Climate change is internationally recognised as being a serious threat to the health of the biosphere and a concerted, robust response is required by government and industry. Whilst the solid waste management (SWM) sector makes a relatively minor contribution to global GHG emissions, it is recognised as occupying a unique position as a potential net reducer of GHG emissions, an opportunity that is yet to be fully exploited. In order for the SWM sector to effectively contribute to climate change mitigation, analytical tools and information are required to assist national and local governments and waste companies in understanding the climate impacts of their SWM systems and activities and in making climate-conscious decisions. This thesis addresses the quantitative evaluation of the potential climate impacts of SWM systems and processes from a life cycle perspective for the purpose of SWM decision support. Corporate ‘carbon footprint’ quantification and communication practice was critically reviewed, highlighting a lack of methodological consistency and transparency. Similar shortcomings were identified in existing GHG emissions factors, which were found to be inadequate to support effective SWM decision making. To address this, a comprehensive series of scientifically robust and fully-transparent GHG emissions factors for the recycling of source-segregated materials were developed using ‘partial’ life cycle assessment (LCA). A practical, systematic approach, combining the complementary methodologies of material flow analysis (MFA) and LCA, for quantitatively evaluating the life cycle climate impacts of complex SWM systems was developed. The approach was applied to evaluate the environmental performance, focusing on GHG emissions, of a real world municipality-scale SWM system and to compare the potential effectiveness of different waste policies. The successful application of the developed approach demonstrates that the combined use of MFA and LCA can provide SWM decision makers with valuable information about the environmental performance of their SWM systems and activities and provides a sound basis to evaluate strategic decisions and policies.
University of Southampton