Earth system models overstate carbon removal: New findings suggest nitrogen fixation is 50% lower than thought

[NickB79]

https://phys.org/news/2025-11-earth-overstate-carbon-nitrogen-fixation.html

High levels of atmospheric carbon dioxide intensify climate change, but high carbon dioxide levels can also stimulate plant growth. Plant growth removes carbon dioxide from the atmosphere, partially mitigating the effects of climate change. However, plants only grow faster in the presence of high levels of carbon dioxide if they can also acquire enough nitrogen from the atmosphere to do so.

The actual amount of nitrogen acquired from the atmosphere was reassessed in a previous study co-led by Columbia faculty that was published this summer; it was shown to be significantly lower than previously estimated.

The climate implications of the overestimation of nitrogen fixation are the focus of a new study published in the Proceedings of the National Academy of Sciences. This new study found that, in Earth system models, the amount of natural nitrogen fixation directly correlates to future plant growth. Therefore, the lower amount of natural nitrogen fixation than previously thought means that Earth system models have been overestimating future plant growth.