How many people can the Qinghai-Tibet Plateau hold, and how large cities can be built in recent hundred years?

The Qinghai-Tibet Plateau (QTP) serves as a vital barrier for both national security and ecological preservation. Overpopulation and urban sprawl pose threats to its ecological security, while underpopulation and small urban cities also undermine national security. Hence, optimizing population distribution and urban development on the QTP is crucial for bolstering the national security perimeter and ensuring basic modernisation across China. Nonetheless, understanding the population carrying capacity (CC) of the QTP and how large cities can safeguard both national security and ecological stability remains limited. To address this research gap, we utilised various model algorithms and methodologies to assess the population CC and urban scale of the QTP from seven different perspectives. The results indicate that the permanent population CC of the QTP in 2050 will be 26.2 million people, with an urbanisation level of 57.25 %, thereby allowing 15 million people to enter cities. Thus, the QTP can add 13.07 million people to its permanent population in the future, with a newly added urban population of 8.75 million, increasing the urbanisation level by 9.67 %. The future permanent population will mainly be distributed in the Xining, Lhasa, and Qaidam metropolitan areas. Combined, the permanent and urban populations will account for 38.54 % and 49.84 % of the QTP, respectively. Moreover, these populations will be moderately dispersed in 11 important node cities and more widely dispersed in key border towns. These findings provide a scientific basis for the sustainable development and high-quality urbanisation of the QTP, which have important implications for achieving sustainable development goals, offering crucial references for governments to formulate resource management policies and achieve sustainable resource utilisation.

Unequal prefecture-level water footprints in China: The urban-rural divide.

Water is vital for inclusive human well-being and economic growth, but water and its benefits are not equally distributed to all. The water gap between city dwellers and rural folks was not well understood. In this paper we assessed prefecture-level urban and rural water footprints (WFs) in China, using an improved multi-region input-output (MRIO) table with resolved urban and rural final consumption data. The assessment provided a quantitative foundation for evaluating and explaining urban and rural water use inequality from the consumption perspective. The results showed that per capita urban WF was on average 2.1 times per capita rural WF. The urban-rural WF divide constituted an important contribution to spatial WF inequality, in addition to provincial-level and prefecture-level differences. Compared to previous provincial-level WF analyses, this high-resolution prefecture-level urban and rural analysis showed clear evidence of economically developed urban areas as hotspots of large WFs. Specifically, our results provided a quantitative assessment revealing that 10 % China's population (urban residents in 51 prefectures) appropriated 25.8 % of the national WF. The dominant driving factor for urban-rural per capita WF disparity in all the prefectures was the consumption level, accounting for on average about 84 % of the disparity. There is an urgent need to leverage socio-economic development and urbanization against equitable and sustainable water use. The results have implications to equitable and sustainable water management from a broader macro-economic view.

Agricultural HANPP Embodied in Consumption: Tracing Pressure on Ecosystems Based on an MRIO Analysis.

Agriculture is one of humankind's most significant sources of biomass; it also places tremendous pressure on ecosystems through its increasing demand for agricultural products. However, few studies have assessed human pressures on ecosystems from agricultural production and consumption based on a whole-supply-chain perspective. Based on the concept of human appropriation of net primary productivity (HANPP), we evaluate trends of agricultural HANPP embodied in consumption from a global perspective and trace the pressure from agriculture production that is exerted on the environment using an environmentally extended multiregional input-output (MRIO) model. The results show that agricultural HANPP embodied in consumption accounted for over two-thirds of total HANPP but brought about less than 7% of global value added. India, Brazil, and China were found to have the highest level of agricultural HANPP embodied in consumption. Agricultural net exporters were found to usually be low- and lower-income countries, while net importers are found to be high-income countries. According to the driving factor analysis, high-income and low-income countries should cooperate by adjusting consumption patterns and sharing agricultural technology to alleviate the pressure from agricultural production. Our study highlights the importance of agrarian expertise sharing and the need to develop sustainable and green agricultural production.

GHG emissions and energy consumption of residential buildings-a systematic review and meta-analysis.

