Stopping climate change, if at all, will be much harder than previously thought.. Some of the hopes of science Plants, which release oxygen by converting CO2 and water into carbohydrates, are among the main carbon sinks on the planet.. Scientists thought that as the CO2 level in the atmosphere increased, photosynthesis rates would increase worldwide, which would stop global warming. And this happened in the last century, but since 2000 these rates have slowed down because the atmosphere has become drier. And the less water there is, the less photosynthesis there is and the more CO2 there is in the environment.
A team of earth scientists from the Grassland Research Institute of the Chinese Academy of Agricultural Sciences, in collaboration with colleagues from several institutions in the United States, found the following evidence: Increase in photosynthesis rates caused by increasing carbon dioxide worldwide has slowed significantly.
In their study published in the journal ‘Science’, the group of researchers measured changes in global photosynthesis rates in recent years. They did not expect the terrible results obtained.
Previous research has shown that As atmospheric CO2 levels increased over the past century, plants took advantage of the increase in gas by speeding up photosynthesis and extracting more carbon from the atmosphere..
The net effect was: stop global warming. Until 2000. New research showed that: The increase in CO2 in the atmosphere so far this century has slowed the rate of increase in global photosynthesis because the atmosphere has also become drier..
Everything changed in 2000
To learn more about the global rate of photosynthesis, researchers examined data collected by ground-based monitors around the world between 1982 and 2016. These monitors collect environmental statistics such as CO2 and water amounts in the air.
The team also collected satellite images of areas covered with vegetation. They then combined multiple machine learning applications with the images to find changes that are difficult to see with the naked eye, such as leaf colors. photosynthesis rates.
The team then built models with the resulting data to graphically illustrate changes in global photosynthesis rates from 2000 to the present. Finally, they used models to predict future changes.
Researchers found that the results of previous studies were true: As CO2 levels increased over the past century, so did global photosynthesis rates.
However Everything changed since 2000: The increase in photosynthesis rates began to decline. The most serious aspect of the case is this: Scientists think it is “possible” that these rates will stop increasing completely in the near futureAs the world gets warmer and drier.
The actual result would be global warming will accelerate further If it does not substantially reduce greenhouse gas emissions, it will seriously endanger the survival of life on the planet. But there’s more: Application nature based solutions (SBN) To fulfill the commitments made in the Paris Agreement.
17% more CO2 in the atmosphere
A study published two years ago in the journal Nature revealed the following: Global photosynthesis increased by 12% between 1982 and 2020. And in the same time period, CO2 concentration in the atmosphere increased by 17 percent.
This increase in photosynthesis led to plants pulling an additional 14 petagrams of carbon from the atmosphere each year; This is roughly equivalent to the carbon emitted worldwide by burning fossil fuels in 2020 alone.
However, not all of the carbon taken from the atmosphere through photosynthesis is stored in ecosystems; most of it is later released into the atmosphere through respiration. And in any case, this study already warned that: This massive increase in photosynthesis was far from eliminating the enormous amounts of CO2 emitted by humans. to the atmosphere.
Even so, scientists were optimistic: The increase in photosynthesis “doesn’t stop climate change, but it does help us slow it down,” said the study’s lead author, Trevor Keenan.
This assessment collapsed with the new study; The increase in global photosynthesis is much smaller than the increase in emissionsand gradually decreases as the atmosphere dries.
Because CO2 remains in the atmosphere decades longer than other greenhouse gases that cause global warming, efforts to reduce it are critical to mitigating climate change.
Plants (through photosynthesis) and soil currently trap approximately one-third of the CO2 emissions released into the atmosphere every decade from the burning of fossil fuels.. And less and less.
Reference report: https://www.science.org/doi/10.1126/science.adf5041
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