Grantee Research Project Results

Final Report: Analysis of the Co-benefits of Greenhouse Gas Abatement for Global and US Air Quality under Future Climate Scenarios

EPA Grant Number: R834285
Title: Analysis of the Co-benefits of Greenhouse Gas Abatement for Global and US Air Quality under Future Climate Scenarios
Investigators: West, J. Jason , Hanna, Adel , Smith, Steven J. , Horowitz, Larry W. , Emmons, Louisa , Vizuete, William
Institution: University of North Carolina at Chapel Hill , Pacific Northwest National Laboratory , NOAA Geophysical Fluid Dynamics Laboratory , National Center for Atmospheric Research
Current Institution: University of North Carolina at Chapel Hill , NOAA Geophysical Fluid Dynamics Laboratory , National Center for Atmospheric Research , Pacific Northwest National Laboratory
EPA Project Officer: Chung, Serena
Project Period: September 1, 2009 through August 31, 2013
Project Amount: $300,000
RFA: Adaptation for Future Air Quality Analysis and Decision Support Tools in Light of Global Change Impacts and Mitigation (2008) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Climate Change , Air

Objective:

Actions to reduce emissions of greenhouse gases (GHGs) will affect air quality directly through reductions in emissions of co-emitted air pollutants, and indirectly through changes in global climate. Research on the effects of climate change on air quality has emphasized meteorological downscaling to translate future climate change from general circulation models (GCMs) to a regional scale. Here, we propose to emphasize methods of chemical downscaling, in which future climate and pollutant emissions will be simulated in a global chemical transport model (CTM), to provide initial and boundary conditions for a U.S.-focused regional CTM. We use these methods to address the air quality co-benefits of actions to reduce GHG emissions, both globally and in the United States, by analyzing the mitigation of methane emissions and the control of GHGs generally in future scenarios to 2050.

Summary/Accomplishments (Outputs/Outcomes):

The main work conducted under this grant was to analyze the global air quality co-benefits of global reductions in GHG emissions, which was written up in a paper by West et al. (2013). This work was a major undertaking, involving extensive global modeling using MOZART-4, collaboration with GFDL to process simulated future meteorological fields, analysis of the RCP emissions scenarios, assessment of human health impacts, and cost-benefit analysis. Here, we went beyond what we proposed by analyzing co-benefits in 2030 and 2100, in addition to 2050, and by conducting the assessment of health impacts and economics, in part taking advantage of new funding we gained through a grant from NIEHS.

Our co-benefits study (West et al., 2013) differed from previous estimates of co-benefits. Those previous studies tended to focus on co-benefits in the near-term and on a regional or national scale. In contrast, we have approached this problem with new methods to assess, for the first time, the co-benefits of GHG reductions globally and in future scenarios in a consistent manner. We account for: the international transport of air pollution and the long-term effects of methane on ozone; new epidemiological evidence that justifies assessing chronic mortality effects of ozone as well as fine particulate matter; and consistent future scenarios (based on the recent and widely used Representative Concentration Pathway 4.5 (RCP4.5) scenario) in which population, income, pollution controls, and susceptibility to air pollution all change through time. We also account for the first time for a second mechanism of co-benefits in which slowing climate change also slows the effect that climate change has on air quality.

We estimate that, relative to a reference case, global GHG mitigation in RCP4.5 avoids 0.5 ± 0.2, 1.3 ± 0.5, and 2.2 ± 0.8 million premature deaths in 2030, 2050, and 2100. Global average monetized co-benefits of avoided mortality are $50-380 (ton CO₂)^-1. Because of our difference in approach, our estimates of monetized co-benefits exceed previous estimates. The co-benefits also exceed the marginal cost of emission controls in 2030 and 2050, and are within the low range of cost estimates in 2100 (West et al., 2013). We also found that co-benefits via direct reductions of co-emitted air pollutants (a short-term and mainly local co-benefit) far exceed the co-benefits via slowing climate change (the long-term and global co-benefit).

In the study by Smith et al. (2011), we demonstrated methods that can be used in the creation of scenarios to evaluate the consistency between air pollutant concentrations and economic income. We found that it was possible to achieve broad consistency for PM_2.5 concentrations by adjusting air pollutant emissions controls within the global energy economics model. We found, however, that it is more difficult to achieve consistency for ozone because of the greater importance of global background ozone concentrations and long-range ozone transport.

