November 17, 2023

expert reaction to modelling study of photosynthesis and carbon uptake by plants

A study published in Science Advances looks at photosynthesis and carbon uptake by plants. 

Prof Simon Lewis, Professor of Global Change Science, University College London, said:

“This is a good study, but the interpretation of what this means for the future carbon uptake from the atmosphere and into forests needs care.

“More photosynthesis does not necessarily mean the amount of carbon stored on the land increases. Rapid future climate change will also kill trees, and the balance between carbon gains from photosynthesis and carbon losses from tree death will determine the resulting carbon stock on land.

“Modelling photosynthesis is a lot more advanced than modelling tree deaths. Faster growing trees tend to have shorter lifespans, so it is possible that we could see greater photosynthesis as this study shows, but without large additional increases in carbon stored on the land. Which species of trees flourish and which suffer matters, as well as the overall levels of photosynthesis.”

Prof Mark Maslin, Professor of Climatology, University College London (UCL), said:

“This latest research does little to change our understanding of how the biosphere will respond in the next few decades to increasing atmospheric carbon dioxide and global temperatures.  The authors used the extreme RCP8.5 climate scenario and showed that at very high carbon dioxide levels and very warm temperatures the biosphere would be respond by increasing productivity more than had been previously modelled.  But with current emission pledges and the massive growth of renewable energy the RCP8.5 scenario is already deeply unlikely and we should do everything we can to avoid going anywhere near this disastrous future. The results of this paper are of interest scientifically, but they have little implication for now and do not change the need to get to net zero emissions as fast as possible.”

‘Higher global gross primary productivity under future climate with more advanced representations of photosynthesis’ by Jürgen Knauer et al. was published in Science Advances at 7pm UK TIME on Friday 17 November 2023. 

Declared interests

None to declare