According to a recent study, in the next two decades, at the current rate of temperature increase, the earth’s ability to absorb nearly one-third of the anthropogenic carbon emissions absorbed by plants may be halved. Scientific progress This was done by researchers from Northern Arizona University, Woodwell Climate Research Center and Waikato University in New Zealand. The research team used more than two decades of data from measurement towers in every major biological community in the world to determine a critical temperature critical point, beyond which plants have the ability to capture and store carbon in the atmosphere. This cumulative effect Known as the “terrestrial carbon sink”
The terrestrial biosphere-the activity of terrestrial plants and soil microorganisms-performs many “breaths” of the earth, exchanging carbon dioxide and oxygen. The global ecosystem absorbs carbon dioxide through photosynthesis and releases it into the atmosphere through the respiration of microorganisms and plants. Over the past few decades, the biosphere has generally absorbed more carbon than it released, thereby mitigating climate change.
However, as record temperatures continue to spread across the globe, this situation may not continue. Researchers at NAU, Woodwell Climate, and Waikato have detected a temperature threshold, beyond which the carbon absorption of plants will decrease and carbon release will accelerate.
NAU’s postdoctoral researcher and lead author Kathalyn Duffy noticed that even after removing other effects such as water and sunlight, the photosynthesis of almost every biome in the world drops sharply above this temperature threshold.
Duffy said: “The earth’s fever has been steadily increasing, just like the human body. We know that every biological process has a temperature range in which its performance is best, and the increase in temperature will deteriorate its function.” So, we want to ask, how much can plants bear?”
This study is the first to detect the temperature threshold of photosynthesis from global observational data. Although the laboratory has studied the temperature thresholds of photosynthesis and respiration, the Fluxnet data provides a window into the actual ecosystems on the entire planet and how they respond.
Duffy said: “We know that the optimal temperature for humans is about 37 degrees Celsius (98 degrees Fahrenheit), but our scientific community does not know what the optimal temperature is for the terrestrial biosphere.”
She collaborated with researchers at Woodwell Climate Corporation and the University of Waikato, who recently developed a new method to answer this question: Macromolecular Rate Theory (MMRT). MMRT is based on the principles of thermodynamics, allowing researchers to generate temperature profiles for each major biological community and globally.
The results are shocking.
The researchers found that nature has exceeded the temperature “peak” of carbon absorption (18 degrees Celsius for the more common C3 plants and 28 degrees Celsius for C4 plants), but no respiration temperature was observed. This means that in many biological communities, continued warming will lead to a decline in photosynthesis and an exponential increase in the respiration rate, thereby shifting the balance of the ecosystem from carbon sinks to carbon sources and accelerating climate change.
NAU co-author George Koch said: “Different types of plants vary in the details of temperature response, but when the temperature is too high, the photosynthesis of all plants will decline.”
Currently, less than 10% of terrestrial biospheres experience temperatures that exceed the maximum temperature of photosynthesis. But at current emission rates, as many as half of the terrestrial biosphere may experience temperatures above the productivity threshold by the middle of this century-some of the world’s most carbon-rich biomes, including tropical rainforests in the Amazon and Southeast Asia, and needles in Russia and Canada. Taiga will be the first country to reach this tipping point.
Vic Alkus, a biologist at the University of Waikato and co-author of the study, said: “Our analysis shows that the most amazing thing is that the optimal temperature for photosynthesis in all ecosystems is very low.” “Combined with the increase in the respiration rate of the ecosystem in the temperature range that we have observed, our results indicate that any temperature increase above 18 degrees Celsius may have an adverse effect on terrestrial carbon sinks. Without restraining warming, it Stay at or below the level determined by the Paris climate. According to the agreement, terrestrial carbon sinks will not continue to offset our emissions and buy us time.”
Plants absorb less carbon in a warming world
KA Duffy and others, “How close are we to the temperature limit of the terrestrial biosphere?”, Scientific progress (2021). advances.sciencemag.org/lookup….1126 / sciadv.aay1052
Provided by Northern Arizona University
Citation: The new research found (January 13, 2021) is the time when the earth will reach a critical temperature in the next 20 to 30 years, starting from January 13, 2021 from https://phys.org/news/2021-01- earth-temperature-years.html retrieved
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