Types of Transient Simulations

• Pre-industrial climate: GHGs constant with time; run for 300+ years
• "Climate of the 20th Century": increase GHGs each year in accordance with recorded values of the 20th Century; insert known effects of volcanoes, fluctuations in output of the sun, recorded atmospheric concentrations of sulfate aerosols, and observed changes in land use.
• "Commitment runs": continue C20C through the 21st Century but with GHGs constant at current values to determine the warming we already are committed to.
• Future scenario runs: Extend C20C runs into 21st Century but with various projections of growth of GHG emissions.

The goal of these more expanded runs is to provide policy makers with a wider range of information on current status of warming we have created and future impacts of alternative ways of limiting greenhouse gas emissions.

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