With the United Nation Climate Change Conference scheduled to convene later this month in Durban, South Africa, to consider a second commitment period to follow the Kyoto Protocol, it seemed like a good time to tune in on the global-warming controversy.

The Kyoto agreement was signed in 1997, took effect in 2005, and, of the 192 original signatories to it, only the US has declined to ratify it – the result of George W. Bush’s decision in the first few months of his administration.

There is no thornier international political issue ahead for the US, at least until the direction of the climatic trend is resolved, one way or the other, by stronger evidence.  In the short term, meaning the next few presidential election cycles, it makes the problems facing the Joint Select Committee on Deficit Reduction look easy.

For example, I don’t know a more interesting young writer on environmental economics than Gernot Wagner. He works for the Environmental Defense Fund:  that makes him a good source, but he is lost to journalism.  (That Austrian first name, he tells people, is pronounced like “juggernaut” without the “jug.”) When his book arrived, But Will the Planet Notice? How Smart Economics Can Save the World, I began reading immediately.

To begin with, Wagner is a Harvard-trained economist, so there’s a lucid account of what he learned there, from Robert Stavins, an authority on emissions agreements; Richard Zeckhauser, a bridge champion and expert on uncertainty; Martin Weitzman, who thinks scientists may be seriously underestimating the likelihood of massive global warming; Dale Jorgenson, an architect of green accounting; and textbook author and former chairman of George W. Bush’s Council of Economic Advisers N. Gregory Mankiw, with his Pigou Club.

Wagner also apprenticed for a time at the Financial Times, so there’s clear and often jaunty writing:  “[M]arkets are truly free only when everyone pays the full price for his or her actions. Anything else is socialism,” he wrote the other day in The New York Times. “We pollute too much because the atmosphere serves as a free Dumpster.”  Proposals to counteract the effect of greenhouse gases through “geo-engineering” – pump dust into the upper atmosphere, create artificial clouds – are schemes to “hack the planet.”

And he worked for Boston Consulting Group (“twenty somethings in suits, armed with spreadsheets, frequent flier miles and circles under their eyes”), so there is no shortage of confidence in what he says. Cloth bags at the grocery store, food grown close home, hybrid automobiles:  volunteerism may be a start, but only economists can devise measures that will change behavior on a broad scale.  From the accompanying material, which conveys :

The hope of mankind, and indeed of every living thing on the planet, is now in the hands of the masters of the dismal science. Fortunately, they’ve been there before albeit on a much smaller scale.  It was economists who solved acid rain in the 1990s, admittedly with a strong assist from a phalanx of lawyers and activists. Economists have helped get lead out of our gas, and they can explain why lobsters haven’t disappeared off the coast of New England, but tuna is on the verge of extinction.  More disquietingly, they can take the lessons of the financial crisis and model with greater accuracy than anyone else the likelihood of environmental catastrophe, and they can rationalize the abandonment of threatened species. They can also solve the climate crisis, if only we let them.

When I finished the book, I thought that somehow I had skipped the chapter on the science.  But when I looked back, it saw that it wasn’t there. Instead, various firm stipulations are scattered at intervals throughout the book – the situation is dire, and rapidly deteriorating, etc. Sure, Wagner says, there are aspects of climate instability that remain to be clarified, including a “teeny, tiny chance that the vast scientific consensus is missing something crucial.” Most of the uncertainties make prospects scarier, he says, not less so.  “Climate change is a serious threat to our planet and human welfare,” he writes. “Case closed.”

This was not entirely persuasive to me.  For one thing, I’ve been keeping one ear open to the Republican debates. For another, the editorial page of The Wall Street Journal doesn’t seem to accept the consensus view. Their most recent enthusiasm is for “the other climate theory,” that abnormal warming stems, not from greenhouse gases, but from an interaction of solar activity and cosmic rays, conjectured but not yet demonstrated. Then, too, the overall temperature of the earth by some measures (whatever that means) seems not to have increased since 1998; some skeptics think that means the problem has been exaggerated.  Finally, my own curiosity has been growing.  Giving the chiliastic fervor of the last few years, right and left, just how firm is the case?  So I went around to see my favorite climate change skeptic, Richard Lindzen, a climate scientist at MIT.

What about this “other theory,” I asked.  “It’s a red herring,” he replied.

According to Lindzen, the question still to be answered is, is warming taking place?  Climate is always changing, he says:  for small changes in climate, associated with tenths of a degree of global temperature anomaly, there is no need for any external cause.  The motions of the oceans, where the heat moves between deep layers and surfaces, conceivably could account for all the reported change since the nineteenth century.

