Plants are a Better CO2 Sink Than Previously Understood, New Research Finds

     This post and the one that will follow it, show that climate models should be adjusted toward less warming. Both stories suggest, based on new research, that we need to revise carbon sink estimates, this one for plants and the following one for the ocean. These new estimates for terrestrial and marine carbon sinks should be incorporated into existing climate models, since both are significant changes to current models, both in favor of less future warming. That is good news, though perhaps not for catastrophists attached to their scenarios. There will also be a third post based on new research that shows that the Arctic boreal zone has been increasing as a carbon source and decreasing as a carbon sink. I don’t think this has implications for future warming as there is nothing new to add to the model. It is rather a study that helps quantify the significant acceleration of warming in the Arctic with effects like the loss of Arctic Sea ice.

 

Plants a Better CO2 Sink

      New research from Cornell University and the DOE’s Oak Ridge National Lab (ORNL) recently found that terrestrial plants are absorbing 31% more, or 38 billion metric tons, or petagrams, more CO2 than previously estimated. If confirmed, it is quite huge, and future warming estimates should be adjusted downward. The amount of carbon dioxide that plants absorb and wipe from the atmosphere is called “Terrestrial Gross Primary Production (GPP).”

According to Phys.org:

“To estimate this updated GPP, researchers employed two key approaches. Instead of monitoring satellite images which could interfere with the cloud cover, they used high-resolution data from environmental monitoring towers. Another approach they used was to measure the photosynthesis in plants by tracing the path of the molecule carbonyl sulfide (OCS). OCS follows a process similar to carbon dioxide as it travels from the air, enters the leaf tissues, and makes its way inside chloroplasts, the factories where photosynthesis happens. The researchers assured that OCS is a reliable indicator of worldwide GPP.”

The researchers studied photosynthesis data from all over the world, seeking to better understand and represent: “mesophyll diffusion,” the process in which OCS and CO2 move from the leaf tissues into the chloroplasts where carbon fixation occurs.”

“Apart from a detailed understanding of mesophyll diffusion and carbon sequestration, the study revealed that pan-tropical forests play a significant role in guzzling down more carbon than they release into the atmosphere. Researchers believe that this refined knowledge will enable them to better predict, understand, and control climate change, while also illuminating how natural ecosystems can be cultivated as marvelous “land sinks” that sop up carbon dioxide from the air and store it in biomass or wood.”

That suggests that tropical forest preservation is more important than previously realized and that enabling and designing more tropical forestation through controlled reforestation could have more carbon sequestration powers. The researchers conclude that the total global terrestrial carbon uptake is 157 petagrams, instead of the 120 petagrams previously estimated by satellite modeling. According to the abstract of the October 2024 paper in Nature:

“This disparity is a source of uncertainty in predicting climate–carbon cycle feedbacks9,10. Here we infer GPP from carbonyl sulfide, an innovative tracer for CO2 diffusion from ambient air to leaf chloroplasts through stomata and mesophyll layers. We demonstrate that explicitly representing mesophyll diffusion is important for accurately quantifying the spatiotemporal dynamics of carbonyl sulfide uptake by plants.”

“This difference predominantly occurs in the pan-tropical rainforests and is corroborated by ground measurements, suggesting a more productive tropics than satellite-based GPP products indicated. As GPP is a primary determinant of terrestrial carbon sinks and may shape climate trajectories, our findings lay a physiological foundation on which the understanding and prediction of carbon–climate feedbacks can be advanced.”

     Below are a few figures from the paper that are dimmed out. One might be able to at least glean the level of improvement graphically.

 

 

References:

 

Plants Are Absorbing 30% More CO2 Than Expected- Here’s What It Means for Climate Change. Green Matters Staff. Green Matters. January 21. 2025. Plants Are Absorbing 30% More CO2 Than Expected- Here’s What It Means for Climate Change

Terrestrial photosynthesis inferred from plant carbonyl sulfide uptake. Jiameng Lai, Linda M. J. Kooijmans, Wu Sun, Danica Lombardozzi, J. Elliott Campbell, Lianhong Gu, Yiqi Luo, Le Kuai & Ying Sun. Nature volume 634, pages855–861.October 16, 2024. Terrestrial photosynthesis inferred from plant carbonyl sulfide uptake | Nature