This report focuses on BC (black carbon) because the Arctic Council Task Force on Short-Lived Climate Forcers (henceforth referred to as the Task Force) decided that, among the SLCFs (short-lived climate forcers), BC requires the most additional technical analyses. BC is the carbonaceous component of particulate matter (PM) formed by incomplete combustion of fossil fuels and biomass. BC particles strongly absorb sunlight and give soot its black colour. Sources of BC emit a complex mixture of substances, including organic carbon (OC),nitrates, and sulphates. BC remains in the atmosphere for days to weeks and warms the climate by absorbing both incoming and outgoing solar radiation and by darkening snow and ice after deposition, thereby reducing the surface albedo, or reflectivity. This albedo effect is particularly prevalent in the Arctic region.