It turns out that [19th century] Bavaria kept remarkably comprehensive crime statistics - the most meticulous in Germany - and when laid out one on top of the other, there was a startlingly robust correlation between the amount of rain, the price of rye and the rate of property crime: they rose and fell together in lockstep.
[...] rainfall often has a surprisingly strong effect on violence
[...] The causes of any war are incredibly complex - or are they? The economists found that one of the most reliable predictors of civil war [in Africa during the 1980s or 1990s] is lack of rain.
[...] the predicted rise in temperature will increase the death rate for American men by 1.7 percent and for women by 0.4 percent.
[...] global warming would produce a net agricultural gain in the US, [some] states would be the big winners and [some] would be the big losers.
Source: Global warming could bring us together - By Stephen Dubner and Steven Levitt