Posted on 08/01/2007 1:32:03 PM PDT by blam
Asia's brown clouds 'warm planet'
The "brown cloud" is pollution from burning wood and fossil fuels
Clouds of pollution over the Indian Ocean appear to cause as much warming as greenhouse gases released by human activity, a study has suggested. US researchers used unmanned aircraft to measure the effects of the "brown clouds" on the surrounding area.
Writing in Nature, they said the tiny particles increased the solar heating of the lower atmosphere by about 50%.
The warming could be enough to explain the retreat of glaciers in the Himalayas, the scientists proposed.
The clouds contain a mixture of light absorbing aerosols and light scattering aerosols, which cause the atmosphere to warm and the surface of the Earth to cool.
The main sources of the pollutants came from wood burning and fossil fuels, the team added.
The unmanned aircraft flew 18 missions through the "brown cloud"
Aerosols, also known as particulates, cool the land or sea below because they filter out light from the Sun.
While this process, known as "global dimming", is fairly well understood, the effect aerosols have on the surrounding atmosphere is still unclear.
The scientists, from the University of California San Diego and the Nasa Langley Research Center, said there remained a degree of uncertainty because, until now, estimates had largely been derived from computer models.
Solar heating
For their study, the team of researchers used three unmanned aircraft, fitted with miniaturised instruments that were able to measure aerosol concentrations, soot amounts and the flow of energy from the Sun.
The crafts flew over the polluted region of the Indian Ocean at varying heights between 500m (1,640ft) and 3,000m (9,840ft).
"During 18 flight missions, the three unmanned aerial vehicles were flown with a separation of tens of metres or less and less than 10 seconds (apart), which made it possible to measure the atmospheric solar heating rates directly," they wrote.
"We found that atmospheric brown clouds enhanced lower atmospheric solar heating by about 50%.
"[The pollution] contributes as much as the recent increase in anthropogenic greenhouse gases to regional lower atmospheric warming trends," they suggested.
"We propose that the combined warming trend of 0.25 Kelvin per decade may be sufficient to account for the observed retreat of the Himalayan glaciers."
Seasonal glacier and snow melt from the mountain range feeds rivers that supplies water to about 40% of the world's population.
The United Nations Environment Programme (Unep), in its latest Snow and Ice Outlook report, said the ice sheets in the region could retreat by up to 81% by the end of the century.
Hey, USA not the bad guys on this one.....
Course it will be spun that if we did not buy so much, China would not have to build so much so its America’s fault.
this is why the enviros want US to live in the ‘stone age’
I wonder what it is about volcanic ash that cools the planet, and this stuff that warms it. Must be the altitude of it making a difference.
Who is Asia Brown?
Bush’s fault.
That stuff comes right through Fairbanks. First noticed it about 25 years ago. It’s fairly constant now although it changes color from yellow to brown to gray to blue depending on something, who knows what. We get a good cross section view of about 100 miles horizontal to the Alaska Range across the Tanana Flats.
If you've been to Nepal (and presumably this holds in India too), one of the main fuels for your cooking fire is dried cow dung.
Now THAT's a cause of the "brown cloud" that would be solved by MORE burning of fossil fuels.
This is the finding. The clouds cause Lower Atmosphere Temps to Rise and Surface temps to Lower. So apparently the Himilayas are tall enough to be within the lower atmosphere. So overall, no net heating. Just some loss of high altitude glaciers but cooler temps near sea level. Again, no mention of the heat generated by the BURNING itself.
Anyone seen an infrared satellite image of the planet surface ? Just asking ?
Ever one knows it's manBearPig's fault.
Along with Al gore's flatulence.
China Industries International
...will...not...make...fart joke...
everything should have a label saying where it's made... labels where it is NOT MADE are optional but a great idea.
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