"There’s One Nasty Wildfire Pollutant We’ve Been Ignoring"

"A newly identified particle in smoke, dark brown carbon, can warm the atmosphere by absorbing sunlight."

"Climate change is worsening wildfires. Increases in drought, air temperature, and lightning cause hotter, drier, and longer fire seasons. By 2100, the number of wildfires is projected to spike worldwide by up to 50 percent. What’s more, fires exacerbate global warming when they burn peatlands, rainforests, and other carbon-rich ecosystems. As a result, huge amounts of carbon dioxide are released into the atmosphere, creating a fiery feedback loop.

Aside from releasing large quantities of greenhouse gasses, wildfires also emit various climate pollutants. Wildfire smoke often contains particulate matter that can be broadly categorized into black carbon and organic carbon, says Nishit Shetty, postdoctoral associate at the Virginia Tech Department of Civil & Environmental Engineering. In a study published recently in Nature Geoscience, Shetty and his co-authors have identified a class of organic carbon that has potent warming effects but is often missing from climate models: dark brown carbon.

“‘Dark brown carbon’ is a term we coined for a subset of brown carbon aerosols we discovered in wildfires across the western US,” says Shetty. “While it absorbs less light than black carbon on a per-particle basis, it is about four times more abundant than black carbon in these plumes, which makes it an important contributor to short-term climate forcing.”"

Carla Delgado reports for Popular Science August 31, 2023.

Source: Popular Science, 09/01/2023