roof or a glass dome around it to trap heat and reflect solar radiation back to its surface. Indeed when drawings depict and descriptions explain the greenhouse effect the principle is simplified to imply that this is the case. Actually the greenhouse effect for the Earth is somewhat different.
When solar radiation passes through out atmosphere the molecules that constitute our air absorb it. The majority of solar heat is absorbed by our planet’s surface. Different types of surfaces absorb or reflect heat in different ways. A white blanket of snow will reflect much more heat than freshly paved asphalt. Still everything that the sun’s rays fall upon either absorbs or reflects heat. In the case of out snowy Polar Regions that heat is reflected back from the planet. In the case of our cities it is trapped on the surface. From there it radiates outward where living things attempt to adjust to the relative heat or cold. Our planet’s original design was for a balance of all the components. Our atmosphere absorbs enough heat to keep us warm but hopefully not bake us. The angle of the sun in areas such as the poles creates an environment suited to North and South Pole inhabitants. The people, creatures and plant life at the Earth’s equator have acclimated to their section of the world.
The greenhouse effect occurs planet wide when solar radiation either bounces off of or is radiated forth from the earth and instead of passing through our atmosphere and outward into space, is absorbed by all kinds of extra amounts of and extraneous gases and particles. These gases et al absorb heat and then radiate it outward in all directions, one of those directions, being the surface of the Earth. From there the process repeats itself until we have a global version of a car with the windows rolled up parked in the noonday sun.
This is fine if you are an orchid or other tropical plant. But living things, including people, require set parameters of climate. When we discuss the greenhouse effect as regarding global warming we place the effect into a specific environment. That is the Earth’s atmosphere. When referencing the Earth, our entire planet becomes the interior of an automobile in the heat of summer. The Earth of course does not have a metal roof or a glass dome around it to trap heat and reflect solar radiation back to its surface. Indeed when drawings depict and descriptions explain the greenhouse effect the principle is simplified to imply that this is the case. Actually the greenhouse effect for the Earth is somewhat different.
When solar radiation passes through out atmosphere the molecules that constitute our air absorb it. The majority of solar heat is absorbed by our planet’s surface. Different types of surfaces absorb or reflect heat in different ways. A white blanket of snow will reflect much more heat than freshly paved asphalt. Still everything that the sun’s rays fall upon either absorbs or reflects heat. In the case of out snowy Polar Regions that heat is reflected back from the planet. In the case of our cities it is trapped on the surface. From there it radiates outward where living things attempt to adjust to the relative heat or cold. Our planet’s original design was for a balance of all the components. Our atmosphere absorbs enough heat to keep us warm but hopefully not bake us. The angle of the sun in areas such as the poles creates an environment suited to North and South Pole inhabitants. The people, creatures and plant life at the Earth’s equator have acclimated to their section of the world.
The greenhouse effect occurs planet wide when solar radiation either bounces off of or is radiated forth from the earth and instead of passing through our atmosphere and outward into space, is absorbed by all kinds of extra amounts of and extraneous gases and particles. These gases et al absorb heat and then radiate it outward in all directions, one of those directions, being the surface of the Earth. From there the process repeats itself until we have a global version of a car with the windows rolled up parked in the noonday sun.
Causes of Global Warming -1
Let us start our examination of Global warming with a study of its causes. Global warming is an overall state of existence that is the cumulative effect of hundreds of environmental factors. All of these join together in both a linear and random model to show global warming as a chain of events.
Most modern attention to the problem of global warming began with discussion of depletion of the Earth’s Ozone layer. Ozone (O3) is a molecular form of Oxygen. The Ozone layer is a relatively thin strata of these molecules set in the lower portion of the Earth’s stratosphere.
Depletion of the Earth’s Ozone layer has resulted in a large increase in Ultra Violet Radiation reaching the surface of the earth. Does this increase in UV rays equate to global warming? Not really. In fact most scientific opinion is that depletion of the Ozone layer results in cooling of both the stratosphere and troposphere. So why mention depletion of the Ozone layer as regards to global warming? Because it represents a needed balance between harmful radiation being allowed to reach the earth’s surface and our desire to stem the rapid increase in our air and water temperature. Remember, we are viewing global warming as a chain of events.
global-warming-3What is the most significant cause of global warming?
The primary cause of global warming is Carbon Dioxide emissions. CO2 is being pumped into our atmosphere at an insane pace; 8 billion tons of CO2 entered the air last year. Of course some of this is due to natural activity such as volcanic eruptions and people breathing. But the Earth is equipped to easily absorb those into the normal regenerative process. No, the beginning of global warming was caused by fossil fuels being burned and emitting plenty of CO2.
Currently in the world 40% of all CO2 emissions are caused by power plants. These are burning coal, natural gas and diesel fuel. Some power plants burn garbage. Some burn methane made from garbage. And discounting those super green electrical generating plants designed to issue negligible pollutants, all of our power plants let loose into the atmosphere CO2.
33% of all the CO2 sent forth is the product of cars and trucks. Internal combustion engines burning fossil fuels…gasoline and diesel spew forth a retching amount of CO2.
3.5% of all CO2 emissions are released from aircraft traveling our friendly skies. Unfortunately, jets and other aircraft deliver their payload of pollutants directly into the troposphere.
The numbers can be confusing
12% of all CO2 released into the atmosphere is related to buildings. This figure varies from one source to the next. Some place the percentage of emissions from buildings as high as 33%. What most of these figures do not address is the actual cause of the CO2 emissions. In newly constructed buildings, production of materials used in building and energy used during construction are sited as the cause of carbon dioxide emissions. In existing buildings the CO2 created by the energy upkeep of the building is the root of the emissions quotient. The general comparison is that buildings consume energy in the way that cars burn fuel. But the pollutants created in providing power for heating, air-conditioning, lights and other usage in buildings has already been factored. Honestly this double billing accounting is more the product of auto manufacturers looking to point the blame for global warming away from gas guzzling cars.
The point to remember is that 98% of all CO2 emissions are related to energy production and 80% of these emissions become greenhouse gases.
Continuing the chain…global-warming-5
Which now mentioned allows us to follow our chain of event’s leading to global warming into the next most defined cause… Methane gas. Methane is released into the atmosphere from a dozen major sources. These include natural and man made emissions. Natural release of Methane is primarily from wetlands, (including agriculture) termites, the ocean, and hydrates. Non-organic releases are based from, landfills, livestock, waste treatment, and biomass burning. (More energy production). Almost all of this is offset by the Earth’s ability to absorb around 97% of the methane released into the air. But that remaining 3% is a serious problem. The molecular structure of Methane makes it 20 times as powerful a Greenhouse gas than CO2. So while there is a great deal less Methane to contend with than CO2, it is still the second largest link in the global warming events chain.
Not every Greenhouse gas is as obvious a villain as Methane. The next most potent problem is simple H2O water. How can water be a cause of global warming? Our atmosphere contains a set parameter of water as vapor. This vapor absorbs and radiates heat as does every molecule in the air. But when the lower atmosphere (troposphere) has excess water vapor that gaseous H2O is a potent greenhouse gas.
Another of the more commonplace greenhouse gases is Nitrous Oxide. NO2 can make your car go faster, or make you relax at the dentist. It has quite few beneficial uses. But as a greenhouse gas all it manages to accomplish is to be one more ingredient in out atmospheric soup. Cars using catalytic converters, fertilizer plants, manufacture of nylon, and nitric acid as well as being produced naturally in our oceans and rain forests, produce Nitrous Oxide.
All of the above plus quite a few other greenhouse gases comprise the foundation of global warming. As above and in all discussion of global warming they are cumulatively referred to as greenhouse gases. To understand the importance of these as the start and endpoint of global warming we must digress into a brief explanation of the greenhouse effect.
Most modern attention to the problem of global warming began with discussion of depletion of the Earth’s Ozone layer. Ozone (O3) is a molecular form of Oxygen. The Ozone layer is a relatively thin strata of these molecules set in the lower portion of the Earth’s stratosphere.
Depletion of the Earth’s Ozone layer has resulted in a large increase in Ultra Violet Radiation reaching the surface of the earth. Does this increase in UV rays equate to global warming? Not really. In fact most scientific opinion is that depletion of the Ozone layer results in cooling of both the stratosphere and troposphere. So why mention depletion of the Ozone layer as regards to global warming? Because it represents a needed balance between harmful radiation being allowed to reach the earth’s surface and our desire to stem the rapid increase in our air and water temperature. Remember, we are viewing global warming as a chain of events.
global-warming-3What is the most significant cause of global warming?
The primary cause of global warming is Carbon Dioxide emissions. CO2 is being pumped into our atmosphere at an insane pace; 8 billion tons of CO2 entered the air last year. Of course some of this is due to natural activity such as volcanic eruptions and people breathing. But the Earth is equipped to easily absorb those into the normal regenerative process. No, the beginning of global warming was caused by fossil fuels being burned and emitting plenty of CO2.
Currently in the world 40% of all CO2 emissions are caused by power plants. These are burning coal, natural gas and diesel fuel. Some power plants burn garbage. Some burn methane made from garbage. And discounting those super green electrical generating plants designed to issue negligible pollutants, all of our power plants let loose into the atmosphere CO2.
33% of all the CO2 sent forth is the product of cars and trucks. Internal combustion engines burning fossil fuels…gasoline and diesel spew forth a retching amount of CO2.
3.5% of all CO2 emissions are released from aircraft traveling our friendly skies. Unfortunately, jets and other aircraft deliver their payload of pollutants directly into the troposphere.
The numbers can be confusing
12% of all CO2 released into the atmosphere is related to buildings. This figure varies from one source to the next. Some place the percentage of emissions from buildings as high as 33%. What most of these figures do not address is the actual cause of the CO2 emissions. In newly constructed buildings, production of materials used in building and energy used during construction are sited as the cause of carbon dioxide emissions. In existing buildings the CO2 created by the energy upkeep of the building is the root of the emissions quotient. The general comparison is that buildings consume energy in the way that cars burn fuel. But the pollutants created in providing power for heating, air-conditioning, lights and other usage in buildings has already been factored. Honestly this double billing accounting is more the product of auto manufacturers looking to point the blame for global warming away from gas guzzling cars.
The point to remember is that 98% of all CO2 emissions are related to energy production and 80% of these emissions become greenhouse gases.
Continuing the chain…global-warming-5
Which now mentioned allows us to follow our chain of event’s leading to global warming into the next most defined cause… Methane gas. Methane is released into the atmosphere from a dozen major sources. These include natural and man made emissions. Natural release of Methane is primarily from wetlands, (including agriculture) termites, the ocean, and hydrates. Non-organic releases are based from, landfills, livestock, waste treatment, and biomass burning. (More energy production). Almost all of this is offset by the Earth’s ability to absorb around 97% of the methane released into the air. But that remaining 3% is a serious problem. The molecular structure of Methane makes it 20 times as powerful a Greenhouse gas than CO2. So while there is a great deal less Methane to contend with than CO2, it is still the second largest link in the global warming events chain.
Not every Greenhouse gas is as obvious a villain as Methane. The next most potent problem is simple H2O water. How can water be a cause of global warming? Our atmosphere contains a set parameter of water as vapor. This vapor absorbs and radiates heat as does every molecule in the air. But when the lower atmosphere (troposphere) has excess water vapor that gaseous H2O is a potent greenhouse gas.
