Does anyone remember about mid 1985 when the British Antarctic Survey announced their discovery of …
The Antarctic Ozone Hole ?
Let’s put things in perspective, firstly it isn’t and never was, a hole. It’s a thin spot in a layer of “special oxygen” about twenty kilometers deep in our upper atmosphere (the letter O denotes elemental oxygen, O2 denotes oxygen gas, and O3 is ozone). It’s depth varies by season and geography but the area over the Antarctic was found to thin considerably every Spring. Ten years before the British Antarctic Survey published their discovery of the “hole”, Science knew damned-well that the chlorine in the man-made chemical CFC, would “eat” ozone. CFC was used for everything from aerosol propellants to refrigerants and it’s O3 eating penchant wasn’t of much interest to it’s manufacturer (nor it’s users – which was us) until the “hole”.
Enter The Montreal Protocol. It has been described as THE most successful international agreement in history, where CFCs were banned globally. Of course it would be decades before we would see if the ozone layer would recuperate. Well, apparently recent Australian data indicates (22 years later) that it is. There have been fluctuations due to natural variability which the Aussie team has determined a way to negate. The result is a measurable increase in ozone of 15% since the late 1990s. Take a look at an atlas and you’ll understand why the Aussies have been so attentive of the Antarctic “hole”.
Why isn’t there an Arctic Ozone Hole ? Or is there ? Well, no there isn’t. That’s because the Southern jet stream crosses ocean surrounding the continent, and so forms a polar vortex spinning over the Antarctic. This vortex allows the formation of clouds which collect CFCS. Come Spring, the increase in sunlight prompts the chlorine to separate from the CFCs and start destroying ozone.
The Northern jet stream crosses a landmass with an uneven topography, producing a wandering, unstable polar vortex (as we’re all familiar with during Winter weather forecasts). The CFC collecting clouds don’t form so there’s no “hole”.
We’re actually fortunate that the Antarctic weather situation makes conditions allowable for a measurable “hole” to form, or we might’ve discovered what we already knew … too late. Science is hesitant to pop the champagne bottle yet, but there is cause for cautious optimism. If nothing else we can take pride in that, we as a species can come together in an initiative like the Montreal Protocol, for the betterment of us all.