Where there's fire, there's soot

Soot is second leading cause of climate change

Vancouver Sun: A new U.S. study probing the role of soot emissions in driving 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 -- from the climate impacts caused by greenhouse gases such as carbon dioxide and methane.

He concluded that soot is currently the No. 2 driver of climate change -- behind CO2 but ahead of methane -- and that curbing emissions of black carbon would produce the fastest, most effective and affordable international response to climate change and the shrinking of the Arctic sea ice...

Jacobson explained that working to reduce soot's effects would have a more immediate impact on the Earth's climate and ice cover because black carbon persists in the environment for a much shorter time than either carbon dioxide or methane. That means reductions in global soot output can quickly curb its heating effects...

Jacobson's research not only accounts for the warming effect of soot as it settles on snow and ice, but also the atmospheric impact as black-carbon particles suspended in the air absorb the sun's heat and create higher ambient temperatures. The subsequent loss of sea ice only reinforces warming by replacing frozen ocean with dark stretches of open water... 'There is a big concern that if the Arctic melts, it will be a tipping point for the Earth's climate.'...

In 2007, the U.S. scientists behind another study of soot's climate impact... identified Canada as key to any global effort to reduce the effect of black carbon emissions. One of the co-authors [said] 'Just as Brazil is the custodian of the Amazon, a world resource whose deforestation has all sorts of negative consequences, so is Canada a custodian of an important swath of snow-covered land that helps to cool the planet.'...

Zender also raised a red flag about increased ship traffic through the Northwest Passage [as] 'likely to exacerbate these effects by putting soot emissions right in the middle of the remaining snow and sea ice. We must think very carefully about this.'

Image source here.