A heretic is a man who sees with his own eyes. – Gotthold Ephraim Lessing
Iain Murray on the four types of global warming denial.
So just what is the nature of the “denial” that these scientists and environmentalists want to eradicate? First, there is the proposition that the Earth may not be warming at all. The truth is that there are not many scientists who publicly express this view nowadays. While there are many who question the reliability of surface temperature records, there are few who dispute the evidence from satellite records showing that the Earth has warmed 0.13 degrees Celsius per decade since the start of the data in the 1970s. These records, however, also show virtually no warming in the Southern Hemisphere (global warming isn’t very global). There is ongoing scientific debate about the calibration of the data, but essentially this debate is over: The Earth has warmed since the 1970s.
Yet that isn’t a very long time at all, certainly not long enough to establish whether or not the warming is so unprecedented that civilization and the biosphere have not had to deal with similar warming before. So the second target of the “denial” charge is those who dispute that the current warming is unprecedented. Yet here there is clearly ongoing scientific debate, with developments in just the past few months. A small group of paleoclimatologists issued a series of temperature reconstructions finding that global temperature was mostly stable for the past thousand years until a precipitous recent rise. Questions, however, were raised about the quality of the data and the statistical methods used to achieve this result. A team of eminent statisticians charged by the House Energy and Commerce Committee to investigate the scientists’ methodology confirmed that the methods they had used virtually guaranteed the result they obtained. Meanwhile, the National Research Council (NRC) found that the quality of the historic data meant that nothing more could be said with certainty than that the current warm period is warmer than at any time since the 1600s, which the NRC agreed was part of the “Little Ice Age”—something that the paleoclimatologists’ reconstruction suggested had not occurred. The NRC found that the suggestion that the current warm period was the warmest for a thousand years was merely plausible, but both unprovable and unfalsifiable given the current state of the historic data. The NRC also upheld the methodological criticisms. It is therefore somewhat of a stretch to claim that science has proven beyond reasonable doubt that the current warm period is unprecedented.
Third, the “denial” charge is aimed at those who purportedly suggest that mankind has nothing to do with the current warming. This represents a considerable oversimplification of the issue. Such “contrarian” scientists—such as S. Fred Singer, Patrick J. Michaels, and Richard S. Lindzen—have affirmed time and again that mankind is responsible for some of the warming. Basic physics indicates that the more greenhouse gases in the atmosphere, the more heat will be trapped there. Yet there are far more climate “forcings” than just greenhouse gases. The Intergovernmental Panel on Climate Change (IPCC) and the NRC both admit that our current understanding of these other forcings is low. Until we know much more about land-use change, aerosols, and solar activity, to name but a few, we cannot be certain that greenhouse gases have been driving the recent warming trend. That is why the NRC concluded that, “Because of the large and still uncertain level of natural variability inherent in the climate record and the uncertainties in the time histories of the various forcing agents (and particularly aerosols), a causal linkage between the buildup of greenhouse gases in the atmosphere and the observed climate changes during the twentieth century cannot be unequivocally established.”
The final charge against “deniers” is that they fail to acknowledge that global warming will be catastrophic. Most deniers would happily cop to this accusation, and they have plenty of evidence to back up their stance. When Al Gore talks about twenty feet of sea-level rise from the melting of the West Antarctic Ice Sheet (WAIS), he is failing to acknowledge the science. The IPCC estimates less than a meter of sea-level rise this century and considers catastrophic destabilization of ice sheets unlikely. Even if the WAIS were to melt, research indicates it would take several thousand years to do so, more than enough time for people to get out of the way.
I’d add two more, the first of which admittedly is related to the theory that global warming is real yet not catastrophic; the argument that even if anthropogenic global warming is real, it’s cheaper to mitigate the effects of global warming than it is to prevent the temperature rise.
The second is this. Assholes have been predicting the end of the world since time immemorial. They have always been wrong. You’re wrong too. I don’t have to know science to know this. I just have to know history.