For the first time, climate scientists have accurately measured how much greenhouse gases are absorbed and produced by the soil, and unexpectedly found that the "point of no return" will come very soon, in 2060. The reasons for this were revealed in an article published in the journal Nature.
Most scientists studying the Earth's climate today have no doubt that global warming exists and that it will radically change the face of the planet if the rise in temperatures cannot be contained at around 1.5 degrees Celsius. This is supported by the results of measurements from dozens of climatic satellites, thousands of meteorological stations and buoys in the sea, and hundreds of computer models of the planet's climate.
To prevent such a scenario, all countries of the world signed in December 2015 the first universal and binding Paris Agreement to combat global warming. Within its framework, the states voluntarily assumed obligations to significantly reduce greenhouse gas emissions in the next few decades and keep them at this level in the future.
Even before America's withdrawal from the agreement, many climatologists were skeptical about the chances that the Paris agreements would be implemented. The reasons for this were different, associated both with deliberately unfulfillable obligations and the unexpected influence of climatic processes on the way flora and fauna produce and absorb greenhouse gases.
Gentin and his colleagues have discovered another example of how different natural climate processes can accelerate the crossing of the “point of no return,” by studying how global warming will affect the amount of water in the soil.
The fact is that the rate of absorption of CO2 and other greenhouse gases by plants and soil microbes can greatly increase or decrease with a lack or excess of moisture in the soil. Global warming, as observations in recent years have shown, will markedly increase the number of extreme weather events, including floods and droughts, which can greatly affect the carbon cycle between the biosphere, soil and atmosphere.
American scientists have studied these processes in detail, creating a climate model that took into account the latest observations of how the increase in biomass changes depending on the amount of water in the soil.
These calculations unexpectedly showed that sharp fluctuations in soil moisture and a general increase in soil dryness led to the fact that the soil and plants began to absorb about half as much carbon dioxide as they would in a more stable environment. As the frequency of extreme events increases with temperatures, scientists predict the situation will get worse in the future.
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“This is an extremely important discovery. If the processes in the soil continue to develop in the same way in the future, then it will begin to absorb not more, but less carbon dioxide by the middle of the century. This will lead to a sharp increase in the concentration of CO2 in the atmosphere and an even greater acceleration of global warming,”concludes Julia Green, Gentin's colleague.