Curiously, something that's rarely mentioned is that temperatures in Greenland were higher in 1941 than they are today. Or that melt rates around Ilulissat were faster in the early part of the past century, according to a new study. And while the delegations first fly into Kangerlussuaq, about 100 miles to the south, they all change planes to go straight to Ilulissat -- perhaps because the Kangerlussuaq glacier is inconveniently growing.

I point this out not to challenge the reality of global warming or the fact that it's caused in large part by humans, but because the discussion about climate change has turned into a nasty dustup, with one side arguing that we're headed for catastrophe and the other maintaining that it's all a hoax. I say that neither is right. It's wrong to deny the obvious: The Earth is warming, and we're causing it. But that's not the whole story, and predictions of impending disaster just don't stack up.

We have to rediscover the middle ground, where we can have a sensible conversation. We shouldn't ignore climate change or the policies that could attack it. But we should be honest about the shortcomings and costs of those policies, as well as the benefits.

Environmental groups say that the only way to deal with the effects of global warming is to make drastic cuts in carbon emissions -- a project that will cost the world trillions (the Kyoto Protocol alone would cost $180 billion annually). The research I've done over the last decade, beginning with my first book, "The Skeptical Environmentalist," has convinced me that this approach is unsound; it means spending an awful lot to achieve very little. Instead, we should be thinking creatively and pragmatically about how we could combat the much larger challenges facing our planet.

Nobody knows for certain how climate change will play out. But we should deal with the most widely accepted estimates. According to the United Nations' Intergovernmental Panel on Climate Change (IPCC), ocean levels will rise between half a foot and two feet, with the best expectation being about one foot, in this century, mainly because of water expanding as it warms. That's similar to what the world experienced in the past 150 years.

Some individuals and environmental organizations scoff that the IPCC has severely underestimated the melting of glaciers, especially in Greenland. In fact, the IPCC has factored in the likely melt-off from Greenland (contributing a bit over an inch to sea levels in this century) and Antarctica (which, because global warming also generally produces more precipitation, will actually accumulate ice rather than shedding it, making sea levels two inches lower by 2100). At the moment, people are alarmed by a dramatic increase in Greenland's melting. This high level seems transitory, but if sustained it would add three inches, instead of one, to the sea level rise by the end of the century.

A one-foot rise in sea level isn't a catastrophe, though it will pose a problem, particularly for small island nations. But let's remember that very little land was lost when sea levels rose last century. It costs relatively little to protect the land from rising tides: We can drain wetlands, build levees and divert waterways. As nations become richer and land becomes a scarcer commodity, this process makes ever more sense: Like our parents and grandparents, our generation will ensure that the water doesn't claim valuable land.

The IPCC tells us two things: If we focus on economic development and ignore global warming, we're likely to see a 13-inch rise in sea levels by 2100. If we focus instead on environmental concerns and, for instance, adopt the hefty cuts in carbon emissions many environmental groups promote, this could reduce the rise by about five inches. But cutting emissions comes at a cost: Everybody would be poorer in 2100. With less money around to protect land from the sea, cutting carbon emissions would mean that more dry land would be lost, especially in vulnerable regions such as Micronesia, Tuvalu, Vietnam, Bangladesh and the Maldives.

As sea levels rise, so will temperatures. It seems logical to expect more heat waves and therefore more deaths. But though this fact gets much less billing, rising temperatures will also reduce the number of cold spells. This is important because research shows that the cold is a much bigger killer than the heat. According to the first complete peer-reviewed survey of climate change's health effects, global warming will actually save lives. It's estimated that by 2050, global warming will cause almost 400,000 more heat-related deaths each year. But at the same time, 1.8 million fewer people will die from cold

Global warming will claim lives in another way: by increasing the number of people at risk of catching malaria by about 3 percent over this century. According to scientific models, implementing the Kyoto Protocol for the rest of this century would reduce the malaria risk by just 0.2 percent.

Wherever you look, the inescapable conclusion is the same: Reducing carbon emissions is not the best way to help the world. I don't point this out merely to be contrarian. We do need to fix global warming in the long run. But I'm frustrated at our blinkered focus on policies that won't achieve it.

In 1992, wealthy nations promised to cut emissions to 1990 levels by 2000. Instead, emissions grew by 12 percent. In 1997, they promised to cut emissions to about 5 percent below 1990 levels by 2010. Yet levels will likely be 25 percent higher than hoped for.

The Kyoto Protocol is set to expire in 2012. U.N. members will be negotiating its replacement in Copenhagen by the end of 2009. Politicians insist that the "next Kyoto" should be even tougher. But after two spectacular failures, we have to ask whether "let's try again, and this time let's aim for much higher reductions" is the right approach.

Even if the policymakers' earlier promises had been met, they would have done virtually no good, but would have cost us a small fortune. The climate models show that Kyoto would have postponed the effects of global warming by seven days by the end of the century. Even if the United States and Australia had signed on and everyone stuck to Kyoto for this entire century, we would postpone the effects of global warming by only five years.

Proponents of pacts such as Kyoto want us to spend enormous sums of money doing very little good for the planet a hundred years from now. We need to find a smarter way. The first step is to start focusing our resources on making carbon emissions cuts much easier.

The typical cost of cutting a ton of CO2is currently about $20. Yet, according to a wealth of scientific literature, the damage from a ton of carbon in the atmosphere is about $2. Spending $20 to do $2 worth of good is not smart policy. It may make you feel good, but it's not going to stop global warming.

We need to reduce the cost of cutting emissions from $20 a ton to, say, $2. That would mean that really helping the environment wouldn't just be the preserve of the rich but could be opened up to everyone else -- including China and India, which are expected to be the main emitters of the 21st century but have many more pressing issues to deal with first.

The way to achieve this is to dramatically increase spending on research and development of low-carbon energy. Ideally, every nation should commit to spending 0.05 percent of its gross domestic product exploring non-carbon-emitting energy technologies, be they wind, wave or solar power, or capturing CO2emissions from power plants. This spending could add up to about $25 billion per year but would still be seven times cheaper than the Kyoto Protocol and would increase global R&D tenfold. All nations would be involved, yet the richer ones would pay the larger share.

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?

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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."