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Sunday, April 13, 2008

Geologist: Sun’s shift could mean global chill

BELLINGHAM — Fluctuations in solar radiation could mean colder weather in the decades ahead, despite all the talk about global warming, retired Western Washington University geologist Don Easterbrook said Tuesday.

Easterbrook is convinced that the threat of global warming from mankind’s carbon dioxide pollution is overblown.

In a campus lecture, he cited centuries of climate data in an effort to convince a somewhat skeptical audience that carbon dioxide’s impact on climate is being much exaggerated by former U.S. Vice President Al Gore and by scientists who appear to have won the debate over global warming.

“Despite all you hear about the debate being over, the debate is just starting,” Easterbrook said.

30-YEAR TREND

Easterbrook doesn’t deny that the Earth’s climate has been warming slowly since about 1980. But he argued that this warming trend fits a longstanding pattern of warming and cooling cycles that last roughly 30 years. Sunspot activity and other solar changes appear to explain the 30-year cycles, he said.

If that pattern persists, the earth could now be close to the next 30-year cooling cycle, Easterbrook said.

He noted that the 2007-08 winter set records for cold and snow in many parts of the globe. According to the data he displayed, the Earth’s temperature hit a peak in 1998 and has been steady or slightly cooler since then.

“One cold winter doesn’t mean much of anything,” he said. “A 10-year trend is interesting.”

He contended that warming periods appear to match periods of sunspot activity, which currently is at a low point.

Easterbrook noted that astrophysicists have been expecting that activity to begin increasing soon, but so far it has not.

Prolonged periods of low activity could lead to a dramatic cooling such as occurred in Europe during the so-called “Little Ice Age,” a term loosely used to describe cooler weather in the 14th to 19th centuries, Easterbrook said.

CONTRASTING PREDICTIONS

Easterbrook didn’t predict another Little Ice Age, but did offer his own climate predictions for the rest of the 21st century — predictions in sharp contrast with those of the Intergovernmental Panel on Climate Change set up by the United Nations.

The panel, which shared the 2007 Nobel Peace Prize with Gore, predicts a 10-degree Fahrenheit rise in global temperature by 2100, resulting from carbon dioxide created by the burning of fossil fuels. Easterbrook said the temperature change from now until the end of the century will be minor, and so will any change in sea level.

A quick scan of scientific literature available online indicated some conflict in scientific opinions on the effect of solar activity on climate.

Some scientists see a significant effect, but others, including those on the IPCC, insist that there is overwhelming evidence for carbon dioxide’s impact, and that impact far outweighs any solar effects that can be demonstrated.

If the warming trend of the past 30 years really is reversing, it won’t take too long to become apparent.

“In three years we’ll at least know the direction we are headed,” Easterbrook said. “If we are one degree warmer in 2010 than we were in 2005, I will appear here and eat my words.”

While Easterbrook is skeptical about the risks from carbon dioxide, he said he strongly supports efforts to curb air pollution.

“There are a lot of things being put in the atmosphere right now that are way more dangerous than (carbon dioxide,)” he said.

But Easterbrook is far more worried about global population growth.

At present growth rates, the world would add another 3 billion people by 2050, putting enormous strains on supplies of food, water and other resources.

“Nobody is talking about it,” he said. “Nobody is doing anything about it, and it’s happening.”

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