I was thinking about what happens when the ocean warms and gets a larger surface area, should this not lead to higher levels of evaporation of water? Seems like we will see higher levels of precipitation. But will that mean?
There are no good projections of what precipitation will look like on a regional basis, the IPCC 2007 report has some estimates but certainly cautions against using them as predictions.
More precipitation should mean more plant growth in many areas. It should mean the average humidity globally will be higher and this should be beneficial to plant growth as well. More plant growth means more carbon captured. The IPCC report indicates that soil moisture will increase in a number of crucial areas specifically the Sahel, northern China and the Steppes.
Higher precipitation will mean more clouds globally, this should mean a higher planetary albedo and less solar radiation reaching the earth. There are concerns about the implication to planetary albedo from an open ocean in the arctic, but would this not be offset by more cloud cover? I am working my way through the IPCC report section dealing with clouds and they are not ready yet to be able to apply the effects of increased clouds to the climate model. The system may be more resilient to change than we are projecting at the moment.
The increases projected for precipitation in 100 years is an increase in the 5% range. This may not sound like much, but many of the most important growing areas in the world are semi arid and the addition on average of one and a half centimeters per year could offer some very significant improvements to crop yields and reduce the need for irrigation.
The modelling for the future climate is still very rough in estimates and we are utterly unclear as to the implications of the changes to the climate. So much of the coverage about climate change is about the disaster scenarios, the Armageddon futures. It does not strike me that it will be apocalyptic in our future.