As a precursor to this study, we used atmospheric modeling (MOZART-2) to inform the air pollutant control assumptions in the Reference Case used to construct RCP4.5 (Smith et al., 2011). Of the four RCP scenarios, only RCP4.5 used atmospheric modeling in the creation of the scenario to simulate future air pollutant concentrations as a means of evaluating assumptions of air pollutant emission controls. We approached this problem aiming to achieve consistency between air pollutant concentration and economic income, evaluating this consistency through time and among world regions. For example, China in the future is expected to have economic income similar to that in the United States; we then expect that China would aspire to the same level of air pollution as we do today. We found that it was possible to achieve broad consistency for PM_2.5concentrations, by adjusting air pollutant emissions controls within the global energy-economics model. We found, however, that it is more difficult to achieve consistency for ozone because of the greater importance of global background ozone concentrations and long-range ozone transport.

Computer modeling was used extensively in this project, but no new models were created. The atmospheric models used were driven by model output from the GCAM global energy-economics model and the Geophysical Fluid Dynamics Laboratory AM3 general circulation model – applications of these models were beyond the scope of this project. In this project, MOZART-2 was used for atmospheric modeling in Smith et al. (2011), and MOZART-4 was used as reported in West et al. (2013). Details on the model setup and model evaluation with measurements can be found in these publications.

We used modeling methods for processing emissions that were developed by the West research laboratory at UNC, but the development of these computer codes is beyond the scope of this project and is described by Fry et al. (2013). In addition, we used computer codes for evaluating human health outcomes related to air pollution that were also developed in the West laboratory, though outside of the scope of this project. These methods are described by Anenberg et al. (2010) and Silva et al. (2013). For the application in the co-benefits study, we used estimates of future population and baseline mortality rates from the International Futures system, as described by West et al. (2013).

Finally, we continue to conduct research to address the goals of the project to downscale to the United States. We are doing so first to understand the effects of methane on ozone concentrations on a fine scale in the United States. For this project, we have completed model simulations with WRF, SMOKE, and CMAQ, and aim to write a paper in the coming year. Second, we are downscaling to the U.S. scale in the context of the co-benefits project, focusing on simulation results in 2050. This project is ambitious in the use of models, as it requires simulations with WRF, SMOKE, and CMAQ. We have completed simulations of WRF and SMOKE for the present-day case (year 2000) and will soon conduct the CMAQ simulations. By conducting downscaling for the 2050 simulations in the co-benefits project, we will address the contribution of domestic GHG reductions on U.S. air quality, and the contributions of foreign GHG reductions. We aim to complete these simulations and write this research as a journal article in the coming year.

Conclusions:

This research improves our understanding of how air pollution and climate change are interrelated through the decisions made to address these problems. First, we have demonstrated a means by which future scenarios can evaluate air pollution concentrations and achieve broad consistency between these concentrations and the future economic well being in different world regions. Second, we have shown that the co-benefits of global GHG mitigation for air quality and human health are substantial, and result mainly from the reduction of co-emitted air pollutants rather than by slowing climate change and the effects that it has on air quality. We have shown that by accounting for future changes in population, health characteristics, and economic growth in long-term scenarios, as well as the international transport of air pollutants, estimates of co-benefits are higher than had previously been estimated. This work shows that co-benefits should be accounted for when evaluating the costs and benefits of actions to reduce greenhouse gas emissions, providing additional motivation for a transition to a low-carbon future.

References:

Anenberg, S. C., L. W. Horowitz, D. Q. Tong, and J. J. West (2010) An estimate of the global burden of anthropogenic ozone and fine particulate matter on premature human mortality using atmospheric modeling, Environmental Health Perspectives, 118(9): 1189-1195, doi:10.1289/ehp.0901220.

Fry, M. M., M. D. Schwarzkopf, Z. Adelman, V. Naik, W. J. Collins, and J. J. West (2013) Net radiative forcing and air quality responses to regional CO emission reductions, Atmospheric Chemistry & Physics, 13, 5381-5399, doi:10.5194/acp-13-5381-2013.

