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INTERPRETATION OF GISS RESULTS 

 by John S. Hoffman 

 The problems with interpreting the GISS model results 

 are twofold: 



1. The model looks at the effects of doubled CO2, while 

 a projection would require looking at the system in 

 transition from current CO2 levels, to the doubled 

 level and beyond. For the mid-range scenario, 

 temperatures reach 4.1°C in the GISS doubled equilibrium 

 run by 2050. A method needs to be developed to 

 determine melting before this doubling and after it. 



2. Melting in situ may not all run off. Some percentage 

 will refreeze, raising the temperature of the ice and 

 changing its physical characteristics. It is undetermined 

 at this time whether those changes cause ice discharges 

 greater than or less than if the melting had resulted 



in runoff. 

 These problems are now being analyzed by a team from GISS, 

 NASA, and Lamont-Doherty Geological Observatory, along with 

 several other issues. In the preceeding analysis the results 

 were used only to check the general validity of the numbers 

 developed through our procedure of extrapolating historical 

 ratios, rather than to generate an ice and snow land-to-sea 

 transfer scenario. 



