Surface Temperatures
Figure 16 shows the surface-temperature change predicted by
the models for January for an equilibrium climate with a doubled CO2
atmosphere. Since a temperature difference is being plotted, a value of
zero indicates the model calculates no change in surface temperature with a
doubled CO2 atmosphere. The GISS model gives very large values of warming
for the enhanced greenhouse climate, with generally higher values at high
latitudes. The GFDL model produces results that are less severe and more
uniform over the domain. The OSU results also are less severe and do not
have such large values at high latitudes. A common feature of all models
is that they all agree that the result of increased CO2 is to produce a
warming that averages something on the order of about 4o C.
The July calculations given in Figure 17 are similar to the previous results in that all models produce a pattern of warming. There is less evidence of severe warming at high latitudes in the July results, and there is somewhat better agreement among the models in the values produced. The GFDL model tends to produce higher temperature changes than the others.