Tropical Forests Could Absorb 820 Million Tons More CO2 Annually

Young tropical forests play a vital role in combating climate change by absorbing carbon dioxide (CO2) from the atmosphere. A new study led by researchers at the Cary Institute of Ecosystem Studies suggests that these forests could absorb nearly 820 million metric tons of CO2 annually if they receive sufficient nitrogen in their soils. Published in Nature Communications, the study highlights the significant impact of nitrogen on the growth rates of recovering tropical forests.

Sarah Batterman, an ecologist at the Cary Institute and senior author of the study, emphasizes the importance of nitrogen for forest recovery. She states, “Nitrogen is limiting how quickly young forests can regrow. When we added nitrogen to the soil, forests grew back almost twice as fast in the first 10 years.” This faster growth rate not only promotes the restoration of forest ecosystems but also aids in carbon absorption, providing a crucial buffer as the world seeks to reduce greenhouse gas emissions.

Research Findings on Nitrogen’s Impact

Approximately 50% of tropical forests are currently in a state of recovery, having been disrupted by logging, wildfires, and agricultural practices that deplete soil nitrogen. The research team, led by Wenguang Tang of the University of Glasgow, conducted an extensive experiment involving 76 plots in Panama, each measuring 1,600 square meters. These plots varied in age and recovery status, allowing researchers to assess the effects of nitrogen and phosphorus on forest regrowth.

The results were striking. Adding nitrogen led to a 95% increase in growth rates in recently abandoned agricultural fields and a 48% increase in forests that had been recovering for a decade. Batterman described the visual impact, noting, “The plots with added nitrogen looked so much bigger than the ones where we didn’t add nitrogen—the trees were just huge.” In contrast, adding phosphorus did not result in any significant growth improvements, challenging previous assumptions about nutrient limitations in tropical forests.

Strategic Approaches to Forest Restoration

The findings indicate that nitrogen limitation may hinder recovering tropical forests from absorbing an additional 470 to 840 million metric tons of CO2 each year. This potential increase in carbon absorption is equivalent to removing 142 million gasoline-powered cars from the roads annually. However, rather than simply applying nitrogen fertilizer—an expensive and environmentally damaging practice—the researchers advocate for a more strategic approach to forest restoration.

Batterman suggests prioritizing the planting of nitrogen-fixing trees in regenerating forests. These trees can naturally enrich the soil with nitrogen, enhancing growth without the need for chemical fertilizers. The team also recommends focusing restoration efforts in areas affected by nitrogen pollution from agricultural runoff and industrial sources. By doing so, these trees can help mitigate pollution while accelerating forest recovery.

The implications of this research are significant, particularly in the context of rising CO2 levels and increased disturbances to forest ecosystems. As forests continue to face challenges from climate change and human activity, understanding the role of nitrogen in their recovery could provide essential insights for global reforestation efforts.

Batterman concludes, “In the long term, the forests are not going to sequester extra carbon, but in that first 10 years, they can do the job faster. We need to make big changes to reduce our fossil fuel emissions, and unfortunately, that switch is taking longer than we need it to. Reforestation is one tool that can buy us more time to decarbonize and delay the worst effects of climate change.”

For more information, refer to the article titled “Tropical forest carbon sequestration accelerated by nitrogen” published in Nature Communications on January 13, 2026.