Coal-fired power plants influence climate via both the emission oflong-lived carbon dioxide (CO) and short-lived ozone and aerosolprecursors. Using a climate model, we perform the first study of the spatialand temporal pattern of radiative forcing specifically for coal plantemissions. Without substantial pollution controls, we find that near-termnet global mean climate forcing is negative due to the well-known aerosolmasking of the effects of CO. Imposition of pollution controls onsulfur dioxide and nitrogen oxides leads to a rapid realization of the fullpositive forcing from CO, however. Long-term global mean forcing fromstable (constant) emissions is positive regardless of pollution controls.Emissions from coal-fired power plants until ~1970, including roughly1/3 of total anthropogenic CO emissions, likely contributed little netglobal mean climate forcing during that period though they may have induceweak Northern Hemisphere mid-latitude (NHml) cooling. After that time many areas imposedpollution controls or switched to low-sulfur coal.Hence forcing due to emissions from 1970 to 2000 and CO emittedpreviously was strongly positive and contributed to rapid global andespecially NHml warming. Most recently, new construction in China and Indiahas increased rapidly with minimal application of pollution controls.Continuation of this trend would add negative near-term global mean climateforcing but severely degrade air quality. Conversely, following the Westernand Japanese pattern of imposing air quality pollution controls at a latertime could accelerate future warming rates, especially at NHmls. More broadly, our resultsindicate that due to spatial and temporal inhomogenaities in forcing,climate impacts of multi-pollutant emissions can vary strongly from regionto region and can include substantial effects on maximum rate-of-change,neither of which are captured by commonly used global metrics. The method weintroduce here to estimate regional temperature responses may provideadditional insight.
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