Soot responsible for over 90% of polar warming?

Scientific American reports that soot - from smokestacks, vehicle tailpipes, and even forest fires[1] may be a major factor in polar warming.

Impure as the Driven Snow: Scientific American:

DIRTY TRICK:  Soot is three times more effective than carbon dioxide [...] at melting polar snow, triggering feedback loops that further accelerate polar warming.

In the atmosphere, such aerosols [as soot] can significantly cool the planet by scattering incoming radiation or helping form clouds that deflect incoming light. But on snow [...] such dark carbon [...] may be responsible for as much as 94 percent of Arctic warming.

[1] Why do they say "even"? Let them spend a typical summer in the southwest, and be amazed at the amount of soot a wildfire can dump into the air...

Seriously, the researchers cited in the article say that about 80% of the observed soot comes from human sources. I bet a lot of that comes from around Karaganda :)