Peatlands, carbon storage, greenhouse gases, and the Kyoto Protocol: Prospects and significance for Canada

The Kyoto Protocol accepts terrestrial sinks for greenhouse gases (GHGs) as offsets for fossil fuel emissions. Only carbon sequestered in Living bioma ss from re- and afforestation is presently considered, but the Protocol con tains a provision for the possible future inclusion of other land uses and soils. As a result, the possibility of sequestration of carbon in wetlands, and particularly peatlands, is being discussed. Natural peatlands are pres ently a relatively small sink for CO2 and a large source of CH4: globally, they store between 400 and 500 Gt C. There are large variations among peatl ands, but when the "global warming potential" of CH4 is factored in, many p eatlands are neither sinks nor sources of GHGs. Some land-use changes may r esult in peatlands acting as net sinks far GHGs by reducing CH4 emissions a nd/or increasing CO2 sequestration (e.g., forest drainage), while other lan d uses may result in large losses of CO2, CH4, and N2O (e.g., agriculture o n organic soils, flooding for hydroelectric generation). Other land uses, s uch as peatland creation and restoration, produce no net change if they are replacing or restoring a previous level of GHG exchange. These are analogo us to reforestation of deforested areas. On closer examination, the inclusi on of peatlands in a national greenhouse gas strategy as sinks, despite the ir large role in the terrestrial carbon cycle, may not significantly reduce net greenhouse gas emissons. If the sinks are to be considered, it is reas onable that terrestrial sources associated with all land uses on peatlands also should be considered. If peatlands are not considered explicitly, but soils in forest and agriculture systems are included in the Kyoto Protocol in the future, then those peatlands impacted by these land uses will be inc orporated implicitly.