Silva, R. A., J. J. West, Y. Zhang, S. C. Anenberg, J.-F. Lamarque, D. T. Shindell, D. Bergmann, T. K. Berntsen, P. Cameron-Smith, W. J. Collins, S. J. Ghan, B. Josse, T. Nagashima, V. Naik, D. Plummer, J. M. Rodriguez, S. Szopa, and G. Zeng (2013) Global premature mortality due to anthropogenic outdoor air pollution and the contribution of past climate change, Environmental Research Letters, 8, 034005, 11 p., doi:10.1088/1748-9326/8/3/034005.

Smith, S. J., J. J. West, and P. Kyle (2011) Economically consistent long-term scenarios for air pollutant and greenhouse gas emissions, Climatic Change, 108: 619-627.

West, J. J., S. J. Smith, R. A. Silva, V. Naik, Y. Zhang, Z. Adelman, M. M. Fry, S. Anenberg, L., W. Horowitz, and J.-F. Lamarque (2013) Co-benefits of mitigating global greenhouse gas emissions for future air quality and human health, Nature Climate Change, 3: 885-889, doi:10.1038/nclimate2009

Journal Articles on this Report : 6 Displayed | Download in RIS Format

Publications Views
Other project views:	All 15 publications	6 publications in selected types	All 6 journal articles

Publications
Type	Citation	Project	Document Sources
Journal Article	Smith SJ, West JJ, Kyle P. Economically consistent long-term scenarios for air pollutant emissions. Climatic Change 2011;108(3):619-627.	R834285 (2009) R834285 (2011) R834285 (2012) R834285 (Final)	Abstract: SpringerLink-Abstract Exit
Journal Article	Smith S, West JJ, Kyle P. Cobenefits of global and domestic greenhouse gas emissions for air quality and human health. MEETING ABSTRACTS 2017;389:23-23.	R834285 (Final)	Full-text: The Lancet - Abstract PDF Exit Abstract: The Lancet - Abstract HTML Exit
Journal Article	West JJ, Smith SJ, Silva RA, Naik V, Zhang Y, Adelman Z, Fry MM, Anenberg S, Horowitz LW, Lamarque J-F. Co-benefits of mitigating global greenhouse gas emissions for future air quality and human health. Nature Climate Change 2013;3(10):885-889.	R834285 (Final)	Full-text from PubMed Abstract from PubMed Associated PubMed link Abstract: Nature Climate Change-Abstract Exit
Journal Article	Zhang Y, Bowden JH, Adelman Z, Naik V, Horowitz LW, Smith SJ, West JJ. Co-benefits of global and regional greenhouse gas mitigation for US air quality in 2050. Atmospheric Chemistry and Physics 2016;16(15):9533-9548.	R834285 (Final)	Full-text from PubMed Abstract from PubMed Full-text: ACP-Full Text PDF Exit Abstract: ACP-Abstract Exit
Journal Article	Zhang Y, Cooper OR, Gaudel A, Thompson AM, Nedelec P, Ogino S-Y, West JJ. Tropospheric ozone change from 1980 to 2010 dominated by equatorward redistribution of emissions. Nature Geoscience 2016;9(12):875-879.	R834285 (Final) R835878 (2016) R835878 (2018) R835878 (2019) R835878 (Final)	Full-text: ResearchGate-Abstract & Full Text PDF Exit Abstract: Nature-Abstract Exit
Journal Article	Zhang Y, Smith SJ, Bowden JH, Adelman Z, West JJ. Co-benefits of global, domestic, and sectoral greenhouse gas mitigation for US air quality and human health in 2050. Environmental Research Letters 2017;12(11):114033 (11 pp.).	R834285 (Final)	Full-text from PubMed Abstract from PubMed Full-text: IOP-Full Text HTML Exit Other: IOP-Full Text PDF Exit

Supplemental Keywords:

PM_2.5, PM₁₀, multi-pollutant strategies, climate-air interactions, RFA, Air, climate change, Air Pollution Effects, Atmosphere, environmental monitoring, greenhouse gases, GHG

Relevant Websites:

Jason West

Progress and Final Reports:

Original Abstract

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.