Permafrost change in Northeast China in the 1950s–2010s

Permafrost in Northeast China is highly sensitive to climate warming. Permafrost degradation significantly affects forest and vegetation ecosystems, as well as the safety of engineering projects and other man-made infrastructures. However, the permafrost change in the region is still unclear. This study uses metrological data from 258 weather stations, alongside reanalysis data, and other environmental data to investigate permafrost degradation and its related environmental impacts in Northeast China from the 1950s to 2010s. Results show that the total permafrost area decreased from 4.8 × 105 to 3.1 × 105 km2 from the 1950s to the 2010s. The southern limit of permafrost moved 0.1–1.1° northward, and its average elevation rose 160.5 m. During the study period, the degradation of predominantly continuous permafrost, and discontinuous and island permafrost was more pronounced than that of sparsely island permafrost. The south boundary of those three permafrost zones northward by 0–3.4°, 0‒5.5° and 0.4–1.1°, the average altitude raised by 339.2 m, 208.3 m, 67.1 m. The permafrost degradation shows the elevation and latitude zonality. Permafrost degradation is mainly caused by the rising of surface temperatures and the impacts of other environmental factors. The snowfall warming the ground of 1.1–10.2 °C in cold seasons and rainfall cooling on surface conditions in warm seasons, those may result in temporal and spatial differences in permafrost degradation. However, there are lack of researches in the impact of environment factors on soil temperatures, moisture and permafrost degradation.