Another of the more commonplace greenhouse gases is Nitrous Oxide. NO2 can make your car go faster, or make you relax at the dentist. It has quite few beneficial uses. But as a greenhouse gas all it manages to accomplish is to be one more ingredient in out atmospheric soup. Cars using catalytic converters, fertilizer plants, manufacture of nylon, and nitric acid as well as being produced naturally in our oceans and rain forests, produce Nitrous Oxide.
All of the above plus quite a few other greenhouse gases comprise the foundation of global warming. As above and in all discussion of global warming they are cumulatively referred to as greenhouse gases. To understand the importance of these as the start and endpoint of global warming we must digress into a brief explanation of the greenhouse effect.
What is global warming? -1
While some would call global warming a theory, others would call it a proven set of facts. Opinions differ vehemently. Let us consider global warming to be both a premise that the environment of the world as we know it is slowly, but very surely increasing in overall air and water temperature, and a promise that if whatever is causing this trend is not interrupted or challenged life on earth will dynamically be affected.
The prevailing counter opinion is that all that is presently perceived to be global warming is simply the result of a normal climactic swing in the direction of increased temperature. Many proponents of this global warming ideology have definitive social and financial interests in these claims.
Global warming and climate change are aspects of our environment that cannot be easily or quickly discounted. Many factions still strongly feel that the changes our Earth is seeing are the result of a natural climatic adjustment. Regardless of one’s perspective the effects of global warming are a quantifiable set of environmental results that are in addition to any normal changes in climate. That is why the effects of global warming have catastrophic potential. Global warming may well be the straw that breaks the camel’s back. It could turn out to be the difference between a category three hurricane and a category four. Global warming as caused by greenhouse gas emissions can lead us to a definite imbalance of nature.
The premise of global warming as an issue of debate is that industrial growth coupled with non-structured methods we as humans use to sustain ourselves has created a situation where our planet is getting progressively hotter. We have seemingly negatively effected our environment by a cycle of harmful processes that now seem to be feeding upon themselves to exponentially increase the damage to our ecosystem.
6 Ekim 2011 Perşembe
U.S. Climate Policy
The Federal government is using voluntary and incentive-based programs to reduce emissions and has established programs to promote climate technology and science. This strategy incorporates know-how from many federal agencies and harnesses the power of the private sector.
EPA plays a significant role in helping the Federal government reduce greenhouse gas emissions and greenhouse gas intensity. EPA has many current and near-term initiatives that encourage voluntary reductions from a variety of stakeholders. Initiatives, such as ENERGY STAR, Climate Leaders, and our Methane Voluntary Programs, encourage emission reductions from large corporations, consumers, industrial and commercial buildings, and many major industrial sectors. For details on these and other initiatives as well as other aspects of U.S. policy, visit the U.S. Climate Policy section of the site.
Top of page
Greenhouse Gas Emissions
In the U.S., our energy-related activities account for over 85 percent of our human-generated greenhouse gas emissions, mostly in the form of carbon dioxide emissions from burning fossil fuels. More than half the energy-related emissions come from large stationary sources such as power plants, while about a third comes from transportation. Industrial processes (such as the production of cement, steel, and aluminum), agriculture, forestry, other land use, and waste management are also important sources of greenhouse gas emissions in the United States.
For a better understanding of where greenhouse gas emissions come from, governments at the federal, state and local levels prepare emissions inventories, which track emissions from various parts of the economy such as transportation, electricity production, industry, agriculture, forestry, and other sectors. EPA publishes the official national inventory of US greenhouse gas emissions, and the latest greenhouse gas inventory shows that in 2008 the U.S. emitted slightly less than 7 billon metric tons of greenhouse gases (a million metric tons of CO2 equivalents (MMTCO2e) is roughly equal to the annual GHG emissions of an average U.S. power plant.) Visit the Emissions section of this site to learn more, or review the answers to some frequent emissions questions.
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Health and Environmental Effects
Climate change affects people, plants, and animals. Scientists are working to better understand future climate change and how the effects will vary by region and over time.
Scientists have observed that some changes are already occurring. Observed effects include sea level rise, shrinking glaciers, changes in the range and distribution of plants and animals, trees blooming earlier, lengthening of growing seasons, ice on rivers and lakes freezing later and breaking up earlier, and thawing of permafrost. Another key issue being studied is how societies and the Earth's environment will adapt to or cope with climate change.
In the United States, scientists believe that most areas will continue to warm, although some will likely warm more than others. It remains very difficult to predict which parts of the country will become wetter or drier, but scientists generally expect increased precipitation and evaporation, and drier soil in the middle parts of the country. Northern regions such as Alaska are expected to experience the most warming. In fact, Alaska has been experiencing significant changes in climate in recent years that may be at least partly related to human caused global climate change.
Human health can be affected directly and indirectly by climate change in part through extreme periods of heat and cold, storms, and climate-sensitive diseases such as malaria, and smog episodes. For more information on these and other environmental effects, please visit the Health and Environmental Effects section of this site, or review the answers to some frequent effects questions.
EPA plays a significant role in helping the Federal government reduce greenhouse gas emissions and greenhouse gas intensity. EPA has many current and near-term initiatives that encourage voluntary reductions from a variety of stakeholders. Initiatives, such as ENERGY STAR, Climate Leaders, and our Methane Voluntary Programs, encourage emission reductions from large corporations, consumers, industrial and commercial buildings, and many major industrial sectors. For details on these and other initiatives as well as other aspects of U.S. policy, visit the U.S. Climate Policy section of the site.
Top of page
Greenhouse Gas Emissions
In the U.S., our energy-related activities account for over 85 percent of our human-generated greenhouse gas emissions, mostly in the form of carbon dioxide emissions from burning fossil fuels. More than half the energy-related emissions come from large stationary sources such as power plants, while about a third comes from transportation. Industrial processes (such as the production of cement, steel, and aluminum), agriculture, forestry, other land use, and waste management are also important sources of greenhouse gas emissions in the United States.
For a better understanding of where greenhouse gas emissions come from, governments at the federal, state and local levels prepare emissions inventories, which track emissions from various parts of the economy such as transportation, electricity production, industry, agriculture, forestry, and other sectors. EPA publishes the official national inventory of US greenhouse gas emissions, and the latest greenhouse gas inventory shows that in 2008 the U.S. emitted slightly less than 7 billon metric tons of greenhouse gases (a million metric tons of CO2 equivalents (MMTCO2e) is roughly equal to the annual GHG emissions of an average U.S. power plant.) Visit the Emissions section of this site to learn more, or review the answers to some frequent emissions questions.
Top of page
Health and Environmental Effects
Climate change affects people, plants, and animals. Scientists are working to better understand future climate change and how the effects will vary by region and over time.
Scientists have observed that some changes are already occurring. Observed effects include sea level rise, shrinking glaciers, changes in the range and distribution of plants and animals, trees blooming earlier, lengthening of growing seasons, ice on rivers and lakes freezing later and breaking up earlier, and thawing of permafrost. Another key issue being studied is how societies and the Earth's environment will adapt to or cope with climate change.
In the United States, scientists believe that most areas will continue to warm, although some will likely warm more than others. It remains very difficult to predict which parts of the country will become wetter or drier, but scientists generally expect increased precipitation and evaporation, and drier soil in the middle parts of the country. Northern regions such as Alaska are expected to experience the most warming. In fact, Alaska has been experiencing significant changes in climate in recent years that may be at least partly related to human caused global climate change.
Human health can be affected directly and indirectly by climate change in part through extreme periods of heat and cold, storms, and climate-sensitive diseases such as malaria, and smog episodes. For more information on these and other environmental effects, please visit the Health and Environmental Effects section of this site, or review the answers to some frequent effects questions.
Climate Change
The Earth's climate has changed many times during the planet's history, with events ranging from ice ages to long periods of warmth. Historically, natural factors such as volcanic eruptions, changes in the Earth's orbit, and the amount of energy released from the Sun have affected the Earth's climate. Beginning late in the 18th century, human activities associated with the Industrial Revolution have also changed the composition of the atmosphere and therefore very likely are influencing the Earth's climate.
The EPA climate change website has four main sections on climate change issues and another section on "What You Can Do" to reduce your contribution. A "Frequent Questions" section is available, and EPA has provided a frequent questions database where users can search for more specific questions and answers on climate change. An eight-page brochure entitled Frequently Asked Questions About Global Warming.
Science
For over the past 200 years, the burning of fossil fuels, such as coal and oil, and deforestation have caused the concentrations of heat-trapping "greenhouse gases" to increase significantly in our atmosphere. These gases prevent heat from escaping to space, somewhat like the glass panels of a greenhouse.
Greenhouse gases are necessary to life as we know it, because they keep the planet's surface warmer than it otherwise would be. But, as the concentrations of these gases continue to increase in the atmosphere, the Earth's temperature is climbing above past levels. According to NOAA and NASA data, the Earth's average surface temperature has increased by about 1.2 to 1.4ºF in the last 100 years. The eight warmest years on record (since 1850) have all occurred since 1998, with the warmest year being 2005. Most of the warming in recent decades is very likely the result of human activities. Other aspects of the climate are also changing such as rainfall patterns, snow and ice cover, and sea level.
If greenhouse gases continue to increase, climate models predict that the average temperature at the Earth's surface could increase from 3.2 to 7.2ºF above 1990 levels by the end of this century. Scientists are certain that human activities are changing the composition of the atmosphere, and that increasing the concentration of greenhouse gases will change the planet's climate. But they are not sure by how much it will change, at what rate it will change, or what the exact effects will be. See the Science and Health and Environmental Effects sections of this site for more detail, or review the answers to some frequent science questions.
The EPA climate change website has four main sections on climate change issues and another section on "What You Can Do" to reduce your contribution. A "Frequent Questions" section is available, and EPA has provided a frequent questions database where users can search for more specific questions and answers on climate change. An eight-page brochure entitled Frequently Asked Questions About Global Warming.
Science
For over the past 200 years, the burning of fossil fuels, such as coal and oil, and deforestation have caused the concentrations of heat-trapping "greenhouse gases" to increase significantly in our atmosphere. These gases prevent heat from escaping to space, somewhat like the glass panels of a greenhouse.
Greenhouse gases are necessary to life as we know it, because they keep the planet's surface warmer than it otherwise would be. But, as the concentrations of these gases continue to increase in the atmosphere, the Earth's temperature is climbing above past levels. According to NOAA and NASA data, the Earth's average surface temperature has increased by about 1.2 to 1.4ºF in the last 100 years. The eight warmest years on record (since 1850) have all occurred since 1998, with the warmest year being 2005. Most of the warming in recent decades is very likely the result of human activities. Other aspects of the climate are also changing such as rainfall patterns, snow and ice cover, and sea level.
If greenhouse gases continue to increase, climate models predict that the average temperature at the Earth's surface could increase from 3.2 to 7.2ºF above 1990 levels by the end of this century. Scientists are certain that human activities are changing the composition of the atmosphere, and that increasing the concentration of greenhouse gases will change the planet's climate. But they are not sure by how much it will change, at what rate it will change, or what the exact effects will be. See the Science and Health and Environmental Effects sections of this site for more detail, or review the answers to some frequent science questions.
