A decades-old international treaty banning ozone-depleting substances has successfully averted mass sea ice loss, delaying the first ice-free summer in the Arctic by up to 15 years, a new report says. research has been published.of The study was published in the journal May 22 Proceedings of the National Academy of Sciences (PNAS) We have found that regulating these harmful substances can slow further global warming.
[Related: Fixing the ozone hole was a bigger deal than anyone realized.]
In 1985, scientists first discovered a hole in the ozone layer above Earth’s South Pole. Representatives from countries around the world have come together to create a treaty to protect the ozone layer that protects the earth from harmful levels of ultraviolet radiation from the sun.as a result Montreal Protocol Signed in 1987 and entered into force in 1989, it aims to reduce atmospheric concentrations of ozone-depleting substances (OSDs) commonly used in refrigerators, air conditioners, fire extinguishers and aerosols.it remains The only UN treaty ratified by nations worldwide.
The new study shows that the treaty’s impact will depend on future emissions and extend to the Arctic.
“The first ice-free Arctic summer, the virtual absence of sea ice in the Arctic Ocean, will mark a major milestone in the climate change process, and our discovery was a surprise to us. said study co-author Lorenzo, a geophysicist at Columbia University.Polvani said in a statement. “Our results show that the climate change benefits of the Montreal Protocol are not in the distant future. The Protocol is slowing the melting of Arctic sea ice even at this very moment. It succeeds.” It is the role of a climate change treaty that has been fully implemented and will bring tangible results within decades of its entry into force.”
According to Polvani and other climate scientists, the rapid melting of Arctic sea ice is the biggest and most obvious sign of human-made climate change. The first completely ice-free Arctic summer Likely to happen by 2050, mainly due to an increase in the concentration of carbon dioxide in the atmosphere. Other potent greenhouse gases, such as ODS, also contributed to this warming, but their concentrations in the atmosphere were began to decline in the mid-1990s.
In this new research, the two authors analyzed new climate model simulations and found that the changes implemented by the Montreal Protocol would delay the first appearance of the ice-free summer Arctic by up to 15 years, depending on future carbon dioxide emissions. discovered. They compared his ODS warming estimates with and without the Montreal Protocol under his two scenarios of future carbon dioxide emissions from 1985 to 2050. If the Montreal Protocol had not been enacted, the estimated average global surface temperature would be about 0.9°F warmer, and their results show that the polar cap in 2050 would be nearly 1.8°F warmer.
[Related: Fixing the ozone hole was a bigger deal than anyone realized.]
“This significant climate mitigation has been attributed solely to reduced greenhouse gas warming by regulated ODS, with avoidance of stratospheric ozone loss playing no role,” co-author Applied Mathematics, University of Exeter author and atmospheric scientist Mark England said. said in a statement. “ODS are not as abundant as other greenhouse gases such as carbon dioxide, but they can have a significant impact on global warming. Stopping these effects was not the main purpose of the Montreal Protocol, but it was a nice byproduct.”
Both authors emphasized the importance of continued vigilance with atmospheric concentrations, especially as ODS concentrations increased slightly from 2010 to 2020, as the ozone layer recovered. In 2016, amendments to the Montreal Protocol (known as the Kigali Amendment) were made to phase out the production and consumption of some hydrofluorocarbons (HFCs) have been added. HFCs are not direct ozone depletors, but they are potent climate change-inducing gases that can contribute to global warming. An increase in CFC usage was detected in 2018, trace to china, but that was quickly fixed. Scientists say the Kigali Amendment is estimated to be: Avoid 0.5-0.9°F warming by 2100does not include the impact of HFC-23 emissions.
