Tonight I want to talk with you about the use and misuse of science in fashioning environmental policies. The reason this subject is so important is that such policies have become very costly--approaching $150 billion dollars per year, or about $1500 dollars per year for the average U.S. household. And so it has become essential to spend this money wisely and apply it to real risks and real environmental problems, rather than to phantom risks and problems.
The only way I know of distinguishing genuine risks from phantom risks is through the use of science. Unless one applies science to these problems, one cannot determine whether substances such as radon, asbestos, or various chemicals are or are not a threat to health--and at what exposure levels.
Science therefore plays a most important role in helping us make wise decisions on the allocation of what are always limited resources. There are so many demands in our society for these resources, there is so much that needs to be done--whether for better health care or education or public safety. All of these require more money; but budgets are invariably limited. Hence, it is essential that we do not waste resources. This is the very purpose of the organization I started a few years ago, The Science & Environmental Policy Project, which has now grown into an active and, we hope, influential institution with many cooperating, affiliated scientists. We spend much of our time and effort in educating the public, the media, decisionmakers, as well as our fellow scientists, on the science that underlies environmental decisions--all in an effort to counteract the pseudo-scientific hype that's become so prevalent.
The example that I've chosen to discuss this evening is the stratospheric ozone layer--partly because of my own personal history. I have worked in this field for more years than I care to mention and have acquired a certain amount of technical expertise and reputation, having researched the subject and published a number of scientific papers. But perhaps a more important reason for choosing the issue of ozone is that it has become an egregious example of the misuse of science, a classic case where policies have been based on fear and emotion, rather than on sound data.
Ozone in the Stratosphere: Cows and Spray Cans
To acquaint you briefly with what this is all about, I remind you that ozone is produced naturally in the upper atmosphere by energetic ultraviolet radiation from the sun, which splits oxygen molecules into two atoms. Each atom soon finds another molecule and combines into a three-atom ozone molecule, O3. There is surprisingly little ozone in the earth's atmosphere - most of it in the strtosphere at around 20 kilometers (12 miles). If I were to take all of the ozone and put it at the surface, at the atmospheric pressure that exists at sea level, the thickness of the layer would be less than a quarter of an inch. Yet these few molecules of ozone are vitally important to the operation and functioning of life on the surface of the earth. This is because the ozone molecule is a strong absorber of solar ultraviolet radiation. Without ozone, we would be bombarded by solar UV, which is essentially lethal if the wavelength is short enough. But with ozone present, the UV at short wavelengths (less than 280 nanometers, referred to as UV-C) is mostly absorbed; just a little gets through in the region which we call UV-B (wavelength 280-320 nm). UV-B produces sunburn and skin damage, and also certain easily cured forms of skin cancer. There is also another region of the ultraviolet called UV-A (wavelength 320-400 nm), adjacent to the visible region of the spectrum (400-600 nm), which is not absorbed by ozone. I'll return to the subject of UV-A when I discuss melanoma skin cancers later on.
I would like to share with you some of my personal involvement in the ozone business; I once wrote an article about it called "My Adventures in the Ozone Layer," which appeared in the National Review in June 1989. These "adventures" started in 1947, when we placed scientific instruments into captured German V-2 rockets, and later American-made Aerobee rockets, which were launched from White Sands, New Mexico. I worked on an experiment that used an ultraviolet spectrometer, an instrument we built at the Applied Physics Laboratory of Johns Hopkins University that could measure the absorption of UV by atmospheric ozone. As the instrument inside the rocket surmounted the stratospheric ozone layer, it received more and more of the solar UV; from these data we were able to deduce the exact vertical distribution of ozone in the upper atmosphere--how much of it there was and where it was located. From such information, one gains important insight into how ozone is produced and destroyed. In the 1960s, satellites finally took over the job of measuring the distribution of ozone all over the earth. By that time I had devised the ozone-measuring instrument which is in current use in satellites. I am happy to say that it is still working very well.
