New Threat to Ozone Layer
Twenty five years after the Montreal Protocol limited the production of ozone-depleting chlorofluorocarbons (CFCs), scientists have discovered four new man-made gases that are eating into the ozone layer. It is still unclear where the chemicals originate from, although it is suspected that they are linked with insecticides and solvents used for cleaning electronic components. All four have entered the atmosphere since the 1960s and have been isolated from ice samples in Greenland and air samples in Tasmania.
Professor Piers Forster from Leeds University says that the discovery points to the fact that monitoring of the stratosphere is still necessary. “The concentrations found in this study are tiny. Nevertheless, this paper reminds us we need to be vigilant and continually monitor the atmosphere for even small amounts of these gases creeping up, either through accidental or unplanned emissions,” he said.
Researchers estimate that around 74,000 tonnes of the suspect gases have been released into the atmosphere up until now. Three of the gases are CFCs, which are destroyed very slowly in the atmosphere, meaning that even if production is stopped in the near future they will have longevity for many years to come. Ironically, the fourth gas is a hydrochlorofluorocarbon (HCFC), a type of chemical that has been used to replace the more damaging CFCs.
At a height of between 15 and 30km above the earth’s surface, the ozone layer plays a crucial role in blocking harmful ultra-violet rays which can cause a variety of cancers.