If you had $50 billion, how would you spend it to best help the world?  Well at the World Economic Forum in January, British Prime Minister Tony Blair said combating global warming would be his top priority.  But according to Courtney Knapp of the Mercatus Center, a different group of experts, including 3 Nobel Laureates, recently gathered for something called the Copenhagen Consensus, and said that addressing climate change is the least feasible and least cost-effective project on its list of top issues.  Since the panel found that just to reach Kyoto limits on emissions would cost 220 billion but provide less than half that in benefits, fighting HIV/AIDS and malaria should be the top global priority.