Earth’s ozone layer still recovering despite setback
Ozone-destroying CFCs were banned in 2010 but returned with temporary spike
The hole in the Earth’s protective ozone layer is still recovering despite a short-term surge in harmful gases blamed on China, researchers concluded.
Chlorofluorocarbons, or CFCs, are chemicals once found in everything from hairspray to refrigerants and are known to destroy the ozone layer.
The 1987 Montreal Protocol mandated that the production of CFCs had to stop by 2010. But just a few years later, levels of CFCs started to rise.
This increase led scientists to anticipate a substantial delay in the ozone’s recovery from two years to up to 18 years. But the new findings, published in two studies in Nature, reveal the recovery may have avoided significant delays.
A new study by the National Oceanic and Atmospheric Administration found that global emissions of CFC-11, a key chemical, fell to 52,000 metric tonnes in 2019, which is comparable with the 2008-2012 average – before the unexpected emissions surge.
At the time the rise was discovered, it was largely attributed to unauthorised production of chemicals in China, but in 2017 researchers determined that equipment manufactured before the ban went into effect had been degrading and leaking significant volumes of CFCs into the atmosphere.
“It seems that any substantial delay in ozone-layer recovery has been avoided, perhaps owing to timely reporting and subsequent action by industry and government in China,” the NOAA study researchers wrote.
In 2018 and 2019, China conducted internal inspections and tightened up its enforcement of CFC regulations, and a second new study by researchers at the University of Bristol in the UK suggests they worked.
Using atmospheric observations from South Korea and Japan, the researchers found that about 60 per cent of the global decline in CFC-11 was from reduced emissions from eastern China after 2017.
“The decline in global emissions suggests a substantial decrease in unreported CFC-11 production,” the researchers wrote.
Updated: February 11, 2021 09:28 PM