Greg Laden's Blog

One item is just published in the Journal of Climate. Simply put, the use of some very sophisticated and probably quite trustworthy models suggests that extratropical cyclones (so this means winter storms and such, mainly) will have a good deal more precipitation in them.

In the model ...

... There is a small reduction in the number of cyclones but no significant changes in the extremes of wind and vorticity in both hemispheres. ... The largest changes are in the total precipitation, where a significant increase is seen. Cumulative precipitation along the tracks of the cyclones increases by some 11% per track ... while the extreme precipitation is close to ... (some 27%).

In another study not available to me but coming out in the same journal in a few days, the overall effects of climate change are predicted to be much worse than previously thought.

This is based on MIT's Integrated Global Systems Model, which is a computer simulation of both global economic activity and climatic systems. This mega-simulation was run 400 times using slight variations in input parameters. According to a press release:

The new projections... indicate a median probability of surface warming of 5.2 degrees Celsius by 2100, with a 90% probability range of 3.5 to 7.4 degrees. This can be compared to a median projected increase in the [previous major study, conducted in] 2003 ... of just 2.4 degrees. The difference is caused by several factors rather than any single big change. Among these are improved economic modeling and newer economic data showing less chance of low emissions than had been projected in the earlier scenarios. Other changes include accounting for the past masking of underlying warming by the cooling induced by 20th century volcanoes, and for emissions of soot, which can add to the warming effect. In addition, measurements of deep ocean temperature rises, which enable estimates of how fast heat and carbon dioxide are removed from the atmosphere and transferred to the ocean depths, imply lower transfer rates than previously estimated.