It is wrong to believe that CO2-induced global warming will result in a temperature increase for all regions of the globe. The absence of desert conditions during greenhouse ages (a fact provided by the geological record that is poorly known outside of geology circles) suggests that profound changes occur in sub-tropical latitudes due to CO2-induced global warming, which may in fact result in substantial cooling for this specific latitudinal range. Due to the dynamics of the Hadley cells, moisture is currently conveyed from sub-tropical (10ø to 30ø) to equatorial latitudes (0ø to 10ø), which explains why the former is mainly characterized by deserts while the latter hosts rain forest. Due to this, sub-tropical latitudes are currently much warmer than equatorial latitudes due to the greater cloud cover in the latter region, which allows less solar radiation to reach the ground.
Somehow (perhaps due to the establishment of a less steep vertical gradient in temperature, which would effectively change the dynamics of Hadley cells), moisture and heat become better distributed during greenhouse ages and sub-tropical deserts cease to exist. It is very likely that tropical storms would subside as well, as they are also the products of excessive heat in the dry, sub-tropical latitudes, whereas equatorial areas are devoid of them. The equatorial region is in effect a "shelter from the storm", as suggested by data compiled by the National Oceanic and Atmospheric Administration. In other words, although alarmist research on global warming pictures a greenhouse Earth as Dante’s Hell, the geological record rather presents it as a worldwide Garden of Eden, with no temperature extremes. (my emphasis)
Pierre Jutras is Associate Professor, Department of Geology, Saint Mary’s University, Halifax, Canada)