Global and regional temperature-change potentials for near-term climate forcers
1Met Office Hadley Centre, FitzRoy Road, Exeter, Devon, EX1 3PB, UK
2Department of Environmental Sciences and Engineering, The University of North Carolina at Chapel Hill, 146B Rosenau Hall, CB #7431, Chapel Hill, North Carolina, 27599, USA
3Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, 20740, USA
4Earth Science Directorate, NASA Goddard Space Flight Center, Greenbelt, Maryland, 20771, USA
5Center for International Climate and Environmental Research – Oslo (CICERO), P.O. Box 1129 Blindern, 0318 Oslo, Norway
6NASA Goddard Institute for Space Studies, 2880 Broadway, New York, New York, 10025, USA
Abstract. We examine the climate effects of the emissions of near-term climate forcers (NTCFs) from 4 continental regions (East Asia, Europe, North America and South Asia) using radiative forcing from the task force on hemispheric transport of air pollution source-receptor global chemical transport model simulations. These simulations model the transport of 3 aerosol species (sulphate, particulate organic matter and black carbon) and 4 ozone precursors (methane, nitric oxides (NOx), volatile organic compounds and carbon monoxide). From the equilibrium radiative forcing results we calculate global climate metrics, global warming potentials (GWPs) and global temperature change potentials (GTPs) and show how these depend on emission region, and can vary as functions of time. For the aerosol species, the GWP(100) values are −37±12, −46±20, and 350±200 for SO2, POM and BC respectively for the direct effects only. The corresponding GTP(100) values are −5.2±2.4, −6.5±3.5, and 50±33.
This analysis is further extended by examining the temperature-change impacts in 4 latitude bands. This shows that the latitudinal pattern of the temperature response to emissions of the NTCFs does not directly follow the pattern of the diagnosed radiative forcing. For instance temperatures in the Arctic latitudes are particularly sensitive to NTCF emissions in the northern mid-latitudes. At the 100-yr time horizon the ARTPs show NOx emissions can have a warming effect in the northern mid and high latitudes, but cooling in the tropics and Southern Hemisphere. The northern mid-latitude temperature response to northern mid-latitude emissions of most NTCFs is approximately twice as large as would be implied by the global average.