30 Eylül 2011 Cuma
Ten Personal Solutions to Global Warming
Individual choices can have an impact on global climate change. Reducing your family's heat-trapping emissions does not mean forgoing modern conveniences; it means making smart choices and using energy-efficient products, which may require an additional investment up front, but often pay you back in energy savings within a couple of years.
Since Americans' per capita emissions of heat-trapping gases is 5.6 tons—more than double the amount of western Europeans—we can all make choices that will greatly reduce our families' global warming impact.
The car you drive: the most important personal climate decision.
When you buy your next car, look for the one with the best fuel economy in its class. Each gallon of gas you use is responsible for 25 pounds of heat-trapping gases in the atmosphere. Better gas mileage not only reduces global warming, but will also save you thousands of dollars at the pump over the life of the vehicle. Compare the fuel economy of the cars you're considering and look for new technologies like hybrid engines.
Choose clean power. More than half the electricity in the United States comes from polluting coal-fired power plants. And power plants are the single largest source of heat-trapping gas. None of us can live without electricity, but in some states, you can switch to electricity companies that provide 50 to 100 percent renewable energy. (For more information go to Green-e.org.)
Look for Energy Star. When it comes time to replace appliances, look for the Energy Star label on new appliances (refrigerators, freezers, furnaces, air conditioners, and water heaters use the most energy). These items may cost a bit more initially, but the energy savings will pay back the extra investment within a couple of years. Household energy savings really can make a difference: If each household in the United States replaced its existing appliances with the most efficient models available, we would save $15 billion in energy costs and eliminate 175 million tons of heat-trapping gases.
Unplug a freezer.
One of the quickest ways to reduce your global warming impact is to unplug the extra refrigerator or freezer you rarely use (except when you need it for holidays and parties). This can reduce the typical family's carbon dioxide emissions by nearly 10 percent.
Get a home energy audit.
Take advantage of the free home energy audits offered by many utilities. Simple measures, such as installing a programmable thermostat to replace your old dial unit or sealing and insulating heating and cooling ducts, can each reduce a typical family's carbon dioxide emissions by about 5 percent.
Light bulbs matter.
If every household in the United States replaced one regular light bulb with an energy-saving model, we could reduce global warming pollution by more than 90 billion pounds over the life of the bulbs; the same as taking 6.3 million cars off the road. So, replace your incandescent bulbs with more efficient compact fluorescents, which now come in all shapes and sizes. You'll be doing your share to cut back on heat-trapping pollution and you'll save money on your electric bills and light bulbs.
Think before you drive.
If you own more than one vehicle, use the less fuel-efficient one only when you can fill it with passengers. Driving a full minivan may be kinder to the environment than two midsize cars. Whenever possible, join a carpool or take mass transit.
Buy good wood.
When buying wood products, check for labels that indicate the source of the timber. Supporting forests that are managed in a sustainable fashion makes sense for biodiversity, and it may make sense for the climate too. Forests that are well managed are more likely to store carbon effectively because more trees are left standing and carbon-storing soils are less disturbed.
Plant a tree.
You can also make a difference in your own backyard. Get a group in your neighborhood together and contact your local arborist or urban forester about planting trees on private property and public land. In addition to storing carbon, trees planted in and around urban areas and residences can provide much-needed shade in the summer, reducing energy bills and fossil fuel use.
Let policymakers know you are concerned about global warming.
Our elected officials and business leaders need to hear from concerned citizens. Sign up for the Union of Concerned Scientists Action Network to ensure that policymakers get the timely, accurate information they need to make informed decisions about global warming solutions.
Since Americans' per capita emissions of heat-trapping gases is 5.6 tons—more than double the amount of western Europeans—we can all make choices that will greatly reduce our families' global warming impact.
The car you drive: the most important personal climate decision.
When you buy your next car, look for the one with the best fuel economy in its class. Each gallon of gas you use is responsible for 25 pounds of heat-trapping gases in the atmosphere. Better gas mileage not only reduces global warming, but will also save you thousands of dollars at the pump over the life of the vehicle. Compare the fuel economy of the cars you're considering and look for new technologies like hybrid engines.
Choose clean power. More than half the electricity in the United States comes from polluting coal-fired power plants. And power plants are the single largest source of heat-trapping gas. None of us can live without electricity, but in some states, you can switch to electricity companies that provide 50 to 100 percent renewable energy. (For more information go to Green-e.org.)
Look for Energy Star. When it comes time to replace appliances, look for the Energy Star label on new appliances (refrigerators, freezers, furnaces, air conditioners, and water heaters use the most energy). These items may cost a bit more initially, but the energy savings will pay back the extra investment within a couple of years. Household energy savings really can make a difference: If each household in the United States replaced its existing appliances with the most efficient models available, we would save $15 billion in energy costs and eliminate 175 million tons of heat-trapping gases.
Unplug a freezer.
One of the quickest ways to reduce your global warming impact is to unplug the extra refrigerator or freezer you rarely use (except when you need it for holidays and parties). This can reduce the typical family's carbon dioxide emissions by nearly 10 percent.
Get a home energy audit.
Take advantage of the free home energy audits offered by many utilities. Simple measures, such as installing a programmable thermostat to replace your old dial unit or sealing and insulating heating and cooling ducts, can each reduce a typical family's carbon dioxide emissions by about 5 percent.
Light bulbs matter.
If every household in the United States replaced one regular light bulb with an energy-saving model, we could reduce global warming pollution by more than 90 billion pounds over the life of the bulbs; the same as taking 6.3 million cars off the road. So, replace your incandescent bulbs with more efficient compact fluorescents, which now come in all shapes and sizes. You'll be doing your share to cut back on heat-trapping pollution and you'll save money on your electric bills and light bulbs.
Think before you drive.
If you own more than one vehicle, use the less fuel-efficient one only when you can fill it with passengers. Driving a full minivan may be kinder to the environment than two midsize cars. Whenever possible, join a carpool or take mass transit.
Buy good wood.
When buying wood products, check for labels that indicate the source of the timber. Supporting forests that are managed in a sustainable fashion makes sense for biodiversity, and it may make sense for the climate too. Forests that are well managed are more likely to store carbon effectively because more trees are left standing and carbon-storing soils are less disturbed.
Plant a tree.
You can also make a difference in your own backyard. Get a group in your neighborhood together and contact your local arborist or urban forester about planting trees on private property and public land. In addition to storing carbon, trees planted in and around urban areas and residences can provide much-needed shade in the summer, reducing energy bills and fossil fuel use.
Let policymakers know you are concerned about global warming.
Our elected officials and business leaders need to hear from concerned citizens. Sign up for the Union of Concerned Scientists Action Network to ensure that policymakers get the timely, accurate information they need to make informed decisions about global warming solutions.
What is global warming? Think of a blanket, covering the Earth.
When CO2 and other heat-trapping emissions are released into the air, they act like a blanket, holding heat in our atmosphere and warming the planet.
Overloading our atmosphere with carbon has far-reaching effects for people all around the world—more extreme storms, more severe droughts, deadly heat waves, rising sea levels, and more acidic oceans, which can affect the very base of the food chain.
What causes global warming? We do.
The primary cause of global warming is human activity, most significantly the burning of fossil fuels to drive cars, generate electricity, and operate our homes and businesses.
Tropical deforestation, also by human hands, is another major contributor. When these forests are burned, they release huge amounts of carbon into the atmosphere and because the forests no longer exist, they are no longer available to absorb CO2.
Who can reduce global warming? We can.
To address global warming, we need to significantly reduce the amount of heat-trapping emissions. As individuals, we can help by being mindful of our electricity use, driving more efficient cars, reducing the number of miles we drive, and taking other steps to reduce our own consumption of fossil fuels (Read Ten Personal Solutions to Global Warming for more great suggestions).
But we can also help by calling for government and corporate decision makers to reduce the threat of global warming by:
Placing limits on the amount of carbon that polluters are allowed to emit.
Investing in clean and efficient energy technologies, industries, and approaches;
Expanding the use of renewable energy;
Increasing the efficiency of the cars we drive ;
Reducing tropical deforestation and wildfire risks; and
Taking other steps to transform our energy system to one that is cleaner and less dependent on oil, coal, and other fossil fuels.
Support Our Work.
For more than 20 years, UCS has worked with leading experts to educate U.S. decision makers and the public about global warming and implement practical solutions at an international, national, regional, and state level.
Overloading our atmosphere with carbon has far-reaching effects for people all around the world—more extreme storms, more severe droughts, deadly heat waves, rising sea levels, and more acidic oceans, which can affect the very base of the food chain.
What causes global warming? We do.
The primary cause of global warming is human activity, most significantly the burning of fossil fuels to drive cars, generate electricity, and operate our homes and businesses.
Tropical deforestation, also by human hands, is another major contributor. When these forests are burned, they release huge amounts of carbon into the atmosphere and because the forests no longer exist, they are no longer available to absorb CO2.
Who can reduce global warming? We can.
To address global warming, we need to significantly reduce the amount of heat-trapping emissions. As individuals, we can help by being mindful of our electricity use, driving more efficient cars, reducing the number of miles we drive, and taking other steps to reduce our own consumption of fossil fuels (Read Ten Personal Solutions to Global Warming for more great suggestions).
But we can also help by calling for government and corporate decision makers to reduce the threat of global warming by:
Placing limits on the amount of carbon that polluters are allowed to emit.
Investing in clean and efficient energy technologies, industries, and approaches;
Expanding the use of renewable energy;
Increasing the efficiency of the cars we drive ;
Reducing tropical deforestation and wildfire risks; and
Taking other steps to transform our energy system to one that is cleaner and less dependent on oil, coal, and other fossil fuels.
Support Our Work.
For more than 20 years, UCS has worked with leading experts to educate U.S. decision makers and the public about global warming and implement practical solutions at an international, national, regional, and state level.
Global Warming - The Earth is warming
The Earth is warming and human activity is the primary cause. Climate disruptions put our food and water supply at risk, endanger our health, jeopardize our national security, and threaten other basic human needs. Some impacts—such as record high temperatures, melting glaciers, and severe flooding and droughts—are already becoming increasingly common across the country and around the world. So far, our national leaders are failing to act quickly to reduce heat-trapping emissions.
However, there is much we can do to protect the health and economic well-being of current and future generations from the consequences of the heat-trapping emissions caused when we burn coal, oil, and gas to generate electricity, drive our cars, and fuel our businesses.
Our country is at a crossroads: the United States can act responsibly and seize the opportunity to lead by developing new, innovative solutions, as well as immediately putting to use the many practical solutions we have at our disposal today; or we can choose to do nothing and deal with severe consequences later. At UCS we believe the choice is clear. It is time to push forward toward a brighter, cleaner future.
Highlights
Irene Is the 10th Billion-Dollar Weather Disaster for 2011, a blog post by senior climate economist Rachel Cleetus. Read more blog posts from our global warming experts.
What is Global Warming?
When CO2 and other heat-trapping emissions are released into the air, they act like a blanket, holding heat in our atmosphere and warming the planet. Overloading our atmosphere with carbon has far-reaching effects for people everywhere.
However, there is much we can do to protect the health and economic well-being of current and future generations from the consequences of the heat-trapping emissions caused when we burn coal, oil, and gas to generate electricity, drive our cars, and fuel our businesses.
