Chill out.

We must accept that climate change is real and that we've helped cause it. There is no hoax. But neither is there a looming apocalypse.

To some people, cutting carbon emissions has become the answer, regardless of the question. Cutting emissions is said to be our "generational mission." But don't we want to implement the most efficient policies first?

Combating the real climate challenges facing the planet -- malaria, more heat deaths, declining polar bear populations -- often requires simpler, less glamorous policies than carbon cuts. We also need to remember that the 21st century will hold many other challenges, for which we need low-cost, durable solutions.

I formed the Copenhagen Consensus in 2004 so that some of the world's top economists could come together to ask not only where we can do good, but at what cost, and to rank the best things for the world to do first. The top priorities they've come up with are dealing with infectious diseases, malnutrition, agricultural research and first-world access to third-world agriculture. For less than a fifth of Kyoto's price tag, we could tackle all these issues.

Obviously we should also work on a long-term solution to climate change. Solving it will take the better part of a century and will require a political will spanning political parties, continents and generations. If we invest in research and development, we'll do some real good in the long run, rather than just making ourselves feel good today.

But embracing the best response to global warming is difficult in the midst of bitter fighting that shuts out sensible dialogue. So first, we really need to cool our debate.

Bjorn Lomborg, an adjunct professor

at the Copenhagen Business School,

is the author, most recently, of "Cool It:

The Skeptical Environmentalist's

Guide to Global Warming."