Particles of soot and other light-absorbing aerosols have a warming rather than cooling effect on temperatures, researchers have learned. It is a surprising revelation that promises to lower even further estimates of the effect of greenhouse gases on global temperatures.
Computers running global warming climate models have been told to assume aerosols in the atmosphere inhibit the warming properties of greenhouse gases. Based on this assumption, the models predict accelerated warming in the future when such aerosol pollutants are likely to be less prevalent in the atmosphere.
“Scientists are convinced these plumes contain so many cooling sulfate particles that they may be masking half of the effect of global warming,” noted the July 20 Wall Street Journal.
Assumption Was Wrong
However, a team of researchers from NASA and the University of California at San Diego reported in the August 2 issue of the British science journal Nature that they sent instruments into “brown clouds” of aerosols over Asia to measure their effect on temperature. To their surprise, the researchers discovered the common assumption that aerosols lower temperatures was wrong.
Instead, aerosols were found to substantially amplify the Earth’s greenhouse effect.
“We found that atmospheric brown clouds enhanced lower atmospheric solar heating by about 50 percent,” explained the researchers.
“[The pollution] contributes as much as the recent increase in anthropogenic greenhouse gases to regional lower atmospheric warming trends,” the researchers added.
Himalayan Melting Explained
The amount of warming due to aerosols was so significant, the researchers reported, that aerosols alone could explain–in and of themselves and completely independent of greenhouse gases–the observed glacier retreat in the Eastern Himalayan Mountains.
“Putting aside the fact that the Himalayan glaciers have been retreating since 1780–some 70 years before the onset of the current post-Little Ice Age warming trend and 100 years before the onset of significant global industrialization–the new data are remarkable,” said Steven Milloy, publisher of Junkscience.com.
Fudge Factor Debunked
Milloy noted the new discovery further calls into question unreliable global warming models that have failed to explain why manmade carbon dioxide emissions steadily increased from about 1940 to 1975 even as global temperatures cooled.
Said Milloy, “Global warming alarmists, such as the UN’s Intergovernmental Panel on Climate Change, attempt to counter this observation by claiming that aerosol particles in the atmosphere–like soot and sulfates from fossil fuel combustion, and dust from volcanic eruptions–can mask the warming effect of greenhouse gases and cool the planet by reflecting solar radiation back into space. Earth has not warmed as predicted, they argue, because aerosol pollution is cooling the planet in a way that temporarily mitigates greenhouse gas warming.
“The new aerosol study doesn’t show that climate alarmists may be just a little off course–it shows that they may be 180 degrees off,” Milloy added. “The aerosol study opens up the possibility for an entirely new hypothesis for global warming, with aerosols as the culprit. Yet up to now, the ‘consensus’ crowd has portrayed aerosols in the opposite light, as cooling agents.”
James M. Taylor ([email protected]) is managing editor of Environment & Climate News and a senior fellow at The Heartland Institute.