In a study published on Sunday, scientists reported on the detection of four new gases in ice samples taken from Greenland ice cores and Tasmanian air samples that are potentially threatening to the ozone layer. The gases were not seen in samples pre-dating the 1960’s indicating a human origin, despite the UN’s Montreal Protocol, which was signed in 1987 to phase out the use of such chemicals. The ban on dangerous chemicals such as refrigerants, hairsprays, and foams was implemented to allow the Earth’s ozone layer to recover from a hole detected over Antactica. The ban was total by 2010, nonetheless, the ozone layer was expected to need 50 years to recover. The newly found gases resembled those covered by the 1987 treaty, despite a near-total ban on the production of such gases. Experts are attempting to locate the source of these new gases to identify if they are being used in the manufacture of refrigerants or pesticides.
The Earth’s stratospheric ozone layer protects the planet’s inhabitants from ultra-violet rays, which are capable of damaging genetic material in vegetation and human, causing skin cancer and cataracts. The ozone has been healing from the damaging effect of the chemicals since the phase-out of those chemicals under the Montreal protocol began in 1989.
Dr. Johannes Laube of England’s University of East Anglia, the study’s lead author, said the concentrations of these four new gases do not yet pose a threat to the ozone layer. The gases are potentially dangerous, however, consisting of three types of chlorofluorocarbon (CFC’s) and one hydrochlorofluorocarbon (HCFC). In the study, published in “Nature Geoscience,” by British, German, Aurstralian, French, Dutch , and Swiss scientists, the researchers estimate the four gases combined totaled more than 74,000 metric tons – all of it released since the 1960s, according to the ice cores from Greenland – but only a small amount by comparison to the outpouring of CFC’s at the rate of a million metric tons every year during their peak production in the 1980s. Martyn Chipperfield, a professor of Atmospheric Chemistry at the University of Leeds was reassuring: though the newly found gases are theoretically damaging to the ozone, their abundance is a small fraction of the levels of the main chemicals that were identified as dangerous by the Montreal Protocol.
Dr. Laube did not know if emissions of the newly detected gases were illegal, as the Montreal Protocol does contain certain loopholes; he did, however, express a need to tighten the loopholes. He also expressed concern over the rising concentrations of one of the CFC’s, since emission increases for the other CFC’s had not been seen since the 1990’s. The gases in the Greenland samples came from an earlier time point than those taken in Tasmania, suggesting the gases originated in the northern hemisphere and were blown south. Laube suggested the sources might be found by taking samples around the world with research planes. He also said the four new gases could potentially threaten the ozone layer, as they are powerful greenhouse gases: even in small quantities, CFC’s are much more effective at trapping atmospheric heat than carbon dioxide. Overall, Laube was not very concerned by the new findings, although he did indicate the need for investigation regarding the origin of the gases and the increase in their incidence.
By Laura Prendergast