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Pollution Shield to Protect Earth?

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Another interesting Globe and Mail article today… Dr. Crutzen of Germany’s Max Plack Institute for Chemistry suggests a human made “shield” of pollution that should protect earth from incoming radiation…

Here is the text of the article:

‘Drastic’ ideas emerge at Kyoto talks Leading scientists propose a ‘shade’ of pollution to fight global warming

CHARLES J. HANLEY Associated Press

NAIROBI — If the sun warms the Earth too dangerously, the time may come to draw the shade.

The “shade” would be a layer of pollution deliberately spewed into the atmosphere to help cool the planet. This over-the-top idea comes from prominent scientists, including a Nobel laureate. The reaction at the United Nations conference on climate change in Nairobi is a mix of caution, curiosity and some resignation to such “massive and drastic” operations, as the chief UN climatologist describes them.

The Nobel Prize winner who first made the proposal is himself “not enthusiastic about it.”

“It was meant to startle the policy makers,” said Paul Crutzen, of Germany’s Max Planck Institute for Chemistry. “If they don’t take action much more strongly than they have in the past, then in the end we have to do experiments like this.”

Serious people are taking Dr. Crutzen’s idea seriously. This weekend, NASA’s Ames Research Center in Moffett Field, Calif., holds a closed-door, high-level workshop on the global haze proposal and other “geo-engineering” ideas for fending off climate change.

In Nairobi, meanwhile, hundreds of delegates were wrapping up a two-week conference expected to only slowly advance efforts to rein in greenhouse gases blamed for much of the one-degree rise in global temperatures in the past century.

The 1997 Kyoto Protocol requires modest emission cutbacks by industrial countries — but not the United States, the biggest emitter of carbon dioxide and other heat-trapping gases, because it rejected the deal. Talks on what to do after Kyoto expires in 2012 are all but bogged down.

When he published his proposal in the journal Climatic Change in August, Dr. Crutzen cited a “grossly disappointing international political response” to warming.

The Dutch climatologist, awarded a 1995 Nobel in chemistry for his work uncovering the threat to Earth’s atmospheric ozone layer, suggested that balloons bearing heavy guns could be used to carry sulphates high aloft and fire them into the stratosphere.

While carbon dioxide keeps heat from escaping Earth, substances such as sulphur dioxide, a common air pollutant, reflect solar radiation, helping to cool the planet.

Tom Wigley, a senior U.S. government climatologist, followed Dr. Crutzen’s article with a paper of his own on Oct. 20 in the leading U.S. journal Science. Like Dr. Crutzen, Dr. Wigley cited the precedent of the huge volcanic eruption of Mount Pinatubo in the Philippines in 1991.

Pinatubo shot so much sulphurous debris into the stratosphere that it is believed it cooled the Earth by nine tenths of a degree for about a year.

Dr. Wigley ran scenarios of stratospheric sulphate injection — on the scale of Pinatubo’s estimated 10 million tonnes of sulphur — through supercomputer models of the world’s climate, and reported that Dr. Crutzen’s idea would, indeed, seem to work. Even half that amount a year would help, he wrote.

A massive dissemination of pollutants would be needed every year or two, as the sulphates precipitate from the atmosphere in the form of acid rain.

Dr. Wigley said a temporary shield would give political leaders more time to reduce human dependence on fossil fuels, the main source of greenhouse gases. He said experts must more closely study the feasibility of the idea and its possible effects on stratospheric chemistry.

Nairobi conference participants agreed.

“Yes, by all means, do all the research,” said Indian climatologist Rajendra Pachauri, chairman of the 2,000-scientist UN network on climate change.

But “if human beings take it upon themselves to carry out something as massive and drastic as this, we need to be absolutely sure there are no side effects,” Dr. Pachauri said.

Philip Clapp, a veteran campaigner for emissions controls to curb warming, also sounded a nervous note, saying, “We are already engaged in an uncontrolled experiment by injecting greenhouse gases into the atmosphere.”

But Mr. Clapp, president of the U.S. non-profit group National Environmental Trust, said, “I certainly don’t disagree with the urgency.”

In past years scientists have scoffed at the idea of air pollution as a solution for global warming, saying that the kind of sulphate haze that would be needed is deadly to people. Last month, the World Heath Organization said air pollution kills about two million people worldwide each year and that reducing large soot-like particles from sulphates in cities could save 300,000 lives annually.

American geophysicist Jonathan Pershing, of Washington’s World Resources Institute, is among those wary of unforeseen consequences, but said the idea might be worth considering “if down the road, 25 years, it becomes more and more severe because we didn’t deal with the problem.”

By telephone from Germany, Dr. Crutzen said that’s what he envisioned: global haze as a component for long-range planning. “The reception on the whole is more positive than I thought,” he said.

Dr. Pershing added, however, that reaction may hinge on who pushes the idea. “If it’s the U.S., it might be perceived as an effort to avoid the problem,” he said.

NASA said this weekend’s conference will examine “methods to ameliorate the likelihood of progressively rising temperatures over the next decades.”

Written by Claus

November 17th, 2006 at 3:09 pm

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