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https://www.sciencealert.com/the-montreal-protocol-turned-out-to-have-an-amazing-world-changing-side-effect>
'A decades-old global environmental pact has averted huge amounts of sea ice
loss in the Arctic, new research shows.
Banning ozone-depleting gases under the historic 1987 Montreal Protocol has
delayed the first, feared ice-free Arctic summer by as much as 15 years, the
study found – once again demonstrating that global treaties can work to huge
effect.
"While stopping [sea ice loss] was not the primary goal of the Montreal
Protocol, it has been a fantastic by-product," says University of Exeter
climate scientist Mark England, who co-authored the study.
Aside from destroying ozone in the atmosphere, the CFCs (chlorofluorocarbons)
outlawed under the Montreal Protocol are also heat-trapping gases. Though not
as abundant as other greenhouse gases such as carbon dioxide (CO₂), studies
like this one show CFCs can have a real impact on global warming.
England and Lorenzo Polvani, a geophysicist from Columbia University in the US,
used climate models to simulate different 'worlds' the Montreal Protocol helped
avoid. They found if the historic treaty had never been enacted, the Arctic
polar cap would be almost 1 °C warmer in 2050, and the first summer without
Arctic sea ice would likely occur seven to 15 years earlier than anticipated,
depending on our future CO₂ emissions.
And that's a conservative estimate: if emissions of ozone-depleting gases had
grown 7 percent per year without the protocol, "the first ice-free Arctic
summer conditions would have occurred as early as the present year," the
researchers write. That's right: Arctic summer ice would already be practically
gone.
Instead, around 7 square kilometers of Arctic sea ice loss has been avoided for
every kilotonne of ozone-depleting gas emissions averted under the treaty,
which entered into force in 1989 and is slowly healing the ozone hole hovering
over Antarctica.
That serendipitous climate benefit amounts to more than half a million square
kilometers of Arctic sea ice not lost by 2020 because of the global pact, the
researchers estimate.'
Via Rixty Dixet.
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
