Building the Belt and Road is initiatives of China to promote win-win international cooperation in the new era, aiming at green, health, intellect and peace and the joint development with people of the countries along the route. Systematic analysis on environmental characteristics, evolutionary tendency and future risks are certainly the scientific fundamentals of sustainable development for the Belt and Road construction. Applied remote sensing monitoring, statistical analysis, this paper investigates the regional characteristics of climate, topography, soil, hydrology, vegetation cover and terrestrial ecosystems production, as well as socio-economic conditions. Based on the regional characteristics, the Belt and Road is divided into 9 sub-regions: Central and Eastern Europe sub-region with cold and humid climate, Mongolia and Russia sub-region with cold and arid climate, Central and West Asia arid sub-region, Southeast Asia sub-region with warm and humid climate, Pakistan arid sub-region, Bangladesh-India-Myanmar sub-region with warm and humid climate, Eastern China monsoon sub-region, Northwest China arid sub-region and Tibetan Plateau sub-region. Combining modeling simulation with scenario projections, natural disaster assessment methodology is used to assess the risk of extreme events including heat waves, droughts and floods in the coming 30 years (2021-2050). Results show that, on the basis of the regional framework, the western Eurasia would be a warming trend; both sides of Qinghai-Tibet Plateau in high temperature and heat waves risk; Central and Eastern Europe sub-region with cold and humid climate in high drought risk; Bangladesh-India-Myanmar sub-region with warm and humid climate as well as Eastern China in high risk of flooding.
The 1998-2012 global warming hiatus has aroused great public interest over the past several years. Based on the air temperature measurements from 622 meteorological stations in China, the temperature response to the global warming hiatus was analyzed at national and regional scales. We found that air temperature changed -0.221℃/10a during 1998-2012, which was lower than the long-term trend for 1960-1998 by 0.427℃/10a. Therefore, the warming hiatus in China was more pronounced than the global mean. Winter played a dominant role in the nationwide warming hiatus, contributing 74.13%, while summer contributed the least among the four seasons. Furthermore, the warming hiatus was spatial heterogeneous across different climate conditions in China. Comparing the three geographic zones, the monsoon region of eastern China, arid region of northwestern China, and high frigid region of the Tibetan Plateau, there was significant cooling in eastern and northwestern China. In eastern China, which contributed 53.79%, the trend magnitudes were 0.896℃/10a in winter and 0.134℃/10a in summer. In the Tibetan Plateau, air temperature increased by 0.204℃/10a, indicating a lack of a significant warming hiatus. More broadly, the warming hiatus in China may have been associated with the negative phase of PDO and reduction in sunspot numbers and total solar radiation. Finally, although a warming hiatus occurred in China from 1998 to 2012, air temperature rapidly increased after 2012 and will likely to continuously warm in the next few years.
The core objective of rural vitalization is to systemically establish a coupling pattern of various rural development elements including population, land and industry. As one of the prerequisites, land resources is required to be optimally allocated via land consolidation. Consequently, land consolidation contributes greatly to population agglomeration, industrial development and resources support under the context of combating rural decline. Based on the key elements affecting rural development, this paper elaborates the connotation of rural vitalization and land consolidation in the new era as well as their relationships. Furthermore, the paper analyzes the alternative paths for achieving rural vitalization via land consolidation, and discusses the future directions of land consolidation and rural vitalization. The conclusions are drawn as follows: (1) To cope with the loss and decline of the intrinsic elements in rural areas, rural vitalization is a development strategy aimed at realizing economic, political, cultural and ecological rejuvenation in rural area by reshaping socio-economic morphology and spatial pattern in rural territory. (2) From the perspective of rural vitalization, land consolidation is endowed with new connotation, which should not only target at activating the key elements of rural development, but also place emphasis on coordinating material space and spirit core as well as integrating the restructuring of the physical space and the rural governance system. (3) Land consolidation should be compatible with regional natural conditions and the current stage of socio-economic development. According to the principle of regional planning and classification strategy, the appropriate models and paths should be adopted to promote the benign interactions of population, land and industry based on engineering techniques and ecological means. (4) Under the background of national strategy of rural vitalization, it is necessary to reshape the value orientation of land consolidation based on a scientific understanding of urban-rural relations and rural territorial functions, coordinate land consolidation planning and rural vitalization planning under the unified spatial planning system, and explore the new model combining land consolidation and multifunctional agriculture.
