Plants across the world absorb and release carbon dioxide faster than previously thought, according to a new study from Imperial College London. The research, led by Dr. Heather Graven, reveals that the global carbon stored by plants is more short-lived and susceptible to climate change than previously believed.

These findings have significant implications for our understanding of nature’s role in mitigating climate change, particularly for nature-based initiatives like mass tree-planting projects. The study suggests that current climate models significantly underestimate how much CO2 is absorbed by vegetation annually and overestimate the duration it is retained. Dr.

Graven, a Reader in Climate Physics at Imperial’s Department of Physics, said, “Plants across the world are actually more productive than we thought they were.” The research shows that while carbon is taken up by plants quicker than thought, it is also locked up for a shorter time, meaning carbon from human activities will be released back into the atmosphere sooner than previously predicted. “Many of the strategies being developed by governments and corporations to address climate change rely on plants and forests to draw down planet-warming CO2 and lock it away in the ecosystem. But our study suggests that carbon stored in living plants does not stay there as long as we thought,” Dr.

Graven noted.

Carbon dynamics in plant ecosystems

The researchers used radiocarbon (C14), a radioactive isotope of carbon, combined with model simulations to understand how plants use CO2 at a global scale.

This approach provided insights into the interaction between the atmosphere and the biosphere. By examining C14 accumulation in plants between 1963 and 1967, a period with no significant nuclear detonations, the authors could assess how quickly carbon moves from the atmosphere to vegetation and its subsequent dynamics. Co-author Dr.

Charles Koven from Lawrence Berkeley National Laboratory commented, “These observations show that the growth of plants at the time was faster than current climate models estimate. This implies that carbon cycles more rapidly between the atmosphere and biosphere than previously thought.”

Dr. Will Wieder from the National Center for Atmospheric Research added, “Scientists and policymakers need improved estimates of historical land carbon uptake to inform projections of this critical ecosystem service in future decades.”

The study highlights the necessity to improve theories about plant growth and interactions with ecosystems to adjust global climate models.

The work, honoring the legacy of German physicist Ingeborg Levin, who contributed significantly to radiocarbon and atmospheric research, underscores the complexities of the biosphere’s role in mitigating climate change. The findings emphasize the urgent need for rapid reduction in fossil fuel emissions to combat climate change effectively. The study prompts a reevaluation of the potential and limitations of nature-based solutions, underlining the importance of a comprehensive approach to address the global climate crisis.