Ozone layer accord in 1987 may have helped slow climate change, new study finds

Source: 1News

An international agreement to help protect the ozone layer may have also helped slow the rate of climate change, according to a new study.

Co-author professor Matthew England says with the chlorofluorocarbons (CFCs) sorted, the next big step is "zeroing out" carbon dioxide emissions.

CFCs were banned when the Montreal Protocol was signed in 1987.

Often used in solvents or refrigerating agents, it was discovered they were destroying the ozone layer, particularly over the Antarctic.

Last year NASA found the ozone layer is recovering thanks to the ban, but research published today suggests it may have had another positive side effect.

"By mass CFCs are thousands of times more potent a greenhouse gas compared to CO2, so the Montreal Protocol not only saved the ozone layer but it also mitigated a substantial fraction of global warming," lead author Rishav Goyal says.

By 2050, the Earth is estimated to be on average at least 1C cooler than it would have been without the Montreal Protocol, the researchers say.

António Guterres was joined by representatives of nearly 200 nations in Madrid for a two-week meeting to tackle global warming.

The temperature difference is even more stark in regions such as the Arctic, at 3C to 4C.

According to the research, the extent of summer sea ice around the Arctic is around 25 per cent greater than it would have been without the CFC emission reductions.

"The success of the Montreal Protocol demonstrates superbly that international treaties to limit greenhouse gas emissions really do work," Mr England says.

"They can impact our climate in very favourable ways, and they can help us avoid dangerous levels of climate change."

The Montreal Protocol was signed by 46 countries and ratified by 197, including New Zealand.

However, the latest big attempt for a global conservation treaty hasn't quite been as unified.

US President Donald Trump famously announced the country would withdraw from the Paris Climate Agreement, which aims to limit warming to 1.5C, in 2017.

Today's research was published in the Environmental Research Letters journal.