Dozens of mysterious ozone-destroying chemicals may be undermining the recovery of the giant ozone hole over Antarctica, researchers have revealed.
The chemicals, which are also extremely potent greenhouse gases, may be leaking from industrial plants or being used illegally, contravening the Montreal protocol which began banning the ozone destroyers in 1987. Scientists said the finding of the chemicals circulating in the atmosphere showed "ozone depletion is not yesterday's story."
Until now, a total of 13 CFCs and HCFCs were known to destroy ozone and are controlled by the Montreal protocol, widely regarded as the world's most successful environmental law. But scientists have now identified and measured four previously unknown compounds and warned of the existence of many more.
"There are definitely more out there," said Dr Johannes Laube, at the University of East Anglia. "We have already picked up dozens more. They might well add up to dangerous levels, especially if we keep finding more." Laube and his colleagues are in the process of fully analysing the dozens of new compounds, but the work completed on the four new chemicals shows them to be very powerful destroyers of ozone.
Laube is particularly concerned that the atmospheric concentrations of two of the new compounds, while low now, are actually accelerating. "They are completely unimpressed by the Montreal protocol," Laube said. "There are quite a few loopholes in the protocol and we hope some of these are tightened. But the good news is that we have picked up these [four] early." The chemicals take decades to break down in the atmosphere, meaning their impact on ozone and climate change is long-lived.
In December, Nasa researchers revealed the discovery of a new greenhouse gas that is 7,000 times more powerful than carbon dioxide at warming the Earth and which has been in use by the electrical industry since the mid-20th century. The four newly identified compounds are also expected to trap heat thousands of times more powerfully than CO2.
|