But what about the unified data base created by the Berkeley Earth Surface Temperature Team?  By assembling 1.6 billion temperature measurements from 40,000 land-based weather stations over a couple of hundred years, the Berkeley team has performed an enormous public service:  the data are available to researchers around the world. Last month the team gingerly concluded that, since the mid-1950s, their data showed the land surfaces of the earth to have warmed by an average of 1.6 degrees Fahrenheit (0.9 Celsius), or just slightly more than the warming since 1950 calculated by the UN’s Intergovernmental Panel on Climate Change.

True, the measurements are incomplete: ocean temperatures, especially, are missing; so too are some satellite observations.  But Richard Muller, a University of California physicist who is scientific director of the Berkeley team (and author of Physics for Future Presidents: the Science behind the Headlines, wrote in “The Case against Global Warming Skepticism,” an op-ed in the WSJ (subscription required), “Global warming is real.”

Lindzen’s attitude:  wait a little longer and see. Of the Berkeley data, he had this to say: “Existing land based records of temperature, showing a small net warming since 1950, are probably correct (at least within the unreported uncertainty limits).  As to whether estimates over the oceans (which cover 70% of the earth) are reliable is left open.  Also, Muller’s results confirm the hiatus in warming since 1998.  While Muller carefully avoided any claims concerning attribution, even attribution is not the main issue.  What was left unsaid was that the observed warming is entirely consistent with there being very little problem.”  Last January, in “A Case against Precipitous Climate Action,” Lindzen wrote, “Wasting resources on symbolically fighting ever present climate change is no substitute for prudence.  Nor is the assumption that the earth’s climate reached a point of perfection in the middle of the twentieth century a sign of intelligence.”

Lindzen makes a number of subsidiary points, most of them recognizably economic. When an issue like global warming is around for twenty years, agendas develop to exploit the issue.  Academic politics tend to reinforce the authority of high-minded scientific reformers, especially where government funding is involved. Entrepreneurial politicians sign on. The issue may be exacerbated especially when powerful interest groups become involved. Goldman Sachs has been an enthusiastic supporter of cap-and-trade legislation, a market that would quickly trade trillions of dollars. The possibilities for corruption are enormous, Lindzen says:  consider the campaign for corn-based ethanol as a gasoline additive that has been conducted by Archer-Daniels-Midland, which has mainly driven large increases in the price of corn.

As a cautionary tale of science enlisted in the cause of politics, Lindzen cites the eugenics movement in the United States in the early twentieth century. Then, biologists enthusiastic about the rediscovery of Mendelian genetics in the early years of the twentieth century tumbled on the idea that feeblemindedness might stem from a single recessive gene. The implication was that better people could be bred as a matter of social policy; that imbeciles, criminals, paupers and those otherwise deemed unfit should be prevented from breeding. Charles Davenport, a Harvard University professor who became director of the Cold Spring Harbor Laboratory, was its foremost figure; Yale’s Irving Fisher was an early supporter.

Glib nonsense was taught to a couple generations of students in America’s leading universities. Occasional programs of forced sterilization sprung up. And when immigration came to the fore as a political issue in the 1920s, the eugenics movement in biology was ready to provide a “scientific” foundation.  The Immigration Restriction Act of 1924 was the result, Lindzen wrote in 1996 (in a provocative paper, “Science and Politics: Global Warming and Eugenics”). The statute stood for four decades, more than long enough to prevent the rescue of most of the victims of far more virulent experiments in social engineering in Europe during those years.

Overwrought?  Perhaps. But the connection between the bad science of eugenics and public policy deserves to be much better remembered than it ordinarily is. Lindzen’s arguments about the social structure of science deserve to be examined carefully. His continuing skepticism and that of a handful of other climate scientists’ part is one of those inconvenient facts that we are programmed to ignore.

Having said that, I must say that it still seems to me that the evidence of global warming, as interpreted by the great preponderance of well-informed scientists, is accumulating – not just those temperature data, but species migration, ice-melting patterns and, yes, even increasing incidents of extreme weather around the world. The danger may very well be real.  That’s why authorities like the Berkeley temperature project are so important. The fact that Muller’s team’s finding turned out to be so close to earlier work is evidence that previous researchers, as he put it,  “had truly been very careful in their work, despite their inability to convince some skeptics of that.”

“Begone, science,” writes Wagner in But Will the Planet Notice?, his mind made up as he plunges ahead with his plans to save the planet. I believe in economics, too, but I am on the lookout for just the opposite – more science, and more independent journalists whose skills are highly developed and whose minds are still not made up even after twenty years. Carl Bialik, the “Numbers Guy” columnist of the WSJ, did an especially good job on the Berkeley project last week (subscription required).  Meanwhile, plenty of excellent blogs by scientists, pro and con, have sprung up – a development promising more consensus eventually, not less. Where the fate of the earth is at stake, belief-producers such as Matt Ridley, Bill McKibben  and even Gernot Wagner will not do. Put me in Wait-and-Watch-Closely camp, especially where the science behind the Durban meeting is concerned.