July 2013 AGU paper finds soot emitted within Arctic and deposited on snow has 5x greater effect on surface temperature than soot carried through the atmosphere from distant latitudes. Hansen 2005 paper found South Asia was source of most Arctic soot

7/30/13, "Arctic surface temperature change to emissions of black carbon within Arctic or midlatitudes," AGU, Journal of Geophysical Research

"Abstract"

"[1] In this study, we address the question of how sensitive the Arctic climate is to black carbon (BC) emitted within the Arctic compared to BC emitted at midlatitudes. We consider the emission-climate response spectrum and present a set of experiments using a global climate model....The climate model includes a snow model to simulate the climate effect of BC deposited on snow. We find that BC emitted within the Arctic has an almost five times larger Arctic surface temperature response (per unit of emitted mass) compared to emissions at midlatitudes. Especially during winter, BC emitted in North-Eurasia is transported into the high Arctic at low altitudes. A large fraction of the surface temperature response from BC is due to increased absorption when BC is deposited on snow and sea ice with associated feedbacks. Today there are few within-Arctic sources of BC, but the emissions are expected to grow due to increased human activity in the Arctic."... via WUWT

=================================

Per 2005 James Hansen and Dorothy Koch study, Arctic black carbon comes mainly from Communist China and India:

Between 1980 and 1995, "BC (black carbon) emissions from developed countries have declined and aircraft are apparently not to blame. However, during this time BC emissions from China and India have nearly doubled:"

2/25/2005, "Distant origins of Arctic black carbon: A Goddard Institute for Space Studies ModelE experiment," Dorothy Koch and James Hansen, NASA Goddard Institute for Space Studies, Journal of Geophysical Research

p.1 "Black carbon (BC) particles, derived from incomplete combustion of fossil fuels and biomass, may have a severe impact on the sensitive Arctic climate, possibly altering the temperature profile, cloud temperature and amount, the seasonal cycle, and the tropopause level and accelerating polar ice melting. We use the Goddard Institute for Space Studies general circulation model to investigate the origins of Arctic BC by isolating various source regions and types. The model suggests that the predominant sources of Arctic soot today are from south Asia (industrial and biofuel emissions) and from biomass burning.

These are the primary global sources of BC (approximately 20% and 55%, respectively, of the global emissions), and BC aerosols in these regions are readily lofted to high altitudes where they may be transported poleward. According to the model the Arctic BC optical thickness is mostly from south Asia (30%) and from biomass (28%) (with slightly more than half of biomass coming from north of 40 N)."...


-----------------------