Levels of ozone-damaging CFC chemicals are falling again, assuaging fears that the ozone layer may have temporarily stopped healing.
Two years ago, a series of atmospheric measurements showed a dangerous plateau in the level of CFCs, chlorofluorocarbons, that led many to warn that regeneration of the ozone layer may be under threat.
But a new study has found that emissions of one particular CFC – trichlorofluoromethane (CFC-11) – are once again falling at a rate consistent with a global ban on CFC production, leading scientists to confirm that the Ozone layer’s decades-long healing process was ‘back on track.’
CFCs are a family of chemicals that were once widely used in households products like refrigerators and aerosol cans. However in the 1980s, scientists studying global warming concluded that the chemicals were contributing to the destruction of the Ozone layer – the part of the Earth’s atmosphere that absorbs most of the sun’s UV radiation. The discovery led to CFCs being banned worldwide by the landmark 1987 Montreal protocols, the first major piece of international environmental legislation, with the so called ‘hole’ in the ozone layer credited with bringing public awareness to the threat of global warming.
The protocols required countries to phase out their use of CFCs, with production of the chemicals entirely banned from 2010. However, in 2018 it was discovered that CFC emission levels weren’t falling as quickly as was expected under the ban, leading to suspicions that some countries may not have been complying with the protocols, BBC News reports.
The discovery led to a rush to investigate the source of the increased CFC emissions, with atmospheric scientists, environmental journalists and the international Environmental Investigation Agency all racing to solve the mystery.
Using data from air monitoring stations in South Korea and Japan, scientists were able to pin the blame on factories in eastern China, which were eventually discovered to be using CFC-11 in the production of insulation foam.
That discovery may have saved the ozone layer from suffering further damage, and now a new study has confirmed that, thankfully, CFC levels are once again on the decline.
In a press release, National Oceanic and Atmospheric Administration scientist Stephen Montzka, whose team first discovered the problem, said:
This was a major test of the Montreal Protocol, and it appears to have passed.
This is a great example of how important early warnings from observational systems can be. It’s pretty hard to solve a problem you don’t know exists.
The ozone’s healing process is a long journey, but scientists are once again optimistic that the Earth’s protective layer will have recovered to pre-CFC levels in a few decades time.
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