Shop Windows to the Universe

Warnings: The True Story of How Science Tamed the Weather by Mike Smith tells the story of our storm warning system. See our online store book collection.
What’s in a global climate model? The Community Climate System Model (CCSM version 3) that is run with the supercomputer at the National Center for Atmospheric Research incorporates data about all of the natural processes shown in this diagram to simulate Earth’s complex climate system.
Click on image for full size
UCAR

What Is a Climate Model?

Global climate models (GCMs) use math - alot of math - to describe how the atmosphere, the oceans, the land, living things, ice, and energy from the Sun affect each other and Earth's climate. Thousands of climate researchers use global climate models to better understand how global changes such as increasing greenhouses gases or decreasing Arctic sea ice will affect the Earth. The models are used to look hundreds of years into the future, so that we can predict how our planet’s climate will likely change.

There are various types of climate models. Some focus on certain things that affect climate such as the atmosphere or the oceans. Models that look at few variables of the climate system may be simple enough to run on a personal computer. Other models take into account many factors of the atmosphere, biosphere, geosphere, hydrosphere, and cryosphere to model the entire Earth system. They take into account the interactions and feedbacks between these different parts of the planet. Earth is a complex place and so many of these models are very complex too. They include so many math calculations that they must be run on supercomputers, which can do the calculations quickly. All climate models must make some assumptions about how the Earth works, but in general, the more complex a model, the more factors it takes into account, and the fewer assumptions it makes. At the National Center for Atmospheric Research (NCAR), researchers work with complex models of the Earth's climate system. Their Community Climate System Model is so complex that it requires about three trillion math calculations to simulate a single day on planet Earth. It can take thousands of hours for the supercomputer to run the model. The model output, typically many gigabytes large, is analyzed by researchers and compared with other model results and with observations and measurement data.

There are currently several other complex global climate models that are used to predict future climatic change. The most robust models are compared by the IPCC (Intergovernmental Panel on Climate Change) as they summarize predictions about future climate change.

Last modified July 18, 2007 by Lisa Gardiner.

Shop Windows to the Universe Science Store!

Cool It! is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store.

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

The Cryosphere

Frozen water is found in many different places on Earth. Snow blankets the ground at mid and high latitudes during winter. Sea ice and icebergs float in the chilly waters of polar oceans. Ice shelves fringe...more

Earth's Greenhouse Gases

Even though only a tiny amount of the gases in Earth’s atmosphere are greenhouse gases, they have a huge effect on climate. There are several different types of greenhouse gases. The major ones are carbon...more

Ice-Albedo Feedback: How Melting Ice Causes More Ice to Melt

The sea ice that floats on the Arctic Ocean is covered with snow all winter. The snow-covered ice is bright white so it absorbs very little of the solar energy that gets to it. And during the Arctic winter,...more

What Is Climate?

The climate where you live is called regional climate. It is the average weather in a place over more than thirty years. To describe the regional climate of a place, people often tell what the temperatures...more

Global Warming: Scientists Say Earth Is Heating Up

Earth’s climate is warming. During the 20th Century Earth’s average temperature rose 0.6° Celsius (1.1°F). Scientists are finding that the change in temperature has been causing other aspects of our planet...more

Accuracy and Uncertainty in Climate Models

Global climate models are used to predict what will happen to Earth’s climate in the future. Groups like the Intergovernmental Panel on Climate Change (the IPCC) compare the results from several different...more

Using Computers for Science

In the last decades, computers have become a normal part of life. They are used to send e-mail, write a school report or look up recipes. They are used to keep track of the balance in your bank account....more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA