This article on Celsias reports on the weird weather patterns seen all over the world in 2006 including the three days of winter (with snow) in the middle of summer in Melbourne last month. The author concludes with:

As the heat is turned up, the social and economic knock-on effects of these weather extremes will bring extreme reactions from the societies most effected by them. Rather than the century of peace people hoped for, expect a very rough ride.