Ozone Healing Could Be Delayed by Rise in CFC Emissions

The environmental concerns of the 1980s and 1990s were dominated by the growing hole in the ozone layer, specifically over the southern hemisphere in places like Antarctica and Australia. However, the introduction of the Montreal Protocol in 1987 achieved agreement from countries all over the world in phasing out the chlorofluorocarbons – or CFCs – responsible for creating the hole.

The ratification of and adherence to the Montreal Protocol was hailed by former UN Secretary General Kofi Annan as “perhaps the single most successful international agreement to date” and as a result, the hole in the ozone layer has been slowly shrinking. However, researchers have recently discovered a new surge in CFC emissions, thought to be traceable to China, which may delay its recovery by as much as two decades.

Damaging delays

The rise in CFC emissions has only recently come to light. Specifically, it’s the concentrations of trichlorofluoromethane (CFC-11) that are believed to be connected to the unregulated use of foam in certain Chinese factories that is thought to be responsible for the spike. Keen to ascertain how big an effect these emissions would have on the recovery of the ozone layer, a team of scientists investigated the issue using sophisticated computer modelling software.

The researchers, led by Professor Martyn Chipperfield (who serves as the director for the Institute for Climate and Atmospheric Science (ICAS)), studied three potential outcomes. The first analysed what would happen if all CFC emissions were immediately stopped, while the second looked at how a gradual phasing out would affect the ozone layer and the third investigated developments if emissions remained constant.

Their findings showed that if CFC emissions ceased altogether, the ozone layer could enjoy a hole-free 12 months within the first few years of the coming decade. If they were phased out by 2030, the delay would be no longer than two years. However, continuing emissions at a constant level would set back recovery of the ozone layer by as many as 18 years.

Uncertainty abounds

Professor Chipperfield and his colleagues undertook the study, published in the journal Nature Communications, in order to try and provide some clarity in a thoroughly murky subject. In the first place, quantifying the recovery of the ozone layer is challenging enough on its own, while identifying concentrations of CFCs in the atmosphere is also a difficult proposition.

In the mid-2000s, the problem became even more complicated when it began to appear that atmospheric concentrations of CFC-11 were not declining as they should be. 2010 was the year in which the substance should theoretically have been phased out of use altogether, but the fact that levels of the chemical remained high in certain sampled areas pointed to the fact that unreported production of CFC-11 is still taking place. China is understood to be the most likely culprit.

Given the widespread uncertainty which characterises the issue, the study’s authors have called on other scientists to undertake further research to try and shed light on ozone hole recovery. At present, previous research projects into depletion of the ozone layer are few and far between, which is why new projects are imperative to understanding this complicated issue.