According to a new study, the Earth’s ability to absorb about one-third of its carbon emissions through plants could be halved at the current rate of warming within the next two decades. Science advance By researchers at the University of Northern Arizona, the Woodwell Climate Research Center and the University of Waikato, New Zealand. Using more than two decades of data from measurement towers in every major biome worldwide, the team identified a critical temperature tipping point beyond which the plants’ ability to capture and store atmospheric carbon — a cumulative effect that Called “Land Carbon Sink”. – Increases as the temperature rises.
Terrestrial biospheres – the activity of land plants and soil microbes – make up most of the Earth’s “breathing,” exchange. carbon di oxide And oxygen. Ecosystems around the world pull in Carbon Dioxide through photosynthesis and send it back to the atmosphere through the respiration of microbes and plants. Over the last few decades, the biosphere has generally taken in more carbon, reducing climate change.
But as record-breaking temperatures continue to spread around the world, this cannot continue; Researchers at NAU, Woodwell Climate and Waikato have detected a temperature range beyond which plant carbon upstream slows and accelerates carbon release.
Lead author Kathorn Duffy, a postdoctoral researcher at NAU, observed a sharp decline in photosynthesis above this temperature range in almost every biome worldwide, even after removing other effects such as water and sunlight.
“The Earth has a constantly rising fever, and there is a lot to like Human body, We know that every biological process has a range of temperatures at which it performs better, and the function above that deteriorates, “Duffy said. So, we wanted to ask, how much can plants withstand? “
This study is the first to explore the temperature range for photosynthesis from observational data globally. While temperature thresholds for photosynthesis and respiration have been studied in the lab, the Fluxnet data provide a window into what ecosystems across the earth are actually experiencing and how they are responding.
“We know that the temperature optima for humans hovers around 37 ° C (98 ° F), but in the scientific community we had no idea what those optimas were for the terrestrial biosphere,” Duffy said.
He worked closely with researchers at Woodwell Climate and the University of Waikato, who recently developed a new approach to answering that question: macromolecular rate theory (MMRT). With its basis in the principles of thermodynamics, MMRT allowed researchers to generate temperature curves for every major biome and globe.
The results were worrying.
Researchers found that the temperature “peaks” for carbon weathering – 18 ° C for more extensive C3 plants and 28 ° C for C4 plants – already crossing into nature, but no temperature checks on respiration were observed . This means that in many biomes, continuous warming will reduce photosynthesis while rapidly increasing respiration rates, accelerating and accelerating the balance of ecosystems from carbon sinks to carbon sources Climate change.
“several kinds The plants NAU co-author George Koch said, “The details of their temperature responses vary, but all fall into photosynthesis when it gets too hot.”
Right now, the photosynthetic maximum experiences temperatures beyond 10 percent of this photosynthetic maximum. But at current rates of emissions, more than half the terrestrial biosphere can experience temperatures beyond that productivity range by mid-century – and the most carbon-rich biome in the world, including tropical rainforests in the Amazon and Southeast Asia, and Russia and Taiga in Canada would be among the first to hit that tipping point.
“The most special thing in our analysis is that the temperature optima for photosynthesis in all ecosystems was very low,” said Vic Arcus, a biologist at the University of Waikato and co-author of the study. “Combined with the increased rate of ecosystem respiration beyond the temperature we observed, our findings suggest that any Temperature Growth above 18 degrees is probably harmful to terrestrial carbon sinks. Without curbing warming to stay at or below the levels established in the Paris Climate Agreement, the land carbon sink will not offset our emissions and give us time. ”
KA Duffy L al., “How close are we to the temperature tipping point of the terrestrial biosphere?” Science advance (2021). In advance. sciencemag.org/lookup… .1126 / Sciadv.aay1052
Northern Arizona University
Quotes: Earth to reach temperature tempering point in next 20 to 30 years, finds new study (2021, 13 January) on 13 January 2021 https://naveenbharat.org/news/2021-01-earth-temper-years. retrieved from html
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