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Figure 3-2 



Yearly Modeling Sequence 



Atmospheric 

 Composition 



Other 



Climate 



Forcings 



— > 



Temperature 

 Change 



— > 



Thermal 

 Expansion 



Snow/Ice 

 Transfer 

 To Sea 



— > 



Global Sea 

 Level Rise 



Atmospheric Composition 



Projecting changes in the atmospheric concentrations of 

 CC>2 and other greenhouse gases required projecting emissions of 

 these gases and their fate as a result of atmospheric chemistry 

 and other biogeochemical cycles that can create and destroy 

 them or remove them from the air. In general, only a percentage 

 of the emissions of each gas is retained in the atmosphere in 

 a chemical form that absorbs infrared radiation. 



Estimating future CO2 emissions required estimating future 

 economic growth and fuel use. Because economic growth is 

 determined by the rate of population increase, productivity 

 growth, and technological change, it was necessary to make 

 assumptions about each of these factors and to integrate them 

 in a consistent manner. 



