Plants’ ability to adapt could change conventional wisdom on climate change, U of M study finds

Plants speed up their respiratory metabolism as temperatures rise, leading to a long-held concern that as climate warms the elevated carbon release from a ramped-up metabolism could flip global forests from a long-term carbon sink to a carbon source, further accelerating climate change.

However, a new University of Minnesota study with more than 1,000 young trees has found that plants also adjust – or acclimate – to a warmer climate and may release only one-fifth as much additional carbon dioxide than scientists previously believed, The study, published today in the journal Nature, is based on a five-year project, known as “B4Warmed,” that simulated the effects of climate change on 10 boreal and temperate tree species growing in an open-air setting in 48 plots in two forests in northern Minnesota. Scientists measured how much carbon dioxide the artificially warmed plants respired – released into the air via their leaves – and learned that over time, the trees acclimated to warmer temperatures and increased their carbon emissions less than expected.

Researchers increased temperatures at the test plots by 3.4 degrees C, an increase that might happen by the end of the 21st century, and learned that plants grown and measured at those higher temperatures increased their leaf respiration by an average 5 percent, compared to plants in ambient temperatures. Had the juvenile plants not been acclimated to the higher temperatures, their respiration would have increased by 23 percent over the plants in ambient temperatures.

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