Emission scenarios developed by the Intergovernmental Panel on Climate Change (IPCC) contain a set of climate forcing factors that can be used for coupled ocean-atmosphere simulations of 20th, 21st and 22nd century climate. The forcing is given in terms of solar irradiance, volcanic aerosol optical depth, anthropogenic aerosols, and atmospheric concentrations of ozone, carbon dioxide, and other well mixed greenhouse gases.

The Intergovernmental Panel on Climate Change recommends modeling groups contributing to the IPCC Fourth Assessment Report (4AR) include the following scenarios of climate forcing:

• a "committed climate change" scenario with realistic 20th century forcing, followed by constant atmospheric concentrations from year 2000 to at least 2050
• a "750 ppm stabilization" scenario with realistic 20th century forcing, followed by atmospheric concentrations based on the IPCC's Special Report on Emissions Scenarios (SRES) scenario A1B for years 2000 - 2100, then extended with constant concentrations to at least 2200
• a "550 ppm stabilization" scenario with realistic 20th century forcing, followed by atmospheric concentrations based on SRES scenario B1 for years 2000 - 2100, then extended with constant concentrations to at least 2200
• a scenario with realistic 20th century forcing, followed by atmospheric concentrations based on SRES scenario A2 for years 2000 - 2100
• idealized scenarios in which atmospheric carbon dioxide (1) increases at the rate of 1% per year, and (2) is doubled or quadrupled and then held fixed until an equilibrium climate state is reached