Record-high CO₂ emissions from boreal fires in 2021

Area of Science:

• Climate Science
• Ecology
• Atmospheric Science

Background:

• Extreme wildfires are increasing globally and impacting Earth's climate.
• Boreal forests, a vast and rapidly warming biome, receive less research attention than tropical forests regarding wildfire impacts.
• Warmer and drier conditions are leading to expanding wildfire activity in boreal regions.

Purpose of the Study:

• To monitor fire emissions in boreal forests using a satellite-based atmospheric inversion system.
• To quantify the contribution of boreal fires to global carbon emissions.
• To understand the drivers and implications of increasing extreme boreal fire events.

Main Methods:

• Utilized a satellite-based atmospheric inversion system for fire emission monitoring.
• Analyzed fire emissions data specifically for boreal forest regions.
• Correlated fire emissions with climate data, including water deficit.

Main Results:

• Boreal fires contributed 23% (0.48 billion metric tons of carbon) to global fire emissions in 2021, the highest fraction since 2000.
• 2021 saw synchronous extreme water deficits in North American and Eurasian boreal forests, exacerbating fire conditions.
• Boreal fire emissions significantly exceeded their typical 10% share of global emissions.

Conclusions:

• Increasing extreme boreal fires pose a significant threat to climate mitigation efforts.
• Stronger climate-fire feedbacks in boreal regions are evident and accelerating.
• Urgent attention and mitigation strategies are needed for boreal forest fire management.