Day By Day

Sunday, February 11, 2007

Another Dent In the Scientific Consensus

The "consensus" position on anthropogenic global warming has been based primarily on computer simulation models. Such models are notoriously imprecise, especially in attempting to predict the future behavior of complex systems like a national economy or the environment. They are only as good as the data fed into them and the equations they use to organize that data. Now comes a claim, presented in the prestigious Proceedings of the Royal Society, that one of the key equations used in these models is wrong.
Scientists say that cosmic rays from outer space play a far greater role in changing the Earth's climate than global warming experts previously thought.... Henrik Svensmark, a weather scientist at the Danish National Space Centre who led the team behind the research, believes that the planet is experiencing a natural period of low cloud cover due to fewer cosmic rays entering the atmosphere.

This, he says, is responsible for much of the global warming we are experiencing.
Here's the kicker:

He said: "It was long thought that clouds were caused by climate change, but now we see that climate change is driven by clouds.

"This has not been taken into account in the models used to work out the effect carbon dioxide has had.

"We may see CO2 is responsible for much less warming than we thought and if this is the case the predictions of warming due to human activity will need to be adjusted...."

"Humans are having an effect on climate change, but by not including the cosmic ray effect in models it means the results are inaccurate. The size of man's impact may be much smaller and so the man-made change is happening slower than predicted."

Read it here.

This is serious stuff. The scientists and the organizations conducting this research are real heavyweights, and they must be taken seriously. They are saying that one of the fundamental assumptions underlying the current climate models is wrong, seriously so. This, if borne out by research, could result in discrediting or at least seriously modifying the models upon which current environmental activism is based.

And here we get to the real problem with using scientific opinion, even consensus opinion, to guide public policy. Scientific opinion shifts, frequently and sometimes radially, and when it does policies based on earlier assumptions are invalidated. But policies have consequences, and often those cannot be undone. I'm not saying we should ignore scientific opinion in the crafting of public policy, but it should be balanced by other considerations, political, economic, and even moral.


Don Boudreaux makes the point that even if the scientific consensus is correct, the environmentalists are by no mean qualified to judge what might be an appropriate response. He writes:

[S]omeone with no firm grasp of economic principles can be as right as right can be about global warming and its causes while simultaneously being utterly benighted about what to do about it and even whether or not something should be done about it.

Read him here.


From the Times [of London]

Nigel Calder, former editor of the New Scientist, writes:

When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works.

Read the whole thing here.

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