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James Hansen, one of the fathers of global warming theory, commented in the online journal Natural Science in September last year, "Emphasis on extreme scenarios may have been appropriate at one time, when the public and decision-makers were relatively unaware of the global warming issue... Now, however, the need is for demonstrably objective climate forcing scenarios consistent with what is realistic under current conditions.” It seems that few in the movement got the memo, however. Recent weeks have provided a couple of excellent examples of how the environmental alarmist movement works. Emphasis on "extreme scenarios" is still at the forefront of its tactics. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
For instance, several news reports recently concentrated on an alarming suggestion that the <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Gulf Stream might shut down as a result of global warming, an event that would cause major cooling in North America as well as Northern Europe. It is undoubtedly true that an end to the Gulf Stream would be catastrophic for many of mankind's most prosperous areas, but how likely is it? The researcher concerned, Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research in Germany, simply told a press conference, "In the worst case it (the Gulf Stream) could shut down... it might even happen this century."
Those words, "in the worst case," cover a multitude of sins. It could simply be the most worrying of a few equally likely scenarios or an event so unlikely that it should be discounted. Yet, from the press accounts of the conference, we have no way of knowing how likely the occurrence is. If Rahmstorf did attempt to quantify the likelihood, that was not picked up by the press. The news consumer is left with a disturbing absence of context. He or she has been told by scientists and journalists that something worrying might happen, but has no idea of how to apply this to daily life.
Yet it is clear that the main offender in circumstances like this is not the reporting journalist (although the question of likelihood should have been raised and reported), but most often the scientists themselves. Academic press releases very often focus on extreme events or worst-case scenarios, for the simple reason that their research is unlikely to be reported on if they don't.
A January 15 press release from the National Science Foundation is a case in point. It covered the unglamorous study of Siberian peat bogs, but used alarm over the prospect of global to draw attention to itself. The main news hook in the release is the contention, "If, as many scientists predict, a regional Arctic warming trend thaws the bogs and causes the trapped gases to be released into the atmosphere, that could result in a major and unexpected shift in climate trends, according to the researchers.” The worry is that these bogs have acted as a carbon sink for thousands of years, but with thawing of the permafrost that could change.
Yet again, that scenario is, in the researchers' own words, extreme: "In an extreme scenario, not only would they stop taking up CO2, they would release a lot of the carbon they have taken up for centuries.” The researchers also admit that they had found no evidence of such an event ever happening.
Those who despair at the way climate science is manipulated in the panic over global warming are used to such tactics. Whenever anyone mentions the Intergovernmental Panel on Climate Change's forecast of temperature rises in the next century of up to 10° F., they are relying on an extreme scenario that is incredibly unlikely. As two distinguished scholars—the economist David Henderson and the statistician Ian Castles—have shown, that scenario relies on economic forecasts in which American economic performance is overtaken by Libya, Algeria, and North Korea (and which The Economist called "dangerously incompetent.") If commentators were to take Hansen at his word and look for objective and realistic projections of warming, they would agree with him that, even if nothing is done to restrict greenhouse gases, the likely temperature increase over the next 50 years is around 1.5°F, something mankind could easily adapt to.
Yet realism is sometimes at issue on the other side of the debate, too. Those of us who are concerned about seeing the truth darkly through the distorting glass of politics should be concerned about the use of some research by the anti-alarmist side in this conflict. For instance, a great deal was made last year about research that suggested that cosmic rays accounted for a large percentage of global warming. Stefan Rahmstorf and his colleagues on this occasion might be right to have advised recently that a study based on just 50 meteorites and with a timescale of millions of years cannot tell us much about warming trends in the comparatively miniscule scale of the last few decades.
Realism and objectivity are, as Hansen says, what are required in taking us forward in this scientific, economic, and political debate. Neither side does itself any favors if it disregards those requirements. Yet the realistic assessment says that global warming is happening, it is probably insignificant and we will be able to adapt to it. If the only counter to that argument is extreme or worst case scenarios, then they should be exposed for the tiny risks they are.