The Hot Zone

Lessons from the Ozone Hole

Posted by Alison Hawkes on May 10, 2010
Category : Climate Science and Scientists

Happy 25th anniversary, ozone hole. Maybe it’s bad juju to celebrate our environmental calamities, but in this case the discovery of a big hole letting in UV radiation over the Antarctic gave us a chance to respond before it was too late. The discovery itself, therefore, is worth celebrating, not least because it happened under bad odds.

You’d think a big hole would be easy to see. But, in fact, up until a May 1985 article in the journal Nature, most scientists had been using satellite measurements of annual, global levels of ozone to show a relatively small drop of some 7 percent over a 60-year period. They knew chlorofluorocarbons and the like wrought havoc on stratospheric ozone, but the problem didn’t seem alarming.

Then a team of scientists at the British Antarctic Survey looked at the data differently. Using on-the-ground, seasonal measurements from a old weather forecasting station in Antarctica — at Halley Bay — they saw an ozone drop of some 50 percent in the Antarctic “springtime,” between October and early December.

“We suggest that the very low temperatures which prevail from midwinter until several weeks after the spring equinox make the Antarctic stratosphere uniquely sensitive to growth of inorganic chlorine, CIX ….,” the authors wrote.

British Antarctic Survey scientists, Joseph Farman, Brian Gardiner and Jonathan Shanklin (left to right) first reported the Antarctic ozone hole in 1985.

British Antarctic Survey scientists, Joseph Farman, Brian Gardiner and Jonathan Shanklin (left to right) first reported the Antarctic ozone hole in 1985.

A year later, NASA scientists, knowing where and when to look, used Nimbus 7 satellite measurements to reveal a frightening “ozone hole” that eventually led to a worldwide ban on the most ozone-noxious chemicals.

The ozone hole grew from 1981 to 1999

The ozone hole grew from 1981 to 1999

In “Reflections on the ozone hole,” published in the May 6, 2010 journal Nature, BAS scientist Jonathan Shanklin recalls how the discovery went down. He attributes a lot of it to dumb luck. They just happened to be compiling the right data set out of measurements from a particularly good location. Halley Station had a continuous ozone record dating back to 1957, and because it was far North, ozone level observations could begin earlier in the spring when the levels of ozone would be at the lowest.

Halley Bay research station

Halley Bay research station

In fact, Shanklin says, in the early 1980s, BAS nearly axed its long-term ozone monitoring program because of budget problems. “… There seemed to be little reason to keep it going,” writes Shanklin. “But it is programs such as these that provide the crucial evidence for political decisions governing the future of the planet.”

There are other lessons to be learned from the ozone hole.  Shanklin writes that back then, when shown the science, the public was ready to act.

“The evidence was strong and clear; the hole sounded threatening; and there was a link between thinning ozone and cancer. And the public did not feel bullied or threatened — no one was telling them to radically change their way of life. There was a problem and something could be done about it.”

Chemical companies could find substitutes for CFCs and still be profitable under a global ban. The Montreal Protocol, he writes, has probably done more to reduce greenhouse gases than the Kyoto Treaty, since CFCs are also a potent greenhouse gas.

“Perhaps the most startling lesson from the ozone hole is just how quickly our planet can change,” Shanklin writes. “Given the speed with which humankind can affect it, following the precautionary principle is likely to be the safest road to future prosperity.”

“Although the focus is on climate change at present, the root cause of all our environmental issues — a human population that overburdens the planet — is growing. Future historians may note that although humanity solved one unexpected environmental problem, it bequeathed many more through its failure to take a holistic approach to the environment.”

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