New research indicates that CO2 uptake of plants via photosynthesis is 31% higher than established estimates currently used in many global carbon cycle models.
Satellite optical observation-driven data has been widely used to estimate plant CO2 uptake since the 1980s. However, these observations can be hindered by clouds and other quality issues, prompting a team led by Cornell University with support from the Department of Energy’s Oak Ridge National Laboratory (ORNL) to devise a new approach.
To assess the amount of CO2 removed from the atmosphere by plants (a process known as Terrestrial Gross Primary Production – GPP), the academics utilized a model that followed the movement of a specific chemical compound from the air into plant cells.
The compound, carbonyl sulfide, follows a similar path through the cells of a leaf as CO2 which meant the team identified it as a useful, globally scalable proxy for the photosynthesis process.
Tracking the movement of carbonyl sulfide indicates that 157 billion metric tons of carbon are sequestered annually through GPP, compared to the previous estimate of 120 billion metric tons.
The largest disparity between the two models is in the pan-tropical rainforests, with the new method suggesting that these regions are even more crucial carbon sinks than previously thought.
The results of this study, published in Nature, represent “a critical step in improving our predictions of future CO2 in the atmosphere, and the consequences for global climate,” according to Peter Thornton, Corporate Fellow and lead for the Earth Systems Science Section at ORNL.
