The production of ozone layer-depleting CFC-11 was completely halted in 2010 since the Montreal Protocol was signed in 1987. A new study finds that global CFC-11 emissions are on the rise again, suggesting that production of the banned chemicals continues from an unidentified source.
Chlorofluorocarbons were once considered a marvel of modern chemistry, and they were used in a wide range of products. However, in 1987, an international team of scientists proved that the emissions of such chemicals were actually harming the environment, particularly the ozone layer. By the end of the year, the Montreal Protocol was signed in a global effort to ban the products and heal the ozone layer.
By 2010, the production of trichlorofluoromethane (CFC-11), the second most abundant CFC controlled by the Montreal Protocol, was believed to be completely halted.
CFC-11 On The Rise Again?
However, a new study published this week in the journal Nature revealed that contrary to what is expected upon the banning of CFC-11 production, the harmful emissions are on the rise again, as the rate of CFC-11 decline in the atmosphere has been cut by 50 percent since 2012. This suggests that there may be a new and unreported production of CFC-11, possibly from East Asia.
To be clear, CFC-11 concentrations in the atmosphere are still declining, but they're declining significantly more slowly because of the possible new source as compared to if there was none. In fact, CFC-11 emissions between 2014 and 2016 were found to be 25 percent higher than the average CFC-11 emissions from 2002 to 2012.
"In the end, we concluded that it's most likely that someone may be producing the CFC-11 that's escaping to the atmosphere. We don't know why they might be doing that and if it is being made for some specific purpose, or inadvertently as a side product of some other chemical process," said Stephen Montzka of the NOAA, lead author of the study.
In response to these new reports, the United Nations Environment Programme released a statement, highlighting the efficacy of the Montreal Protocol with science at its very core. The statement also takes note of the importance of identifying the source of the emission increase, and taking the necessary actions against it. If not, it could possibly slow down the recovery of the ozone layer, especially since CFC-11 is responsible for about a quarter of all chlorine reaching the stratosphere.
"So long as scientists remain vigilant, new production or emission of ozone depleting chemicals will not go unnoticed," sites the UN Environment statement.