Monday, February 12, 2007

Global Warming Again

The topic of global warming to me is like rotgut whiskey to an alcoholic. I can't resist.

The TimesOnline (UK) reported yesterday on some new research into global warming, and it doesn't point in the same direction all the doomsday alarmists are pointing.

When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works. We were treated to another dose of it recently when the experts of the Intergovernmental Panel on Climate Change issued the Summary for Policymakers that puts the political spin on an unfinished scientific dossier on climate change due for publication in a few months’ time. They declared that most of the rise in temperatures since the mid-20th century is very likely due to man-made greenhouse gases.

The small print explains “very likely” as meaning that the experts who made the judgment felt 90% sure about it. More positively, a 10% uncertainty in any theory is a wide open breach for any latterday Galileo or Einstein to storm through with a better idea. That is how science really works.

Enthusiasm for the global-warming scare also ensures that heatwaves make headlines, while contrary symptoms, such as this winter’s billion-dollar loss of Californian crops to unusual frost, are relegated to the business pages. The early arrival of migrant birds in spring provides colourful evidence for a recent warming of the northern lands. But did anyone tell you that in east Antarctica the Adélie penguins and Cape petrels are turning up at their spring nesting sites around nine days later than they did 50 years ago? While sea-ice has diminished in the Arctic since 1978, it has grown by 8% in the Southern Ocean.

Which leaves the question: What is really driving the climate around the world?

The best measurements of global air temperatures come from American weather satellites, and they show wobbles but no overall change since 1999.

That levelling off is just what is expected by the chief rival hypothesis, which says that the sun drives climate changes more emphatically than greenhouse gases do. After becoming much more active during the 20th century, the sun now stands at a high but roughly level state of activity. Solar physicists warn of possible global cooling, should the sun revert to the lazier mood it was in during the Little Ice Age 300 years ago. (emphasis added)

And we shouldn't forget the even-more-distant past:

Climate history and related archeology give solid support to the solar hypothesis. The 20th-century episode, or Modern Warming, was just the latest in a long string of similar events produced by a hyperactive sun, of which the last was the Medieval Warming.

The Chinese population doubled then, while in Europe the Vikings and cathedral-builders prospered. Fascinating relics of earlier episodes come from the Swiss Alps, with the rediscovery in 2003 of a long-forgotten pass used intermittently whenever the world was warm.

To recap the approved, alarmist view of the global climate, there are two main concerns:

1. The globe is warming, and it's all human-caused.

2. Warming of the globe would be a complete disaster (followed by, "We're from the government, and we're here to help.").

But a 10-year-old theory by Henrik Svensmark of Copenhagen, which was confirmed by experimentation in the summer of 2005, shows how the sun's activity has a direct effect on the earth's climate.

[Svensmark] saw from compilations of weather satellite data that cloudiness varies according to how many atomic particles are coming in from exploded stars. More cosmic rays, more clouds. The sun’s magnetic field bats away many of the cosmic rays, and its intensification during the 20th century meant fewer cosmic rays, fewer clouds, and a warmer world. On the other hand the Little Ice Age was chilly because the lazy sun let in more cosmic rays, leaving the world cloudier and gloomier.

Where does all that leave the impact of greenhouse gases? Their effects are likely to be a good deal less than advertised, but nobody can really say until the implications of the new theory of climate change are more fully worked out.

The reappraisal starts with Antarctica, where those contradictory temperature trends are directly predicted by Svensmark’s scenario, because the snow there is whiter than the cloud-tops. Meanwhile humility in face of Nature’s marvels seems more appropriate than arrogant assertions that we can forecast and even control a climate ruled by the sun and the stars.

There's much more in the article, and it's a refreshing change from the standard, "We're doomed!" reporting we usually get. Still, I'm realistic enough to know that the arrogant assertions about mankind's ability to control the climate won't be stopping anytime soon.

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