BLACK CARBON (SOOT)
Another factor that reduces Arctic albedo is black carbon (soot) emissions from northern hemisphere air pollution. Dirty snow cover from carbon pollution is transported to the Arctic and dumped on the snow. Black carbon is an additional source of global warming from fossil fuel combustion, in additiOn to the direct atmospheric global warming effect of soot. \
Bounding the role of black carbon in the climate system published Fed 2013, a very large scientific assessment confirmed that black carbon (soot) is second only to CO2 in causing global warming.
An AGU release says accounting for all of the ways black carbon can affect climate, it is believed to have a warming effect of about 1.1 Watts per square meter (W/m2), approximately two-thirds of the effect of the largest man made contributor to global warming – carbon dioxide.
Black carbon is a significant cause of the rapid warming in the Northern Hemisphere at mid to high latitudes, including the northern United States, Canada, northern Europe and northern Asia, according to the report.
2012 research supports previous findings that black carbon is second only to CO2 in causing global warming. This is almost all through a direct greenhouse heat absorption property with a small additional warming of reducing snow albedo,
Research by M. Jacobson in 2010 found that the overall global warming effect of black soot may be second only to CO2. Jacobson's calculations indicate that controlling soot could reduce warming above parts of the Arctic Circle by almost 3 degrees Fahrenheit within 15 years. That would virtually erase all of the warming that has occurred in the Arctic during the last 100 years.
A 2008 paper by V Ramanathan Global and regional climate changes due to black carbon concluded that black carbon (BC) is second only to CO2 in causing global warming, and could be a very large cause of melting glaciers in the Himalayas.
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.