Bjorgn Lomborg, Global priorities

Bjorn Lomborg isn't afraid to voice an unpopular opinion. He was named one of the 100 Most Influential People by Time magazine after the publication of his controversial book The Skeptical Environmentalist, which challenged widely held beliefs that the environment is getting worse. Now the Danish economist is taking on the world's biggest problems. In 2004, he convened the Copenhagen Consensus, which tries to prioritize the world's greatest challenges based on the impact we can make, a sort of bang-for-the-buck breakdown for attacking problems such as global warming, world poverty and disease.

It begins from the premise that we can't solve every problem in the world, and asks: Which ones should we fix first? The Copenhagen Consensus 2004 tapped the expertise of world-leading economists, as well as a diverse forum of young participants; collectively, they determined that control of HIV/AIDS was the best investment -- and mitigating global warming was the worst. Lomborg summarized these findings in How to Spend $50 Billion to Make the World a Better Place. The next Copenhagen Consensus is scheduled for spring 2008.