The ozone layer above
Antarctica has recovered so much, it's actually stopped many worrying
changes in the Southern Hemisphere's atmosphere, according to a new study.
Background
A new study suggests the
Montreal Protocol, the 1987 agreement to stop producing ozone depleting
substances (ODSs), could be responsible for pausing, or even reversing, some
troubling changes in air currents around the Southern Hemisphere.
Details
Ø Before the turn of the
century, ozone depletion had been driving the southern jet stream further south
than usual. This ended up changing rainfall patterns, and potentially ocean
currents as well.
Ø Using a range of models and
computer simulations, researchers have now shown this pause in movement was not
driven by natural shifts in winds alone.
Ø In Australia, for
instance, changes to the jet stream have increased the risk of drought by
pushing rain away from coastal areas. If the trend does reverse, those rains
might return.
Ø While improvements in
cutting back our reliance on ODSs have certainly allowed the ozone to recover
somewhat, carbon dioxide levels continue to creep upwards and place all that
progress at risk.
Ø Last year, the Antarctic
ozone hole hit its smallest annual peak on record since 1982, but the
problem isn't solved, and this record may have something to do with unusually
mild temperatures in that layer of the atmosphere.
Ø The Montreal Protocol is
proof that if we take global and immediate action we can help pause or even
reverse some of the damage we've started. Yet even now, the steady rise in
greenhouse gas emissions is a reminder that one such action is simply not
enough.
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