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The evolution process of socio–ecological systems from 1990 to 2020 in the Tianzhu Tibetan Autonomous County, located in the National Key Ecological Function Area of western China, was analyzed quantitatively based on resilience theory and methodology combined with catastrophe theory and adaptive cycle theory, through field investigation, questionnaires and interviews, social data collection and remote sensing data analysis. The results show that the coordinated development of socio–ecological systems has made great progress in recent decades in the study area, and the coordinated development of social systems and ecosystems has a high degree of coupling and a strong connection. Changes in ecosystem resilience regularly surpassed changes in the social system, indicating the significant impact and success of ecological protection policies and projects in recent decades. In future, improvements in the social sub-system will be the key to developing the socio–ecological system in the study area. Enhancing social sub-system resiliency, implementing transformational development and green industry development, and transforming and realizing ecological product values are important topics for further investigation in the study area. Substantial changes in policy, production, population and climate change are needed to promote the evolution of socio–ecological systems. Stable national policies are crucial for improving people's livelihoods and providing ecological protections. [ABSTRACT FROM AUTHOR]

This study outlines the paleoglacial history and paleoclimatic conditions that were present during the Last Glacial Maximum (LGM) and Lateglacial (LG) in the Songlong and Zhuxi valleys in the eastern Nyainqêntanglha Range, southeastern Tibet. Two sets of moraines were identified at the valley mouths, and were dated using cosmogenic 10Be exposure and optically stimulated luminescence (OSL) dating. The ages suggest that two glaciations occurred at ~20–21 and ~14–16 ka, respectively, coinciding with the LGM and LG. Using glacier–climate modeling, temperature drops were calculated to have ranged from 6.3 to 7.8 °C during the LGM–LG, with precipitation being 40–60% of the present‐day value. The results in the modeled domain appear generally consistent with other climatic records from the Tibetan Plateau. Glacial advances in monsoon‐dominated southeastern Tibet during the LGM–LG were probably driven by low temperatures rather than by high precipitation, which was usually produced by an enhanced Indian Summer Monsoon during periods of climatic warming. [ABSTRACT FROM AUTHOR]

Alpine sparsely vegetated areas (ASVAs) in mountains are sensitive to climate change and rarely studied. In this study, we focused on the response of ASVA distribution to climate change in the eastern Qilian Mountains (EQLM) from the 1990s to the 2010s. The ASVA distribution ranges in the EQLM during the past three decades were obtained from the Thematic Mapper remote sensing digital images by using the threshold of normalized difference vegetation index (NDVI) and artificial visual interpretation. Results indicated that the ASVA shrank gradually in the EQLM and lost its area by approximately 11.4% from the 1990s to the 2010s. The shrunken ASVA with markedly more area than the expanded one was mainly located at altitudes from 3700 m to 4300 m, which were comparatively lower than the average altitude of the ASVA distribution ranges. This condition led to the low ASVA boundaries in the EQLM moving upwards at a significant velocity of 22 m/decade at the regional scale. This vertical zonal process was modulated by topography-induced differences in local hydrothermal conditions. Thus, the ASVA shrank mainly in its lower parts with mild and sunny slopes. Annual maximum NDVI in the transition zone increased significantly and showed a stronger positive correlation with significantly increasing temperature than insignificant precipitation variations during 1990–2015. The ASVA shrinkage and up-shifting of its boundary were attributed to climate warming, which facilitated the upper part of alpine meadow in the EQLM by releasing the low temperature limitation on vegetation growth. [ABSTRACT FROM AUTHOR]

Climate change due to global warming is a world concern, particularly in Africa. In this study, precipitation and temperature variables are taken as a proxy to assess and quantify the long-term climate change and drought in the Horn of Africa (HOA) (1930–2014). We adapted a simple linear regression and interpolation to analyze, respectively, the trend and spatial distribution of the mean annual precipitation and temperature. In addition, standardized precipitation evapotranspiration index (SPEI) was applied to evaluate the drought condition of the HOA. The results revealed that statistically the trend of precipitation decreased insignificantly; the trend of temperature was observed to drop very significantly between 1930 and 1969, but it was dramatically elevated very significantly from 1970 to 2014. The SPEI showed that the HOA experienced from mild to moderate drought throughout the study period with severe to extreme drought in some regions, particularly in 1943, 1984, 1991, and 2009. The drought was a very serious environmental problem in the HOA in the last 85 years. Thus, an immediate action is required to tackle drought and hence poverty and famine in the HOA. [ABSTRACT FROM AUTHOR]

Intense human activities and rapid climate changes both have obvious impacts on alpine ecosystems. However, the magnitudes and directions of the impacts by these two drivers remain uncertain due to a lack of a reasonable assessment method to distinguish between them. The impact of natural resilience is also generally included in the dynamics of a disturbed ecosystem and is liable to be mixed into the impact of human activity. It is urgent that we quantitatively discriminate human activity impacts on the ecosystem under climate change, especially for fast-developing alpine regions. Here, we propose an assessment method to determine human activity impacts under a dynamic climate, taking the potential net primary production (NPP) of an ecosystem as a benchmark. The potential NPP (NPPP) series under the changing climate was retrieved by an improved integrated biosphere simulator based on the initial disturbed ecosystem status of the assessment period. The actual NPP (NPPA) series monitored by remote sensing was considered as the results derived from the joint impacts of climate change, natural resilience and human activity. Then, the impact of human activity was quantified as the difference between the NPPP and NPPA. The contributions of human activity and natural forces to ecosystem NPP dynamics were then calculated separately and employed to explore the dominant driver(s). This assessment method was demonstrated in a typical alpine ecosystem in Northwest China. The results indicate that this method capably revealed the positive impacts of local afforestation and land-use optimization and the negative impacts caused by grazing during the assessment period of 2001–2017. This assessment method provides a quantitative reference for assessing the performances of ecological protections or human damage to alpine ecosystems at the regional scale. [ABSTRACT FROM AUTHOR]

