concentration in the atmosphere. The results from these six numerical 

 experiments indicate the climatic signatures of large COj changes in the 

 atmosphere and in the abyssal and surface waters of the ocean. As the COj 

 concentration in the model atmosphere increased from 1 to 8 times the normal 

 value, the meridional gradient of surface air temperature decreased, while 

 that of upper tropospheric temperature increased in agreement with the results 

 of earlier COj climate sensitivity studies. However, the intensity and 

 latitudinal placement of the atmospheric jet hardly changed. Despite the 

 reduction of meridional temperature gradient, the meridional density gradient 

 of water at the ocean surface changed little because of the increase of 

 thermal expansion coefficient of seawater with increasing temperature. Thus 

 the intensity of thermohaline circulation in the ocean model does not diminish 

 as expected in the range from 1 to 8 times the normal atmospheric COj 

 concentration. As was shown in an earlier study, the COj-induced changes in 

 the deep sea follow the change of sea surface temperature in high latitudes 

 and thus are much larger than the globally averaged changes of sea surface 

 temperature. The model predicts that the area mean rates of precipitation, 

 evaporation, and runoff increase with increasing CO2 concentration in the 

 atmosphere. The latitudes of the arid zone and the high surface pressure belt 

 in the subtropics are almost constant in the entire range of 1-8 times normal 

 CO,. In general, the climatic signature obtained from the model appears to be 

 consistent with a CO, hypothesis for the climatic changes in the Cenozoic with 

 the following exception: the tropical sea surface temperature in the model 

 has a small but significant increase with increasing atmospheric CO2 

 concentration, while tropical sea surface temperature as deduced from the 

 isotopic record appears to have no systematic trend during the Tertiary. It 

 is found that the climate corresponding to one -half normal COj is markedly 

 different from the normal and high CO, gases. Sea ice extends to middle 

 latitudes, and the thermohaline circulation in the model ocean loses its 

 intensity and is largely confined to an area between the sea ice margin and 

 the equator. The poleward heat transport by ocean currents is very small in 

 high latitudes, markedly reducing the surface air temperature there. It is 

 suggested that a similar process, which enhances the positive albedo feedback 

 effect of sea ice, played a key role in reducing surface air temperatures over 

 the North Atlantic during the last glacial maximum. (Authors). 



203 MARANTO, G. 1986. "Are We Close to the Road's End?" Discovery . 

 January, 1986, pp 28-50. 



The author interviewed a half-dozen leading climatologists and 

 scientists on the current research and theories on how CO2 may affect the 

 earth. Climatic consequences such as sea- level rise, greenhouse effect, and 

 glacial melting are also discussed. (Gorman). 



94 