Our country is at a crossroads: the United States can act responsibly and seize the opportunity to lead by developing new, innovative solutions, as well as immediately putting to use the many practical solutions we have at our disposal today; or we can choose to do nothing and deal with severe consequences later. At UCS we believe the choice is clear. It is time to push forward toward a brighter, cleaner future.
Highlights
Irene Is the 10th Billion-Dollar Weather Disaster for 2011, a blog post by senior climate economist Rachel Cleetus. Read more blog posts from our global warming experts.
What is Global Warming?
When CO2 and other heat-trapping emissions are released into the air, they act like a blanket, holding heat in our atmosphere and warming the planet. Overloading our atmosphere with carbon has far-reaching effects for people everywhere.
23 Eylül 2011 Cuma
CIA classified global warming as top secret
Global warming is simply not happening, folks, and if it is, then it's classified information that must be kept secret by the CIA at all costs.
The top secrecy of the world's weather system was revealed when a well-meaning National Security Archive scholar by the name of Jeffrey Richelson attempted to use the Freedom of Information Act to delve into the CIA's natural disaster center.
CIA classified global warming as top secretThe center, set up two years ago with the sketchy aim to keep its beady eye on phenomena such as desertification, rising sea levels, population shifts and heightened competition for natural resources," has maintained near radio silence since launch and Richelson wanted to know what was going on.
The answer he received, however, is not much of an answer at all, which begs the question why climate change should be seen as something so confidential by America's watch dogs?
"We completed a thorough search for records responsive to your request and located material that we determined is currently and properly classified and must be denied in its entirety," was the official response from the agency's information and privacy coordinator Susan Viscuso, as quoted in Wired.
The statement seems odd in light of the center's scientific focus and early goals to become "a powerful asset recognized throughout our government, and beyond, for its knowledge and insight."
Perhaps we mere mortals couldn't handle that knowledge. Perhaps Al Gore was merely sugar coating his "Inconvenient Truth" and we're all really in for "The Day After Tomorrow" by the day after tomorrow?
Or perhaps someone at the CIA hasn't been recycling the plastic water cooler bottles and is afraid of being found out and hounded by a nation passionate about going green. Oh, wait, no, that can't be it.
Whatever secrets the center harbors, however, we may never get the chance to find out, what with budget cuts quickly closing in and eco-political scapegoats up for financial slaughter.
Better start building that hurricane resistant bunker, folks, because when weather strikes, not a one of us will have seen it coming.
The top secrecy of the world's weather system was revealed when a well-meaning National Security Archive scholar by the name of Jeffrey Richelson attempted to use the Freedom of Information Act to delve into the CIA's natural disaster center.
CIA classified global warming as top secretThe center, set up two years ago with the sketchy aim to keep its beady eye on phenomena such as desertification, rising sea levels, population shifts and heightened competition for natural resources," has maintained near radio silence since launch and Richelson wanted to know what was going on.
The answer he received, however, is not much of an answer at all, which begs the question why climate change should be seen as something so confidential by America's watch dogs?
"We completed a thorough search for records responsive to your request and located material that we determined is currently and properly classified and must be denied in its entirety," was the official response from the agency's information and privacy coordinator Susan Viscuso, as quoted in Wired.
The statement seems odd in light of the center's scientific focus and early goals to become "a powerful asset recognized throughout our government, and beyond, for its knowledge and insight."
Perhaps we mere mortals couldn't handle that knowledge. Perhaps Al Gore was merely sugar coating his "Inconvenient Truth" and we're all really in for "The Day After Tomorrow" by the day after tomorrow?
Or perhaps someone at the CIA hasn't been recycling the plastic water cooler bottles and is afraid of being found out and hounded by a nation passionate about going green. Oh, wait, no, that can't be it.
Whatever secrets the center harbors, however, we may never get the chance to find out, what with budget cuts quickly closing in and eco-political scapegoats up for financial slaughter.
Better start building that hurricane resistant bunker, folks, because when weather strikes, not a one of us will have seen it coming.
Global warming’s CO2 culprit jumps 45% since 1990
Global emissions of carbon dioxide, the main cause of global warming, jumped 45% between 1990 and 2010, and reached an all-time high of 33 billion tons last year, the European Commission reports.
The emission cuts in some industrialized countries that are relying more on energy efficiency and renewable power are not enough to offset the escalating demand for energy, especially in developing countries, according to the new report by the EC’s Joint Research Centre and PBL Netherlands Environmental Assessment Agency.
The report, based on the latest data, shows large national differences. The 27 member nations of the European Union (EU-27) cut CO2 emissions 7% during the 1990-2010 peri0d and Russia slashed them 28%. In contrast, U.S. emissions increased 5% and Japanese emissions remained fairly constant.
Continued growth in developing countries and economic recovery in the industrialized world account largely for the record 5.8% hike in global CO2 emissions between 2009 and 2010, according to the report. Major economies contributed to this upswing, led by China, the U.S., India and the EU-27 with increases of 10%, 4%, 9% and 3% respectively. The report says the U.S. emits 16.9 tons of CO2 per capita per year, more than twice that of the EU-27′s 8.1 tons and China’s 6.8 tons.
The emission cuts in some industrialized countries that are relying more on energy efficiency and renewable power are not enough to offset the escalating demand for energy, especially in developing countries, according to the new report by the EC’s Joint Research Centre and PBL Netherlands Environmental Assessment Agency.
The report, based on the latest data, shows large national differences. The 27 member nations of the European Union (EU-27) cut CO2 emissions 7% during the 1990-2010 peri0d and Russia slashed them 28%. In contrast, U.S. emissions increased 5% and Japanese emissions remained fairly constant.
Continued growth in developing countries and economic recovery in the industrialized world account largely for the record 5.8% hike in global CO2 emissions between 2009 and 2010, according to the report. Major economies contributed to this upswing, led by China, the U.S., India and the EU-27 with increases of 10%, 4%, 9% and 3% respectively. The report says the U.S. emits 16.9 tons of CO2 per capita per year, more than twice that of the EU-27′s 8.1 tons and China’s 6.8 tons.
20 Eylül 2011 Salı
Global warming 'past the point of no return'
A record loss of sea ice in the Arctic this summer has convinced scientists that the northern hemisphere may have crossed a critical threshold beyond which the climate may never recover. Scientists fear that the Arctic has now entered an irreversible phase of warming which will accelerate the loss of the polar sea ice that has helped to keep the climate stable for thousands of years.
They believe global warming is melting Arctic ice so rapidly that the region is beginning to absorb more heat from the sun, causing the ice to melt still further and so reinforcing a vicious cycle of melting and heating.
The greatest fear is that the Arctic has reached a "tipping point" beyond which nothing can reverse the continual loss of sea ice and with it the massive land glaciers of Greenland, which will raise sea levels dramatically.
Related articles
Satellites monitoring the Arctic have found that the extent of the sea ice this August has reached its lowest monthly point on record, dipping an unprecedented 18.2 per cent below the long-term average.
Experts believe that such a loss of Arctic sea ice in summer has not occurred in hundreds and possibly thousands of years. It is the fourth year in a row that the sea ice in August has fallen below the monthly downward trend - a clear sign that melting has accelerated.
Scientists are now preparing to report a record loss of Arctic sea ice for September, when the surface area covered by the ice traditionally reaches its minimum extent at the end of the summer melting period.
Sea ice naturally melts in summer and reforms in winter but for the first time on record this annual rebound did not occur last winter when the ice of the Arctic failed to recover significantly.
Arctic specialists at the US National Snow and Ice Data Centre at Colorado University, who have documented the gradual loss of polar sea ice since 1978, believe that a more dramatic melt began about four years ago.
In September 2002 the sea ice coverage of the Arctic reached its lowest level in recorded history. Such lows have normally been followed the next year by a rebound to more normal levels, but this did not occur in the summers of either 2003 or 2004. This summer has been even worse. The surface area covered by sea ice was at a record monthly minimum for each of the summer months - June, July and now August.
Scientists analysing the latest satellite data for September - the traditional minimum extent for each summer - are preparing to announce a significant shift in the stability of the Arctic sea ice, the northern hemisphere's major "heat sink" that moderates climatic extremes.
"The changes we've seen in the Arctic over the past few decades are nothing short of remarkable," said Mark Serreze, one of the scientists at the Snow and Ice Data Centre who monitor Arctic sea ice.
Scientists at the data centre are bracing themselves for the 2005 annual minimum, which is expected to be reached in mid-September, when another record loss is forecast. A major announcement is scheduled for 20 September. "It looks like we're going to exceed it or be real close one way or the other. It is probably going to be at least as comparable to September 2002," Dr Serreze said.
"This will be four Septembers in a row that we've seen a downward trend. The feeling is we are reaching a tipping point or threshold beyond which sea ice will not recover."
The extent of the sea ice in September is the most valuable indicator of its health. This year's record melt means that more of the long-term ice formed over many winters - so called multi-year ice - has disappeared than at any time in recorded history.
Sea ice floats on the surface of the Arctic Ocean and its neighbouring seas and normally covers an area of some 7 million square kilometres (2.4 million square miles) during September - about the size of Australia. However, in September 2002, this dwindled to about 2 million square miles - 16 per cent below average.
Sea ice data for August closely mirrors that for September and last month's record low - 18.2 per cent below the monthly average - strongly suggests that this September will see the smallest coverage of Arctic sea ice ever recorded.
As more and more sea ice is lost during the summer, greater expanses of open ocean are exposed to the sun which increases the rate at which heat is absorbed in the Arctic region, Dr Serreze said.
Sea ice reflects up to 80 per cent of sunlight hitting it but this "albedo effect" is mostly lost when the sea is uncovered. "We've exposed all this dark ocean to the sun's heat so that the overall heat content increases," he explained.
Current computer models suggest that the Arctic will be entirely ice-free during summer by the year 2070 but some scientists now believe that even this dire prediction may be over-optimistic, said Professor Peter Wadhams, an Arctic ice specialist at Cambridge University.
"When the ice becomes so thin it breaks up mechanically rather than thermodynamically. So these predictions may well be on the over-optimistic side," he said.
As the sea ice melts, and more of the sun's energy is absorbed by the exposed ocean, a positive feedback is created leading to the loss of yet more ice, Professor Wadhams said.
"If anything we may be underestimating the dangers. The computer models may not take into account collaborative positive feedback," he said.
Sea ice keeps a cap on frigid water, keeping it cold and protecting it from heating up. Losing the sea ice of the Arctic is likely to have major repercussions for the climate, he said. "There could be dramatic changes to the climate of the northern region due to the creation of a vast expanse of open water where there was once effectively land," Professor Wadhams said. "You're essentially changing land into ocean and the creation of a huge area of open ocean where there was once land will have a very big impact on other climate parameters," he said.
They believe global warming is melting Arctic ice so rapidly that the region is beginning to absorb more heat from the sun, causing the ice to melt still further and so reinforcing a vicious cycle of melting and heating.
The greatest fear is that the Arctic has reached a "tipping point" beyond which nothing can reverse the continual loss of sea ice and with it the massive land glaciers of Greenland, which will raise sea levels dramatically.
Related articles
Satellites monitoring the Arctic have found that the extent of the sea ice this August has reached its lowest monthly point on record, dipping an unprecedented 18.2 per cent below the long-term average.
Experts believe that such a loss of Arctic sea ice in summer has not occurred in hundreds and possibly thousands of years. It is the fourth year in a row that the sea ice in August has fallen below the monthly downward trend - a clear sign that melting has accelerated.
