Russia fires cause 'brown cloud' may hit Arctic
soot may settle on sea ice & add to melting
"The Russian fires are in principle similar to what you see from other brown clouds," said Henning Rodhe of Stockholm University, a vice-chair of the UNEP Atmospheric Brown Cloud study. "The difference is that this only lasts a few weeks."
Asian pollution has been blamed for dusting Himalayan glaciers with black soot that absorbs more heat than reflective snow and ice and so speeds a thaw.
For the climate, "the main concern ... is what impact the Russian smoke would have on the Arctic, in terms of black carbon and other (particles) in the smoke settling on the sea ice," Ramanathan said.
In past years "we have had episodes of biomass burning that have brought clouds in over the Arctic," said Kim Holmen, director of research at the Norwegian Polar Institute.
Holmen, who runs a pollution monitoring station in Svalbard in the high Arctic, said the air over Russia was fairly stable in recent days, concentrating smoke over land. But a shift in winds, easing pollution in Moscow, could sweep smog northwards.
Arctic sea ice, which shrinks in mid-September to an annual minimum before the winter freeze, now covers a slightly bigger area than in 2007 and 2008, the smallest extents since satellite measurements began in the 1970s.
The exposure of Arctic Ocean water to sunlight is a threat to the livelihoods of Arctic peoples and creatures such as polar bears. It also accelerates global warming, blamed by the UN panel of climate experts on mankind's use of fossil fuels.
Holmen also echoed Russian authorities' worries that the fires may also release radioactive elements locked in vegetation since the Chernobyl nuclear disaster of 1986.
Radioactive isotopes include strontium 90 and caesium 137. Other industrial pollutants such as PCBs could also be freed.