Possible effect of boreal wildfire soot on Arctic sea ice and Alaska glaciers

The role of black carbon (BC) soot in the Arctic as an agent of climate warming through forcing/feedback of sea ice/glacier albedo is an uncertainty in need of addressing. In-situ measurements of BC-aerosols and gas byproducts from the FROSTFIRE experiment burn, 8–11 July 1999, are used with a coupled high-resolution wind field/empirical fall-out model to assess transport/dispersion and estimate deposition. Results suggest that BC-aerosols (soot) are quickly transported from central Alaska to the Arctic Ocean region of multi-year sea ice and to southern Alaska glaciers, where up to 20% can be deposited. The estimate of BC soot concentration from Alaska boreal wildfires favorably compares to in-situ sea ice observations made in 1998 and snow albedo observation on Gulkana Glacier in 2001. We hypothesize that northern boreal wildfires are a possible contributor in the reduction of first/multi-year sea ice/glacier extent by enhancing summer melting from albedo reduction. Should the occurrence and severity of northern boreal wildfires continue as in summer 2004, during which more than 670 km2 burned and was the worst wildfire year on record, there will be implications for Northern hemisphere climate warming.