Scientists are now preparing to report a record loss of Arctic sea ice for September, when the surface area covered by the ice traditionally reaches its minimum extent at the end of the summer melting period.
Sea ice naturally melts in summer and reforms in winter but for the first time on record this annual rebound did not occur last winter when the ice of the Arctic failed to recover significantly.
Arctic specialists at the US National Snow and Ice Data Centre at Colorado University, who have documented the gradual loss of polar sea ice since 1978, believe that a more dramatic melt began about four years ago.
In September 2002 the sea ice coverage of the Arctic reached its lowest level in recorded history. Such lows have normally been followed the next year by a rebound to more normal levels, but this did not occur in the summers of either 2003 or 2004. This summer has been even worse. The surface area covered by sea ice was at a record monthly minimum for each of the summer months - June, July and now August.
Scientists analysing the latest satellite data for September - the traditional minimum extent for each summer - are preparing to announce a significant shift in the stability of the Arctic sea ice, the northern hemisphere's major "heat sink" that moderates climatic extremes.
"The changes we've seen in the Arctic over the past few decades are nothing short of remarkable," said Mark Serreze, one of the scientists at the Snow and Ice Data Centre who monitor Arctic sea ice.
Scientists at the data centre are bracing themselves for the 2005 annual minimum, which is expected to be reached in mid-September, when another record loss is forecast. A major announcement is scheduled for 20 September. "It looks like we're going to exceed it or be real close one way or the other. It is probably going to be at least as comparable to September 2002," Dr Serreze said.
"This will be four Septembers in a row that we've seen a downward trend. The feeling is we are reaching a tipping point or threshold beyond which sea ice will not recover."
The extent of the sea ice in September is the most valuable indicator of its health. This year's record melt means that more of the long-term ice formed over many winters - so called multi-year ice - has disappeared than at any time in recorded history.
Sea ice floats on the surface of the Arctic Ocean and its neighbouring seas and normally covers an area of some 7 million square kilometres (2.4 million square miles) during September - about the size of Australia. However, in September 2002, this dwindled to about 2 million square miles - 16 per cent below average.
Sea ice data for August closely mirrors that for September and last month's record low - 18.2 per cent below the monthly average - strongly suggests that this September will see the smallest coverage of Arctic sea ice ever recorded.
As more and more sea ice is lost during the summer, greater expanses of open ocean are exposed to the sun which increases the rate at which heat is absorbed in the Arctic region, Dr Serreze said.
Sea ice reflects up to 80 per cent of sunlight hitting it but this "albedo effect" is mostly lost when the sea is uncovered. "We've exposed all this dark ocean to the sun's heat so that the overall heat content increases," he explained.
Current computer models suggest that the Arctic will be entirely ice-free during summer by the year 2070 but some scientists now believe that even this dire prediction may be over-optimistic, said Professor Peter Wadhams, an Arctic ice specialist at Cambridge University.
"When the ice becomes so thin it breaks up mechanically rather than thermodynamically. So these predictions may well be on the over-optimistic side," he said.
As the sea ice melts, and more of the sun's energy is absorbed by the exposed ocean, a positive feedback is created leading to the loss of yet more ice, Professor Wadhams said.
"If anything we may be underestimating the dangers. The computer models may not take into account collaborative positive feedback," he said.
Sea ice keeps a cap on frigid water, keeping it cold and protecting it from heating up. Losing the sea ice of the Arctic is likely to have major repercussions for the climate, he said. "There could be dramatic changes to the climate of the northern region due to the creation of a vast expanse of open water where there was once effectively land," Professor Wadhams said. "You're essentially changing land into ocean and the creation of a huge area of open ocean where there was once land will have a very big impact on other climate parameters," he said.
Arctic sea ice melts to 2nd-lowest level on record
More ominous signs Wednesday have scientists saying that a global warming "tipping point" in the Arctic is happening before their eyes: Sea ice in the Arctic Ocean has melted to its second lowest level since satellite observations began.
The National Snow and Ice Data Center in the U.S. state of Colorado reported that the extent of sea ice in the Arctic is down to 2.03 million square miles. The lowest point since 1979 is 1.65 million square miles set last September.
With about three weeks left in the Arctic summer, this year could wind up breaking the previous record, scientists said.
Arctic ice always melts in summer and refreezes in winter. But over the years, more and more of the ice is lost to the sea and not recovered in winter. That is important because the Arctic acts as a refrigerator for the globe.
Sea ice also serves as primary habitat for threatened polar bears.
"We could very well be in that quick slide downward in terms of passing a tipping point," said center senior scientist Mark Serreze. "It's tipping now. We're seeing it happen now."
Within a few years — "five to less than 10 years" — the Arctic could be free of sea ice in the summer, said NASA ice scientist Jay Zwally.
"It also means that climate warming is also coming larger and faster than the models are predicting and nobody's really taken into account that change yet," he said.
Other scientists, including James Hansen, director of NASA's Goddard Institute of Space Studies in the state of New York, agreed. Hansen in a Wednesday e-mail said the sea ice "is the best current example of a tipping point."
Last year was an unusual year when wind currents and other weather conditions coincided with global warming to worsen sea ice melt, Serreze said. Scientists wondered if last year's melt was an unusual event or the start of a new and disturbing trend.
This year's results suggest the latter because the ice had recovered a bit more than usual thanks to a somewhat cooler winter, Serreze said. Then this month, when the melting rate usually slows, it sped up, he said.
And the melt in sea ice has kicked in another effect, long predicted, called "Arctic amplification," Serreze said.
That's when the warming up north is increased in a feedback mechanism and the effects spill southward starting in autumn, he said. Over the last few years, the bigger melt has meant more warm water that releases more heat into the air during fall cooling, making the atmosphere warmer than normal.
The data center has been tracking Arctic sea ice levels since 1979. According to scientists at the data center, sea ice is in a state of ongoing decline that is greater than natural causes could account for.
The National Snow and Ice Data Center in the U.S. state of Colorado reported that the extent of sea ice in the Arctic is down to 2.03 million square miles. The lowest point since 1979 is 1.65 million square miles set last September.
With about three weeks left in the Arctic summer, this year could wind up breaking the previous record, scientists said.
Arctic ice always melts in summer and refreezes in winter. But over the years, more and more of the ice is lost to the sea and not recovered in winter. That is important because the Arctic acts as a refrigerator for the globe.
Sea ice also serves as primary habitat for threatened polar bears.
"We could very well be in that quick slide downward in terms of passing a tipping point," said center senior scientist Mark Serreze. "It's tipping now. We're seeing it happen now."
Within a few years — "five to less than 10 years" — the Arctic could be free of sea ice in the summer, said NASA ice scientist Jay Zwally.
"It also means that climate warming is also coming larger and faster than the models are predicting and nobody's really taken into account that change yet," he said.
Other scientists, including James Hansen, director of NASA's Goddard Institute of Space Studies in the state of New York, agreed. Hansen in a Wednesday e-mail said the sea ice "is the best current example of a tipping point."
Last year was an unusual year when wind currents and other weather conditions coincided with global warming to worsen sea ice melt, Serreze said. Scientists wondered if last year's melt was an unusual event or the start of a new and disturbing trend.
This year's results suggest the latter because the ice had recovered a bit more than usual thanks to a somewhat cooler winter, Serreze said. Then this month, when the melting rate usually slows, it sped up, he said.
And the melt in sea ice has kicked in another effect, long predicted, called "Arctic amplification," Serreze said.
That's when the warming up north is increased in a feedback mechanism and the effects spill southward starting in autumn, he said. Over the last few years, the bigger melt has meant more warm water that releases more heat into the air during fall cooling, making the atmosphere warmer than normal.
The data center has been tracking Arctic sea ice levels since 1979. According to scientists at the data center, sea ice is in a state of ongoing decline that is greater than natural causes could account for.
Global Warming Tipping Point
If climate change is irreversible, does that mean it could take all cars off the road and it would never have an effect?
It's not quite that dire. According to the 2009 study, we could be looking at a thousand years of warmer temperatures even if we make dramatic cuts in CO2 emissions right now. So technically, it's not "irreversible" -- any of our descendants born after the year 3000 will be able to reap the benefits of our CO2 cuts (whew!).
We have apparently made it to the point of no timely return.
In terms of sea ice, that point became apparent years ago when Arctic ice stopped replenishing itself. Usually, ice melts to a certain level in summer months and freezes back to a certain level in winter months. Starting around 2003, the ice stopped recovering [source: Connor]. For that year and each year since, the ice melted more than usual in summer, and froze less than usual in winter, resulting in an overall loss of "permanent" ice. For September, the average sea ice coverage has typically been 2.4 million square miles (7 million square kilometers); in September 2007, sea ice covered only 1.65 million square miles (4.27 square kilometers) of the Arctic Ocean, the lowest point on record [source: USA Today]. Some experts believe there may be no summer ice in the Arctic within 10 years [source: USA Today].
The atmospheric CO2 situation isn't much better. We currently have 385 parts per million (ppm) of CO2 in our air; scientists are pushing for CO2 caps that will get us stabilized at 450 ppm in the next few decades [source: New Scientist]. Many people believe this goal isn't politically feasible, and have set 550 ppm as a more reasonable target [source: New Scientist]. But new research suggests it may not even matter. That 2009 NOAA-led study states that at 450 ppm, we're still looking at severe, unavoidable drought conditions in Africa, southern Europe, western Australia and the American southwest. And if we reach 600 ppm, expanding warm waters could make ocean levels rise by 3 feet (1 meter) in the next thousand years [source: Modine]. That number gets even higher if you take into account melting glaciers.
Scientists aren't proposing we stop buying hybrid cars, though. The faster we act to make huge cuts in CO2, the better the prognosis. If we can make dramatic changes right now, perhaps we could get the atmosphere stabilized at 400 ppm instead of 550 ppm. That would at least increase the chances that the U.S. West Coast will still be above water in 3000. Probably.
It's not quite that dire. According to the 2009 study, we could be looking at a thousand years of warmer temperatures even if we make dramatic cuts in CO2 emissions right now. So technically, it's not "irreversible" -- any of our descendants born after the year 3000 will be able to reap the benefits of our CO2 cuts (whew!).
We have apparently made it to the point of no timely return.
In terms of sea ice, that point became apparent years ago when Arctic ice stopped replenishing itself. Usually, ice melts to a certain level in summer months and freezes back to a certain level in winter months. Starting around 2003, the ice stopped recovering [source: Connor]. For that year and each year since, the ice melted more than usual in summer, and froze less than usual in winter, resulting in an overall loss of "permanent" ice. For September, the average sea ice coverage has typically been 2.4 million square miles (7 million square kilometers); in September 2007, sea ice covered only 1.65 million square miles (4.27 square kilometers) of the Arctic Ocean, the lowest point on record [source: USA Today]. Some experts believe there may be no summer ice in the Arctic within 10 years [source: USA Today].
The atmospheric CO2 situation isn't much better. We currently have 385 parts per million (ppm) of CO2 in our air; scientists are pushing for CO2 caps that will get us stabilized at 450 ppm in the next few decades [source: New Scientist]. Many people believe this goal isn't politically feasible, and have set 550 ppm as a more reasonable target [source: New Scientist]. But new research suggests it may not even matter. That 2009 NOAA-led study states that at 450 ppm, we're still looking at severe, unavoidable drought conditions in Africa, southern Europe, western Australia and the American southwest. And if we reach 600 ppm, expanding warm waters could make ocean levels rise by 3 feet (1 meter) in the next thousand years [source: Modine]. That number gets even higher if you take into account melting glaciers.
