NASA Probes Pyrocumulonimbus Clouds in Wildfire Study

In late 2023, NASA revealed findings on pyrocumulonimbus (pyroCb) clouds, towering storm systems formed by intense wildfires. These clouds inject smoke into the stratosphere, significantly impacting global climate dynamics.

The study focused on pyroCb events during Australia’s Black Summer fires of 2019–2020, which burned over 18 million hectares and released about 715 million tonnes of CO2 equivalent, as reported by the Australian Department of Industry. Satellite data from NASA’s CALIPSO confirmed that these wildfires produced pyroCb clouds reaching altitudes over 16 kilometers.

“PyroCbs are an underestimated force in the climate system,” said Susan Strahan, an atmospheric scientist at NASA’s Goddard Space Flight Center. “Their ability to transport smoke into the stratosphere means they create a direct pathway for wildfire emissions to affect atmospheric composition on a global scale.” The smoke from these clouds can linger for months, warming the atmosphere while cooling the surface below and disrupting regional weather patterns.

NASA's research combines satellite data and atmospheric models to quantify the feedbacks initiated by pyroCb smoke. A 2022 paper in Nature Communications discussed how Australian pyroCb smoke altered Southern Hemisphere jet stream dynamics, accelerating ozone depletion. These impacts underscore the significance of pyroCb events in climate models.

As wildfires intensify due to climate change—a trend projected by the UN Environment Programme to increase extreme fire events by 30% globally by 2050—understanding pyroCb formation becomes essential. NASA has expanded its pyroCb monitoring, deploying the Multi-Angle Imager for Aerosols (MAIA) in 2022 and utilizing data from the Earth Observing System to track aerosol dispersion and assess public health risks from wildfire smoke.

However, significant gaps remain. Current climate models struggle to accurately incorporate pyroCb impacts, according to Strahan. “The unpredictability of these events, coupled with their dual impacts—localized air quality degradation and stratospheric perturbations—makes them a ‘wild card’ in atmospheric studies.”

To tackle these challenges, NASA collaborates with international institutions. The Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign, in partnership with the National Oceanic and Atmospheric Administration (NOAA) since 2019, combines airborne measurements with ground observations to enhance aerosol modeling.

The urgency for improved monitoring aligns with rising public and governmental awareness of wildfire risks. In 2023, the EU’s Copernicus Atmosphere Monitoring Service reported over 41 megatonnes of carbon emissions from wildfires during the northern hemisphere’s summer. Events like Canada’s June wildfire smoke plume, which blanketed New York City in hazardous haze, highlight the need for better predictive systems.

NASA’s findings emphasize the need for increased investment in climate adaptation and resilience infrastructure. Stratospheric aerosols from pyroCbs could amplify warming in sensitive regions or disrupt hydrological cycles, reminding us that localized fires can have global repercussions.

As wildfires become more frequent, the window for action narrows. Questions about the long-term climate forcing effects of pyroCbs and their interactions with other atmospheric systems ensure this research area remains crucial.