The Coastal Post - January, 1998

Arctic Ozone Hole Appears

By Jim Scanlon

Ozone values have finally fallen so low over the north polar region of our Hemisphere that scientists are using the the term "Arctic Ozone Hole". While not as large, or as severe as its older sibling Ozone Hole over Antarctica, the history and extent of ozone loss during the last two winters make it completely deserving of the name.

While the Arctic stratosphere has been much more contaminated with industrial pollutants than Antarctica, it is normally warmer and, until recently this has not permitted the formation of icy polar stratospheric clouds which activate chlorine from stable compounds. This has suddenly changed.

You, dear reader, should ask why this subject has not been reported in the media so preoccupied with scientific uncertainty over "Global Warming" and the conference in Kyoto.

On November 15, 1997, one of the world's most prestigious scientific journals. Geophysical Research Letters, published eight papers in a "Special Section: Arctic Ozone Loss in 1966-1997. The American Geophysical Union issued two press releases which were not picked up by the media. "How come?" one might legitimately ask.

While there is no "proof" (in the O.J. Simpson "Dream Team" legalistic sense) that the unusual cold temperatures necessary for catastrophic ozone depletion are connected with the cooling of the stratosphere predicted by "global warming" models, there are no other candidates available at present.

The existence of the infant "Arctic Ozone Hole" has been confirmed by a large variety of satellite, balloon and ground based observations and is, it would seem, beyond argument. What remains to be seen is if the new hole will continue to enlarge and deepen over the next few years as the old familiar one did.

It has often been stated that the springtime Antarctic Ozone Hole could not get much worse because there is virtually nothing left to destroy and also that its size was limited by the strong circum polar winds that form a "wall" around the icy continent. During the last two years, it did not get bigger or deeper, but it has begun to more strongly affect populated parts of South America and perhaps even Southern Africa.

Both "Ozone Holes" are, or course, separate and apart from the global decline in the Ozone Layer of five percent in the Northern Hemisphere and ten in the South. (You may feel the added strength of the sun and find that your skin burns faster than before.)

So far, satellites have not been able to precisely measure a "warming" of the earth's turbulent atmosphere attributable to human activities, and this has led to aggressive opposition by energy corporations, to all attempts to limit emissions of heat trapping gases. There may be many smoking chimneys, but in the legal jargon that runs our lives, there is no "smoking gun"

Whether an unequivocal "warming" is ever discovered in time to do something about it, is hard to say. The stratosphere, however, is a different thing. It is stable and doesn't change much. It changes only slowly like the desert or high altitude ecosystems. Compounds that might stay in the stratosphere for months or years, last days or weeks in the lower troposphere.

There is little doubt that the stratosphere has cooled over the past decade. The question is how cool will it get!? And will this liberate more chlorine? It is conceivable that even with chlorine declining substantially, if temperatures drop enough to form icy aerosols, there could be more chlorine available to destroy ozone. Not a pleasant thought.

What does this really mean for us? Arctic ozone levels have declined over the past twenty years in the same way that Antarctic levels declined, but there are differences. In the Arctic, normal springtime ozone levels were around 500 Dobson Units, now normal values are 350 with lows of 250. To put this into perspective, the normal Antarctic highs used to be around 350 and now sink to well under 200 with occasional lows of under 100. The Arctic always had more to lose. Whether this loss will be felt in other parts of the hemisphere through export of ozone poor stratospheric air further south, remains to be seen.

All things being equal (clouds, pollution, time of day, time of year) less ozone means more ultraviolet radiation. In South America, humans are being affected right now (see Coastal Post December 1997). This news is being officially ignored and/or blocked, most likely for economic reasons. People are not dropping dead in the streets-at least not yet. But they know something is happening and it is truly awesome to think that for trivial, mostly cosmetic reasons, we have accidentally changed the light from the sun. It will get worse and we can't do anything about it except hide.

In the North there are millions of people living at high latitudes and in the months of low ozone, March and April, much of the land is covered with snow which effectively doubles the amount of ultraviolet radiation by reflection. Skiers know what normal sunlight on snow can do to unprotected skin, particularly light skin. An increase in the shorter, more powerful wavelengths of ultraviolet could be very dangerous.

While human health is only one aspect of the harmful effects of ozone depletion, it is the one most likely to surface as a problem because humans talk and can complain-whereas, invertebrates and wild animals

only suffer and die in silence.

Life may get a little more difficult for the people of the North, and it is perhaps no accident that Canadians contributed two of the eight papers which appeared in Geophysical Research Letters.

So far, scientists have tended to distance themselves from the environmental effects of ozone depletion and climate warming, preferring to view these effects as coming, 20 or 50 or 100 years from now.

I wonder how long will it take before it is realized these problems are with us here, there, right now, today, tomorrow, yesterday !

Stay tuned.

:;

Now˙vwz|2Fysmyymy@€$){

Coastal Post Home Page