There's something about the issue of climate change that prompts people to immediately head off to opposite sides of the room — with very few people congregating in the middle.

On Friday, the United Nations' Intergovernmental Panel on Climate Change will publish its first overview of climate science in six years. The report ought to strengthen the pragmatic middle. That's because we know pretty much what the report will say, because of extensive leaks of its contents.

Here is what it will mean and, not the least, what it won't tell you.

The panel's main message will be that global warming is real and mostly caused by man. But it will not support the alarmist predictions of global temperature rises by the end of the century of up to 9 degrees Fahrenheit.

Actual predictions will center around 1.8 F to 6.6 F.

Likewise, sea level rises of 3 feet to 6 feet are standard for alarmist rhetoric (not to mention Al Gore's 20 feet that in his movie inundated New York, Florida and San Francisco.) Yet, the panel estimates a much more manageable 1.5 feet to 2 feet by the end of the century.

For scale, the sea level rose about a foot in the past 150 years. That was no catastrophe.

The real problem for the climate panel is to explain why for the past 15 years to 20 years, while we have kept pumping out more CO2, thermometers have refused to budge.

This doesn't mean that there is not some global warming, but it likely means that temperature rises will be lower, not higher, than previous estimates. That fact makes alarmist scenarios ever more implausible.

Benefits of warming

This matters because it is the high temperature rises that are disconcerting. What the panel will not be emphasizing is that the moderate global warming that the world is experiencing is actually positive. An analysis of the major economic climate models shows that the global benefits of temperature rises of up to 3 F to 4 F outweigh the costs.

Look for instance at heat and cold deaths. Globally, and in almost all regions, many more people die from cold than heat. With increasing temperatures, fewer cold deaths will vastly outweigh extra heat deaths.

Likewise, CO2 fertilizes crops and will increase production more in temperate countries than it will slow down crop increases in tropical countries. It will lower heating costs more than it will increase cooling costs.

All these benefits are well-known to Americans. When people retire, they move to Florida, Arizona or California, but rarely Vermont.

Global warming will become a significant problem only toward the end of the century when, for instance, cooling costs begin to outweigh savings on heating, when heat effects on crops start to outweigh CO2 fertilization. One model estimates that global warming will become a net cost around the year 2075.

Ineffective solutions

Neither will the U.N. panel emphasize that the leading current solutions have almost no impact and at a very high cost.

The only major global climate policy is the European Union's 20/20 policy, which promises to cut CO2 emissions 20% by 2020. Even if the EU keeps that promise for the rest of the century, we won't be able to measure the temperature reduction by the end of the century. (Models estimate it at a trivial 0.1 F.) The cost, as estimated by the average of the major macroeconomic models, is $250 billion annually, or $20 trillion across the century. Paying $25 trillion to barely help the world in 100 years is a steep price.

And similar U.S. proposals, focusing on subsidies to wind turbines and solar power, have comparable and unaffordable costs and will unfortunately do just as little good.

The ugly truth about climate change is that unless we make green energy much cheaper, we (and especially the developing world, including China and India) will continue to use cheap fossil fuels. Right now, we spend billions of dollars on subsidies for inefficient feel-good solar panels. If we want to make a difference, we need instead to focus on research and development to drive down the price of the next generations of green energy.

We'll never succeed in making fossil fuels so expensive that nobody wants them. But we could innovate green energy to become so cheap, everybody wants it.



Bjørn Lomborg, an adjunct professor at the Copenhagen Business School, directs the Copenhagen Consensus Center. His new book is How Much have Global Problems Cost the World? A Scorecard from 1900 to 2050.