Every day, our scientific understanding of climate change grows more sophisticated. Too often, the new information can’t be described as anything but plain bad news, as with research reported today in the Washington Post detailing how warming has “irreversibly altered” and “destabilized the Earth’s poles.”
Sometimes, however, the news isn’t all bad. Into this category falls a groundbreaking study published last week by Nature magazine that adds to our knowledge about the relationship between rising atmospheric CO2 and growing photosynthesis by plants (which allows them to absorb more CO2.) According to a summary published by the Lawrence Berkeley National Laboratory, home institution of the study’s lead author, Trevor Keenan, plants are “buying us time to slow climate change,” but increased rates of photosynthesis are not enough on their own to stop it.
The study involved the pioneering use of remote sensing and machine learning to find that:
plants are indeed photosynthesizing more, to the tune of 12% higher global photosynthesis from 1982 to 2020. In that same time period, global carbon dioxide concentrations in the atmosphere grew about 17%, from 360 parts per million (ppm) to 420 ppm. The 12% increase in photosynthesis translates to 14 petagrams of additional carbon taken out of the atmosphere by plants each year, roughly the equivalent of the carbon emitted worldwide from burning fossil fuels in 2020 alone.
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The study will aid policymakers tasked with measuring the value of “land sinks” in plans to reduce atmospheric carbon and slow climate change. While these sinks are currently a mitigating factor, they should not be relied upon, and their lifespan remains unclear.
“We don’t know what the future will hold as far as how plants will continue to respond to increasing carbon dioxide,” said Keenan. “We expect it will saturate at some point, but we don’t know when or to what degree. At that point land sinks will have a much lower capacity to offset our emissions. And land sinks are currently the only nature-based solution that we have in our toolkit to combat climate change.”
Read the full study in Nature here.