Montreal Gazette: A new U.S. study probing the role of soot emissions in driving global climate change highlights the severe impact that black carbon in the air and dirty snow on the Earth’s surface have in melting Canada’s Arctic sea ice. During a 10-year investigation detailed in the latest issue of the Journal of Geophysical Research, Stanford University scientist Mark Jacobson isolated the widespread warming effects of soot — the visible residue of burned wood, crops, oil, biomass and other fuels …