Arctic Fires Fill the Skies with Soot

In June and July 2019, more than 100 long-lived and intense wildfires blazed within the Arctic Circle. Most of them burned in Alaska and Siberia, though a few raged even in Greenland. As these fires lofted thick plumes of smoke into the skies, they also launched megatons of tiny, harmful particles into the air.

The animation above shows the concentration of black carbon particulates—commonly called soot—around the Arctic from July 1-29, 2019. The black carbon data come from the GEOS forward processing (GEOS-FP) model, which assimilates data from satellite, aircraft, and ground-based observing systems. To simulate black carbon, modelers include satellite observations of aerosols and fires. GEOS-FP also ingests meteorological data like air temperature, moisture, and winds to project the plume’s behavior.

Black carbon can harm humans and other animals by entering the lungs and bloodstream; it also plays a role in global warming. In the animation above, a burst of sooty emissions appears over Alaska in early July, and the natural-color image below (acquired by NASA’s Aqua satellite) shows thick wildfire smoke swirling over the state on July 8, 2019. So far in 2019, nearly 400 fires have been reported in Alaska.

The third image shows wildfire smoke over Russia on July 24, 2019; it appears as another black carbon burst in the animation. The image was acquired by the Visible Infrared Imaging Radiometer Suite on the Suomi NPP satellite. The blanket of smoke created by multiple fires extends across more than 4.5 million square kilometers of central and northern Asia—acting like a thin cloud blocking sunlight.

“One fire here and there is not a big deal, as far as immediate local weather and climate impacts,” said Santiago Gassó, an atmospheric scientist at NASA’s Goddard Space Flight Center. “But when you have so many fires continuously emitting, the smoke remains in the atmosphere for so long that it can actually change temperature profiles for several days and has a meteorological and climatic impacts.”

Scientists have strong evidence that black carbon can accelerate melting in the Arctic. Dark soot readily absorbs sunlight and warms the atmosphere. It also can fall on top of ice or snow, which darkens the surface, reduces reflectivity, and traps more heat.

Fires in the Arctic have also released large amounts of carbon dioxide this summer, according to data from the Copernicus Atmosphere Monitoring Service, which includes some observations from NASA’s Moderate Resolution Imaging Spectroradiometer instruments. The Arctic fires emitted 50 megatons of CO2 in June 2019, equivalent to Sweden’s total annual emissions and more than the past eight Junes combined. Preliminary data suggest that July 2019 has also registered the highest CO2 in the past decade or so.

One reason so much carbon has been released into the atmosphere is because many of the fires are burning through peatlands. Peat is made of decomposed organic matter and it is a large natural carbon source. Thanks to high temperatures (June 2019 was the hottest June on record), frozen peatlands are drying up and becoming highly flammable. Simple lightning strikes have caused massive peat fires, which tend to burn longer than regular forest fires. Researchers worry that the increase in CO2 from the Arctic fires will warm the atmosphere even more, leading to drier peat soils and consequently more fires.

NASA Earth Observatory images by Lauren Dauphin, using GEOS-5 data from the Global Modeling and Assimilation Office at NASA GSFC, VIIRS data from NASA EOSDIS/LANCE and GIBS/Worldview, and the Suomi National Polar-orbiting Partnership, and MODIS data from NASA EOSDIS/LANCE and GIBS/Worldview. Story by Kasha Patel.

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