Ozone nightmare: A lucky escape?Atoms of bromine (Br) are 45 times more efficient than chlorine (Cl)at destroying ozone."… if the chemical industry had developed organobrominecompounds [halons] instead of CFCs… then without anypreparedness, we would have been faced with a catastrophic ozonehole everywhere and in all seasons …Noting that nobody had given any thought to the atmosphericconsequences of the release of Cl or Br before 1974, I can onlyconclude that mankind has been extremely lucky ” Paul Crutzen,Nobel Prize acceptance speech, 1995(The 1995 Nobel Prize in Chemistry was shared between Paul Crutzen,Mario Molina, and Sherwood Rowland for their work on ozone chemistry)WMO projectionsHalting ozone depletionMontreal Protocol (1987)with various amendmentsreplaced CFCs with ozone-friendly chemicals.Graph: when willstratospheric chlorineget back down topre-1980 levels?After about 2050Freon substitutes:HCFCs - vulnerable to chemical removal in troposphereHFCs - contain no chlorineKump, Fig 17-14chlroineLessonsfrom ozoneLessons from the ozone experience- Earth is a coupled system:>> actions can have unanticipated consequences>> these can be sudden and dramatic- Be careful of anything that has a long atmospheric lifetime-Vigilant monitoring is good even if it doesn’t seem interestingWe caught the ozone hole this way.- High-tech monitoring systems can screw up. Good to havesomeone actually looking at the data.- Dramatic events drive public policy far more than theoreticalpredictions.- A successful model for coping with global change: Internationalscientific assessments and international treaties based on them.Ozone misinformation & ignorance1990s - Wall Street Journal, Washington Post,Washington Times, Omni (a science/science fiction mag)question ozone hole despite abundant evidenceknown to all atmospheric chemists. Why?Journalists pick up misinformation spread inbooks by Dixy Lee Ray and Rush Limbaugh.This propagates through the media, copy-cat styleDobson: seasonal differenceDobson:Attributesseasonaldifference todifferentstratosphericcirculation insouthern vs.northernhemisphereNo hole hereDixy Lee Ray incorrectly says that thisearly data showed an ozone hole: it did not.Cl comes from CFCsNature 379, 526 - 529 (1996); doi:10.1038/379526a0Satellite confirmation of the dominance of chlorofluorocarbons in theglobal stratospheric chlorine budgetJames M. Russell III, Mingzhao Luo, Ralph J. Cicerone & Lance E. DeaverOBSERVED increases in concentrations of chlorine in the stratosphere have been widely implicated in the depletion of lower-stratospheric ozone over the past two decades.The present concentration of stratospheric chlorine is more than five times that expected from knownnatural 'background' emissions from the oceans and biomass burning, and the balance has been estimated to be dominantly anthropogenic in origin, primarily due to the breakdown products of chlorofluorocarbons (CFCs). But despite the wealth of scientific data linkingchlorofluorocarbon emissions to the observed chlorine increases, the political sensitivity of theozone-depletion issue has generated a re-examination of the evidence. Here we reporta four-year global time series of satellite observations of hydrogen chloride (HC1) and hydrogenfluoride (HF) in the stratosphere, which shows conclusively that chlorofluorocarbon releases—ratherthan other anthropogenic or natural emissions—are responsible for the recent global increasesin stratospheric chlorine concentrations. Moreover, all but a few per cent of observed stratosphericchlorine amounts can be accounted for by known natural and anthropogenic tropospheric emissions.Altogether, these results implicate the chlorofluorocarbons beyond reasonable doubt as dominatingozone depletion in the lower stratosphere.Dixy’s 1958 ozone hole? Nope.French 1958 datashow a random scatteri.e., data with no accuracyor repeatability,e.g. jumps 130 DUin one day (April 18-19)Rejected by WMOas useless, unreliable data.The Japanese dataNote:Uncertainty bars onHalley Bay data (+/-15 DU)No bars on Japanese data; alsoJapanese data miss severalseasons.Halley Bay is 76 S,whereasSyowa is -69 S (furtherout in ozone hole/ vortex) accountsfor some of the differenceRoots of ozone misinformationRogelio Maduro is a writer (not a scientist) and associateeditor of 21st Century Science & Technology publishedby supporters of politician Lyndon LaRouche (who wasconvicted of fraud and tax evasion and sentenced to 15 yearsin jail in 1985)Rush Limbaugh notes Dixy Lee Ray as his source in hisbestseller The Way Things Ought to Be that claims there is noozone hole.Dixy Lee Ray cites Rogelio Maduro frequently as her sourceDixy Lee Ray cites virtually no “primary sources”, i.e. scientificpeer-reviewed publications. Those cited are distorted when cited(e.g. Dobson, Japanese group) or background material
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