THE OTHER DAY, I was moving some paperback books off a shelf when down toppled An Inquiry into the Human Prospect by Robert L. Heilbroner, one of the gloomy tomes I read as an undergraduate at Boston College.

If memory serves, Mr. Heilbroner didn’t think the prospect of human survival was very good, what with shorter growing seasons and exploding population numbers. Back then, we were alarmed about “global cooling” — the terrifying, imminent approach of a new ice age. The Great Blizzard of 1978 — which my somewhat inebriated classmates celebrated by leaping from our fourth-floor dorm windows into giant snowdrifts — only confirmed the fears of many.

Time magazine warned of impending doom when I was still in high school: “Telltale signs are everywhere — from the unexpected persistence and thickness of pack ice in the waters around Iceland to the southward migration of a warmth-loving creature like the armadillo. Since the 1940s the mean global temperature has dropped about 2.7 degrees F.”

Oh no! Talk about a frosty future!

Well, 30 years later, I am happy to report that the armadillos and I survived the ice age.

Which may be why I think a degree of skepticism is in order about some of the more extreme claims about global warming, even as Al Gore collects his Nobel prize for whipping up a fair amount of hysteria, some unfounded. A British court, recently reviewing whether the Gore documentary An Inconvenient Truth should be shown in public schools, identified 11 major inaccuracies in the movie.

Like most people who think about the matter, I assume that humans are helping to drive up global temperatures at an unprecedented rate through putting vast amounts of CO{-2} in the atmosphere, thanks in large part to the burning of fossil fuels — and that it would be a very good idea to wean ourselves off such energy. But I am not enough of an expert to wish to shut up all scientists and analysts who challenge my assumption.

Some, for example, argue that solar activity has a much greater effect on global warming than the small percentage of CO{-2} produced by human activity. That would account for what seems to be global warming on Mars. Others maintain that high CO{-2} levels in the atmosphere have always followed periods of warming rather than caused the warming.

There is the little problem that temperatures have always fluctuated on earth, even before the dawn of SUVs. Between 900 and 1200, the Medieval Warm Period, mean temperatures were much warmer than today’s, letting the Vikings colonize such places as Greenland — inhospitable now, but in that age apparently deserving of its name. Somehow, man survived those hot times.

There are questions about the accuracy of our temperature readings — the basis for today’s alarm. If collected in or near urban centers, the readings may measure development as well as climate change, since cities replace vegetation with asphalt, cement and brick, driving up temperatures by several degrees (the “urban-heat island”).

There are inconvenient truths about nature that the alarmists often ignore. Much is made of the shrinking Arctic ice cap, for example, while little attention is paid the expanding Antarctic ice cap, now apparently record size.

Finally, we cannot even accurately predict next week’s snowfall, never mind temperatures 100 years from today.

Climate science, in short, is incredibly complex stuff, and it would seem that a fair degree of humility and openmindedness would be called for in approaching the subject. Instead, those in Al Gore’s camp often sound like members of a fundamentalist sect, who try to intimidate into silence anyone they deem to be advancing heretical notions, branding them liars, reprobates, “deniers” or worse.

I don’t know about you, but the bullying approach rarely increases my confidence in the strength of someone’s argument.

One of the people driving the fundamentalists nuts is Danish author Bjorn Lomborg, notwithstanding that he is a True Believer himself (“Global warming is real and man-made,” he writes). Mr. Lomborg, who once headed Denmark’s Environmental Assessment Institute, argues in his new book Cool It (Knopf, $21) that alarmism and emotionalism, global treaties and energy rationing are not the best ways to deal with the problem.

Mr. Lomborg contends that, rather than strangling economic growth with costly “solutions” that will do little to alter CO{-2} emissions, the world would be much better off using its wealth to fight AIDS, malaria, malnutrition and poverty, while radically increasing research and development of fossil-fuel alternatives.

He dares to note such politically incorrect facts as that far more people die from cold than from heat; that the number of polar bears (the poster children of the alarmists) is actually growing, and that hunting presents a far greater threat to them than warming; and that the United Nations estimates that sea levels will rise by only about 5 inches by 2050, no more than what we have experienced since 1940 — and a small fraction of the 20 feet that Al Gore projects by the end of the century.

Is Mr. Lomborg’s approach the correct one? I’m not sure, but I’m glad someone is out there raising these questions. It would be nice if free and unfettered discussion, information and reason — rather than lock-step allegiance to an excessively apocalyptic vision — shaped our decisions about this highly complicated problem.

Edward Achorn is The Journal’s deputy editorial-pages editor ( eachorn@projo.com).