Paleomagnetic determinations on lithological profiles of two paralleled long drilling cores covering the past 130 kyr B.P., GT40 and GT60, from the Yanchi Playa in the arid Northwestern China, indicate that a series of pronounced paleomagnetic excursions have been documented. By correlating our results with published regional and worldwide reports, 4 excursion events out of 10 apparent reversal signals (labeled from GT-1 to GT-10) were identified as excursion events coeval with the Mono Lake Event (28.4 kyr–25.8 kyr), Laschamp Event (43.3 kyr–40.5 kyr), Gaotai Event (82.8 kyr–72.4 kyr) and the Blake Event (127.4 kyr–113.3 kyr), respectively. GT-9 correlates with the above-mentioned Gaotai Event, GT-7 and GT-6 correspond to two stages of the Laschamp Event and GT-5 to the Mono Lake Event. It is noteworthy that the so-called Gaotai Event has not been reported as a pronounced paleomagnetic excursion in the Northwestern China. Every magnetic excursion event corresponds to paleointensity minima, anteceding those established abrupt paleoclimatic change events, such as the Younger Drays and the Heinrich Events (H1–H6). Here, we tentatively propose that these geomagnetic excursions/reversals can be viewed as precursors to climate abruptness. During the transitional stages when the earth’s magnetic field shifted between a temporal normal and a negative period, the earth’s magnetic paleointensity fell correspondingly to a pair of minima. Although more precise chronology and more convincing rock magnetic parameter determinations are essentially required for further interpretation of their intricate coupling mechanism, these results may have revealed, to some extent, that the earth’s incessantly changing magnetic field exerts an strong influence on the onset of saw-tooth shaped abrupt climate oscillations through certain feedback chains in arid Central Asia or even North Hemispheric high latitude regions. [ABSTRACT FROM AUTHOR]

Accurate assessment and response analysis of land use and land cover change (LUCC), and ecosystem service values (ESV), are critical to regional ecological security and economic development. There is a lack of detailed reports on the impact of LUCC on the temporal and spatial evolution of ESV in Yinchuan City, which is inconsistent with the pilot urban design policy. This paper, using the LUCC data of Yinchuan City from 1980 to 2018, calculated the ESV, analyzed the temporal and spatial patterns of LUCC and ESV, and discussed the response of ESV to LUCC. The results show that, from 1980 to 2018, the building land increased significantly in Yinchuan City, as did the cultivated land. Meanwhile, grassland and bare land decreased, while forest and the water body remained stable. The spatial connectivity of the building land showed regular improvements, while the urban landscape developed in a regular and balanced direction. During the study period, the total ESV of Yinchuan City decreased by 0.75 × 109 yuan. This was due to the decrease in grasslands and the increase in building area. The supply, regulation and support of three types of services have a high correlation with different land types. The prosperity and progress of culture reduces the ESV value of cultivated land to some extent, while the change in land use type leads to the significant loss of ESV in Yinchuan City. [ABSTRACT FROM AUTHOR]

Research on the spatial access to medical services has become a hot topic in recent years. The representative provincial capital in the underdeveloped region of northwestern China, Lanzhou, was selected for the research area. In this paper, methods such as the two-step floating catchment area and ArcGIS network analysis are used to analyze the geographic spatial accessibility of medical services and differences of spatial access between urban and rural areas in Lanzhou city. The results show that 1. Areas in General and below grade of accessibility account for most of Lanzhou city. Therefore, the spatial accessibility of whole Lanzhou city is comparatively unsatisfactory. It shows a tendency of the north region to be worse than south region, and areas in parts of the main districts, parts of HG, and other tiny minority show Great grade of accessibility, and most of other areas distribute in poorer grade of accessibility, especially the surrounding mountainous region. 2. There are obvious differences in accessibility between urban and rural regions, mainly reflected in that residents and areas are basically districted in the Great and Good grade in the urban region, while almost 75% of the population and 35% of the areas are distributed in the Great and Good grade, and nearly 25% of the residents and 65% of the areas are still in the unsatisfactory accessibility grade in the rural region. According to the results, the researchers put forward corresponding suggestions to improve the current situation, which are roughly as follows: The construction of hospitals and primary health care should be strengthened in the rural region, especially the construction of township health centers and health stations. High-class hospitals are needed in Honggu district, Yongdeng county, Yuzhong county, and Gaolan county, while the medical capacity and facility grade of existing hospitals should be improved to satisfy the demand of local residents. Meanwhile, rural areas should strengthen the construction of road networks. [ABSTRACT FROM AUTHOR]