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Posted on 07/07/2003 6:14:04 PM PDT by PeaceBeWithYou
Controversial climate claim exonerates carbon dioxide.
The impact of cosmic rays on our climate might outweigh that of the greenhouse gas carbon dioxide, a controversial new report suggests1.
"It's no excuse to ignore sensible resource use," says one of the report's authors, physicist Nir Shaviv of the Hebrew University of Jerusalem in Israel. "But the bottom line is that carbon dioxide is not the bad boy that people claim it is."
The suggestion has met with scepticism, however: "I don't buy it," says climate-change expert Wallace Broecker of Columbia University in New York.
Shaviv and climatologist Ján Veizer of Ruhr University, Germany, reckon that the spiral arms of our galaxy hold the secret to the Earth's see-sawing climate. Every 150 million years, blasts of cosmic rays cool the planet on its stately passage through the cosmos, they argue2.
Cosmic rays thrown out by dying stars in the dust-rich arms of the Milky Way increase the number of charged particles in our atmosphere. There is some evidence that these may encourage low-level clouds to form, which cool the Earth.
Shaviv and Veizer have created a mathematical model of the number of cosmic rays hitting our atmosphere. They compared its predictions with other researchers' estimates of global temperatures and carbon dioxide levels over the past 500 million years.
They conclude that cosmic rays alone can account for 75% of the change in global climate during that period, and that less than half of the global warming seen since the beginning of the twentieth century is due to greenhouse gases.
The links are tenuous, others counter. Palaeontologist Paul Olsen, also of Columbia University, warns that Shaviv's study shows only a correlation between temperature, as inferred from ancient sediment records, carbon dioxide, as inferred from fossilized sea shells and cosmic rays, as inferred from meteorites. All three techniques are open to interpretation. Plus, geologists consider one of the 'cool' periods in the mathematical reconstruction to be a warm period, Olsen points out.
Despite these uncertainties - which hamper many efforts to reconstruct past climate - some researchers are more receptive. "It's intriguing," says Giles Harrison of the University of Reading, UK, who studies cosmic rays' impact on climate.
Shaviv attempts to explain how the Sun's natural variability affects the number of cosmic rays hitting the Earth, says Harrison. The Sun also produces radiation similar to cosmic rays, especially at the hottest part - called the solar maximum - of its 11-year cycle. Previous studies have failed to tease apart the climatic impacts of this radiation, of cosmic rays from the galaxy, and of warmth from the Sun.
Upcoming research should help clarify the situation. Physicists plan to mimic cloud formation in the lab by using particle accelerators to create cosmic-ray-like radiation.
References:
1. Shaviv, N. J. & Veizer, J. Celestial driver of Phanerozoic climate? GSA Today, 13, 4 - 10, (2003).Homepage
2. Shaviv, N. J. Cosmic ray diffusion from the galactic spiral arms, iron meteorites, and a possible climatic connection? Physical Review Letters, 89, (2002).Article
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FreeRepublic , LLC PO BOX 9771 FRESNO, CA 93794
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It is in the breaking news sidebar! |
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Heck, Newsweek or Time ran a Global Cooling article back in 1975 or so. Leftists will say **anything** if it advances their agenda of social and government control.
Like the links to global warming aren't equally tenuous... Give me a break, un-named "others".
/john
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And before and during that too, Earth would be barely habitable without it. Natural Global Warming is a fact, no doubt about it.
It's that anthropormorphic watermelon nonsense that is in dispute.
Ah, but does it have a probability drive?
Remember, the answer is 42.
Strange rant off
This is all dimly in my memory from somewhere.
--Boris
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So in other words we gotta pump this carbon dioxide into the atmosphere continuously, or the cosmic rays will freeze us out. People in the past didn't have any SUV's... all they could do was breathe out, and get their animals to breath out with 'em. Not good enough, the ice age came anyway. Prevent ice ages! Drive a Hummer! I like that.