Some years later, around 1970, I chaired a governmental panel looking into the environmental effects of the supersonic transport aircraft (SST). It was feared that a fleet of 500 SSTs flying in the stratosphere might damage the ozone layer because the exhaust from the aircraft would chemically interact with ozone. At that time we did not know enough about the chemistry of the stratosphere to judge how important the effect would be. Subsequent research produced the scientific knowledge that has become so fundamental to understanding the behavior of stratospheric ozone.
At the time also, we began to consider the possibility that human activities on the earth's surface could produce large amounts of methane. (Chemically, it is the same as natural gas from gas wells.) Methane gas is constantly released from swamps and bogs; but it also comes from cows and rice paddies. As human population increases, requiring more rice and more beef, more methane is released into the atmosphere. Once released, methane has a "lifetime" of about 12 years, long enough to percolate from the ground into the stratosphere where it can attack ozone.
It became evident as early as 1971 that methane produced by human activities on the ground could play an important role in ozone chemistry. This sounded far-fetched to most people; environmental advocates could not imagine that a naturally produced substance, not derived from modern technology, could act as a pollutant. And, of course, no one suggested thata a "natural" substance be controlled. However, only a few years later, by 1974, it became accepted that man-made chlorofluorocarbons could attack stratospheric ozone. Once this idea was adopted by the scientific community, it led to important policy actions. In the United States, for example, the government banned the use of CFCs in spray cans as early as the mid-1970s. Spray cans now use gases under high pressure, or butane and propane, which are flammable. By eliminating one kind of risk, we may have introduced another.
b>CFC Theory and Policy: An Ongoing Debate
The CFC theory was taken seriously only after 1985, when the so-called Antarctic "ozone hole" was discovered. Ironically, the hole was never predicted by the theory, which tells you something about the theory's credibility, and the gullibility of the media. The hole is a genuine phenomenon, a temporary thinning of the layer every October, during the Antarctic spring. The thinning lasts for several weeks, and then the layer recovers. The exact mechanism is not understood even today, and it is still not possible to make sure predictions about what the ozone hole will be like next year, or ten years from now. There is a consensus that the effect is produced by chlorine atoms, whose source is partly from man-made chemicals that have percolated into the stratosphere. But while chlorine atoms are the actual agent, they can only act in the presence of ice particles that form when the stratospheric layer becomes extremely cold. It appears, therefore, that the hole is really controlled by climatological factors: it could disappear and reappear depending on stratospheric temperature.
The debate about the exact cause of the ozone hole illustrates the kinds of disagreements that exist within the scientific community. Some believe that the hole existed before CFCs came into general use. Others point to chlorine from the Antarctic volcano Erebus as the main cause. There are also those who argue that CFC molecules are too heavy to rise into the stratosphere--or if they do, there are too few to do any harm. I think this is wrong on both counts: we have direct evidence that CFCs mix with efficiently in the atmosphere and that chlorine can destroy ozone by catalytic action, thus requiring relatively few chlorine atoms.
On the other hand, there are extremists who argue that the release of CFCs will promote a worldwide catastrophe, and that the Antarctic hole will grow larger and larger, and deplete the ozone layer worldwide. Their fertile imagination has invented catastrophes that don't exist. For example, they have blamed the existence of blind sheep in Argentina on the Antarctic ozone hole. They have linked the disappearance of frogs to the depletion of the ozone layer. They have even hinted that the AIDS epidemic may be related in some way to the destruction of ozone. All of this is nonsense.
Nevertheless, the constant repetition and hyping of pseudo- scientific facts has led the world community to impose controls on the production of CFCs. It started in 1985 with an innocuous agreement, the Vienna Convention, to keep a scientific "eye" on ozone. But it was followed two years later by the Montreal Protocol, which imposed first a limit on CFC production, then a rollback of 20 percent, later 50 percent, and finally, a complete phaseout of production by the year 2000. This date was advanced by 5 years during the Bush Administration, so that by the end of 1995 there will be no further manufacturing of CFCs and other important halocarbon chemicals. Note clearly here, that the Protocol applies only to countries that have subscribed, but not to countries like China or India that have not joined the Protocol.