Farmland marginalization has become the main trend of land-use change in the mountainous areas of China. Using annual survey data of major agricultural production costs and earnings at national and provincial levels in China, this study aims to analyze the reasons and mechanism behind farmland marginalization in mountainous areas. We find that farmers on plains are able to reduce their per mu labor input effectively through intensive use of agricultural machinery, which has minimized the impact of the increase in labor price. However, it is extremely challenging for farmers in mountainous areas to use the same method owing to the rough terrain. Thus, per laborer farming area in these areas has increased relatively slowly, causing a widening gap in agricultural labor productivity between the two regions. With the rapid rise in labor costs since 2003, the marginalization of cultivated land in mountainous areas is evident. In 2013, the net profit of agricultural production in mountainous China fell below zero. Since 2000, the land-use and land-cover change in these areas was characterized by the reduction of farmland area, reforestation, and the enhancement of the NDVI value. The high correlation between the NDVI change rate and the ratio of change in farmland (r = -0.70) and forest (r = 0.91) in mountainous areas at provincial level further attests to the trend of farmland marginalization there. Finally, we summarize the mechanism of such marginalization against the backdrop of the rapid increase in the opportunity cost of farming and the rapid fall of agricultural labor forces in mountainous areas. This study contributes to a deep understanding of the development process of farmland marginalization and abandonment as well as forest transition in Chinese mountainous areas.
Land-use efficiency is low for the urban agglomeration of China. High-speed transportation construction has been an important factor driving land use change. It is critically important to explore the spatial relationship between the high-speed transportation superiority degree and land-use efficiency. We built a model to evaluate the benefits of convenient high-speed transportation using the relative density of highways and the distance from high-speed rail stations and airports as a metric. We used 42 counties of the Shandong Peninsula urban agglomeration as an example. Land-use efficiency was calculated by a DEA model with capital, labor, economic benefits and environmental benefits as input and output factors. We examined the spatial relationships between high-speed transport superiority degree and land-use efficiency and obtained the following results. First, there are significant spatial differences in the relationships between the high-speed transportation superiority degree and land-use efficiency. Taking the two major cities of Jinan and Qingdao as the hubs, the core surrounding counties show significant spatial relationship between land-use efficiency and the high-speed transportation superiority degree. Spatial correlation declines as the distance from the hubs increases. Land-use efficiency is less than high-speed transportation convenience in areas along the transportation trunks that are distant from the hub cities. Correlation is low in areas that are away from both hub cities and transportation trunk routes. Second, high-speed transportation has a positive relationship with land-use efficiency due to the mechanism of element agglomeration exogenous growth. Third, high-speed transportation facilitates the flow of goods, services and technologies between core cities and peripheral cities as space spillover (the hub effect). This alters the spatial pattern of regional land-use efficiency. Finally, the short-board effect caused by decreased high-speed transport construction can be balanced by highway construction and the proper node layouts of high-speed rail stations and airports, resulting in a well-balanced spatial pattern of land-use efficiency.
Discussions regarding the functional transformation of agricultural utilization and the mechanisms that underlie these changes within the Three Gorges Reservoir Area (TGRA) reflect variations in the relationship between people and their environment in China’s central and westerns part, an area of mountains and reservoirs. A clear understanding of these changes also provides the scientific basis for the development of multi-functional agriculture in typical mountainous areas. Five counties were selected for analysis in this study from the hinterland of the TGRA; we analyzed changes in farmland scaling and corresponding underlying mechanisms by defining the concepts of “Scaling Farmland” (SF) and by using the software packages ArcGIS10.2, SPSS, and Geographical Detectors. The results of this analysis show that sources of increased SF have mainly comprised cultivated and shrub land. Indeed, with the exception of some alpine off-season vegetables, SF growth has mainly occurred in low altitude areas and in places where the slope is less than 30°. We also show that spatial changes in various SF types have also been substantially different, but in all cases are closely related to road and township administrative centers. Natural factors at the patch level, including elevation and slope, have contributed significantly to SF, while at the township level, underlying socioeconomic and humanistic factors have tended to include road traffic and agricultural population density. In contrast, at the regional level, underlying driving forces within each have tended to be more significant than overall study area scale. We show that while changes in, and the development of, SF have been driven by numerous factors, agricultural policies have always been amongst the most important. The results clearly elucidate general land use transformation patterns within the mountain regions of western China.
