Earth's average temperature over the past 100 years is shown in the black line. Predictions of future warming are shown by the red, green, and purple lines. These predictions make different assumptions about how many greenhouse gases we release into the atmosphere in the future.
A Windows to the Universe image based on a graph from the IPCC 4th Assessment Report

Global Warming: Scientists Say Earth Is Heating Up

Earth’s climate is getting warmer. During the past 100 years Earth’s average temperature rose about 0.6° Celsius (1.0° F). Things that people are doing like burning fossil fuels, changing the way land is used, and farming, are a big part of the causes of global warming.

The air and oceans are warming. Snow and ice in Earth’s polar regions is melting. Sea level rises because of warmer oceans and the added water from melting glaciers and snow. Temperatures in the Arctic have risen twice as fast as the global average in the past century. The amount of rain and snow in different regions of the world has changed too. So have extreme weather events such as droughts, heat waves, and hurricanes.

According to computer models, more global warming is in our future. During the next hundred years computer models predict that Earth’s average temperature will rise between 1.8 and 4.0° Celsius (3.2° and 7.2° F) according to the Intergovernmental Panel on Climate Change (IPCC).

There are many ways to help slow down global warming. For example, many people and companies are trying to be "Carbon Neutral" to prevent more greenhouse gases from entering the atmosphere.

Last modified July 22, 2008 by Lisa Gardiner.

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