People often ask me why I spend so much time and effort on the ozone issue. After all, they say, isn't the CFC phaseout a "done deal"? I agree that there is little chance that anything we might say or publish will change the existing policy. But this is precisely my concern. One of the serious problems we face is that policy does not follow the science. The science may change, or even reverse, and the policy marches on as if nothing had changed. I'm afraid that this is the case here. The reason I keep working and writing about the subject of ozone is that the phaseout of CFCs is a frightening paradigm for what is happening in other areas where policy is also based on incomplete or shaky science, or even on science that is completely wrong.
A good example is the global warming situation; it has nothing to do with ozone except that it refers to the same atmosphere. As you undoubtedly know from reading the newspapers and watching television, an "enhanced" greenhouse effect, stemming from the increase in atmospheric greenhouse gases, is supposed to lead to a major increase in world temperatures in the next century. Activists therefore insist that we reduce the amounts of carbon dioxide and other greenhouse gases going into the atmosphere. But whereas we may be able to do without CFCs, we cannot operate our economies without releasing carbon dioxide; it is produced every time we burn fuel--for heating a home, driving a car, or producing electricity. Of course, nuclear reactors will produce energy without carbon dioxide but you won't find global warming activists promoting nuclear power.
The best reason I can give for continuing work on the ozone problem came from an environmental activist on an ABC News- "Nightline" television program in February 1994. Dr. Michael Oppenheimer of the Environmental Defense Fund complained that "if [skeptical scientists] can get the public to believe that ozone wasn't worth acting on, that they [the public] were led in the wrong direction..., then there is no reason for the public to believe anything about any environmental issue." Given the miserable record of unfounded scares promoted by environmental activist groups, working hand-in-glove with a catastrophe-hunting news media and a power-hungry international bureaucracy, I can only hope he is right!
Ozone, Ultraviolet Radiation, and Skin Cancer
Before discussing the economic and political implications of the ozone/CFC issue let me take you briefly over four scientific points that are claimed to connect CFCs to deaths from skin cancer:
The first question to ask is: Do CFCs contribute to ozone- destroying chlorine in the stratosphere? Or are natural sources of chlorine more important? Natural sources include volcanoes and the vast oceans that continually put salt spray--sodium chloride--into the atmosphere. Observations of stratospheric chlorine, up until 1991, showed no increasing trend over time; it should have led one to conclude that CFCs are an insignificant source. Nevertheless, the Montreal Protocol was concluded in 1987. The experimental situation reversed in 1991 when another set of data did show an increasing chlorine trend--albeit less than expected--reflecting the growth of CFCs in the atmosphere.
For many, this is still a matter of contention, almost a quasi-religious controversy between two opposing factions. One side claims that the ocean and volcanoes put 100,000 times more chlorine into the atmosphere than CFCs--and they are right. The opposing side says: "But it all rains out, with less than 1 part in 10,000 surviving to get into the stratosphere." This survival figure is based on calculations; but one cannot calculate rainfall with such accuracy. Is 99% rained out, or 99.9%, or 99.99%? In the final analysis, therefore, only measurements of stratospheric chlorine itself can provide the answer.
The next question is: What is the evidence for ozone depletion? Is ozone decreasing in the stratosphere? The answer, again, must be based on observations, but these show both upward and downward trends. It's a common problem with any kind of geophysical data. For example, it's hard to tell whether global rainfall has increased or decreased in the last decades, simply because the natural fluctuations are so large. For ozone, there is an additional technical problem in that the data themselves may be contaminated.
