A no-nonsense introduction to the worst pollutant on the planet

A tiny aerosol particle called "black carbon" can float in the atmosphere for just a few weeks and profoundly alter the weather. It's one of the main drivers of climate change. But how can one tiny particle change the world? Here is a scientific explanation that pulls no punches.

Image of black carbon aerosol cloud droplets from NASA

Writes Liz O'Connell on SciLogs:

Minuscule dark sooty aerosol particles called black carbon absorb solar radiation. While carbon dioxide lingers in the air for roughly 100 years, airborne particles like black carbon may have a lifespan of only days or weeks before they drift back to ground or are carried down by precipitation. Still, their impact is evident. According to black carbon specialist Tami Bond of the University of Illinois, in one-to-two weeks, one pound of black carbon absorbs 650 times as much energy as one pound of carbon dioxide gas will absorb over the span of 100 years. That makes black carbon a short-lived climate forcer . . .

The impact of sunlight-absorbing black carbon on climate is complex. Functionally, the tiny dark particles absorb solar radiation and hold heat near the Earth . . . When black carbon falls on snow or ice it reduces the ice's albedo, or reflectiveness. Instead of bouncing the sun's rays back into space the darker ice absorbs solar radiation, heats, and melts. Enough black carbon deposited on a glacier's surface speeds glacial melting. Yet the aerosol particles can also promote cloud formation or change cloud reflectivity. Clouds are amazingly versatile and have either a cooling or warming effect. To add to the complexity, sources which emit black carbon often emit other particles; sometimes those co-emitted polluting particles have a cooling effect.

Burning fossil fuels releases a lot of black carbon, but so do forest fires and other natural disasters. O'Connell describes how humans can change the percentage of black carbon in the environment by changing our fuel sources — but she doesn't shy away from explaining how complicated climate is, and how many factors influence warming and cooling. If you want to understand climate change in its full complexity, check out the full article on SciLogs.