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This study uses life-cycle analysis to examine the net greenhouse gas (GHG) emissions from the Canadian peat industry for the period 1990-2000. GHG exchange is estimated for land-use change, peat extraction and processing, transport to market, and the in situ decomposition of extracted peat. The estimates, based on an additive GHG accounting model, show that the peat extraction life cycle emitted 0.54 x 10(6) t of GHG in 1990, increasing to 0.89 x 10(6) t in 2000 (expressed as CO2 equivalents using a 100-y time horizon). Peat decomposition associated with end use was the largest source of GHGs, comprising 71% of total emissions during this 11-y period. Land use change resulted in a switch of the peatlands from a GHG sink to a source and contributed an additional 15%. Peat transportation was responsible for 10% of total GHG emissions, and extraction and processing contributed 4%. It would take approximately 2000 y to restore the carbon pool to its original size if peatland restoration is successful and the cutover peatland once again becomes a net carbon sink.

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Background, aim, and scope Municipal solid waste (MSW) management organizations commonly address both waste treatment and diversion activities in their management plans, yet the application of life cycle assessment (LCA) to MSW rarely incorporates the effects of waste prevention activities (WPAs) in an explicit manner. The primary objective of this paper is to further develop the methodological options for attributional LCAs of MSW to address waste prevention, including product reuse. Main features This article introduces the waste management and prevention (WasteMAP) LCA, a conceptual model that applies system expansion to generate a hybrid of the traditional product and waste LCA. The WasteMAP LCA, unlike the traditional LCA of MSW, can be used to compare functionally equivalent MSW management scenarios incorporating both treatment and prevention. This functional equivalence necessitates that waste prevention takes place through dematerialization. This form of WPA is analogous to waste management techniques such as landfilling in that it does not affect the functional output (product services) of MSW-generating product systems. Results Integral to the WasteMAP LCA is the requirement that the sum of the MSW managed through treatment and prevention, and the level of consumption of product services contributing to MSW generation, are identical for each scenario. A partial abandonment of the zero-burden assumption is also required. Consequently, product life cycles associated with WPAs, excluding the waste treatment stages, comprise the 'upstream' component of the system boundary, while the 'downstream' component encompasses the waste treatment life cycle. WasteMAP also possesses primary and secondary functional units, with the former accounting for the amount of waste managed, and the latter depicting the product services provided by the product systems responsible for the waste targeted for prevention. Discussion The WasteMAP LCA method can be used to identify in the results the burdens and avoided burdens attributed to waste prevention, recycling, biological and thermal treatments, as well as landfilling, within a particular MSW management system. This method also distinguishes itself through its ability to evaluate scenarios that target the prevention of particular waste streams to obtain downstream efficiency gains for the management of all waste materials. Conclusions An attributional LCA of MSW can be applied to a wider array of possible waste management scenarios, including those with waste prevention, by expanding the system boundary, and in the case of waste prevention through dematerialization, by introducing an additional type of functional unit.

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