Climate change: Models ‘underplay plant CO2 absorption’

Global climate models have underestimated the amount of CO2 being absorbed by plants, according to new research. Scientists say that between 1901 and 2010, living things absorbed 16% more of the gas than previously thought. The authors say it explains why models consistently overestimated the growth rate of carbon in the atmosphere. But experts believe the new calculation is unlikely to make a difference to global warming predictions.

The research has been published in the journal, Proceedings of the National Academy of Sciences. Working out the amount of carbon dioxide that lingers in the atmosphere is critical to estimating the future impacts of global warming on temperatures. About half the CO2 that’s produced ends up in the oceans or is absorbed by living things. But modelling the exact impacts on a global scale is a fiendishly complicated business.

In this new study, a team of scientists looked again at the way trees and plants absorb carbon. By analysing how CO2 spreads slowly inside leaves, a process called mesophyll diffusion, the authors conclude that more of the gas is absorbed than previously thought. Between 1901 and 2100 the researchers believe that their new work increases the amount of carbon taken up through fertilisation from 915 billion tonnes to 1,057 billion, a 16% increase.

“There is a time lag between scientists who study fundamental processes and modellers who model those processes in large scale model,” explained one of the authors, Dr Lianhong Gu at Oak Ridge National Laboratory in the US. “It takes time for the the two groups to understand each other.” Via Climate change: Models ‘underplay plant CO2 absorption’.

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