2016 Climate Trends Continue to Break Records

2016 Climate Trends Continue to Break Records Two key climate change indicators -- global surface temperatures and Arctic sea ice extent -- have broken numerous records through the first half of 2016, according to NASA analyses of ground-based observations and satellite data. Each of the first six months of 2016 set a record as the warmest respective month globally in the modern temperature record, which dates to 1880, according to scientists at NASA's Goddard Institute for Space Studies (GISS) in New York. The six-month period from January to June was also the planet's warmest half-year on record, with an average temperature 1.3 degrees Celsius (2.4 degrees Fahrenheit) warmer than the late nineteenth century. Each of the first six months of 2016 set a record as the warmest respective month globally in the modern temperature record, which dates to 1880. Meanwhile, five of the first six months set records for the smallest monthly Arctic sea ice extent since consistent satellite records began in 1979. This video is public domain and can be downloaded from the Scientific Visualization Studio. Five of the first six months of 2016 also set records for the smallest respective monthly Arctic sea ice extent since consistent satellite records began in 1979, according to analyses developed by scientists at NASA's Goddard Space Flight Center, in Greenbelt, Maryland. The one exception, March, recorded the second smallest extent for that month. While these two key climate indicators have broken records in 2016, NASA scientists said it is more significant that global temperature and Arctic sea ice are continuing their decades-long trends of change. Both trends are ultimately driven by rising concentrations of heat-trapping carbon dioxide and other greenhouse gases in the atmosphere. The extent of Arctic sea ice at the peak of the summer melt season now typically covers 40 percent less area than it did in the late 1970s and early 1980s. Arctic sea ice extent in September, the seasonal low point in the annual cycle, has been declining at a rate of 13.4 percent per decade. overhead view of sea ice showing brown sediments Chunks of sea ice, melt ponds and open water are all seen in this image captured at an altitude of 1,500 feet by the NASA's Digital Mapping System instrument during an Operation IceBridge flight over the Chukchi Sea on Saturday, July 16, 2016. Credits: NASA/Goddard/Operation IceBridge "While the El Niño event in the tropical Pacific this winter gave a boost to global temperatures from October onwards, it is the underlying trend which is producing these record numbers," GISS Director Gavin Schmidt said. Previous El Niño events have driven temperatures to what were then record levels, such as in 1998. But in 2016, even as the effects of the recent El Niño taper off, global temperatures have risen well beyond those of 18 years ago because of the overall warming that has taken place in that time. graph showing upward trend The first six months of 2016 were the warmest six-month period in NASA's modern temperature record, which dates to 1880. Credits: NASA/Goddard Institute for Space Studies The global trend in rising temperatures is outpaced by the regional warming in the Arctic, said Walt Meier, a sea ice scientist at NASA Goddard. "It has been a record year so far for global temperatures, but the record high temperatures in the Arctic over the past six months have been even more extreme," Meier said. "This warmth as well as unusual weather patterns have led to the record low sea ice extents so far this year." NASA tracks temperature and sea ice as part of its effort to understand the Earth as a system and to understand how Earth is changing. In addition to maintaining 19 Earth-observing space missions, NASA also sends researchers around the globe to investigate different facets of the planet at closer range. Right now, NASA researchers are working across the Arctic to better understand both the processes driving increased sea ice melt and the impacts of rising temperatures on Arctic ecosystems. NASA's long-running Operation IceBridge campaign last week began a series of airborne measurements of melt ponds on the surface of the Arctic sea ice cap. Melt ponds are shallow pools of water that form as ice melts. Their darker surface can absorb more sunlight and accelerate the melting process. IceBridge is flying out of Barrow, Alaska, during sea ice melt season to capture melt pond observations at a scale never before achieved. Recent studies have found that the formation of melt ponds early in the summer is a good predictor of the yearly minimum sea ice extent in September. "No one has ever, from a remote sensing standpoint, mapped the large-scale depth of melt ponds on sea ice," said Nathan Kurtz, IceBridge’s project scientist and a sea ice researcher at NASA Goddard. "The information we’ll collect is going to show how much water is retained in melt ponds and what kind of topography is needed on the sea ice to constrain them, which will help improve melt pond models." Operation IceBridge is a NASA airborne mission that has been flying multiple campaigns at both poles each year since 2009, with a goal of maintaining critical continuity of observations of sea ice and the ice sheets of Greenland and Antarctica. At the same time, NASA researchers began in earnest this year a nearly decade-long, multi-faceted field study of Arctic ecosystems in Alaska and Canada. The Arctic-Boreal Vulnerability Experiment (ABoVE) will study how forests, permafrost and other ecosystems are responding to rising temperatures in the Arctic, where climate change is unfolding faster than anywhere else on the planet. ABoVE consists of dozens individual experiments that over years will study the region's changing forests, the cycle of carbon movement between the atmosphere and land, thawing permafrost, the relationship between fire and climate change, and more. *when you free time you can check it some of free miniclip games and y8 free web based games sites.

