Sunday, January 17, 2010

8. Climate Change Science: A Summary




The atmospheric concentration of carbon dioxide has increased by 30% since the late 19th century, but the best evidence we have indicates that at least 40% of the increase is due to natural causes. While the actual temperature record for this period will remain in limbo until Climategate is resolved, it is very likely that by 2000 the global average temperature had increased by around 0.7oC (1.3oF), and virtually certain that it has since been declining. The cooling trend is probably due to the quiet sun.

The projections by the analysts of the Intergovernmental Panel on Climate Change (IPCC) are questionable because they are based on purely theoretical computer representations of the extremely complex (indeed, chaotic) climate system of our planet. As evolutionary biologist John Maynard Smith noted in 1995, most scientists "have a general feeling of unease when contemplating complex systems dynamics. Its devotees are practicing fact-free science. A fact for them is, at best, the output of a computer simulation: it is rarely a fact about the world." The IPCC is quite explicit about this Orwellian NewSpeak: in the Fourth Assessment Report, the word "experiment" never means anything except a computer run with a new set of input parameters.

The ice core data as well as the cooling since 2002 support the finding, devastating to the case for anthropogenic global warming (AGW), that cloud formation makes water vapor feedback negative. If confirmed by more research, it will mean that AGW is an insignificant problem.

In any case, however ingenious and wonderfully complex the IPCC computer models may be, their failure to predict the present cooling is convincing proof that they are, at best, inadequate as bases for policy. The apparent fact that the solar connection has overwhelmed the previous warming trend is a further strong indication that the climate will warm or cool, as it always has, largely unaffected by anthropogenic CO2. The odds are now better than even that we will see substantial cooling, not warming, during the next several decades.

Note that these conclusions are based on observations, not "fact-free science," and that, despite vociferous claims by the AGW Lobby, the real science is far from settled.

Given these doubts about the reality of AGW, there are two possible arguments for proceeding with stringent regulation of emissions. The first is the so-called Precautionary Principle: as adopted in 1992 by the UN-sponsored Earth Summit in Rio de Janeiro, it insists that "where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation."

In the present context, a major problem with this proposition is that we do not know how long the present cooling trend may continue. Since the consequences of significant cooling are much more serious than those of warming, the Precautionary Principle seems to suggest that our "cost-effective measures," such as they are, should be aimed at promoting rather than preventing warming. Does this mean that we should maximize rather than minimize CO2 emissions?

The truth, of course, is that the Precautionary Principle offers little useful guidance, because it does not avoid the need to understand the problem. Defining cost-effective measures requires a determination (a) that there is high confidence that the consequences of inaction are known; (b) that they could be severely damaging; (c) that there is a reasonable probability that the proposed countermeasures would be effective; and (d) that the cure would not be worse than the disease. The best information we have so far is that the answers to all four of these questions are negative.

The second argument for enacting the suggested regulations is that they are justified, even if AGW proves negligible, because they will help us solve perceived societal problems while giving us a cleaner, more sustainable, better world. Christine Stewart, then Canadian Minister for the Environment, expressed this point of view in 1998, when she said "It doesn't matter if the science is all phony…Climate change [provides] the greatest chance to bring about peace and equality in the world." There is no doubt that this opinion is influential in the AGW Lobby, as evidenced by the frequent furious rejections of possible technical fixes for the problem. People who insist that societal changes are the only acceptable way to fight AGW reveal that they are more interested in an ideological agenda than in maintaining a salubrious climate. 

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