Climate models project 21st century global temperatures.
Roughly every six years, the United Nations' Intergovernmental Panel on Climate Change (IPCC) enlists hundreds of climate scientists worldwide in producing assessment reports. IPCC report authors rigorously evaluate the latest results from climate models run on supercomputers. Internationally, a few dozen modeling groups—including NASA’s Goddard Institute for Space Studies—contributed projections of 21st century climate to the current IPCC Fifth Assessment Report. The models simulated how Earth might respond to different scenarios of greenhouse gas emissions and reduction measures. Watch the video to see how global temperatures respond to the “business as usual” scenario, where carbon dioxide concentrations rise to 936 parts per million—more than double today's levels of 400 parts per million—by the year 2100.