Warmer spring conditions increase annual methane emissions from a boreal peat landscape with sporadic permafrost

摘要: About a fifth of the global wetland methane emissions originate from boreal peatlands, which represent an important land cover type in landscapes sporadic permafrost zone. There, rising air temperatures could lead to warmer spring and longer growing seasons, changing landscape emissions. To quantify effect conditions on peat zone northwestern Canada, we analyzed four years (2013 – 2016) fluxes measured with eddy covariance technique long-term (1951-2016) meteorological observations nearby climate station. In May, after snowmelt was complete, mean were more than 2 °C 2013, 2015, 2016 2014. Mean season (May-August) temperatures, contrast, differed by less 1 over years. Warmer May caused earlier soil warming, ~0 g12 25 40 days leading ~6 between June. However, July August, similar among August annual (6.4 g CH4 m-2 9.4 m-2, respectively) (i.e., May) exceeded during cooler year 20-30 % (4.5 7.2 respectively). Among springs, varied little (0.5 m-2). The observed interannual differences are most likely strong temperature control large spring. Thus, warming climate, waterlogged at southern limit increase response frequent occurrences warm springs.