Acid rain and the ozone hole
Solving the big environmental calamities requires measuring, monitoring.
Dateline: Tuesday, November 01, 2011
by Graham Saunders Lakehead University, Thunder Bay Chronicle-Journal
Last August, the Harper government announced plans to disable most functions of the ozone measuring network in Canada. Tom Duck, a Dalhousie atmospheric scientist commented, "This is kind of like taking the batteries out of your smoke detector."
Everybody's talking about the weather these days. But contrary to Mark Twain's quip, collectively we have done something about it — or at least about looming hazards such as acid rain and ozone depletion.
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Some 81 countries agreed to eliminate CFCs by 2000; most met their targets ahead of schedule.
Four decades ago, acid rain stories made headlines, due to the death of our lakes and die back of some forests. In some lakes in eastern Canada, the water was so clear that you could see to the bottom. More and more lakes downwind from coal plants and heavy industries were becoming sterile from sulphur dioxide and nitrous oxide emissions, which killed off fish and aquatic ecosystems.
The obvious solution was to reduce or eliminate sulphur dioxide and other emissions that combine with water vapour and then fall as acid rain or snow. Since winds and air flow are not influenced by political boundaries, the problem required an international solution. Some familiar arguments arose for delaying action: that restrictions would hurt the economy, or be ineffective, or were aimed at the wrong target.
Nonetheless, in the 1970s, Canada, the United States and other countries proceeded with clear air legislation and international agreements. "Scrubbers" and other technology dramatically reduced emissions. Certain countries, including Canada, met their agreed targets ahead of schedule.
Also in the 1970s, scientists and policy makers started discussing ozone depletion in the upper atmosphere. Ozone is a gas present in trace amounts mainly at an altitude 20 to 25 km above the Earth's surface.
Ozone absorbs some ultraviolet (UV) wavelengths, almost all of extremely hazardous UV-C and most of UV-B wavelengths. Without this diffuse layer of ozone, life as we know it could not exist on this planet.
Scientists predicted further declines in ozone amounts because of increased use of supersonic aircraft like the Concorde and extensive use of chlorofluorocarbons (CFCs) in refrigeration and aerosol spray cans. (Chlorofluorocarbons do not exist naturally and were created in labs and factories.) Expected harmful effects of ozone depletion include a considerable jump in human and animal skin cancers and depletion of phytoplankton in oceans.
Major CFC producers like Dupont Corporation fiercely resisted attempts to ban CFCs with the usual arguments about possible harm to the economy, distrust of the science, and so on. Some partial bans began around 1980 and the issue briefly faded from view.
Then came the shocking 1985 discovery of the Antarctic ozone hole. It was not technically a "hole", but a decline to 40 percent of normal coverage alarmed scientists. So unexpected was the finding that it was first dismissed as an instrument defect.
Worse, ozone loss was also apparent in the mid-latitudes of the Northern Hemisphere and a smaller and a more mobile hole was detected over the Arctic. And additional research suggested links with cataracts, damage to the human immune system and reduced crop yields.
Faced with this urgent threat, the United Nations Environmental Program convened a world meeting in Montreal in September, 1987. The US Environmental Protection Agency set the tone with warnings of additional skin cancers for tens of millions of people; the EPA suggested 95 percent reduction in CFC production by 1996.
The 31 countries attending agreed to a 50 percent reduction by the end of the century. Then they and an additional 50 countries met two years later in Helsinki, and agreed to a 100 percent reduction by the year 2000. Most countries, including Canada, met their targets ahead of schedule.
We cannot know precisely what would have resulted without clean air and ozone legislation but the saying, "You don't want to go there" almost certainly applies.
These collective responses to impending threats offer heartening examples of what can be achieved when governments and the public heed scientists' warnings. But since then, a few exceptions and deferrals have snuck into international regulation of ozone depletion. For example, the Bush Administration removed restrictions on methyl bromide, a banned chemical under the Montreal Protocol.
Nor is the situation stable. For some reason, massive ozone destruction — on the order of 40 to 80 percent — occurred at altitudes of 18 - 20 km in the Arctic in the 2011 spring season. The "hole" drifted across northern Canada, Europe, central Russia to northern Asia and prompted scientists in some jurisdictions to issue radiation warnings.
This record ozone depletion is troubling because the ozone problem should be improving and this reversal is not well understood.
In spite of this, the Harper government announced plans in August to disable most functions of the ozone measuring network in Canada. And it gets worse. The Harper government does not permit interviews with the scientists involved and has sent letters warning of "discontinuance of job function" to those employed in this and related programs.
Ozone depletion is only one of the areas where the Harper government is employing a veil of silence. The organization that tracks mercury and other toxins and monitors various indicators in Lake Superior, is still waiting for its annual funding pittance.
Measuring and monitoring changes in our environment are essential for protecting human health and the wilderness ecology. Choosing not to monitor hazards is dangerous behaviour on several levels, ranging from health risks to undermining the democratic process. Canadians should be aware that the Harper government is deliberately choosing not to collect or make available essential information for setting environmental policies.
Graham Saunders teaches at Lakehead University in Thunder Bay, Ontario and writes about weather, climate and gardening for several publications. His weather and climate background includes work with the Australian Weather Bureau, the Atmospheric Environment Service of Canada and forest fire weather prediction for the Ontario Ministry of Natural Resources.
His “Weather Whys” column for the Thunder Bay Chronicle-Journal is one example of his writing for several publications about weather, climate, Lake Superior, agriculture and northern gardening issues, including his book Gardening with Short Growing Seasons.
He teaches meteorology and has taught Climate Change, The Geography of the Lake Superior Basin and other courses at Lakehead University, Thunder Bay. Graham is a board member of the Bay Credit Union and President of Environment North, an organization of long standing in Northwestern Ontario.
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