How Predictions Are Made

The climate models to which NASA refers are powerful computer programs used to simulate climate and predict future climate changes. Models can be used to simulate temperature changes that occur from both natural and anthropogenic causes. Scientists enter data on different conditions, such as atmospheric concentrations of greenhouse gases, ocean currents, cloud cover, energy from the sun, and ocean circulation, as well as others. Then, as they change and adjust the variables, they can simulate what might happen when actual climate conditions change. NASA compares climate models to the computer programs used by detectives to envision what missing persons would look like years after their disappearance. In the same way the detective programs are constructed on information about people's faces, climate models are constructed based on data that relate to the earth's climate.

There are many...