04/13/2012
Variable Impacts of Ozone Precursors from Four World Regions on Global Warming
Summary
This study addressed the impact of a class of short-lived climate forcers, radiatively active substances whose rate of turnover in the atmosphere makes them candidates for possible climate mitigation strategies. The study describes estimates of different ozone precursor emission contributions from different geographical regions towards global net radiative forcing. Ozone (O3) precursor emissions influence regional and global climate and air quality through changes in tropospheric O3 and other oxidants, which also influence methane (CH4) and sulfate aerosols (SO4=). The Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model (CTM) was used to simulate changes in the tropospheric composition of O3, CH4, SO4=, and global net radiative forcing (RF) for 20% reductions in global CH4 burden and in anthropogenic O3 precursor emissions (nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOC), and carbon monoxide (CO)) from four regions (East Asia, Europe and Northern Africa, North America, and South Asia). NOx reductions produced positive RF, while CH4, NMVOC, and CO reductions yielded a negative RF. A positive RF (more incoming energy) tends to warm the system, while a negative RF (more outgoing energy) tends to cool it. RF is also more sensitive to NOx and NMVOC emission reductions from regions closer to the equator. Variability in the global warming potential among different regions for NOx and NMVOCs suggests that the availability and use of regionally specific estimates would be important. This information will be useful for policymakers as they try to control future air quality and climate change.
References
Fry, M. M., V. Naik, J. J. West, M. D. Schwarzkopf, A. M. Fiore, W. J. Collins, F. J. Dentener, D. T. Shindell, C. Atherton, D. Bergmann, B. N. Duncan, P. Hess, I. A. MacKenzie, E. Marmer, M. G. Schultz, S. Szopa, O. Wild, and G. Zeng. 2012. “The Influence of Ozone Precursor Emissions from Four World Regions on Tropospheric Composition and Radiative Climate Forcing,” Journal of Geophysical Research Atmospheres 117, D07306, DOI: 10.1029/2011JD017134.