Intensity of hydrological cycles in warmer climates

The fact that the surface and tropospheric temperatures increase with increasing CO₂ has been well documented by numerical model simulations; however, less agreement is found for the changes in the intensity of precipitation and the hydrological cycle. Here, it is demonstrated that while both the radiative heating by increasing CO₂ and the resulting higher sea surface temperatures contribute to warm the atmosphere, they act against each other in changing the hydrological cycle. As a consequence, in a warmer climate forced by increasing CO₂ the intensity of the hydrological cycle can be either more or less intense depending upon the degree of surface warming.