آلودگی هوای محلی و تغییر آب و هوایی جهانی: یک تحلیل ترکیبی هزینه – سود Local air pollution and global climate change: A combined cost-benefit analysis

Two interrelated environmental policy problems are global climate change (GCC) and local air pollution (LAP). Both are discussed in the political arena: the first notably in the United Nations Framework Convention on Climate Change (UNFCCC) and the second in, e.g. the United Nations Economic Commission for Europe’s task-force on Long-Range Transboundary Air Pollution (UNECELRTAP). Emissions from the combustion of fossil fuels contribute to both GCC and LAP. Options to mitigate these problems are typically chosen to address each exclusively. For example, to reduce the emissions of SO2, NOx, or particulates, one often uses end-of-pipe abatement techniques specifically dedicated to these respective effluents, but not to CO2. Their application thus only contributes to diminishing LAP, not GCC. Alternatively, one of the ways to cut down emissions of CO2 is to equip fossil-fired power plants with CO2 Capture and Storage (CCS) technology, which in principle only addresses this greenhouse gas, and not the emissions of air pollutants. CCS equipment installed in isolation therefore alleviates GCC, not LAP. Still, options exist capable of simultaneously addressing both environmental problems, such as the substitution of fossil fuels by various types of renewables or nuclear energy. This paper investigates, through an integrated cost-benefit analysis of GCC and LAP, to what extent synergies between solutions for these environmental challenges can be created by using technologies that are beneficial to both at once. Nordhaus became one of the early protagonists in the cost-benefit analysis of GCC by deriving an analytical solution to a simple climate change maximization problem (Nordhaus, 1977, 1982). The answer to the problem involved an optimal time-profile for the concentration of CO2 in the atmosphere. Nordhaus later developed a numerical model (DICE) that simulated a rudimentary world climate–economy system (Nordhaus, 1993). Estimates for climate change damage costs, however, fundamentally determined his modeling results, like those of others who meanwhile had undertaken similar research (see, for example, Fankhauser, 1995; Manne and Richels, 1995; Tol, 1999; Rabl et al., 2005). The reason was a very incomplete scientific understanding of potential climate change impacts, resulting in large cost uncertainties. Another shortcoming of this type of work was, and still is, that none of the GCC cost-benefit analyses cover the LAP problem, even while these two issues are closely linked. Indeed, they are both much driven by current energy production and consumption patterns. This paper attempts to correct for this, by presenting a single model that includes detailed descriptions of the costs and benefits of both GCC and LAP control strategies. In 1999, the EU adopted the Gothenburg Protocol to Abate Acidification, Eutrophication and Groundlevel Ozone. This protocol set emission ceilings for the year 2010 for SO2, NOx, NH3, and VOC (volatile organic components). A few years later, the EU developed the National Emission Ceiling Directive that stipulated more stringent targets for these pollutants. The multi-national negotiations, leading to the agreement of these targets, used insights from scientific assessments and estimates for the economic costs of pollutant abatement options obtained with the LAP model RAINS (Amann et al., 2004a,b). Recently, results from RAINS have been used for restricted cost-benefit analyses of LAP, notably to serve the Clean Air For Europe program (CAFE, see Holland et al., 2005). Other studies of costs and benefits of air pollution policy packages have been performed that focused on isolated environmental problems or single pollutants (such as RIVM, 2000). All these analyses conclude that the monetary benefits of air pollution policies can be much larger than their costs. They all imply that the benefits are dominated by the avoided number of premature deaths from the chronic exposure of the population to concentrations of particulate matter (PM). A few studies merely signal potential LAP benefits resulting from GCC policies (Criqui et al., 2003; van Vuuren et al., 2006). They typically fix the carbon price, however, and restrict their analysis to Europe and the year 2010. These analyses therefore disregard the potential benefits of other and more costly options that simultaneously avoid GCC and LAP. Burtraw et al. (2003), in a similar study, also fix the carbon price and restrict themselves to the electricity sector in the United States for the year 2010. They find ancillary benefits from a decline in SO2 and NOx emissions, as well as avoided compliance costs under existing or anticipated emission caps. The authors also conclude that the initial carbon prices are significantly lowered because of these ancillary benefits. However, their analysis does not consider longer term or nonelectric energy options. Thus, they give little guidance on how to design optimal strategies for addressing global warming and local air pollution. To our knowledge no multi-region model exists, that (1) covers the world and has a long time horizon, (2) jointly analyzes optimal greenhouse gas and PM emission reductions, and (3) allows balancing the costs of abatement with the benefits of avoided damages for both GCC and LAP. Our study aims to fill this gap.