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.
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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.
