Forest Fires Push Carbon Sequestration to 20-Year Low

The latest data from the World Resources Institute (WRI)’s Global Forest Watch (GFW) and the Land & Carbon Lab present sobering evidence: in both 2023 and 2024, forests absorbed significantly less carbon than their annual averages.

Instead of removing vast amounts of carbon dioxide from the atmosphere, forests only managed to capture about a quarter of their usual sequestration levels.

Alarmingly, 2023 recorded the lowest level of forest carbon absorption in the last two decades, mainly due to the combined loss of stored carbon and the release of greenhouse gases (GHGs) from unprecedented forest fires.

A narrowing gap: From carbon sink to carbon source

Traditionally, forests have acted as vital carbon sinks, absorbing more carbon than they emit. However, recent findings indicate a narrowing gap between forests functioning as net sinks and becoming net carbon sources — a shift with potentially catastrophic consequences.

If left unaddressed, this trend could accelerate climate change, intensify deadly extreme weather events, alter rainfall patterns, and threaten global livelihoods, food systems, and water security.

Over the past 25 years, 80% of forest emissions have been attributed to human activities, primarily agricultural expansion, logging, and land clearance. Agriculture alone accounted for half of the tree cover loss emissions between 2001 and 2024.

However, in 2023 and 2024, a different driver dominated: massive wildfires in South America, Canada, and Russia. Each region emitted an estimated four gigatons of GHGs annually, with fires releasing 2.5 times more emissions than their long-term average.

Regional differences: Sinks, sources, and shifting patterns

The report highlights regions where forests remain strong carbon sinks versus areas where they have tipped into becoming net sources.

• Strong carbon sinks are located in the Eastern United States and China. In the Appalachian region, naturally regenerating forests have rebounded into powerful carbon absorbers, demonstrating the resilience of forest ecosystems when left to recover.
• New carbon sources – Bolivia and Canada. Bolivia’s forests, once net absorbers, became net emitters due to agricultural expansion between 2016 and 2020. In 2023 and 2024, fires became significant sources, accounting for 60% of emissions, with a substantial portion traced to wildfires.

Canada’s boreal forests, meanwhile, faced devastating wildfires that caused 65% of national tree cover loss and contributed 79% of global forest fire emissions in 2023 and 2024.

Remarkably, 74% of these fires occurred in carbon-rich peatlands, where “zombie fires” smoulder through winter beneath the snow, re-igniting in spring and releasing enormous GHG volumes.

In 2024 alone, Canada’s fires accounted for 32% of global tree cover loss and 53% of forest fire emissions.

What needs to change: WRI’s recommendations

To safeguard forests’ ability to act as carbon sinks, the WRI recommends:

• Protecting existing forests and halting further deforestation.
• Proactive fire prevention, including prescribed burns, fuel thinning, and fire-resilient restoration.
• Better management of working forests, such as reduced-impact logging, longer harvest rotations, and planting climate-resilient tree species.
• Forest restoration, both natural and assisted, to strengthen carbon absorption.
• Supporting Indigenous and local communities, who are often the most effective forest stewards. Redirecting funding towards locally led conservation and restoration projects is key.
• Making climate data timely and actionable, enabling effective decision-making.
• Global cooperation, ensuring companies and governments eliminate deforestation from commodity supply chains (e.g., beef, soy, palm oil).
• Cutting fossil fuel emissions, addressing the root driver of climate change.