The world is facing enough potential sources of going public, so it is comforting to know that a threat is back in its box for the moment. New research has found that the release of the banned chemical CFC-11 (technically known as trichlorofluoromethane) has increased the discomfort. Observations will continue, but for the moment, we can go back to worrying about global warming, antibiotic resistance, incoming asteroids, the destruction of biodiversity and the threat of robot revolt, freed from any immediate threat of death by UV radiation.
Two journals in nature highlight the success of CFC-11 control efforts, one of which indicates lower emissions from East Asia in 2018-19; the other confirms that the entire atmosphere is declining in density. When Sherwood Rowland and Mario Molina proved that certain synthetic chemicals threatened the ozone layer – and therefore most of Earth’s life – CFC-11 was the main culprit. Although refrigeration and insulating foams are very useful for expansion, CFC-11 in the atmosphere breaks down into chemicals that break down ozone molecules, converting them into ordinary oxygen. Stratospheric ozone blocks almost all-moderate frequency ultraviolet radiation that allows skin cancer and defecation in humans and other animals if allowed.
In an admirable – and unusually prompt – response, Jimmy Carter banned CFC-11 for specific use in America and encouraged chemical companies to look for alternatives in other cases. A few other countries followed immediately, but a decade later when the danger confirmed, the replacements quite advanced. The Montreal Protocol has banned CFC-11 from 2010 for other ozone destroyers, with varying dates. At first, it went well. The concentrations of related gases begin to decrease before the date of their final ban. Therefore, it was with considerable concern that atmospheric scientists reported in 2018 that CFC-11 emissions have been increasing since 2013. The source of at least half of the emissions identified with northeastern China.
“Increased emissions during this period may not cause significant delays in ozone recovery, although emissions at the observation level between 2014 and 2017 may be delayed for decades if they continue,” notes the first paper. Fortunately, these emissions did not continue in 2018-19, probably because of the attention attracted by previous discoveries. Both papers reported that thousands of tons less gas released than in 2017.
“The studies are highly welcome news and hopeful that regulatory violations will bring an end to a frustrating period,” said Dr. Luck Western, co-lead author of one study. “Since CFC-11 is a powerful greenhouse gas, new emissions have contributed to climate change at the same level as a megacity of carbon-dioxide emissions.” Nevertheless, Weston’s paper notes that perhaps some of the CFC-11s it produced during 2013-2017 are still in storage and could pose a threat to the atmosphere if finally released.