Once again, vast expanses of Canadian wilderness they are on fire, threatening cities and forcing thousands of people to flee. He appears to be a leak of “zombie fires”: wildfires from last year that were never actually completely extinguished, but continued to burn underground, reigniting ground vegetation again this year. They have been fuming, once again, in the cities of the northern United States. That haze is loaded with a darker form of carbon, compared to its famous cousin CO.2: black carbon. Through May 16, monthly carbon emissions from wildfires exceeded 15 megatonsrising above previous years.
Black carbon consists of small particles generated from the incomplete combustion of fuels, whether Canadian trees and soils, cooking fuels such as wood and charcoal, or charcoal. “The problem is that they don’t burn efficiently,” says Yusuf Jameel, who investigate Black carbon at Project Drawdown, a climate solutions nonprofit. “They don’t burn properly. That is why they emit many poisonous particles and gases.”
In a home in an economically developing country that might use a wood stove for cooking, that can lead to catastrophic indoor air quality and all kinds of health consequences, including heart problems, difficulty breathing, and cancer. If black carbon rises from these Arctic wildfires, it darkens the ice and snow, dramatically accelerating melting. “It is a big health problem. It is a big climate problem,” says Jameel. “And yet it is barely mentioned when we talk about a powerful climate solution.”
CO2 and methane (CH4) get all the attention as planet-warming gases. And rightly so: humanity has to massively reduce its emissions as quickly as possible to stop climate change. At the same time, we are neglecting simple ways to reduce black carbon emissions.
Although it is not a greenhouse gas like CO2 and methane, black carbon has its own significant impacts on the climate. Clouds of dark smoke from forest fires, for example, absorb the sun’s energy, warming the atmosphere. While the CO2 remains there for centuries, and methane for about a decade, the black carbon falls back to Earth after no more than a few weeks.
That short lifespan is fortunate, from an atmospheric point of view, but unfortunate for the Arctic and other frigid places where black carbon lands. Snow and ice can typically persist because they are highly reflective and reflect the sun’s energy back into space. But if they are sprinkled with black charcoal, the dark coloring absorbs the heat. “You can see these small particles drilling holes in the ice. It’s very dramatic how black carbon can absorb sunlight and heat things up,” says Brenda Ekwurzel, director of scientific excellence at the Union of Concerned Scientists. And if the highly reflective snow or ice completely melts, she says, you discover darker soil or ocean beneath, which absorbs sunlight much more easily, helping to warm the region.
This then forms a feedback loop. As the world warms, wildfires in northern latitudes are becoming more frequent and intense, as higher temperatures absorb moisture left in vegetation. Warming also provides more ignition sources for these fires by encouraging thunderstorms: models show that lightning in the Arctic could double by the end of the century. The wildfires have become so intense that they are even generating their own storm clouds made of smoke, which wander across the landscape causing new fires.