We now come to an important point. If ozone is being depleted then there should be an increase in the ultraviolet radiation that is normally absorbed by ozone. But long-term observations between 1974 and 1985 at 8 different locations in the United States, show no increase whatsoever. In 1993, two Canadian scientists reported measurements of ultraviolet radiation that appeared to show large increasing trends of up to 35 percent per year! On further examination, however, my University of Virginia colleague Patrick Michaels and I found that their trends were spurious and based on an incorrect statistical analysis of the data.
The portion of the ultraviolet spectrum that is absorbed by ozone--termed UV-B--increases naturally as one moves toward the equator, by about 10 percent for every 100 kilometers. The main reason is the steepening angle of the sun, with the rays traversing less ozone as they pass through the ozone layer. Therefore one gets the kind of increase in UV-B feared from ozone depletion, about 10 percent, by just moving 60 miles to the south. A move from New York City to Miami results in a 200 percent increase in UV exposure. So if all the horror stories about UV causing cataracts, immune deficiency, etc., were true then people in Florida should be in real trouble.
Skin cancer has been the main reason for propelling us to a CFC phaseout. In 1987, the Environmental Protection Agency published cost-benefit calculations asserting that there would be 3 million additional skin cancer deaths in the United States alone by 2075. Malignant melanoma, the deadly form of skin cancer, has been increasing worldwide over the last 50 or so years, however -- long before CFCs came into general use; it seems to be related to exposure to the sun.
A pioneering scientific paper, published in the July 1993 issue of the Proceedings of the National Academy of Sciences by Richard Setlow and colleagues, demonstrates that melanoma is caused by UV-A, the portion of the ultraviolet spectrum (between 320 and 400 nanometers) which is not absorbed by ozone. Hence, the thickness of the ozone layer is irrelevant to the incidence of melanoma and the EPA's cost-benefit analysis is based on outdated and incorrect scientific assumptions. Yet it was this cost-benefit analysis which persuaded the U.S. government to enter into the Montreal Protocol, and more recently to phase out CFCs altogether.
Economics and International Politics of the Ozone Scare
The main issue is this: Why do we take hasty policy actions based on shaky or simply bad science, and what can be done about it? It is clear that the public and policymakers have been confused by incomplete or even wrong information. One of the sources of confusion has been the emphasis on the Antarctic "ozone hole," a genuine phenomenon, but geographically limited, and of little significance to the health and welfare of the world's human population. The existence of the ozone hole--a temporary thinning of the ozone layer--does not prove the existence of global depletion.
Another source of confusion comes from the constant repetition in press releases that ozone depletion is "worse than expected." The press and the public, however, never question these assertions, which are seldom backed by published data that would allow independent verification. Yet logically, expectations must be based on theory; therefore "worse than expected" must mean one of three things: Either (1) the theory is wrong;, or (2) the observations are wrong; or (3) they are both wrong.
The media and the public should ask additional questions: Why was the Montreal Protocol signed at a time when the published evidence suggested that CFCs were not a significant source of chlorine? Another question: Why hasn't the EPA revised their 1987 cost-benefit analysis in light of the new research on the causes of melanoma? And finally, why do we let our actions be dictated by hype, by obviously faked stories about blind sheep, disappearance of frogs and toads, and hints that the AIDS epidemic may somehow be tied to ozone depletion? These fears have been propagated widely through the media and have certainly affected public attitudes-- even though we have no clear evidence of ozone depletion and no evidence whatsoever for an increase in ultraviolet radiation.
The economic consequences of our present policies are likely to be severe. This will become evident soon when trying to replace the CFCs in automobile air-conditioners. We had better get used to driving with the windows open, as CFCs will become more costly as time goes on. Retrofitting existing cars to use CFC substitutes is an expensive alternative. The best estimate is that capital costs of the changeover will range up to $130 billion in the United States alone. Yet, if the phaseout of CFCs had been scheduled in a less hasty fashion, the natural replacement of worn-out equipment would have reduced this cost considerably.
