Greenhouse gas dynamics of municipal solid waste alternatives

Previous greenhouse gas studies comparing landfilling with combustion of mu nicipal solid waste (MSW) are limited to examinations of the emissions weig hted by their relative radiative activity. This paper adds another dimensio n by analyzing the atmospheric response to these emissions. The heart of th e analysis is a time-dependent model using a perturbation analysis of the I S92a results of the Intergovernmental Panel on Climate Change (IPCC). Using as inputs the emissions from the two technologies, the model calculates at mospheric concentration histories. Scenarios for a landfill and a combustor envision each accepting 1000 Mg refuse/day for a 30-year operating period followed by a 70-year postclosure period. The baseline scenario examines th e basic greenhouse impact of each technology. The other scenario adds activ e gas collection at the landfill and energy offset credits for avoided powe r plant carbon emissions. For both scenarios, CH4 and trace gases from the landfill persist in the atmosphere, and they are relatively potent at forci ng IR heating. The combination of these features place the landfill much hi gher than previously expected on the greenhouse impact scale. For the basel ine scenario, the time-integrated radiative forcing from landfilling is 115 times that of combustion, and this ratio is 45 for the second scenario.