WATERS WARS. Let me recommend Jon Margolis's fascinating piece on TAP Online about Canada's strange, and potentially untenable, refusal to export their fresh water. As Margolis writes, "Canada has 20 percent of all the world�s fresh water, to slake the thirsts and irrigate the crops of only 0.5 percent of the world�s population. [And] with the United Nations estimating that almost two-thirds of everybody, or almost 5.5 billion people, will face chronic water shortages by 2050," such protectiveness of their reserves will eventually appear cruel. Margolis focuses mostly on Canada's unwillingness to sell water to the profligate United States, but I'd be interested to know their position on dampening drought and quenching Third World thirst. And if you're interested in reading more on the issue, Brad Plumer has further context and commentary.

--Ezra Klein