Air & Waste Management Association (A&WMA)

Greenhouse gas emissions from waste management-assessment of quantification methods


Of the many sources of urban greenhouse gas (GHG) emissions, solid waste is the only one for which management decisions are undertaken primarily by municipal governments themselves and is hence often the largest component of cities’ corporate inventories. It is essential that decision-makers select an appropriate quantification methodology and have an appreciation of methodological strengths and shortcomings. This work compares four different waste emissions quantification methods, including Intergovernmental Panel on Climate Change (IPCC) 1996 guidelines, IPCC 2006 guidelines, U.S. Environmental Protection Agency (EPA) Waste Reduction Model (WARM), and the Federation of Canadian Municipalities– Partners for Climate Protection (FCM-PCP) quantification tool. Waste disposal data for the greater Toronto area (GTA) in 2005 are used for all methodologies; treatment options (including landfill, incineration, compost, and anaerobic digestion) are examined where available in methodologies. Landfill was shown to be the greatest source of GHG emissions, contributing more than threequarters of total emissions associated with waste management. Results from the different landfill gas (LFG) quantification approaches ranged from an emissions source of 557 kt carbon dioxide equivalents (CO2e) (FCM-PCP) to a carbon sink of 53 kt CO2e (EPA WARM). Similar values were obtained between IPCC approaches. The IPCC 2006 method was found to be more appropriate for inventorying applications because it uses a waste-in-place (WIP) approach, rather than a methane commitment (MC) approach, despite perceived onerous data requirements for WIP. MC approaches were found to be useful from a planning standpoint; however, uncertainty associated with their projections of future parameter values limits their applicability for GHG inventorying. MC and WIP methods provided similar results in this case study; however, this is case specific because of similarity in assumptions of present and future landfill parameters and quantities of annual waste deposited in recent years being relatively consistent.

The release of landfill gas (LFG) resulting from anaerobic decomposition of municipal solid waste (MSW) is generally quantified in greenhouse gas (GHG) emissions inventories conducted by cities. For 2007, this emissions source represented 21 Mt ( 3%) of total emissions tabulated in the Canadian national GHG inventory and 127 Mt (2%) in the U.S. inventory.1,2 Municipalities, which have been strong jurisdictional champions in addressing climate change, play the principal role in managing these GHGs because their decisions dictate diversion, treatment, and mitigation (such as LFG capture) practices. The opportunity for reductions is large; an example from the 2004 City of Toronto inventory suggests solid waste contributed 3% of community-wide emissions; however, its proportion of corporate emissions (those stemming strictly from municipal government activities) was 45%.3 Additionally, waste emissions generally contribute a larger proportion of community-wide municipal emissions in the developing world (e.g., up to 40% in Rio De Janeiro4). The method selected for quantifying waste-related emissions is important because projects to mitigate MSWrelated GHG emissions are likely to be a high priority; Kennedy et al.5 demonstrated that waste emissions reduction strategies tend to be the most cost-effective of municipal projects targeting GHGs regardless of region, underscoring the importance of proper quantification for planning purposes.

Customer comments

  1. By Peter Hurrell on

    Very interesting observations were made here, and the authors need recognition for that. There are too many applications for funding that do not take full cogniscence of the water content of the municipal solid wastes and that is their downfall when we come to assess the merits of applicability to the CDM (Clean Development Mechanism) in particular. We have also calculated that there is a disproportionate under-estimation of the fullest effects of the emissions arising from dumping waste on to land deposit sites and this is a serious issue in the whole IPPC calculations.

  2. By Mohamad Unose Othman on

    I am interested regarding solid waast management industries. I would like to learn more and might be one of the local company can introduce this industries to my country.