Emissions of halon-1211, a fire retardant, are increasing at the rate of approximately 200 tonnes per year, based on measurements on the atmosphere made in Tasmania. Until now, Montreal Protocol calculations assumed that halon-1211 had peaked in 1988. In fact, emissions have since risen by about 25 per cent.
Current emissions make it the most damaging of the halons.
Halons are now responsible for about 20 per cent of global ozone destruction. The continued growth of halon-1211 could be due to increased legal manufacture and release in China,' says Dr Fraser. China is responsible for about 90 per cent of the world's production of halon-1211. Montreal Protocol calculations based on production data indicate that halon levels in the air will stabilise during the next few years. The Journal of Geophysical Research has accepted the team's results for publication.