So the planet's warming? So what's so bad about that?
The question is trickier than it sounds, because in addition to being a noisy bit of the Climate Wars argy-bargy, it's a big source of uncertainty for policy makers trying to understand what sort of adaption will be required and what sort of mitigation should be undertaken.
The problem is that there's actually precious little data about how bad it really might be - where might crops whither and where might they prosper, and what's the net difference? Where might water supplies dwindle, and where might they increase?
This afternoon in Science Express, a team led by Dagmar Schröter at the Potsdam Institute for Climate Impact Research published a serious and useful look at the question for Europe, matching up climate models with economic scenarious to try to get a clearer picture of impacts over the next century. Especially significant was what they called "water stress," with lots of people living in places that in the future may not have enough water to support them the way they live today. Cropland declines significantly, and forest fires go up:
Among all European regions, the Mediterranean appeared most vulnerable to global change. Multiple potential impacts were projected, related primarily to increased temperatures and reduced precipitation. The impacts included water shortages, increased risk of forest fires, northward shifts in the distribution of typical tree species, and losses of agricultural potential. Mountain regions also seemed vulnerable because of a rise in the elevation of snow cover and altered river runoff regimes.