Keep global warming within 1.5-2degrees Celsius can be much more difficult than previously thought, says an article published in the journal Proceedings of the National Academy of Sciences (PNAS). An international team of scientists found that even if all the conditions of the Paris Climate Agreement are met, the average temperature on the planet will be 4-5 degrees Celsius higher than the pre-industrial level. As a result, the planet can turn into a "greenhouse", and a large number of regions will simply become uninhabitable.
The Paris Climate Agreement was signed inDecember 2015. It was joined by 195 countries, including Russia. States agreed to take measures to prevent the average temperature on Earth from rising by more than two degrees Celsius by 2100. At present, the average temperature on Earth is about 1 degree Celsius higher than the pre-industrial level and rises by 0.17 degrees Celsius for each subsequent decade. According to the lead author of the study, Will Steffen of the Australian National University, even if the temperature target is met, the likelihood of the Earth becoming a “greenhouse” remains.
"Greenhouse gas emissions are notthe only factor affecting global warming. Our research shows that global warming of 2 degrees Celsius caused by human activity, even if greenhouse gases are cut off to the atmosphere, can trigger other processes on Earth, often called “response,” which ultimately leads to an even higher average temperatures on the planet, ”says Will Steffen.
“In order to avoid such a scenario, humanity must redirect its activities from a purely operational system into the moderate control of the earth system.”
According to scientists, because of human activity innature, there are other irreversible processes that may contribute to further warming of the atmosphere. These include thawing of permafrost, rise of methane from the ocean floor, a decrease in carbon absorbed by land and ocean, an increase in the intensity of bacterial respiration in the oceans, a decrease in forest areas in the Amazon, a decrease in snow cover in the Arctic in summer. as well as a reduction in polar ice sheets.
"All these elements act like falling knucklesdominoes. One knuckle falls and she knocks over all the others. We will be very difficult or even impossible to stop the fall of a number. If the Earth turns into a greenhouse, many regions will simply become uninhabitable, ”adds study co-author Johan Rokstrom of the Potsdam Institute for the Study of Climate Change.
Scientists claim that to minimizeconsequences not only reduce gas emissions, but also create natural reservoirs for storing carbon through plantations, soil conservation and biodiversity. We also need to develop new technologies to absorb carbon dioxide from the atmosphere and save it underground, experts say.
The researchers suggest that these processesbecome irreversible when overcoming a certain planetary "stress threshold". At the same time, experts are not yet ready to definitely answer the question of where the climatic equilibrium point will be.