Black carbon is a carbonaceous aerosol. It is produced both naturally and by human activities as a result of the incomplete combustion of fossil fuels, biofuels, and biomass. Primary sources include emissions from diesel engines, cook stoves, wood burning and forest fires. Black carbon particles strongly absorb sunlight and give soot its black color. Thus, black carbon has emerged as a major contributor to global climate change, possibly second only to CO2 as the main driver of change.