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. Nitrous oxide (from fertilizers and other chemicals) is fourth.
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.
Global warming is real and it’s mainly caused by human activities and presents serious challenges. Earth's climate has been warming at a rapid rate since the start of intensive use of coal and oil in the late 1800s. The ozone hole does not cause global warming. Global warming will have significant impacts on people and nature.
As temperatures continue to rise, precipitation is projected to come more frequently in the form of heavy downpours. We can probably expect more extreme wet and dry conditions. Plant and animal species will migrate or disappear in response to changes in climate. While global warming will have impacts on natural and human systems all around the world, the largest