I first encountered the strong case for global warming in the early 1970s in an Isaac Asimov science column. As an elementary school student, I merely nodded my head, assumed that America’s political leadership would address the danger, and moved on to an explanation of quarks.

Even in those days, the subject was hardly new. The Asimov column had originally run in the late 1950s, before I was even born, and the possibility that burning fossil fuels might raise the Earth’s temperature via the “Greenhouse Effect” had already been around for many decades, going back to the late 19th century. Whether it occurred in the real world was a different matter.

My next encounter with climate change came in the mid-1970s. Suddenly all the magazines and newspapers were filled with stories that scientists had determined that the world was on the brink of a new Ice Age, with global cooling about to devastate our civilization. I still recall Newsweek’s famous cover depicting an American street scene blanketed by an arctic blizzard. Although I wondered at how quickly warming had switched to cooling, I was in junior high and assumed that our scientists—and the media that presented them—knew what they were talking about. Fortunately, no glaciers appeared, and the topic was soon forgotten.

By the late 1970s, I had joined high-school debate, and one year the topic was the environment, with climate-related issues being the biggest sub-topic. So I diligently gathered vast quantities of highly credible evidence from noted scientific experts proclaiming the certainty of global warming, global cooling, both, or neither, and lugged them around in my evidence boxes to all the tournaments. Random lot would determine whether I persuasively argued that CO2 emissions would fry us to a crisp or whether solar blockage from particulate emissions would freeze us to an icicle, or whether perhaps the two effects would perfectly cancel out. Since debate tournaments often had four rounds, I might alternate my claims of glaciers growing and glaciers melting every hour or so, always backing my position with copious evidence from expert sources. I reluctantly concluded that climatology was merely a pseudoscience, at least compared to my own field of theoretical physics, and I was glad when the debate topic switched to foreign policy the following year.

I had almost forgotten about both warming and cooling when the unusually hot summer of 1988 stampeded our media and political elites into suddenly declaring that global warming was a proven reality. As I joked to my friends, going from Ice Age to oven in just a dozen years seemed a bit much, especially since both trends were allegedly decades or centuries long.

But as the years went by and more and more mainstream voices endorsed global warming, I began to assume it must be true because “everyone said so,” or at least everyone not subsidized by Exxon Mobil. For similar reasons, I later assumed that Saddam must have WMDs—at least of the chemical or biological variety—given the absolutely uniform proclamations of our mainstream media commentariat.

In that latter case, I eventually discovered that I—together with the entire American public—had fallen for a massive hoax, and this raised huge doubts about the credibility of the establishment media. But even so, I was quite shocked in 2007 to read a series of major Counterpunch columns by the late Alexander Cockburn denouncing global warming as the same sort of massive hoax, protected and promoted by the establishment media just like the Iraqi WMDs. Obviously Cockburn himself was no scientist, but those he quoted seemed to be, and more importantly, Big Oil probably didn’t own one of America’s foremost radical-left journalists.

So what is one to think? The scientific topic involved is complex and specialized, requiring years of academic study to properly comprehend. The experts seem divided, with nasty accusations of dishonesty and corruption flying in both directions. The mainstream media and our political elites seem overwhelmingly to favor one side, but given their recent track record, that almost constitutes a negative indicator. Tens of billions of dollars are at stake, so the volume of propaganda is enormous, and I would need hundreds of hours just to dip my toe into the topic. Therefore, my considered verdict is: I just don’t know.

But if I were prodded to take some position, I would focus on the simplest, clearest argument, the one least requiring expertise in complex atmospheric modeling or meteorological theories. Alex’s original April 28, 2007 column did just that.

As he explained, the early years of the Great Depression had seen worldwide industrial output drop by about one quarter, along with carbon emissions from coal, oil, and natural gas, requiring most of a decade to return to previous levels. Yet during these same years, there appears no significant change in the trends of rising CO2 or temperature. If enormous changes in human carbon output have negligible impact on the atmospheric trends of the global warming hypothesis, how can there be a causal connection?

This relates to another point made by Alex and also mentioned in the original Asimov column. The oceans contain perhaps 50 times more dissolved CO2 than is found in the atmosphere, and as our planet warms, evaporating seawater releases carbon dioxide. Is the increase of CO2 producing the warming or is it the other way around? He cited claims that over the last million or so years, changes in CO2 had always tended to lag the corresponding changes in temperature by many centuries, implying that CO2 was a consequence rather than a cause of the warming.

Five minutes spent with Google uncovers a vast wealth of articles debunking or supporting these simple claims, with endless data and citations all around. Can I effectively judge these competing arguments? Certainly not, and a dozen or more years ago I would have assumed that establishment opinion was probably correct, with the near-unanimous verdict of elite-media sources outweighing a few scattered figures mostly drawn from the political fringe. But that was before the Iraqi WMDs. And Bernie Madoff. And the housing bubble, and so many other revealed hoaxes and scandals that have so totally undermined the credibility of our official sources in almost everything. Consider that one of the strongest private-sector backers of global warming had been the Enron Corporation, up until the moment that it collapsed in the largest corporate fraud in history.

The tendency to attack dissent as heresy hardly engenders free and open debate. Just a couple of years after I read those Counterpunch columns, the New York Times Magazine ran a cover story on Freeman Dyson, one of the most brilliant physicists of his generation. He was labeled “The Civil Heretic” for his strong public skepticism on global warming theories. Given the recent track record of the Times and its peers, I’m half inclined to automatically favor the heretics.

Ron Unz is publisher of The American Conservative.