Rapid urbanization and continuous loss of rural labor force has resulted in abandonment of large areas of farmland in some regions of China. Remote sensing technology can indirectly help detect abandoned farmland size and quantity, which is of great significance for farmland protection and food security. This study took Qingyun and Wudi counties in Shandong Province as a study area and used CART decision tree classification to compile land use maps of 1990-2017 based on Landsat and HJ-1A data. We developed rules to identify abandoned farmland, and explored its spatial distribution, duration, and reclamation. CART accuracy exceeded 85% from 1990-2017. The maximum abandoned farmland area was 5503.86 ha during 1992-2017, with the maximum rate being 5.37%. Farmland abandonment rate was the highest during 1996-1998, and abandonment trend decreased year by year after 2006. Maximum abandonment duration was 15 years (1992-2017), mostly within 4 years and only a few exceeded 10 years. From 1993-2017, the maximum reclaimed abandoned farmland was 2022.3 ha, and the minimum ~20 ha. The maximum reclamation rate was 67.44%m, with annual average rate being 31.83%. This study will help analyze farmland abandonment driving forces in the study area and also provide references to identify abandoned farmland in other areas.
Topographical relief is a key factor that limits population distribution and economic development in mountainous areas. The limitation is especially apparent in the mountain-plain transition zone. Taking the transition zone between the Qinling Mountains and the North China Plain (i.e. the mountainous area in western Henan Province) as an example and based on the 200-m resolution DEM data, we used the mean change-point analysis to determine the optimal statistical unit for topographical relief, and thereafter extracted the relief degree. Taking the 1:100,000 land use data, township population and county-level industrial data, population and economic spatial models were constructed, and 200-m resolution grid population and economic density maps were generated. Afterwards, statistical analysis was carried out to quantitatively reveal the impact of topographical relief on population and economy. In addition, the impacts of other topographical factors were discussed. The results showed the following. (1) The relief degree in western Henan is generally low, where 58.6% of the regional topography does not exceed half the height of a reference mountain (relative elevation ≤250 m). Spatially, the relief degree is high in the west while low in the east, and high in the middle while low in the north and south. There is a positive correlation between relief degree and elevation, and a much stronger correlation between relief degree and slope. (2) The linear fitting degree between the population and economic validation data and the corresponding simulation data are 0.943 and 0.909, respectively, indicating that the spatialized results can reflect the actual population and economic distribution. (3) The impact of topographical relief on population and economy was stronger than that of other topographical factors. The relief degree showed a good logarithmic fit relationship with population density (0.911) and economic density (0.874). Specifically, 88.65% of the population lives in areas where the topographical relief is ≤0.5 and 88.03% of the gross regional product was from areas where the relief is ≤0.3. Compared with the population distribution, the economic development showed an obvious agglomeration trend towards low relief areas.
Lateral migration of the Bhagirathi River temporally creates unavoidable geomorphic hazards in West Bengal, India. The Bhagirathi River flows SW for ~67.30 km between the confluence point of Ajay and Jalangi rivers in East Burdwan and Nadia districts of West Bengal. The course of Bhagirathi is notably migration prone and cultivates problematic changes along its course over time. In the study, we have looked into its migration tendency and unpredictability for past 238 years and then predicted the lateral shifting of river centerline using temporal satellite imageries - Landsat-5 (TM) of 1987 (8, December), 1995 (28, January), 2005 (7, January) and LISS-IV satellite imagery (2017, 5 January);SOI Toposheet - 1968-1969 (79A/2, 79A/3, 79A/6 and 79A/7) and Rennell’s map of 1779. Other highlights are the quest of fluvial features, oxbow lakes, mid-channel bars, channel migration rate, meander geometry, channel sinuosity in different parts of river course and the parts that experience intensive bank erosion. The entire river course has been subdivided into three segments; viz. reaches A, B and C. Investigation displays that degree of sinuosity decreases from its anterior course (1968) to the existing course (2017). Reach-specific outputs display that reach B is highly sinuous (SI value 1.94 in 2017) and SI increases temporarily, whereas for reaches A and C it decreases with time. The rate of migration is higher in reach B than that in reaches C and A. The study displays a notably decreasing trend of migration in comparison with its previous lateral migration and shows that the migration nature over time is intensively inconsistent and unpredictable except very few portions of the river course. The nature of deposition within the river channel shows an unstable behavior during the entire period of the study. Meander geometry depicts a rapid change of river course innate to meander bends and shows a higher rate of migration by meander loop cut-off rather than lateral migration that reflects the inconsistency, erosion vulnerability and unpredictable nature of migration. The present work offers a valuable source to comprehend channel changes in Bhagirathi River and serve as an efficacious base for river-bank migration and erosion hazard planning and management.
