Montreal, July 2, 2006 • No 182




Bradley Doucet is a writer living in Montreal. He has studied philosophy and economics, and is currently completing a novel on the pursuit of happiness.




by Bradley Doucet

          A QL reader, Jason Henry, wrote in a couple of months ago wondering about the state of the global warming debate. He asks,

          Is there any new data that supports or refutes global warming? I had always thought it was hotly contested, but over the past year it seems that more and more people are taking it (global warming) as fact. At least that is how it appears in the papers. I hate the idea of being sucked into a phoney cause. Has anything radical happened in the last five years that would support global warming?

          While I am far from being a climate expert, I have been following the issue in the popular press for a few years now, and I have also noticed a shift in global warming coverage over the past 12 months. Let’s have a look at what has changed – and what hasn’t – in this important debate.


Change Is in the Air…

          Our planet is warmed by the greenhouse effect, by which certain gases, among them carbon dioxide (CO2), trap the sun’s heat in the atmosphere. This natural process is crucial to our survival. At issue in the ongoing debate is the anthropogenic greenhouse effect, which is to say the additional warming caused primarily by the release of extra CO2 into the atmosphere by human activity. Disentangling the signal of anthropogenic warming from the background noise in the data is difficult, but an article entitled “Changing Science” in the December 10th, 2005 issue of The Economist lists six reasons from the recent scientific literature for increased confidence that the signal is strong. Briefly, they are:

1) the continuation of the observed warming trend at the Earth’s surface;
2) continuing observations of an amplified warming trend in the Arctic;
3) the resolution of the inconsistency between, on the one hand, surface measurements indicating significant warming, and on the other, satellite and weather balloon measurements showing little or no warming in the lower atmosphere;
4) changes in the way the oceans have warmed over the past 65 years that match the predictions of anthropogenic greenhouse warming theory better than those of alternate theories;
5) an increase in intense hurricane activity which could be linked to the warming oceans; and
6) the faltering of ocean currents in the North Atlantic as predicted by climate models.

          Not all of these reasons appear equally convincing to me, but according to The Economist, together they provide increased confidence that global warming is indeed happening and that human activity is likely the main culprit. The third reason deserves some special attention as it has recently won over a prominent global warming skeptic, and one whom libertarians in particular may consider a credible source: Ronald Bailey, science correspondent for Reason magazine.

          This past May, in “Global Warming Data Sets Reconciled,” Bailey writes about the National Oceanic and Atmospheric Administration’s report which found that atmospheric data sets, when corrected for errors(1), were in fact consistent with man-made global warming caused primarily by the release of carbon dioxide from the burning of fossil fuels. In response to comments posted by readers who were surprised by his change of heart, Bailey writes,

          I've been reporting on and talking with climate scientists and actually reading long IPCC reports for over 20 years. […] it is true that my reporting on decades of environmentalist scares (overpopulation, synthetic chemical cancer epidemics, biotech run amok) is what inclined me toward the skeptical camp in the first place. All I asked for was evidence and I am now persuaded.


…But Let’s Not Get Carried Away

          So, according to these two sources at least, change does appear to be in the air, but we must be careful not to overstate the case. As the Economist article is quick to point out, there is still quite a lot of uncertainty. For one thing, some researchers maintain that increases in the sun’s output of heat, which is known to vary according to both short (11-year) and longer cycles, may be responsible for some significant part of observed warming. There is also uncertainty about the role of particulate pollution, and more generalized uncertainty due to “a lack of enough good-quality, long-term, internally consistent data.”

"While extreme warming would be overwhelmingly negative and should be avoided (if possible), moderate warming would entail not just costs, but significant benefits as well, such as the opening up of Arctic sea lanes and longer crop-growing seasons in places like Canada."

          In addition, the question of what, if anything, to do about the problem is still very much an open one. While extreme warming would be overwhelmingly negative and should be avoided (if possible), moderate warming would entail not just costs, but significant benefits as well, such as the opening up of Arctic sea lanes and longer crop-growing seasons in places like Canada (see "Canadian Opportunities from Global Warming" in this issue of QL). As the article states, “There is, to put it politely, a lively debate about how far the temperature can rise before things get really nasty and how much carbon dioxide would be needed to drive the process.”

          As for Ronald Bailey, in spite of his change of heart about the existence of significant anthropogenic global warming, he has hardly become a climate change alarmist. In his recent review of Al Gore’s new film, An Inconvenient Truth, Bailey points out several ways in which Gore exaggerates or distorts the science of global warming while claiming to be presenting the scientific consensus.

          For example, Gore claims that sea levels could rise by 20 feet by the year 2100, whereas Bailey points out that the UN’s Intergovernmental Panel on Climate Change – which one might think could be counted upon to represent the scientific consensus if anyone can – predicts that sea levels will rise between 4 and 35 inches by the year 2100. Gore also devotes some time to the plight of photogenic polar bears, but Bailey reminds us that Arctic temperatures were significantly warmer than they are now just 6000 years ago, and the polar bears clearly survived that climatic episode.

          Gore also presents as established fact the notion that global warming is increasing the intensity of hurricanes, but according to Bailey, this claim “is hotly contested by climate scientists.” Gore also repeats the oft-heard scare that rising temperatures will expand the range of diseases like malaria, but Bailey counters that malaria was endemic to places like the United States not so long ago, and it was advancing technology and increasing wealth that allowed such places to eradicate the disease within their borders. As Bailey concludes, “These are little inconvenient truths that cut against [Gore’s] belief that global warming constitutes a climate emergency.”

Moving the Goalposts?

          Bailey makes an interesting observation about the changing nature of the debate: “Unfortunately, those who have been skeptical that global warming was happening at all will now have a credibility problem with the public when it comes to policy recommendations on how best to handle any future warming.” In essence, skeptics might be accused of moving the goalposts, of shifting the argument to different grounds when it becomes convenient to do so. In reality, though, there are many different reasons to be skeptical of global warming alarmists. There is simply nothing wrong with admitting, as Bailey himself has done, that some of the skeptics’ arguments now appear to have been mistaken, while maintaining that others are far more robust. Indeed, it is the mark of an intellectually honest person to be willing to change one’s mind when faced with new evidence.

          Bailey is surely right that some will pounce on skeptics who relent on certain points. This is a shame, because regardless of who turns out to be right in the end, the attempt to discredit skeptics instead of engaging their arguments does us all a grave disservice. It obscures the issues, preventing an accurate assessment of reality and interfering with the pursuit of appropriate reactions to perceived problems. On the other hand, we all stand to gain from shining as much light as possible on all of the arguments put forward by both sides.


1. For readers who are suspicious of the idea of “correcting” data, an accessible account of what’s going on can be found in another Economist article, this one from August 13th, 2005, entitled “Heat and Light.”