January 2022

Black carbon – the power of soot

This article is the eleventh in a series focused on the causes and consequences of a warming planet

Have you ever experienced a cloud of black soot coming out of the exhaust of the diesel truck in front of you when the stoplight turns green? A major component of this soot is "black carbon." It is the material formed by the incomplete combustion of fossil fuels. Black carbon is emitted from gas and diesel engines and coal-fired power plants, including other sources that burn fossil fuels. It also comes from the burning of biomass (including wildfires).

Black carbon has negative implications for both human health and our climate. The inhaling of black carbon is associated with several health problems such as respiratory and cardiovascular diseases, cancer, and birth defects. But that is another story. We are concerned about the global warming impacts of black carbon.

Black carbon is not included as a greenhouse gas like carbon dioxide because it is not a gas but a solid. But its warming impact is significant. The bad news is that it is approximately 360,000 times more powerful at absorbing heat than carbon dioxide, according to the EPA. The good news is that black carbon only stays in the atmosphere for about a week.

Because of its short lifetime in the atmosphere, black carbon needs to be constantly replenished in the atmosphere to maintain its warming impact. This provides an opportunity to quickly negate its warming impact by reducing black carbon emissions. Emissions in the US may decline substantially due mostly to controls on new diesel engines. Reductions are also expected in most other developed countries.

In the Arctic, black carbon falls out of the atmosphere and lands on snow. This darkens the surface of the snow and reduces the ability of the snow to reflect sunlight. So more sunlight is absorbed, creating heat that melts the snow.

See the Ag Decision Maker website for more from this series.

Don Hofstrand, retired extension agricultural business specialist, agdm@iastate.edu
Reviewed by Dr. Eugene Takle, retired professor emeritus Iowa State University


Don Hofstrand

retired extension agricultural business specialist
View more from this author
Reviewed by

Dr. Eugene Takle

retired professor emeritus Iowa State University