Some supercomputers can do more than 12 trillion calculations a second! Click on image for full size (55 Kb) Courtesy of UCAR Digital Image Library

To figure out the future of climate change, scientists need tools to measure how Earth responds to change. Some of these tools are global climate models. Using models, scientists can better understand how the Earth works and how it will react to change in the future.

Global climate models (GCMs) use math to describe how the Earth works. Supercomputers are needed to run large global climate models. These speedy computers can sometimes do more than 80 million math problems in an hour.

Climate models usually try to take into account all the parts of the Earth system including:

• The animals and plants (the biosphere)
• The oceans, lakes, and rivers (the hydrosphere)
• Icebergs, glaciers and ice sheets (the cryosphere)
• Air (the atmosphere)
• Volcanoes and moving continents (the geosphere)

• What Is a Climate Model?
• How Climate Models Work
• Accuracy and Uncertainty in Climate Models

What will the next century bring? According to scientists, it is likely that temperatures will rise 1.8 to 4.0°C (3.1 to 7.2°F) in the next 100 years if we continue to let more greenhouse gases loose in the atmosphere. A smaller amount of warming (0.6°C or 1.0 °F) over the past century has caused disruptions to the planet. So, more warming over the next century would likely cause many more changes to Earth.