Human-Produced Aerosols in Many Arctic Clouds Contribute to Climate Warming
29 January 2006
|
| Enhanced aerosol concentrations can make the clouds more opaque and emit more thermal energy to the surface. |
Two scientists from Scripps Institute of Oceanography and Brookhaven National Laboratory have measured the impact of a significant anthropogenic source of warming: aerosol concentrations in Arctic clouds. The research is published in the current issue of Nature.
The team used radiometric data to show that increased concentrations of aerosols in the clouds cause the cloud droplets to become smaller and, within clouds of fixed water amounts, more abundant. This process, known as the “first indirect” effect makes many clouds more opaque and to emit more thermal energy to the surface by an average of 3.4 watts per square meter, which is comparable to the effect of increased greenhouse gases.
The Arctic is showing the first unmistakable signs of climate warming caused by human activities, in the form of rapidly retreating and thinning sea ice. This rapid climate change in the Arctic may have profound implications for both fragile ecosystems and unique modes of human habitation. Our study illustrates how human activity can influence Arctic climate in more than one way, by changing the way clouds warm the climate, in addition to the carbon dioxide increases. It is also another example of human industrial activity’s surprising impact on remote polar regions, the most famous example being the Antarctic ozone hole discovered in the mid-1980s.
—Ray Lubin, Scripps
The Arctic region also experiences significant periodic influxes of anthropogenic aerosols, which originate from the industrial regions in lower latitudes.
Because sunlight is generally weak in the Arctic, the clouds, via their emission of thermal energy, normally exert a net warming on the Arctic climate system throughout most of the year, except briefly during the summer.
Resources:
“A climatologically significant aerosol longwave indirect effect in the Arctic”; Dan Lubin and Andrew M. Vogelmann; Nature 439, 453–456 (26 January 2006); doi:10.1038/nature04449
Mike,
Newscientist has article on Nitrogen which was very revealing.
http://www.newscientist.com/channel/earth/mg18925351.500
Posted by: argod | 29 January 2006 at 04:05 PM
Jet airplanes leave trails of particulate matter that sometimes causes the water vapor in the exhaust to consense around it (or freeze) and form a contrail. These happen at high elevation and you normally see them vanish in a few seconds. Aerosols have been intentionally sprayed from other jets as well, they appear similar to contrails, except they can form at any elevation. They don't evaporate, instead they spread out and form a layer of aerosol-cloud, sometimes even reaching ground level. They appear to block out the sun, and I would have imagined that the white clouds would reflect the sunlight back into space.
http://www.carnicom.com/
Why the heck would the military be adding particulate matter to the air? Is that part of their published plan to "own the weather by 2025"? I have to shake my head when I see stuff like this happening in the sky and then a report comes out saying how aerosols are causing warming by trapping heat in.
Posted by: Schwa | 01 February 2006 at 05:09 AM