With CFC prices up by a factor of nearly 10 since the Montreal Protocol, illegal imports are increasing. We now read about CFC smuggling, a growing cottage industry. Chemical companies are promoting various expensive and often inadequate substitutes for CFCs, but are worried that the public isn't making the changeover as fast as they should. This seems to be the concern of a Washington-based organization called the Alliance for Responsible CFC policy, which promotes the ozone depletion scare and the use of CFC substitutes--all in the name of ecology. Interestingly, this organization has recently changed its name to the Alliance for Responsible Atmospheric Policy, perhaps to hide the fact that it is set up and supported by the manufacturers of CFC substitutes. Moreover, they are working hand-in-glove with the Internal Revenue Service by advising people on how to blow the whistle on illegal CFC imports. It's always nice to have eager citizens helping out government in the tax collection business. But there is divine justice after all, because environmental zealots, having gotten rid of CFCs, have decided that many of the substitutes are also "ozone- unfriendly." As a result, the industry is getting panicky over the fate of their capital investments in the CFC substitutes.
Bromine is another substance believed to destroy ozone. Bromine compounds--such as halons--are used in fire extinguishers. According to the Federal Aviation Administration, there are no substitutes as yet for putting out aircraft fires. It is something to think about. Methyl bromide is the only agricultural fumigant currently available. The Department of Agriculture warns that without methyl bromide we will not be able to control pests in the soil and in crops shipped from country to country. Yet the EPA proposes that halon production be phased out in 1995 and methyl bromide by the year 2000.
Again, there is little concern about the science. Atmospheric methyl bromide comes mainly from natural sources--biota in the ocean. Further, the lifetime of methyl bromide in the atmosphere is only one year--unlike CFCs which have a lifetime of a hundred years or so. While decisions about CFC use could have long-range consequences, decisions about methyl bromide would result in immediate consequences; if there is found to be a problem with methyl bromide and its production is stopped, its contribution to the atmospheric content would diminish within a year. Finally, and most important, there is absolutely no observational evidence as yet that bromine is increasing in the stratosphere over time. The EPA's bromine policy, therefore, is entirely based on speculation rather than firm evidence.
The international impact of the Montreal Protocol is rather unfortunate for much of the world. Since we are dealing here with a global issue, where all sources of halocarbons must be eliminated to achieve success, it will be necessary to persuade all countries to cooperate. The cost burden will be especially heavy, however, on those in less developed countries. And how do these costs compare to any possible benefits?
The March 12, 1994, issue of The Spectator (London) raised just this concern: "...the consequences of banning CFCs will certainly be disastrous...The proposed replacements are less efficient and some of them are toxic, endangering the health of fridge workers and people nearby. In Africa, refrigeration saves lives, not only by protecting food against decay and disease but by preserving medicines, notably vaccines. Anything that makes refrigeration more expensive or more difficult will cost lives in Africa and add to poverty; and anything that adds to poverty in Africa increases the destruction of the African environment... Somehow it is all right for people in the West to benefit from modern technology but wrong for poor people in Africa and Asia. It is more wholesome for black Africans to die in infancy of 'natural' agents such as malaria and food poisoning than to be safeguarded into healthy old age by unnatural agents such as pesticides and CFCs. The outstanding feature of the Greens is that they are rich. The outstanding feature of their victims is that they are poor."
The bitter irony, not mentioned in the article, is that even if the CFC-ozone theory were correct in all respects, darker- skinned people living in the tropics would get none of the alleged benefits of "protecting" the ozone layer. The depletion of ozone is calculated to occur mainly at middle and high latitudes, and skin cancers are confined almost exclusively to fair-skinned people. What then is the incentive for tropical nations to phase out CFCs? And if they don't go along, will it be worthwhile for the developed countries to impose high costs on their citizens for a negligible return, in the absence of full international participation?