An ecological perspective on methane emissions from northern wetlands

Wetlands are significant sources of atmospheric methane, an important radiatively active 'greenhouse' gas that accounts for an estimated 12% of total greenhouse warming. Since global climate models predict the greatest temperature and precipitation changes at high latitudes, and as the largest areas of wetland (346 × 10(6)ha) are in the boreal and subarctic regions (40-70°N), recent research has focused on Identifying the factors that control methane emission from northern wetlands. Over the past few years, the database has expanded tremendously, and much progress has been made in understanding the environmental controls on methane emission at small spatial and temporal scales. However, we now need to broaden our understanding of regional differences in methane emission, ecological responses of northern wetlands to climate change, and the effect of other perturbations such as drainage and flooding.