Residential buildings generate significant greenhouse gas (GHG) emissions and consume energy throughout their life cycle. In recent years, research on GHG emissions and energy consumption of buildings has developed rapidly in response to the growing climate change and energy crisis. Life cycle assessment (LCA) is an important method for evaluating the environmental impacts of the building sector. However, LCA studies of buildings show widely varying outcomes across the world. Besides, environmental impact assessment from a whole life cycle perspective has been undeveloped and slow. Our work presents a systematic review and meta-analysis of LCA studies on GHG emissions and energy consumption in the preuse, use, and demolition stages of residential buildings. We aim to examine the differences among the results of diverse case studies and demonstrate the spectrum of variations under contextual disparities. Results show that residential building emits about 2928 kg GHG emission and consumes about 7430 kWh of energy per m2 of gross building area on average throughout the life cycle. Residential buildings have an average GHG emission of 84.81% in the use phase, followed by the preuse phase and demolition phase; the mean energy consumption in the use stage occupied the largest share of 84.52%, followed by preuse stage and demolition stage. GHG emissions and energy use vary significantly in different regions due to different building types, natural conditions, and lifestyles. Our study stresses the compelling requirement to slash GHG emissions and optimize energy consumption from residential buildings by use of low carbon building materials, energy structure adjustment, consumer behavior transformation, etc.

Impact of International Trade on the Carbon Intensity of Human Well-Being.

There has been a longstanding debate about the impact of international trade on the environment and human well-being, yet there is little known about such environment and human well-being trade-off. Here, we explore the effect of international trade on the carbon intensity of human well-being (CIWB) globally under the current global trade system and a hypothetical no-trade scenario. We found that between 1995 and 2015, CIWB of 41% of countries declined and 59% of countries increased, caused by international trade, and this resulted in a reduction of the global CIWB and a decline in CIWB inequality between countries. International trade decreased CIWB for high- and upper-middle-income countries and increased CIWB for lower- and middle-income countries. In addition, our results also show that decreases in emission intensity are the most important driver of lower CIWB and the percentage contribution of emission intensity to the improvement in CIWB increases with income. The reduction of emission intensity, population growth, and increase in life expectancy all contribute to CIWB reduction, while the consumption level is the primary factor driving CIWB growth. Our results underscore the importance of studying the impact of international trade on the CIWB of countries at different stages of development.

Governance matters: Urban expansion, environmental regulation, and PM2.5 pollution.

Increasing PM2.5 pollution in urban expansion threatens citizens' health. Environmental regulation has proven to be an effective tool to directly combat PM2.5 pollution. However, whether it can moderate the impacts of urban expansion on PM2.5 pollution, in the context of rapid urbanization, is an interesting and unexplored topic. Therefore, this paper constructs a Drivers-Governance-Impacts framework and explores in depth the interactions among urban expansion, environmental regulation, and PM2.5 pollution. Based on 2005-2018 sample data from the Yangtze River Delta region, the estimation results of the Spatial Durbin model imply that (1) urban expansion has an inverse U-shaped association with PM2.5 pollution. The positive correlation may reverse when the ratio of urban built-up land area hits 0.21. (2) Of the three environmental regulations, investment in pollution control has little impact on PM2.5 pollution. Pollution charges and public attention exhibit a U-shaped and inverted U-shaped relationship with PM2.5 pollution, respectively. (3) In terms of moderating effects, pollution charges can exacerbate PM2.5 pollution from urban expansion, while public attention can inhibit it through its monitoring role. Therefore, we suggest that cities adopt differentiated strategies of urban expansion and environmental protection according to their urbanization levels. Meanwhile, appropriate formal regulation and strong informal regulation will help improve air quality.

Water footprint of nations amplified by scarcity in the Belt and Road Initiative.

The growing water scarcity due to international trade poses a serious threat to global sustainability. Given the intensified international trade throughout the Belt and Road Initiative (BRI), this paper tracks the virtual water trade and water footprint of BRI countries in 2005-2015. By conducting a multi-model assessment, we observe a substantial increase in BRI's water footprint after taking water scarcity into account. Globally the BRI acts as a net exporter of virtual water, while the export volume experiences a decreasing trend. Noticeable transitions in nations' role (net exporters vs. net importers) are found between the BRI and global scales, but also between with and without considering water scarcity. Overall economic and population growth is major drivers of scarcity-weighted water footprint for BRI nations, as opposed to the promotion of water-use efficiency and production structure that can reduce water scarcity. Improving international trade and strengthening cooperation on water resources management deserve priority in alleviating the water scarcity of BRI.

Spatial-temporal evolution and driving force analysis of eco-quality in urban agglomerations in China.