Scientists aren't proposing we stop buying hybrid cars, though. The faster we act to make huge cuts in CO2, the better the prognosis. If we can make dramatic changes right now, perhaps we could get the atmosphere stabilized at 400 ppm instead of 550 ppm. That would at least increase the chances that the U.S. West Coast will still be above water in 3000. Probably.
An Irreversible State of Global Warming: The Cycle
A study published in 2009, led by a scientist with the National Oceanic and Atmospheric Administration, shows that climate change may in fact be irreversible. Instead of it taking a couple hundred years to reverse global warming if we cut emissions right now, it looks like it could take more like a millennium. The issue is the oceans' absorption of atmospheric carbon dioxide.
The world's oceans play a central role in climate control. It's not just plants that absorb CO2; oceans absorb even more of it. Ocean waters absorb CO2 from the air, effectively cooling the atmosphere. The ocean also emits heat from the sunlight it absorbs, warming the atmosphere. This constant cycle of cooling and warming keeps the Earth at a stable temperature. Or at least, that's how it's supposed to work.
The system starts to break down when the amount of CO2 pumped into the atmosphere rises exponentially, as it has in the last couple of centuries. The ocean can only absorb so much CO2 in a period of time: The upper layers of water absorb CO2, and then, as currents move, lower layers of water replace those saturated surface waters, offering new absorption surfaces. The snail-like turnover pace means any actions we take now to curb CO2 emissions won't have any effect for a long, long time.
There are other cycles involved in the problem, too. The loss of sea ice in the Arctic due to global warming creates further warming conditions that are difficult to undo. Sea ice and glacial mass are another big part of the Earth's climate-control system. While water absorbs sunlight, ice reflects it. Glaciers help keep ocean waters at a stable temperature. When glaciers melt, as they've been doing steadily since the United States started recording their levels in 1978, there's less ice to reflect sunlight and more water to absorb it. With more sunlight absorption, ocean temperatures increase. When ocean temperatures increase, more heat is released into the atmosphere, and overall temperatures increase, leading to more melting.
The end result of these combined cycles could be what some experts are calling an irreversible state of global warming. But are we really at that tipping point where there's no turning back climate change?
The world's oceans play a central role in climate control. It's not just plants that absorb CO2; oceans absorb even more of it. Ocean waters absorb CO2 from the air, effectively cooling the atmosphere. The ocean also emits heat from the sunlight it absorbs, warming the atmosphere. This constant cycle of cooling and warming keeps the Earth at a stable temperature. Or at least, that's how it's supposed to work.
The system starts to break down when the amount of CO2 pumped into the atmosphere rises exponentially, as it has in the last couple of centuries. The ocean can only absorb so much CO2 in a period of time: The upper layers of water absorb CO2, and then, as currents move, lower layers of water replace those saturated surface waters, offering new absorption surfaces. The snail-like turnover pace means any actions we take now to curb CO2 emissions won't have any effect for a long, long time.
There are other cycles involved in the problem, too. The loss of sea ice in the Arctic due to global warming creates further warming conditions that are difficult to undo. Sea ice and glacial mass are another big part of the Earth's climate-control system. While water absorbs sunlight, ice reflects it. Glaciers help keep ocean waters at a stable temperature. When glaciers melt, as they've been doing steadily since the United States started recording their levels in 1978, there's less ice to reflect sunlight and more water to absorb it. With more sunlight absorption, ocean temperatures increase. When ocean temperatures increase, more heat is released into the atmosphere, and overall temperatures increase, leading to more melting.
The end result of these combined cycles could be what some experts are calling an irreversible state of global warming. But are we really at that tipping point where there's no turning back climate change?
Is global warming irreversible?
By the time Al Gore's award-winning documentary "An Inconvenient Truth" hit theaters in 2006, most of the world had accepted the fact of global warming, if not humanity's causative role in it. But over the last few years, as more and more scientific organizations have backed up the claim that human activity is to blame for rising temperatures, including a United Nations science panel in 2007, government actions attempting to curtail greenhouse-gas emissions have gained even more supporters. Most of the developed world is now onboard in the fight to save the world from warm, certain doom -- but suddenly, it appears all the effort might be futile.
The situation is indeed dire. As factories, cars and power plants emit tons of gases like carbon dioxide, methane and nitrous oxides into the atmosphere, and all the while deforestation activities remove the plant life that absorbs carbon dioxide, lots of those "greenhouse gases" build up in the atmosphere. There, they act like the glass of a greenhouse, allowing sunlight in but trapping it once it's there.
Up Next
How Global Warming Works
How the Earth Works
Curiosity Project: Man's Destruction of the Environment Quiz
So far, in the last century, Earth's average temperature has increased about 1 degree F (0.6 degrees C) [source: New York Times]. That may not seem like much, but it can have profound effects, like altering weather systems and changing the balance of sea life. Polar bears are looking at possible extinction in the next few decades [source: NGN]. Experts predict that by 2100, sea levels could rise by up to 2 feet (61 centimeters), leaving major coastal areas underwater [source: New York Times].
Most scientists say that an increase of more than 3.3 degrees F (2 degrees C) would be catastrophic [source: SFS].
The world is taking action to curb the danger, like setting limits on industrial CO2 pollution and developing alternative energy sources. But some new research could throw a wrench in the works of ecological optimism: It seems all our efforts may be for naught.
In this article, we'll look at some newer research suggesting that global warming might be irreversible. We'll find out why we may not be able to undo the damage and see if we might as well just emit to our hearts' content.
The situation is indeed dire. As factories, cars and power plants emit tons of gases like carbon dioxide, methane and nitrous oxides into the atmosphere, and all the while deforestation activities remove the plant life that absorbs carbon dioxide, lots of those "greenhouse gases" build up in the atmosphere. There, they act like the glass of a greenhouse, allowing sunlight in but trapping it once it's there.
Up Next
How Global Warming Works
How the Earth Works
Curiosity Project: Man's Destruction of the Environment Quiz
So far, in the last century, Earth's average temperature has increased about 1 degree F (0.6 degrees C) [source: New York Times]. That may not seem like much, but it can have profound effects, like altering weather systems and changing the balance of sea life. Polar bears are looking at possible extinction in the next few decades [source: NGN]. Experts predict that by 2100, sea levels could rise by up to 2 feet (61 centimeters), leaving major coastal areas underwater [source: New York Times].
Most scientists say that an increase of more than 3.3 degrees F (2 degrees C) would be catastrophic [source: SFS].
The world is taking action to curb the danger, like setting limits on industrial CO2 pollution and developing alternative energy sources. But some new research could throw a wrench in the works of ecological optimism: It seems all our efforts may be for naught.
In this article, we'll look at some newer research suggesting that global warming might be irreversible. We'll find out why we may not be able to undo the damage and see if we might as well just emit to our hearts' content.
16 Eylül 2011 Cuma
What causes global warming?
Many things cause global warming. One thing that causes global warming is electrical pollution. Electricity causes pollution in many ways, some worse than others. In most cases, fossil fuels are burned to create electricity. Fossil fuels are made of dead plants and animals. Some examples of fossil fuels are oil and petroleum. Many pollutants (chemicals that pollute the air, water, and land) are sent into the air when fossil fuels are burned. Some of these chemicals are called greenhouse gasses.
We use these sources of energy much more than the sources that give off less pollution. Petroleum, one of the sources of energy, is used a lot. It is used for transportation, making electricity, and making many other things. Although this source of energy gives off a lot of pollution, it is used for 38% of the United States’ energy.
We use these sources of energy much more than the sources that give off less pollution. Petroleum, one of the sources of energy, is used a lot. It is used for transportation, making electricity, and making many other things. Although this source of energy gives off a lot of pollution, it is used for 38% of the United States’ energy.
What are greenhouse gasses?
Greenhouse gasses are gasses are in the earth’s atmosphere that collect heat and light from the sun. With too many greenhouse gasses in the air, the earth’s atmosphere will trap too much heat and the earth will get too hot. As a result people, animals, and plants would die because the heat would be too strong.
What is global warming doing to the environment?
Global warming is affecting many parts of the world. Global warming makes the sea rise, and when the sea rises, the water covers many low land islands. This is a big problem for many of the plants, animals, and people on islands. The water covers the plants and causes some of them to die. When they die, the animals lose a source of food, along with their habitat. Although animals have a better ability to adapt to what happens than plants do, they may die also. When the plants and animals die, people lose two sources of food, plant food and animal food. They may also lose their homes. As a result, they would also have to leave the area or die. This would be called a break in the food chain, or a chain reaction, one thing happening that leads to another and so on.
The oceans are affected by global warming in other ways, as well. Many things that are happening to the ocean are linked to global warming. One thing that is happening is warm water, caused from global warming, is harming and killing algae in the ocean.
Algae is a producer that you can see floating on the top of the water. (A producer is something that makes food for other animals through photosynthesis, like grass.) This floating green algae is food to many consumers in the ocean. (A consumer is something that eats the producers.) One kind of a consumer is small fish. There are many others like crabs, some whales, and many other animals. Fewer algae is a problem because there is less food for us and many animals in the sea.
Global warming is doing many things to people as well as animals and plants. It is killing algae, but it is also destroying many huge forests. The pollution that causes global warming is linked to acid rain. Acid rain gradually destroys almost everything it touches. Global warming is also causing many more fires that wipe out whole forests. This happens because global warming can make the earth very hot. In forests, some plants and trees leaves can be so dry that they catch on fire.
What is global warming doing to the environment?
Global warming is affecting many parts of the world. Global warming makes the sea rise, and when the sea rises, the water covers many low land islands. This is a big problem for many of the plants, animals, and people on islands. The water covers the plants and causes some of them to die. When they die, the animals lose a source of food, along with their habitat. Although animals have a better ability to adapt to what happens than plants do, they may die also. When the plants and animals die, people lose two sources of food, plant food and animal food. They may also lose their homes. As a result, they would also have to leave the area or die. This would be called a break in the food chain, or a chain reaction, one thing happening that leads to another and so on.
The oceans are affected by global warming in other ways, as well. Many things that are happening to the ocean are linked to global warming. One thing that is happening is warm water, caused from global warming, is harming and killing algae in the ocean.
Algae is a producer that you can see floating on the top of the water. (A producer is something that makes food for other animals through photosynthesis, like grass.) This floating green algae is food to many consumers in the ocean. (A consumer is something that eats the producers.) One kind of a consumer is small fish. There are many others like crabs, some whales, and many other animals. Fewer algae is a problem because there is less food for us and many animals in the sea.
Global warming is doing many things to people as well as animals and plants. It is killing algae, but it is also destroying many huge forests. The pollution that causes global warming is linked to acid rain. Acid rain gradually destroys almost everything it touches. Global warming is also causing many more fires that wipe out whole forests. This happens because global warming can make the earth very hot. In forests, some plants and trees leaves can be so dry that they catch on fire.
What is global warming?
Global warming is when the earth heats up (the temperature rises). It happens when greenhouse gases (carbon dioxide, water vapor, nitrous oxide, and methane) trap heat and light from the sun in the earth’s atmosphere, which increases the temperature. This hurts many people, animals, and plants. Many cannot take the change, so they die.
