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<br />
<br />ROGER A. PIELKE. JR.
<br />
<br />Vilkins. L.: 1996. 'Living with the Flood: Human and Governmental Responses to Real and Sym-
<br />bolic Risk'. (Chapler 10), in Changoon. S. A. (ed.), The Great Flood of /993: Causes, Impacts.
<br />and Responus, Weslview Press, Boulder, CO.
<br />VMO (World Meteorological Organization): 1992, Il1fernational Glossary of Hydrology. UNESCO
<br />and WMO. Geneva, Switzerland.
<br />'1ood, R. A.: 1993, 'Flash FloodIFlood State-by-Slate Fatality Statistics 1945-93', in Storm Data
<br />1993: A CompvsiU of Outstunding SWrm.\' 35 (13), NOAA, Washington, D.C.. pp. 80--81.
<br />Nood. R. A.: 1994. 'Flash FloodIFlood Fatalities - 1960 through ]994 - United Stales, Puerto
<br />Rico and the Virgin Islands. Year-by- YearIState-by-Stale'. in 5wrm DoUJ. and Unusual Weather
<br />Phenomtrlo with Late Repom and Correct;on,f 36 (12), NOAA, Washington, D.C., pp. 56-58.
<br />Nrighl, J.: 1996, 'Effects of the Flood on National Policy: Some Achievements, Major Challenges
<br />Remain', (Chapter II), in Changnon, S. A. (ed.), The Great Flood of 1993: Cause.f, Impact.f, and
<br />Response,f, Westview Press, Boulder, CO.
<br />levin, S. F.: 1994. 'Steps Toward an Integrated Approach to Hydrometeorological Forecasting
<br />Services', Bull. Amer. MeleoroI. 50c 75 (7), 1267-1276.
<br />
<br />IMPACTS ON GLOBAL OZONE AND CLIMATE FROM USE AND
<br />EMISSION OF 2,2-DlCHLORO-I,I,I-TRIFLUOROETHANE (HCFC.I23)
<br />
<br />JAMES M, CALM', DONALD J, WUEBBLES' and ATUL K, JAIN'
<br />
<br />I Engineering COn.fU/Wnl. 10887 Wood/euf Lune, Great Fulls, Vif,l~i/liu 22066.3003. USA.
<br />E.mail: jmc:@~pec:trum.internet.com
<br />2 Department of Atmo.fpheric Sciences. University of Illinois at Urbana. Champaign,
<br />105 South Gregory Street, Urbana, Illinois 61801.4723, U.S.A.
<br />E-mail: wuebb!es@almO.f.lliuc.edu and jain@uiatma.atmos.uiucedu
<br />
<br />(Received 13 March 1998; in revised form 27 August 1998)
<br />
<br />Abstract. Analyses of emissions, and consequent chlorine loading, show that projected use of 2,2-
<br />dichloro.I.l,I-trifluoroethane (HCFC-I23) will result in a virtually indiscernible impact on strato-
<br />spheric ozone. Parametric scenarios uphold this conclusion, even for extreme levels of emissions far
<br />exceeding those of current technologies and practices. Additional scenarios reaffirm the conclusion
<br />for continued use - beyond the scheduled phaseout date - as a refrigerant in closed systems. By
<br />contrast, use of this compound offers unique opportunities to reduce global warming. Moreover,
<br />time-dependent analyses show thaI the minimal contribution to stratospheric chlorine from HCFC.
<br />123 emissions will not peak until more than a decade after the residual peaks of chlorine and bromine,
<br />from prior chlorofluorocarbon and halon releases. subside. While no single index exists to compare
<br />the relative demerits of ozone depletion and climate change, three conclusions arc clear. First, reversal
<br />of the buildup of bromine and chlorine (Le., healing of the 'ozone layer') is underway and progressing
<br />on target. while sufficient practical remedies for global climate change are far more difficult. Se(;Ond,
<br />the analyses show that phaseout of all chlorinated, and conceptually - but much less probably - all
<br />brominated, compounds of anthropogenic origin targets some compounds that provide environmental
<br />benefits. Most chlorinated and brominated compounds do warrant phaseout; the exceptions are those
<br />with very short atmospheric lifetimes, and consequent low ozone depletion potential (ODP), that
<br />also offer offsetting environmental benefits. And third, since new global environmental concerns
<br />may, and probably will, be identified in the future, a more scientific approach is needed to determine
<br />environmental acceptability or rejection.
<br />
<br />1. Introduction
<br />
<br />Scientific assessments and regulatory actions usually group organohalides by their
<br />molecular composition. These broad distinctions imply degrees of relative con-
<br />cern with their potentials, upon emission, for depletion of stratospheric ozone.
<br />The chlorinated and fluorinated species are most commonly divided inlO the chlo.
<br />rofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), and hydro fluorocarbon
<br />(HFC) families (WMO, 1995; UNEP, ]993). These distinctions follow similarities
<br />in industrial applications and comparalive magnitudes for ozone depletion potential
<br />(ODP) when released. As shown in Table ], which addresses the chemicals used
<br />and under consideration as refrigerants. the OOPs for these groups are of the order
<br />of 1 for CFCs, 0.01-0.1 for HCFCs, and less than 0.001 - approximately zero-
<br />
<br />.l" Climatic Change 42: 439-474, 1999.
<br />.,~ @ 1999 Kluwf!f Academic Puhli.fhers. Printed in the Nether/UIl(/,\
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