A groundbreaking study by scientists from 11 countries has highlighted the critical role of forests in mitigating climate change and revealed the various threats imperiling Earth’s vital climate sink. Published in Nature, the study underscores the importance of global forests in absorbing carbon dioxide and calls for immediate action to protect these ecosystems.
The U.S. Forest Service (USFS), which co-led the study, announced on Wednesday that the world’s forests have consistently absorbed carbon dioxide for the past three decades, despite facing regional threats like deforestation and wildfires. “These vital ecosystems have consistently absorbed carbon dioxide for the past three decades, even as disruptions chip away at their capacity,” the USFS said in a statement.
The study shows that forests take up an average of 3.5 ± 0.4 billion metric tons of carbon per year, which is nearly half of the carbon dioxide emissions from burning fossil fuels between 1990 and 2019.
Key findings of the study
Researchers examined long-term ground measurements combined with remote sensing data and found significant regional variations in the capacity of forests to act as carbon sinks:
Boreal Forests:
• Significant decline in carbon sink capacity by 36 percent.
• Factors: increased disturbances from wildfires, insect outbreaks, and soil warming.
Tropical Forests:
• 31 percent decrease in carbon absorption capacity due to deforestation.
• Regrowth in previously abandoned agricultural lands and logged areas partially offsets these losses.
Temperate Forests:
• 30 percent increase in carbon sink capacity.
• Reasons: extensive reforestation efforts, particularly in China.
“Our research team analyzed data from millions of forest plots around the globe,” USFS researcher Yude Pan said in a statement. “What sets this study apart is its foundation in extensive ground measurements—essentially, a tree-by-tree assessment of size, species, and biomass.”
Richard Birdsey of the Woodwell Climate Research Center, another lead author, noted that “the persistence of the global forest carbon sink was a surprise given global increases in wildfire, drought, logging, and other stressors.” He added, “These findings support the potential for improving protection and management of forests as effective natural climate solutions.”
The study’s recommendations include reducing deforestation, promoting reforestation, and improving timber harvesting practices to minimize emissions from logging and related activities. Effective international cooperation, financial and legislative incentives, and deforestation-free supply chains are crucial for sustaining and increasing the forest carbon sink.
Despite efforts to enhance carbon sequestration, significant challenges remain. The world lost around 3.7 million hectares of primary tropical forests last year—a rate of approximately 10 soccer fields per minute. Felling trees released 2.4 metric gigatons of climate pollution into the atmosphere in 2023, almost half of all annual U.S. emissions from burning fossil fuels.
In the United States, green groups cautiously welcomed the USFS introduction last month of a draft environmental impact statement for the proposed national old-growth forest plan amendment, which followed President Joe Biden’s 2022 directive to protect old-growth forests.
Globally, efforts to protect forests face challenges in regions like Canada, Brazil, and Indonesia, where deforestation rates remain high.
Study authors and researchers emphasize the significance of their findings:
“Although soil carbon is not included, this global account underlines the importance of sustainable conservation of protected areas and restoration of the degraded land sector, especially in the tropics,” said Daniel Murdiyarso, a principal scientist at the Center for International Forestry Research and World Agroforestry (CIFOR-ICRAF) and a co-author of the study.
“Harvested wood products (HWP) also need robust scrutiny, in light of the contribution of wood-based industries to global carbon dynamics,” Murdiyarso added.
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