What is the greenhouse effect?
The greenhouse effect is when the temperature rises because the sun’s heat and light is trapped in the earth’s atmosphere. This is like when heat is trapped in a car. On a very hot day, the car gets hotter when it is out in the parking lot. This is because the heat and light from the sun can get into the car, by going through the windows, but it can’t get back out. This is what the greenhouse effect does to the earth. The heat and light can get through the atmosphere, but it can’t get out. As a result, the temperature rises.
The squiggle lines coming from the sun are visible light and the lines and arrows inside the car are infrared light.
The sun’s heat can get into the car through the windows but is then trapped. This makes what ever the place might be, a greenhouse, a car, a building, or the earth’s atmosphere, hotter. This diagram shows the heat coming into a car as visible light (light you can see) and infrared light (heat). Once the light is inside the car, it is trapped and the heat builds up, just like it does in the earth’s atmosphere.
Sometimes the temperature can change in a way that helps us. The greenhouse effect makes the earth appropriate for people to live on. Without it, the earth would be freezing, or on the other hand it would be burning hot. It would be freezing at night because the sun would be down. We would not get the sun’s heat and light to make the night somewhat warm. During the day, especially during the summer, it would be burning because the sun would be up with no atmosphere to filter it, so people, plants, and animals would be exposed to all the light and heat.
Although the greenhouse effect makes the earth able to have people living on it, if there gets to be too many gases, the earth can get unusually warmer, and many plants, animals, and people will die. They would die because there would be less food (plants like corn, wheat, and other vegetables and fruits). This would happen because the plants would not be able to take the heat. This would cause us to have less food to eat, but it would also limit the food that animals have. With less food, like grass, for the animals that we need to survive (like cows) we would even have less food. Gradually, people, plants, and animals would all die of hunger.
What is the greenhouse effect?
The greenhouse effect is when the temperature rises because the sun’s heat and light is trapped in the earth’s atmosphere. This is like when heat is trapped in a car. On a very hot day, the car gets hotter when it is out in the parking lot. This is because the heat and light from the sun can get into the car, by going through the windows, but it can’t get back out. This is what the greenhouse effect does to the earth. The heat and light can get through the atmosphere, but it can’t get out. As a result, the temperature rises.
The squiggle lines coming from the sun are visible light and the lines and arrows inside the car are infrared light.
The sun’s heat can get into the car through the windows but is then trapped. This makes what ever the place might be, a greenhouse, a car, a building, or the earth’s atmosphere, hotter. This diagram shows the heat coming into a car as visible light (light you can see) and infrared light (heat). Once the light is inside the car, it is trapped and the heat builds up, just like it does in the earth’s atmosphere.
Sometimes the temperature can change in a way that helps us. The greenhouse effect makes the earth appropriate for people to live on. Without it, the earth would be freezing, or on the other hand it would be burning hot. It would be freezing at night because the sun would be down. We would not get the sun’s heat and light to make the night somewhat warm. During the day, especially during the summer, it would be burning because the sun would be up with no atmosphere to filter it, so people, plants, and animals would be exposed to all the light and heat.
Although the greenhouse effect makes the earth able to have people living on it, if there gets to be too many gases, the earth can get unusually warmer, and many plants, animals, and people will die. They would die because there would be less food (plants like corn, wheat, and other vegetables and fruits). This would happen because the plants would not be able to take the heat. This would cause us to have less food to eat, but it would also limit the food that animals have. With less food, like grass, for the animals that we need to survive (like cows) we would even have less food. Gradually, people, plants, and animals would all die of hunger.
12 Eylül 2011 Pazartesi
Stop Global Warming
Problem----We are all personally responsible for releasing carbon dioxide into the atmosphere by burning fossil fuels for transportation (driving and flying) and home energy (electricity, heating, and cooling). This leads to global warming, which is destroying Earth's biodiversity and native ecosystems.
Solutions
1.Reduce your use of fossil fuels
2.Protect native forests as "carbon storehouses"
3.Help plant native trees in urban and deforested areas
4.Volunteer for NWP
5.Donate to NWP. Based on NWP total program costs and conservation project accomplishments since 1999, every $10 donation allows us to sponsor one Apprentice Ecologist and plant 3.1 native trees.
Benefits of planting native trees
1.They help stop global warming by reducing greenhouse gases
2.They reduce soil erosion and water pollution
3.They provide habitat for native wildlife (including songbirds)
4.They improve human health by producing oxygen and improving air quality
5.They reduce home energy needs by providing shade in summer and a windbreak in winter
Facts about the benefits provided by planting one tree
1.Absorbs over a ton of harmful greenhouse gases over its lifetime (U.S. Environmental Protection Agency)
2.Produces enough oxygen for four people every day (Tree Canada Foundation)
3.Provides the equivalent cooling effect of ten room-size air conditioners operating 20 hours a day (U.S. Department of Agriculture)
4.Provides an estimated $273 of environmental benefits in every year of its life (American Forests)
We work directly with youth volunteers, including those who are at-risk and disadvantaged, throughout North America and Africa and can help you be part of the solution to global warming. We award a $500 educational scholarship each year to the winner of our Apprentice Ecologist Awards.
Officially recognized by the U.S. EPA, the Apprentice Ecologist Initiative™, our youth-based volunteer program, allows us to plant native trees at a size where they can quickly mature into large adult trees and become part of the native forested landscape. We have had great success in engaging youth volunteers (from large urban areas to small rural villages) in these tree-planting projects, which helps us keep costs to an absolute minimum. Native trees planted in North America and Africa only a few years ago are now over 7 meters (23 feet) tall!
Solutions
1.Reduce your use of fossil fuels
2.Protect native forests as "carbon storehouses"
3.Help plant native trees in urban and deforested areas
4.Volunteer for NWP
5.Donate to NWP. Based on NWP total program costs and conservation project accomplishments since 1999, every $10 donation allows us to sponsor one Apprentice Ecologist and plant 3.1 native trees.
Benefits of planting native trees
1.They help stop global warming by reducing greenhouse gases
2.They reduce soil erosion and water pollution
3.They provide habitat for native wildlife (including songbirds)
4.They improve human health by producing oxygen and improving air quality
5.They reduce home energy needs by providing shade in summer and a windbreak in winter
Facts about the benefits provided by planting one tree
1.Absorbs over a ton of harmful greenhouse gases over its lifetime (U.S. Environmental Protection Agency)
2.Produces enough oxygen for four people every day (Tree Canada Foundation)
3.Provides the equivalent cooling effect of ten room-size air conditioners operating 20 hours a day (U.S. Department of Agriculture)
4.Provides an estimated $273 of environmental benefits in every year of its life (American Forests)
We work directly with youth volunteers, including those who are at-risk and disadvantaged, throughout North America and Africa and can help you be part of the solution to global warming. We award a $500 educational scholarship each year to the winner of our Apprentice Ecologist Awards.
Officially recognized by the U.S. EPA, the Apprentice Ecologist Initiative™, our youth-based volunteer program, allows us to plant native trees at a size where they can quickly mature into large adult trees and become part of the native forested landscape. We have had great success in engaging youth volunteers (from large urban areas to small rural villages) in these tree-planting projects, which helps us keep costs to an absolute minimum. Native trees planted in North America and Africa only a few years ago are now over 7 meters (23 feet) tall!
Global Warming Fast Facts 2
The report, based on the work of some 2,500 scientists in more than 130 countries, concluded that humans have caused all or most of the current planetary warming. Human-caused global warming is often called anthropogenic climate change.
RELATED
Global Warming: How Hot? How Soon? Global Warming Can Be Stopped, World Climate Experts Say Global Warming Interactive: Learn About Its Causes and Effects • Industrialization, deforestation, and pollution have greatly increased atmospheric concentrations of water vapor, carbon dioxide, methane, and nitrous oxide, all greenhouse gases that help trap heat near Earth's surface. (See an interactive feature on how global warming works.)
• Humans are pouring carbon dioxide into the atmosphere much faster than plants and oceans can absorb it.
• These gases persist in the atmosphere for years, meaning that even if such emissions were eliminated today, it would not immediately stop global warming.
• Some experts point out that natural cycles in Earth's orbit can alter the planet's exposure to sunlight, which may explain the current trend. Earth has indeed experienced warming and cooling cycles roughly every hundred thousand years due to these orbital shifts, but such changes have occurred over the span of several centuries. Today's changes have taken place over the past hundred years or less.
• Other recent research has suggested that the effects of variations in the sun's output are "negligible" as a factor in warming, but other, more complicated solar mechanisms could possibly play a role.
What's Going to Happen?
A follow-up report by the IPCC released in April 2007 warned that global warming could lead to large-scale food and water shortages and have catastrophic effects on wildlife.
• Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by century's end, the IPCC's February 2007 report projects. Rises of just 4 inches (10 centimeters) could flood many South Seas islands and swamp large parts of Southeast Asia.
• Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world's population is concentrated in vulnerable coastal cities. In the U.S., Louisiana and Florida are especially at risk.
• Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water.
• Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world. The growth of deserts may also cause food shortages in many places.
• More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.
• The ocean's circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.
• At some point in the future, warming could become uncontrollable by creating a so-called positive feedback effect. Rising temperatures could release additional greenhouse gases by unlocking methane in permafrost and undersea deposits, freeing carbon trapped in sea ice, and causing increased evaporation of water.
What is Climategate?
In late November 2009, hackers unearthed hundreds of emails at the U.K.'s University of East Anglia that exposed private conversations among top-level British and U.S. climate scientists discussing whether certain data should be released to the public. [Do we know who the hackers were? Were they skeptics? Might be worth noting]
The email exchanges also refer to statistical tricks used to illustrate climate change? trends, and call climate skeptics idiots, according to the New York Times.
One such trick was used to create the well-known hockey-stick graph, which shows a sharp uptick in temperature increases during the 20th century. Former U.S vice president Al Gore relied heavily on the graph as evidence of human-caused climate change in the documentary An Inconvenient Truth.
The data used for this graph come from two sources: thermostat readings and tree-ring samples.
While thermostat readings have consistently shown a temperature rise over the past hundred years, tree-ring samples show temperature increases stalling around 1960.
On the hockey-stick graph, thermostat-only data is grafted onto data that incorporates both thermostat and tree-ring readings, essentially presenting a seamless picture of two different data sets, the hacked emails revealed.
But scientists argue that dropping the tree-ring data was no secret and has been written about in the scientific literature for years.
Climate change skeptics have heralded the emails as an attempt to fool the public, according to the Times.
Yet climate scientists maintain that these controversial points are small blips that are inevitable in scientific research, and that the evidence for human-induced climate change is much broader and still widely accepted.
RELATED
Global Warming: How Hot? How Soon? Global Warming Can Be Stopped, World Climate Experts Say Global Warming Interactive: Learn About Its Causes and Effects • Industrialization, deforestation, and pollution have greatly increased atmospheric concentrations of water vapor, carbon dioxide, methane, and nitrous oxide, all greenhouse gases that help trap heat near Earth's surface. (See an interactive feature on how global warming works.)
• Humans are pouring carbon dioxide into the atmosphere much faster than plants and oceans can absorb it.
• These gases persist in the atmosphere for years, meaning that even if such emissions were eliminated today, it would not immediately stop global warming.
