In 2004, a group of experts on various global crises teamed up with the world's best economists to talk about saving lives. The idea was this: if you're going to spend $50 billion per annum on foreign aid (and we know you are), then try to spend it wisely. $50 billion, while a lot of money, is still a scarce resource. The team, known as the Copenhagen Consensus, made a priority list of global crises they thought could reasonably be tackled with finite resources.

The economics behind such global prioritization is an imperfect science. But the team concluded HIV/AIDS was the best investment in helping people - and Global Warming, the worst (out of 10 crises). Ironically, these are the two issues on the G8 docket. Politicians would do well to learn the lessons of opportunity costs and risk analysis before they continue throwing around the world's money as they have - with little positive results - since Bretton Woods. Indeed, the call for "doubling" foreign aid should be tempered by a view to spending the current aid totals where they'll do the most good.