A new study unveils that plants absorb 31% more CO2 than previously believed, revolutionizing understanding of Earth’s carbon cycle and climate predictions.
Scientists have found that plants around the world are absorbing significantly more carbon dioxide than previously estimated, with new data showing an uptake increase of around 31%. This discovery has substantial implications for predicting future climate scenarios and underscores the essential role that natural carbon sinks play in mitigating greenhouse gas emissions.
Published in the journal Nature, the research re-evaluates global Terrestrial Gross Primary Production (GPP), the largest carbon exchange between land and the atmosphere.
Conducted by a team from Cornell University, supported by the Department of Energy’s Oak Ridge National Laboratory (ORNL), the study places GPP at 157 petagrams of carbon per year in contrast to the long-standing estimate of 120 petagrams. To put this in perspective, one petagram equals 1 billion metric tons, approximately the annual CO2 emissions from 238 million gas-powered vehicles.
The research team achieved this breakthrough by using a novel approach.
By tracking the movement of carbonyl sulfide (OCS), a compound that closely follows the same path as CO2 through plant leaves, scientists could estimate photosynthetic activity more accurately. OCS is easier to measure than CO2, making it a reliable proxy for assessing photosynthesis on a global scale.
Lianhong Gu, a co-author of the study and distinguished staff scientist at ORNL, explained the significance of the new model.
“Figuring out how much CO2 plants fix each year is a conundrum that scientists have been working on for a while… It’s important that we get a good handle on global GPP since that initial land carbon uptake affects the rest of our representations of Earth’s carbon cycle,” Gu said in a news release.
The recalculated GPP has crucial implications for better climate prediction models. Pan-tropical rainforests, in particular, showed a higher carbon absorption rate than previously recorded, suggesting these ecosystems are even more critical in sequestering carbon than once thought.
The findings stress the need to include vital processes like mesophyll conductance, the movement of OCS and CO2 into plant chloroplasts, in climate modeling to enhance the accuracy of predictions.
“We have to make sure the fundamental processes in the carbon cycle are properly represented in our larger-scale models,” Gu added. “For those Earth-scale simulations to work well, they need to represent the best understanding of the processes at work. This work represents a major step forward in terms of providing a definitive number.”
The discovery promises to inform the development of more precise models that incorporate key mechanisms such as mesophyll diffusion.
“Nailing down our estimates of GPP with reliable global-scale observations is a critical step in improving our predictions of future CO2 in the atmosphere, and the consequences for global climate,” Peter Thornton, corporate fellow and leader of Earth Systems Science at ORNL, said in the news release.
In addition to Cornell University and ORNL, collaborators included researchers from Wageningen University, the Carnegie Institution for Science, Colorado State University, the University of California Santa Cruz and NASA’s Jet Propulsion Laboratory.
The revised estimates of plant CO2 uptake highlight not only the complexity of the Earth’s carbon cycle but also the pivotal role of natural ecosystems in regulating the planet’s climate. As scientists continue to refine their models, these findings will be instrumental in addressing some of the most pressing environmental challenges facing our world today.