• Some experts point out that natural cycles in Earth's orbit can alter the planet's exposure to sunlight, which may explain the current trend. Earth has indeed experienced warming and cooling cycles roughly every hundred thousand years due to these orbital shifts, but such changes have occurred over the span of several centuries. Today's changes have taken place over the past hundred years or less.
• Other recent research has suggested that the effects of variations in the sun's output are "negligible" as a factor in warming, but other, more complicated solar mechanisms could possibly play a role.
What's Going to Happen?
A follow-up report by the IPCC released in April 2007 warned that global warming could lead to large-scale food and water shortages and have catastrophic effects on wildlife.
• Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by century's end, the IPCC's February 2007 report projects. Rises of just 4 inches (10 centimeters) could flood many South Seas islands and swamp large parts of Southeast Asia.
• Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world's population is concentrated in vulnerable coastal cities. In the U.S., Louisiana and Florida are especially at risk.
• Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water.
• Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world. The growth of deserts may also cause food shortages in many places.
• More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.
• The ocean's circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.
• At some point in the future, warming could become uncontrollable by creating a so-called positive feedback effect. Rising temperatures could release additional greenhouse gases by unlocking methane in permafrost and undersea deposits, freeing carbon trapped in sea ice, and causing increased evaporation of water.
What is Climategate?
In late November 2009, hackers unearthed hundreds of emails at the U.K.'s University of East Anglia that exposed private conversations among top-level British and U.S. climate scientists discussing whether certain data should be released to the public. [Do we know who the hackers were? Were they skeptics? Might be worth noting]
The email exchanges also refer to statistical tricks used to illustrate climate change? trends, and call climate skeptics idiots, according to the New York Times.
One such trick was used to create the well-known hockey-stick graph, which shows a sharp uptick in temperature increases during the 20th century. Former U.S vice president Al Gore relied heavily on the graph as evidence of human-caused climate change in the documentary An Inconvenient Truth.
The data used for this graph come from two sources: thermostat readings and tree-ring samples.
While thermostat readings have consistently shown a temperature rise over the past hundred years, tree-ring samples show temperature increases stalling around 1960.
On the hockey-stick graph, thermostat-only data is grafted onto data that incorporates both thermostat and tree-ring readings, essentially presenting a seamless picture of two different data sets, the hacked emails revealed.
But scientists argue that dropping the tree-ring data was no secret and has been written about in the scientific literature for years.
Climate change skeptics have heralded the emails as an attempt to fool the public, according to the Times.
Yet climate scientists maintain that these controversial points are small blips that are inevitable in scientific research, and that the evidence for human-induced climate change is much broader and still widely accepted.
Global Warming Fast Facts 1
Global warming, or climate change, is a subject that shows no sign of cooling down.
Here's the lowdown on why it's happening, what's causing it, and how it might change the planet.
RELATED
Global Warming: How Hot? How Soon? Global Warming Can Be Stopped, World Climate Experts Say Global Warming Interactive: Learn About Its Causes and Effects Is It Happening?
Yes. Earth is already showing many signs of worldwide climate change.
• Average temperatures have climbed 1.4 degrees Fahrenheit (0.8 degree Celsius) around the world since 1880, much of this in recent decades, according to NASA's Goddard Institute for Space Studies.
• The rate of warming is increasing. The 20th century's last two decades were the hottest in 400 years and possibly the warmest for several millennia, according to a number of climate studies. And the United Nations' Intergovernmental Panel on Climate Change (IPCC) reports that 11 of the past 12 years are among the dozen warmest since 1850.
• The Arctic is feeling the effects the most. Average temperatures in Alaska, western Canada, and eastern Russia have risen at twice the global average, according to the multinational Arctic Climate Impact Assessment report compiled between 2000 and 2004.
• Arctic ice is rapidly disappearing, and the region may have its first completely ice-free summer by 2040 or earlier. Polar bears and indigenous cultures are already suffering from the sea-ice loss.
• Glaciers and mountain snows are rapidly melting—for example, Montana's Glacier National Park now has only 27 glaciers, versus 150 in 1910. In the Northern Hemisphere, thaws also come a week earlier in spring and freezes begin a week later.
• Coral reefs, which are highly sensitive to small changes in water temperature, suffered the worst bleaching—or die-off in response to stress—ever recorded in 1998, with some areas seeing bleach rates of 70 percent. Experts expect these sorts of events to increase in frequency and intensity in the next 50 years as sea temperatures rise.
• An upsurge in the amount of extreme weather events, such as wildfires, heat waves, and strong tropical storms, is also attributed in part to climate change by some experts.
Here's the lowdown on why it's happening, what's causing it, and how it might change the planet.
RELATED
Global Warming: How Hot? How Soon? Global Warming Can Be Stopped, World Climate Experts Say Global Warming Interactive: Learn About Its Causes and Effects Is It Happening?
Yes. Earth is already showing many signs of worldwide climate change.
• Average temperatures have climbed 1.4 degrees Fahrenheit (0.8 degree Celsius) around the world since 1880, much of this in recent decades, according to NASA's Goddard Institute for Space Studies.
• The rate of warming is increasing. The 20th century's last two decades were the hottest in 400 years and possibly the warmest for several millennia, according to a number of climate studies. And the United Nations' Intergovernmental Panel on Climate Change (IPCC) reports that 11 of the past 12 years are among the dozen warmest since 1850.
• The Arctic is feeling the effects the most. Average temperatures in Alaska, western Canada, and eastern Russia have risen at twice the global average, according to the multinational Arctic Climate Impact Assessment report compiled between 2000 and 2004.
• Arctic ice is rapidly disappearing, and the region may have its first completely ice-free summer by 2040 or earlier. Polar bears and indigenous cultures are already suffering from the sea-ice loss.
• Glaciers and mountain snows are rapidly melting—for example, Montana's Glacier National Park now has only 27 glaciers, versus 150 in 1910. In the Northern Hemisphere, thaws also come a week earlier in spring and freezes begin a week later.
• Coral reefs, which are highly sensitive to small changes in water temperature, suffered the worst bleaching—or die-off in response to stress—ever recorded in 1998, with some areas seeing bleach rates of 70 percent. Experts expect these sorts of events to increase in frequency and intensity in the next 50 years as sea temperatures rise.
• An upsurge in the amount of extreme weather events, such as wildfires, heat waves, and strong tropical storms, is also attributed in part to climate change by some experts.
9 Eylül 2011 Cuma
Divining Perry’s Meaning in ‘Galileo’ Remark
In one of the more curious moments in the Republican debate on Wednesday night, Gov. Rick Perry of Texas invoked 17th-century science in discussing his doubts about climate change. He cited the astronomer and philosopher Galileo Galilei — often called the father of modern science — in suggesting that the current thinking that climate change is a result of human activity could be overturned. “Galileo got outvoted for a spell,” he said.
On the surface, though, his example seemed to illustrate the opposite of the point that Mr. Perry might have been trying to make. Galileo, whose astronomical observations confirmed the Copernican theory that the Earth revolved around the Sun, was basing his assertions on empirical knowledge and faced opposition from the Roman Catholic Church, which supported the Ptolemaic view of an Earth-centered universe.
Mr. Perry, by contrast, has said repeatedly that he does not believe the empirical evidence compiled by scientists in support of climate change, but that he does adhere to faith-based principles.
Was Mr. Perry trying to depict Galileo as a maverick among scientific thinkers of his time? If so, the governor was wrong, says one historian who has studied the trial of Galileo.
“If Perry means to say that at some point some body of scientists said Galileo was wrong, that didn’t happen,” said the historian, Thomas F. Mayer, who teaches at Augustana College in Rock Island, Ill.
Galileo and Copernicus were long ago proved right, but even in Galileo’s day there were scientists who supported him, Dr. Mayer said. “His notions about science were not that far out there,” he said. “There were a lot of other scientists, especially in Rome, who more or less agreed with his scientific observations.”
Perhaps, then, Mr. Perry was referring to the church’s condemnation of Galileo for his views, in 1616, and its trial of him on charges of heresy, in 1633, in which Galileo was convicted and sentenced to house arrest. In that case he was “outvoted” not by other scientists but by church leaders.
But even the 1633 trial was not really about science, many historians say.
“I think it was motivated primarily by disobedience on Galileo’s part,” Dr. Mayer said. “That’s how the trial was construed by the people who conducted it.”
Mark Miner, a spokesman for the Perry campaign, said, “The governor was referring to vetting policies before implementing ideas that will result in job losses.” Mr. Miner did not elaborate.
In 1616, Galileo had been ordered to abandon his Copernican ideas. He violated the order in 1632 by publishing a book comparing the Copernican and Ptolemaic systems and laying out his case against the Earth-centered view. In October of that year he was ordered to appear before the Roman Inquisition.
Galileo’s disobedience also cost him a lot of scientific support, Dr. Mayer said, but again the objections had to do more with religion.
“The problems arose when he tried to fit his new observations and construction of them into interpretations of the Bible,” he said. “As a layman, he wasn’t allowed to do that. That cost him a lot of support from scientists who would ordinarily have backed him.”
On the surface, though, his example seemed to illustrate the opposite of the point that Mr. Perry might have been trying to make. Galileo, whose astronomical observations confirmed the Copernican theory that the Earth revolved around the Sun, was basing his assertions on empirical knowledge and faced opposition from the Roman Catholic Church, which supported the Ptolemaic view of an Earth-centered universe.
Mr. Perry, by contrast, has said repeatedly that he does not believe the empirical evidence compiled by scientists in support of climate change, but that he does adhere to faith-based principles.
Was Mr. Perry trying to depict Galileo as a maverick among scientific thinkers of his time? If so, the governor was wrong, says one historian who has studied the trial of Galileo.
“If Perry means to say that at some point some body of scientists said Galileo was wrong, that didn’t happen,” said the historian, Thomas F. Mayer, who teaches at Augustana College in Rock Island, Ill.
Galileo and Copernicus were long ago proved right, but even in Galileo’s day there were scientists who supported him, Dr. Mayer said. “His notions about science were not that far out there,” he said. “There were a lot of other scientists, especially in Rome, who more or less agreed with his scientific observations.”
Perhaps, then, Mr. Perry was referring to the church’s condemnation of Galileo for his views, in 1616, and its trial of him on charges of heresy, in 1633, in which Galileo was convicted and sentenced to house arrest. In that case he was “outvoted” not by other scientists but by church leaders.
But even the 1633 trial was not really about science, many historians say.
“I think it was motivated primarily by disobedience on Galileo’s part,” Dr. Mayer said. “That’s how the trial was construed by the people who conducted it.”
Mark Miner, a spokesman for the Perry campaign, said, “The governor was referring to vetting policies before implementing ideas that will result in job losses.” Mr. Miner did not elaborate.
In 1616, Galileo had been ordered to abandon his Copernican ideas. He violated the order in 1632 by publishing a book comparing the Copernican and Ptolemaic systems and laying out his case against the Earth-centered view. In October of that year he was ordered to appear before the Roman Inquisition.
Galileo’s disobedience also cost him a lot of scientific support, Dr. Mayer said, but again the objections had to do more with religion.
“The problems arose when he tried to fit his new observations and construction of them into interpretations of the Bible,” he said. “As a layman, he wasn’t allowed to do that. That cost him a lot of support from scientists who would ordinarily have backed him.”
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