Global Warming
Global warming is caused primarily by carbon dioxide from burning coal, oil and gas.
Certain gases that trap heat are building up in Earth's atmosphere. The primary culprit is carbon dioxide, released from burning coal, oil and natural gas in power plants, cars, factories, etc. (and to a lesser extent when forests are cleared). The second is methane, released from rice paddies, both ends of cows, rotting garbage in landfills, mining operations, and gas pipelines. Third are chlorofluorocarbons (CFCs) and similar chemicals, which are also implicated in the separate problem of ozone depletion (see #5 below). Nitrous oxide (from fertilizers and other chemicals) is fourth.
#2 Earth's average temperature has risen about 1 degree F in the past 100 years and is projected to rise another 3 to 10 degrees F in the next 100 years.
While Earth's climate has changed naturally throughout time, the current rate of change due to human activity is unprecedented during at least the last 10,000 years. The projected range of temperature rise is wide because it includes a variety of possible future conditions, such as whether or not we control greenhouse gas emissions and different ways the climate system might respond. Temperatures over the US are expected to rise more than over the globe as a whole because land areas closer to the poles are projected to warm faster than those nearer the equator.
#3 There is scientific consensus that global warming is real, is caused by human activities, and presents serious challenges.
Scientists working on this issue report that the observed global warming cannot be explained by natural variations such as changes in the sun's output or volcanic eruptions. The most authoritative source of information is the UN Intergovernmental Panel on Climate Change (IPCC) which draws upon the collective wisdom of many hundreds of scientists from around the world. The IPCC projects global temperature increases of 3 to 10 degrees F in the next 100 years and
Certain gases that trap heat are building up in Earth's atmosphere. The primary culprit is carbon dioxide, released from burning coal, oil and natural gas in power plants, cars, factories, etc. (and to a lesser extent when forests are cleared). The second is methane, released from rice paddies, both ends of cows, rotting garbage in landfills, mining operations, and gas pipelines. Third are chlorofluorocarbons (CFCs) and similar chemicals, which are also implicated in the separate problem of ozone depletion (see #5 below). Nitrous oxide (from fertilizers and other chemicals) is fourth.
#2 Earth's average temperature has risen about 1 degree F in the past 100 years and is projected to rise another 3 to 10 degrees F in the next 100 years.
While Earth's climate has changed naturally throughout time, the current rate of change due to human activity is unprecedented during at least the last 10,000 years. The projected range of temperature rise is wide because it includes a variety of possible future conditions, such as whether or not we control greenhouse gas emissions and different ways the climate system might respond. Temperatures over the US are expected to rise more than over the globe as a whole because land areas closer to the poles are projected to warm faster than those nearer the equator.
#3 There is scientific consensus that global warming is real, is caused by human activities, and presents serious challenges.
Scientists working on this issue report that the observed global warming cannot be explained by natural variations such as changes in the sun's output or volcanic eruptions. The most authoritative source of information is the UN Intergovernmental Panel on Climate Change (IPCC) which draws upon the collective wisdom of many hundreds of scientists from around the world. The IPCC projects global temperature increases of 3 to 10 degrees F in the next 100 years and