The strident attempt to silence the skeptics who question the popular thesis that humans are adversely affecting the earths climate hit a new high over the past couple of weeks with the release of the Berkeley Earth Surface Temperature Project (BEST) report from a group of scientists centered at U.C. Berkeley. It was supposed to be an impeccably crafted review of existing temperature data from worldwide stations which would settle the argument once and for all. Its lead author, Richard Muller, did indeed report that the earth had been warming and that was enough for the true believers, from the mainstream media on down. Time ran a blunt quote from Muller featuring him as a converted skeptic, and the New York Times ran a scurrilous comic strip ( The Strip ) in its Sunday review section mocking the skeptics, thousands (yes) of them reputable scientists, with unusually fierce calumny, treating them all as fools or tools of corporate interests. Even the Wall Street Journal sub-headlined its report, There were good reasons for doubt, until now .
As if the BEST report were not enough, now comes the new report from the Intergovernmental Panel on Climate Change, the UN body responsible for much of the climate alarmism. This one is about extreme weather events, and they claim that these will increase over the next 20-30 years due to global warming. Put simply, just like that, the usual media suspects seized upon the document as further proof that the skeptics should shut up and go home.
There are two issues here: What did the BEST study and the IPCC report show, or prove? And what difference does it make? Although Muller was incautious (You should not be a skeptic, at least not any longer, he wrote) and although he committed the scientific faux pas of submitting his paper to the popular media before its peer review, the BEST report is actually rather cautious. Its data have always been contaminated by improperly sited recording stations, and deal with land temperatures only. At most they show a slight uptick in land temperatures over the past half-century and a curious plateau over the last decade orcurious, because CO2 in the atmosphere, supposedly the main driver of global warming, has been steadily increasing. The oceans go through cycles of warming and cooling, and anyway a third of the BEST land stations report cooling. What warming there has been is modest enough that it easily falls within natural 100-year climate variability. Mullers co-author, Judith Curry of Georgia Tech, has publically distanced herself from his publicity release, saying that his claim to have proved the skeptics wrong was an unscientific huge mistake.
The IPCC report is surprisingly downbeat, considering the groups track record of scary predictions. It anticipates more heat waves and flooding, but does not make judgments about many natural disasters like ocean storms, and, most tellingly, says that for the next two or three decades there will be little or no discernible human influence on climate. The human imprint, it acknowledges, will not be distinguishable from natural climate variability. There can be no confidence in any predictions for a longer term.
The real issue is not whether the earth is warming at the present time (over longer periods it both warms and cools), but whether humans are causing it, and if so, whether mitigation measures are possible and worth the economic cost. Both of these reports abstain from identifying human action as the principal cause of global warming. The human component of global warming may be somewhat overestimated, says BEST, in a noteworthy retreat from the reigning paradigm. If humans are not the culprits, then the proposals for human action to change natures course look a lot less possible. Moreover, they involve some terrible economic sacrifices which are even now creating real hardship wherever they are being tried, in the UK for example, where the cost of heating ones home has driven many households into fuel poverty and green taxes of various sorts are seriously hurting the British economy. It is even arguable that the economic shrinkage meant to save the planet may actually cost more lives than it saves. Given the real scientific uncertainty the moral course of action is at least open to debate, and attempts to foreclose the debate by demonizing the skeptics are in gross moral error. And if anyone doubts that the alarmists are trying to do exactly that, please look at the second round of climate gate e-mails released this week.
Thomas Sieger Derr is professor emeritus of religion and ethics at Smith College and the author of Environmental Ethics and Christian Humanism