]]]]]]]]] OZONE SCARE GENERATES MUCH HEAT, LITTLE LIGHT [[[[[[[[[ By S. Fred Singer (9/8/88) [From The Wall Street Journal, 16 April 1987, p. 30:3] [Kindly uploaded by Freeman 10602PANCZ] Another ozone scare appears to be upon us, and it could be just as misleading as the one that led Congress to cancel the SST prototype in 1971. Following congressional testimony last month that dangerous melanoma skin cancers had increased 83% in the past seven years, press reports implied that the increase was the result of the destruction of the ozone in the atmosphere, which allowed more ultraviolet radiation to reach Earth. The ozone supposedly was destroyed by widely used chemicals known as chlorofluorocarbons (CFCs). But there is no reliable evidence that the total amount of ozone has decreased, and any increase in the incidence of melanoma, the most serious type of skin cancer, must therefore involve other causes. Indeed, oncologists have proposed many such causes: viruses, genetic predisposition, environmental carcinogens, population shifts to the Sun Belt, changes in life style, earlier detection of melanomas, and even diet. In addition, there has been only a modest increase -- well explained without assuming any change in ozone -- in the incidence of non-melanoma skin cancers. (These cancers, which are easily cured, are 20 times more frequent than melanomas) Non-melanoma cancers, such as those removed from the Reagans, seem directly related to exposure to ultraviolet rays and would be expected to increase markedly if ozone were destroyed. It is true that over the past several years, localized and temporary decreases in ozone levels have been observed high in the Antarctic stratosphere during mid-autumn. But these findings do not prove that CFCs are destroying ozone. A complete explanation is not yet available; in the presence of the world's lowest temperature, atmospheric chemistry may be quite unusual. Some scientists believe that ozone is not lost at all but simply moves about as atmospheric motions bring in ozone-depleted air for a few weeks. In any case, ozone changes over the Antarctic cannot affect melanoma rates in the U.S. This is not the first ozone scare. Before 1970, it was generally believed that the creation and destruction of ozone in the stratosphere -- where most of it is located -- was caused by only by solar ultraviolet radiation. But then the political controversy over the construction of prototypes for a supersonic transport aircraft focused attention on potential environmental effects of an eventual fleet of 500 SSTs. According to then-prevailing scientific wisdom, water vapor from the SST exhaust was supposed to destroy ozone, admitting more ultraviolet radiation to the earth's surface. It was soon discovered, however, that water vapor doesn't destroy ozone very effectively. Attention next focused on nitrogen oxides (NOX), which also were produced by SST fuel combustion and were said to be a much more potent ozone-destroyer than water vapor. Based on our present knowledge, however, while NOX would lead to a modest destruction of ozone in the upper stratosphere, it would increase the amount of ozone in the lower stratosphere. So much for the accuracy of predictions. The latest candidate as an ozone destroyer -- and the one that is causing concern today -- is chlorine, and its most important stratospheric source may be the CFCs. These are inert gases used mainly in aerosol cans and refrigeration, and as blowing agents for plastic foams and as solvents. Chemically stable, they survive in the lower atmosphere, but are finally broken down by solar ultraviolet radiation when they percolate into the stratosphere, releasing chlorine. The U.S. Environmental Protection Agency has estimated that constant growth of CFC use at an annual rate of 2.5% could remove sufficient ozone to cause an additional one million non-melanoma skin cancers over the lifetime of the present U.S. population. These numbers look huge until they are compared with the current U.S. rate of about 500,000 new cases each year. Even so, the EPA numbers are only upper limits, and about as likely as the lower limits, which are zero. The relation between ozone depletion and skin-cancer increases is based on a simple-minded statistical analysis that neglects all factors except the variation of solar ultraviolet radiation with geographic latitude. With this fragile scientific base, and many questions still unanswered, the U.S. has taken the lead on international controls of CFCs, supported mainly by the Scandinavian countries -- which do not manufacture CFCs. Opposed are Britain, France, Japan and the East Block -- which do manufacture CFCs and would be forced to close down existing facilities if an international production phasedown is agreed upon. Because skin cancers occur mainly among Caucasians, the Third World has not gotten too excited about CFCs, even though ultraviolet intensity is greatest near the equator. DuPont has already developed substitutes -- albeit more costly ones -- to comply with the self-imposed U.S. ban on the use of CFCs in aerosol cans that went into effect in the mid-1970s. Substitution for spray cans is simple -- compressed hydrocarbons. But it is costly for refrigerators and other industrial uses. U.S. production of CFCs today is only half of its 1974 peak of 400,000 tons, but is rising. Non-U.S. production has been increasing slowly since 1974 and now stands at 600,000 tons a year. Plans to phase out CFCs internationally have made substantial progress, spearheaded by the U.S. State Department. In 1985, the Vienna Convention for the Protection of the Ozone Layer created a framework for a protocol to control CFCs. The U.S. Senate ratified this convention last July [1986]. Having achieved this first step, the enthusiasts for international controls, backed by the EPA and assorted environmental groups, are now pushing for a protocol to phase out, or at least freeze, CFC production world-wide. Even if such controls are rejected by the world community, there are likely to be consequences in terms of U.S. legislation for further unilateral controls, plus pressure on friendly governments to go along with the U.S. Such pressure may lead to trade policies that could harm international relations. These economic and political costs will have to be weighed against the risk of damage from a possible reduction in ozone. The well-established greenhouse effects of the CFCs that could lead to climate warming need to be included in the risk assessment. However, their effects are small compared with those of carbon dioxide from the burning of fossil fuels, and no one is suggesting that we stop energy production and freeze in the dark. One final note: As chemical calculations improve, the projected decreases in ozone caused by CFCs have shrunk. The National Academy of Sciences issued reports in 1979, 1982 and 1984 projecting ozone losses after the year 2000 of 18%, 7% and about 3%, respectively, from present levels. Furthermore, human activity will continue to generate pollutants such as carbon dioxide, methane and nitrogen oxides, which will counteract the destruction of ozone by CFCs. It may well turn out that the effects will cancel each other out, leading to little net change in total ozone. --------------------------------- Mr. Singer, an atmospheric physicist at George Mason University, in 1970-71 headed a committee that evaluated the environmental effects of the SST for the Department of Transportation. * * *
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