New Greenie villain: Nitrous oxide!

It's not actually a new villain but it has now been upgraded to Jack-the-ripper status. Reading between the lines, this would appear to be an apology for the fact that the Antarctic ozone hole is just fluctuating as normal instead of shrinking -- despite the much touted ban on CFCs. An attempt to ban N2O would be a joke, though. There's a lot of it about

Stratospheric ozone is depleted by many different chemicals; most prominently, chlorofluorocarbons (CFCs) responsible for causing the Antarctic ozone hole. Nitrous oxide is also an ozone-depleting substance that has natural sources in addition to anthropogenic ones. Moreover, unlike CFCs, its use and emission are not regulated by the Montreal Protocol, which has helped to reverse the rate of growth of the ozone hole. Surprisingly, Ravishankara et al. (p. 123, published online 27 August; see the Perspective by Wuebbles) now show that nitrous oxide is the single greatest ozone-depleting substance that, if its emissions are not controlled, is expected to remain the dominant ozone-depleting substance throughout the 21st century. Reducing nitrous oxide emissions would thus enhance the rate of recovery of the ozone hole and reduce the anthropogenic forcing of climate.

SOURCE

Journal abstract follows:

Nitrous Oxide (N2O): The Dominant Ozone-Depleting Substance Emitted in the 21st Century

By A. R. Ravishankara et al.

By comparing the ozone depletion potential-weighted anthropogenic emissions of N2O with those of other ozone-depleting substances, we show that N2O emission currently is the single most important ozone-depleting emission and is expected to remain the largest throughout the 21st century. N2O is unregulated by the Montreal Protocol. Limiting future N2O emissions would enhance the recovery of the ozone layer from its depleted state and would also reduce the anthropogenic forcing of the climate system, representing a win-win for both ozone and climate.

Science 2 October 2009: Vol. 326. no. 5949, pp. 123 - 125

Posted by John Ray (M.A.; Ph.D.).