Tuesday, June 22, 2021

How Saving the Ozone Layer in 1987 Slowed Global Warming

New research published in Environmental Research Letters has revealed that thanks to the Montreal Protocol, today’s global temperatures, and global warming in general, are considerably lower. And by mid-century, the Earth will be — on average — at least 1°C cooler than it would have been without the agreement. Mitigation is even greater in regions such as the Arctic, where the avoided warming will be as much as 3°C-4°C.

The lead author of the paper, Rishav Goyal, said:

The findings were made inadvertently when the team set out to quantify how the Montreal Protocol had affected atmospheric circulation around Antarctica. To get their results, the researchers modeled global climate under two scenarios of atmospheric chemistry — one with, and one without the Montreal Protocol being enacted.

Below is the film The Hole — a film on the Montreal Protocol narrated by Sir David Attenborough.

They then extended these simulations into the future using conservative estimates for unmitigated CFC emissions — set to 3 percent growth per annum, much less than the observed CFC growth rates at the time of the establishment of the Montreal Protocol. Their results therefore likely underestimate the actual impact of the international treaty to reduce CFCs.

Montreal Protocol reduced global warming

The success of the Montreal Protocol in mitigating climate change is even more striking when focusing on regional domains. For example, warming of between 0.5°C and 1°C has already been avoided over North America, Africa, and Eurasia. By mid-century, avoided warming in some of these areas will be 1.5°C-2°C and over the Arctic avoided warming will be as much as 3°C-4°C.

The researchers also found an amount of avoided ice melt due to the Protocol, with the extent of sea ice around the Arctic during summer around 25 percent greater today than it would have been without any reduction in CFC emissions. The avoided warming over Greenland also suggests that the observed accelerating ice sheet melt there and the associated sea-level rise have also been reduced by the Protocol. Co-author Dr. Martin Jucker said:

Looking ahead, co-author Prof. Matthew England said:

Provided by: Alvin Stone,  [Note: Materials may be edited for content and length.]

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Troy Oakes
Troy was born and raised in Australia and has always wanted to know why and how things work, which led him to his love for science. He is a professional photographer and enjoys taking pictures of Australia's beautiful landscapes. He is also a professional storm chaser where he currently lives in Hervey Bay, Australia.

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