There's a scientific consensus, we're often told, that global warming is a problem—despite the opinion of qualified experts ranging from the <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Russian Academy of Sciences to the Alfred P. Sloan Professor of Meteorology at MIT that it isn't. Yet, even if those worried scientists are right, science can't tell us whether acting to prevent further global warming is worth the trouble. For that, we have to look to economics. And in that field there is a growing consensus that global warming is the least of our problems. This was underlined recently in Denmark, where The Economist magazine and Bjørn Lomborg, author of "The Skeptical Environmentalist," brought together eight of the world's leading economists, including three Nobel laureates, for the "Copenhagen Consensus" project. The consensus ranked four projects as representing very good value for money. They were new programs to prevent the spread of HIV/AIDS; reducing the prevalence of iron-deficiency anemia by means of food supplements; multilateral and unilateral abolition of tariffs and non-tariff barriers, together with the elimination of agricultural subsidies; and the control and treatment of malaria. The panel ranked all three suggestions for action concerning global climate change—an "optimal carbon tax," a "value-at-risk carbon tax," and the Kyoto Protocol—last among 17 project possibilities, and even termed these options "bad investments." This ranking backed up previous research that has shown that all the main suggestions for dealing with global warming would lead to economic disaster, slapping the world with a cost that would far exceed the benefit. A widely accepted 1999 study, for instance, found the cost of the Kyoto Protocol to be $220 billion in 1990 dollars, while providing only $95 billion in benefits. We are better off doing nothing. It is unfortunate that the world cannot currently alleviate all of its challenges. But with the world's limited resources, efficient spending is a critical aspect to accomplishing the greatest benefit globally. Wasting money on climate-change programs like the Kyoto Protocol is a misallocation of scarce resources that is at best negligent and at worst reckless. Environmental alarmism—including scientists emphasizing unlikely worst-case scenarios and Hollywood making up impossible catastrophes –merely moves us away from a rational, dispassionate assessment of the issues. There is no reason why a warmer world cannot remain an enlightened, rational world.