new glimpse of melting under Antarctic glaciers

NASA's Earth Science News Team A view from Operation IceBridge's aircraft of Crosson Ice Shelf, foreground. Mt. Murphy is in the background. Credit: NASA/OIB/Michael Studinger. A view from Operation IceBridge's aircraft of Crosson Ice Shelf, foreground. Mt. Murphy is in the background. Credit: NASA/OIB/Michael Studinger. Two new studies by researchers at NASA and the University of California, Irvine (UCI), detect the fastest ongoing rates of glacier retreat ever observed in West Antarctica and offer an unprecedented direct view of intense ice melting from the floating undersides of glaciers. The results highlight how the interaction between ocean conditions and the bedrock beneath a glacier can influence the glacier's evolution, with implications for understanding future ice loss from Antarctica and global sea level rise. The two studies examined three neighboring glaciers in West Antarctica that are melting and retreating at different rates. Smith, Pope and Kohler glaciers flow into the Dotson and Crosson ice shelves in the Amundsen Sea Embayment in West Antarctica, the part of the continent with the largest loss of ice mass. A study led by Bernd Scheuchl of UCI, published in the journal Geophysical Research Letters on Aug. 28, used radar measurements from the European Space Agency’s Sentinel-1 satellite and data from the earlier ERS-1 and ERS-2 satellites to look at changes in the glaciers' grounding lines — the boundary where a glacier loses contact with bedrock and begins to float on the ocean. The grounding line is important because nearly all glacier melting takes place on the underside of the glacier's floating portion, called the ice shelf. If a glacier loses mass from enhanced melting, it may start floating farther inland from its former grounding line, just as a boat stuck on a sandbar may be able to float again if a heavy cargo is removed. This is called grounding line retreat. Flow speeds of Pope, Smith and Kohler glaciers. Flow speeds of Pope, Smith and Kohler glaciers. Credit: NASA/EO. Scheuchl's team found a rapid retreat of Smith Glacier's grounding line of 1.24 miles (2 kilometers) per year since 1996. Pope retreated more slowly at 0.31 mile (0.5 kilometer) per year since 1996. Kohler, which had retreated at a slower pace, actually readvanced a total of 1.24 miles (2 kilometers) since 2011. These differences motivated Ala Khazendar of NASA's Jet Propulsion Laboratory, Pasadena, California — a coauthor of Scheuchl's study — to measure the ice losses at the bottoms of the glaciers, which he suspected might be underlying the changes in their grounding lines. Khazendar’s study, published Oct. 25 in the journal Nature Communications, used measurements of changes in the thickness and height of the ice from radar and laser altimetry instruments flown by NASA's Operation IceBridge and earlier NASA airborne campaigns. Radar waves penetrate glaciers all the way to their base, allowing direct measurements of how the bottom profiles of the three glaciers at their grounding lines changed between 2002 and 2014. Laser signals reflect off the surface, so for the floating ice shelves, laser measurements of changes in surface elevation can be used to infer changes in ice thickness. Previous studies using other techniques estimated the average melting rates at the bottom of Dotson and Crosson ice shelves to be about 40 feet per year (12 meters per year). Khazendar and his team, using their direct radar measurements, found stunning rates of ice loss from the glaciers' undersides on the ocean sides of their grounding lines. The fastest-melting glacier, Smith, lost between 984 and 1,607 feet (300 and 490 meters) in thickness from 2002 to 2009 near its grounding line, or up to 230 feet per year (70 meters per year). Those years encompass a period when rapid increases in mass loss were observed around the Amundsen Sea region. The regional scale of the loss made scientists strongly suspect that an increase in the influx of ocean heat beneath the ice shelves must have taken place. "Our observations provide a crucial piece of evidence to support that suspicion, as they directly reveal the intensity of ice melting at the bottom of the glaciers during that period," Khazendar said. "If I had been using data from only one instrument, I wouldn’t have believed what I was looking at, because the thinning was so large,” Khazendar added. However, the two IceBridge instruments, which use different observational techniques, both measured the same rapid ice loss. Khazendar said Smith's fast retreat and thinning are likely related to the shape of the underlying bedrock over which it was retreating between 1996 and 2014, which sloped downward toward the continental interior, and oceanic conditions in the cavity beneath the glacier. As the grounding line retreated, warm and dense ocean water could reach the newly uncovered deeper parts of the cavity beneath the ice shelf, causing more melting. As a result, "More sections of the glacier become thinner and float, meaning that the grounding line continues retreating, and so on,” he said. The retreat of Smith might slow down as its grounding line has now reached bedrock that rises farther inland of the 2014 grounding line. Pope and Kohler, by contrast, are on bedrock that slopes upward toward the interior. The question remains whether other glaciers in West Antarctica will behave more like Smith Glacier or more like Pope and Kohler. Many glaciers in this sector of Antarctica are on beds that deepen farther inland, like Smith's. However, Khazendar and Scheuchl said researchers need more information on the shape of the bedrock and seafloor beneath the ice, as well as more data on ocean circulation and temperatures, to be able to better project how much ice these glaciers will contribute to the ocean in a changing climate. Scheuchl's study is titled "Grounding Line Retreat of Pope, Smith, and Kohler Glaciers, West Antarctica, Measured with Sentinel-1a Radar Interferometry Data." It was published in Geophysical Research Letters. Khazendar's paper, titled "Rapid Submarine Ice Melting in the Grounding Zones of Ice Shelves in West Antarctica," was published in Nature Communications. *when you free time you can check it some of free miniclip games and y8 free web based games sites.