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Response to Comment on “Intercontinental Transport of Air Pollution: Will Emerging Science Lead to a New Hemispheric Treaty?” We appreciate Selin’s thoughtful response (1) to our paper (2). Our work was intended to stimulate dialogue on the policy implications of intercontinental transport (ICT) of air pollution, and we are pleased that such a dialogue is beginning. As Selin (1) notes (also discussed in ref 3), there are a range of possible means to tackle long-range air pollution transport, including regional accords, technology transfer, and international development organizations. Most likely a range of strategies will be required to reduce the health, ecosystem, and climate risks posed by current levels of atmospheric emissions. We do not assert that a hemispheric treaty is the best or easiest answer, but we maintain it as a reasonable option that should not be dismissed without due consideration. Most of Selin’s response (1) expands on the issues in our paper in a manner entirely consistent with the intent of our work. However, there were a few points that deserve clarification. His overarching criticism of our approach is the emphasis we give to the scientific aspects of the problem, neglecting thorough treatment of political and economic considerations. We clearly state that the paper is not intended as a policy analysis but rather aims to “highlight the opportunity for joint advancement of science and policy developments related to ICT”. Intercontinental transport of air pollution had not been on the agenda of the social science community, despite being an active area of research in the atmospheric chemistry and climate communities. As our review of the science indicates, many scientific questions and uncertainties remain. Engaging policy and scientific concerns early, however, may be an efficient course of action as emerging scientific results bear clear consequences for national and international environmental goals. Selin (1) notes “an institutional design and its outcomes cannot easily be copied from one region to another region that is politically, economically, and culturally differentsas proposed by Holloway et al. (2)swithout very careful adaptations”. We do not suggest that the structure be copied. Rather, we point to the existing treaty as a “starting point” for considering the policy implications of ICT. Any multilateral treaty is a product of unique political circumstances and cannot be transplanted as-is to new actors, problems, and times. Still, successful aspects of existing structures should inform the development of future institutions. Selin (1) points to the “extensive involvement of sophisticated and well-funded research organizations such as IIASA and EMEP” as an example of difficult-to-reproduce aspects of Convention on Long-Range Transboundary Air Pollution (CLRTAP). Difficult indeed, but these aspects of the CLRTAP process are among those best-suited for application to new regions and problems. For example, Acid Deposition Monitoring Network in East Asia (EANET, noted in refs 2 and 4) follows closely on the EMEP model for monitoring regional air quality and acid deposition. Based presumably on the studies reviewed in our paper, Selin (1) argues that the scientific evidence does not support European interest in a hemispheric air pollution treaty. He may have overlooked studies indicating that annual mean ozone (O3) enhancements in Europe due to Asian emissions are only 20% lower than the parallel enhancements over the 1914
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United States (5) or that O3 production over Europe due to Asian emissions is about 50% that due to North American emissions (6) (all numbers taken from Table 4 in ref 2). While more research is needed, existing studies suggest that air quality managers in Europe may benefit from a hemispheric perspective. Selin (1) comments that we “offer no real evidence why a hemispheric treaty on aerosols and O3 would defuse conflicts among the leading industrialized countries on international climate policy”. We are unsure what type of “real evidence” Selin seeks to assess the potential success in defusing political conflicts. We outline the idea that air pollution could be used to leverage agreement on CO2 abatement. The idea rests on two fairly sound premises. First, many air pollutants are important greenhouse forcing agents, so regulation of O3, CH4, and BC would advance both air quality and climate goals simultaneously (7). Second, the CLRTAP experience has illustrated the potential benefits of joint science-policy engagement in a multi-national dialogue on emission reduction strategies. We cannot guarantee such an approach would succeed, just as Selin cannot guarantee it would fail. But air pollution offers an alternate starting point for negotiating climate policy. We hope that members of the social science community will increasingly engage with natural scientists to advance our understanding of intercontinental-scale air pollution to help guide effective management.
Literature Cited (1) Selin, H. Environ. Sci. Technol. 2004, 38, 0000-0000. (2) Holloway, T.; Fiore, A.; Hastings, M. G. Environ. Sci. Technol. 2003, 37, 4535-4542. (3) Keating, T.; West, J. J.; Farrell, A. in Intercontinental Transport of Air Pollution Stohl, A., Ed.; Springer Publishers: in press, 2004. (4) Acid Deposition Monitoring Network in East Asia, http:// www.adorc.gr.jp/eanet.html, accessed 1/2004. (5) Wild, O.; Akimoto, H. J. Geophys. Res. 2001, 106, 27, 729. (6) Derwent, R. G.; Stevenson, D. S.; Collins, W. J.; Johnson, C. E. Presented at the U. S. EPA/EMEP Workshop on Hemispheric Pollution, Bad Breisig, Germany, October 2002. (7) Hansen, J.; Sato, M.; Ruedy, R.; Lacis, A.; Oinas, V. Proc. Natl. Acad. Sci. 2000, 97, 9875.
Tracey Holloway* Gaylord Nelson Institute for Environmental Studies University of WisconsinsMadison 1710 University Avenue, Room 201A Madison, Wisconsin 53726
Arlene Fiore NOAA Geophysical Fluid Dynamics Laboratory Forrestal Campus, U.S. Route 1 P.O. Box 308 Princeton University Princeton, New Jersey 08542
Meredith Galanter Hastings Department of Geosciences Princeton University B-78 Guyot Hall Princeton, New Jersey 08544 ES0498944 10.1021/es0498944 CCC: $27.50
2004 American Chemical Society Published on Web 02/14/2004
