Evidence for a link between climate and northern wetland methane emissions

摘要: Wetlands are an important source of atmospheric methane (CH 4 ), but the strength this and its sensitivity to potential changes in climate still uncertain. In study, continuous measurements from 1990 1998 CH Canadian observational sites at Fraserdale (49°53'N 81°34'W) Alert (82°27'N 62°31'W) used estimate emissions Hudson Bay Lowland (HBL), a 320,000 km 2 semicontinuous wetland region central Canada. The HBL comprises ∼ 10% total area northern wetlands. A conceptually simple approach was calculate emission flux using concentration difference between Fraserdale, residence time air mass over HBL, mixing height convective boundary layer. Emission rates estimated for compare well with empirical aircraft tower made within during same period, thus indicating that methodology is reasonable. Annual range 0.23 0.50 Tg yr -1 much lower than many observed other sites. seasonal temperature Q 10 about found. Moreover, interannual variations correlated annual temperatures corresponding 7. That is, 10°C change would result sevenfold which larger values current global models (typically 1.5). Our findings suggest probably overestimated date may increase significantly due predicted warming.