permaculture

["Lawrence F. London, Jr." <lflj@intrex.net>]

-------- Original Message --------
Subject: [SANET-MG] global warming due to soot
Date: Tue, 1 Apr 2008 11:06:08 -0400
From: jcummins <jcummins@UWO.CA>
To: SANET-MG@LISTS.IFAS.UFL.EDU

Nature Geoscience 1, 221 - 227 (2008)
Published online: 23 March 2008 | doi:10.1038/ngeo156
Global and regional climate changes due to black carbon
V. Ramanathan1 & G. Carmichael2
Abstract
Black carbon in soot is the dominant absorber of visible solar radiation
in the atmosphere. Anthropogenic sources of black carbon, although
distributed globally, are most concentrated in the tropics where solar
irradiance is highest. Black carbon is often transported over long
distances, mixing with other aerosols along the way. The aerosol mix can
form transcontinental plumes of atmospheric brown clouds, with vertical
extents of 3 to 5 km. Because of the combination of high absorption, a
regional distribution roughly aligned with solar irradiance, and the
capacity to form widespread atmospheric brown clouds in a mixture with
other aerosols, emissions of black carbon are the second strongest
contribution to current global warming, after carbon dioxide emissions.
In the Himalayan region, solar heating from black carbon at high
elevations may be just as important as carbon dioxide in the melting of
snowpacks and glaciers. The interception of solar radiation by
atmospheric brown clouds leads to dimming at the Earth's surface with
important implications for the hydrological cycle, and the deposition of
black carbon darkens snow and ice surfaces, which can contribute to
melting, in particular of Arctic sea ice.