Warming leads to significant loss of CO2 in high-altitude regions (HAR), posing threat to the carbon sink of terrestrial ecosystem. Additionally, the spatial distribution of environmental factors and underlying surfaces also determine the carbon sink pattern. Therefore, it is necessary to systematically explore the carbon sink of HAR. Based on it, choosing the Qilian Mountains (QLM) as the study area, the continuous observation data of 14 eddy covariance in different ecosystems was used to analyze the variation characteristics of carbon use efficiency (CUE) and net ecosystem primary productivity (NEP), which is helpful to systematically understand the response of carbon cycle to climate change in alpine ecosystem. The research results indicated that the QLM serves as an effective carbon sink (13 of the sites yielded a net carbon sink), owing to the combined influences of environmental factors and vegetation characteristics. Annual NEP varied across the 14 sites, ranging from-192.6 to 524.5 g C/m(2)/yr. Limited observation indicated that wetland/swamp had the highest carbon sink, followed by forest, and shrub have the lowest carbon sink in this study. Along the altitudinal gradient, both gross primary productivity (GPP) and ecosystem respiration (Re) demonstrated a declining trend ( P < 0.05), while, CUE displayed an increasing trend. Soil temperature and photosynthetically active radiation dominated the variation in carbon exchange and CUE along the altitudinal gradient. However, soil moisture was the dominant factor in drought ecosystem. This study provides basis for the assessment of carbon sink of the HAR.

The Arctic amplification (AA) has exacerbated permafrost degradation, posing a serious threat to infrastructure security and other areas. Therefore, it is crucial to accurately assess the current status and future changes of permafrost, and reliable soil thermal conductivity (STC) is an important prerequisite for permafrost prediction. However, few methods and products are available for regional-scale STC simulations in permafrost of the Arctic, which lead to greater uncertainty in the simulation of land surface temperatures. This study conducted a preliminary STC simulation based on the XGBoost method. The results show that the average STC during the freezing period is between 0.71 similar to 0.73 W center dot m-1K-1, and around 0.67 W center dot m-1K-1 during the thawing period; The variation of STC between the thawing and freezing period ranged from -0.34-0.23 W center dot m-1K-1, with an average value of -0.02 W center dot m-1K-1; The areas where STC of the thawing period is smaller than that of the freezing period are mainly concentrated in the marginal areas near the sea on the continental side of North America and in the typical areas of plains, lowlands, and plateaus on the continental side of Eurasia. The areas with large STC during the thawing period are concentrated in mountainous areas.

Society could sustain the impact of climate change by adapting to the change and mitigating risks from adverse effects of increasing changes, so that it can continue maintaining its prospect and improving wellbeing. Nevertheless, climate change is more or less affecting society's functions at different scales, including both individuals and communities. In this review, we discuss the relationship between society and climate change in China from the aspects of the needs at different socioeconomic developing stages. The relationship as well as the current spatial pattern and future risks of the climate change impacts on societies are summarized. The complexity of social and climatic systems leads to the spatial heterogeneity of climate impacts and risks in China. To more effectively leverage increasing knowledge about the past, we advocate greater cross-disciplinary collaboration between climate adaption, poverty alleviation and Nature-based Solutions (Nbs). That could provide decision makers with more comprehensive train of thoughts for climate policy making.