Urban agglomerations are important spatial carriers of regional economic development, and their ecological quality (EQ) is closely related to economic growth and human development. However, the rapid urbanization in China has generated a series of EQ problems that threaten the sustainable development of the country. Therefore, it is essential to explore changes in EQ for the development of sustainable "human-land" relations in urban agglomerations. Using GIS, GeoDetector, Stepwise multiple regression, and Sen'trend analysis, to reveal the spatial-temporal evolution of EQ in urban agglomerations along with the spatial heterogeneity of its driving forces in China. Results show that: (1) The annual change rate of EQ of urban agglomerations ranges from -0.0312 to 0.0334. Taking the Hu-line as a boundary, the EQ of urban agglomerations is spatially high in the east and low in the west. (2) The Global Moran's I index ranged from 0.740 to 0.687 during the study period, indicating a positive correlation in the EQ spatial distribution. The EQ of urban agglomerations has significant spatial agglomeration, with hot spots concentrated in the eastern region and cold spots in the northwestern region. (3) Main drivers of EQ of urban agglomerations are elevation, population density, nighttime light index, arable land area, real GDP per capita, precipitation, and built-up urban area (q > 10 %). (4) The stepwise multiple regression model spatially reveals that the nighttime light index, built-up urban area land and GDP per capita dominate the ecological quality changes of urban agglomerations, accounting for 73.68 % of the total number of urban agglomerations. This study provides an effective method for assessing spatial-temporal changes of EQ in urban agglomerations, supports scientific decision-making support for the construction of ecological civilization and the development of human-land harmony in urban agglomerations, and promotes the development and construction of "Beautiful China."

Spatio-temporal interaction heterogeneity and driving factors of carbon emissions from the construction industry in China.

Global warming caused by carbon emissions has become a major issue that countries need to address. As the largest carbon emitter globally, the construction industry is one of the major contributors to carbon emissions in China. It is of significance for carbon reduction to study carbon emission from construction industry. Based on various methods, this study explored the spatio-temporal characteristics of carbon emissions and the driving factors of construction industry. This study found, in 2007, 2010, and 2012, carbon emissions from the construction industry exhibited an increasing trend, and the indirect carbon emissions accounted for approximately 77% of the total carbon emissions overall; in addition, the regional gaps in carbon emissions are widening. The space centers of gravity of direct, indirect, and total carbon emissions showed similar rotations in the counterclockwise direction and gradually shifted to the northeast direction. Carbon emissions from the construction industry were predominantly influenced by the total population, number of employees in construction industry, labor productivity in construction industry, added value of the construction industry, energy consumption in construction industry in 2007, evolution to the mutual influence of the total population, labor productivity in construction industry, and energy consumption in construction industry in 2012. The finds can make references for the regional sustainable development.

Water transfer infrastructure buffers water scarcity risks to supply chains.

Inter-basin water transfer (IBWT) infrastructure has been expanding to deliver water across China to meet water demands in populated and industrial areas. Water scarcity may threaten the ability to produce and distribute goods through supply chains. Yet, it is not clear if IBWTs transmit or buffer water scarcity throughout supply chains. Here we combine a national database of IBWT projects and multi-region input-output analysis to trace water transferred by IBWT and virtual scarce water (scarcity weighted water use) from IBWT sourcing basins to production sites then to end consumers. The results indicate that production and final consumption of sectoral products have been increasingly supported by IBWT infrastructure, with physically transferred water volumes doubling between 2007 and 2017. Virtual scarce water is about half of the virtual water supporting the supply chain of the nation. IBWT effectively reduced virtual scarce water supporting the supply chains of most provinces, with the exposure to water scarcity reduced by a maximum of 56.7% and 15.0% for production and final consumption, respectively. IBWT Infrastructure development can thus buffer water scarcity risk to the supply chain and should be considered in water management and sustainable development policy decisions.

How Neighborhood Characteristics Influence Neighborhood Crimes: A Bayesian Hierarchical Spatial Analysis.

Urban crimes are a severe threat to livable and sustainable urban environments. Many studies have investigated the patterns, causes, and strategies for curbing the occurrence of urban crimes. It is found that neighborhood socioeconomic status, physical environment, and ethnic composition all might play a role in the occurrence of urban crimes. Inspired by the recent interest in exploring urban crime patterns with spatial data analysis techniques and the development of Bayesian hierarchical analytical approaches, we attempt to explore the inherently intricate relationships between urban assaultive violent crimes and the neighborhood socioeconomic status, physical environment, and ethnic composition in Paterson, NJ, using census data of the American Community Survey, alcohol and tobacco sales outlet data, and abandoned property listing data from 2013. Analyses are set at the census block group level. Urban crime data are obtained from the Paterson Police Department. Instead of examining relationships at a global level with both non-spatial and spatial analyses, we examine in depth the potential locally varying relationships at the local level through a Bayesian hierarchical spatially varying coefficient model. At both the global and local analysis levels, it is found that median household income is decisively negatively related to urban crime occurrence. Percentage of African Americans and Hispanics, number of tobacco sales outlets, and number of abandoned properties are all positively related with urban crimes. At the local level of analysis, however, the different factors have varying influence on crime occurrence throughout the city of Paterson, with median household income having the broadest influence across the city. The practice of applying a Bayesian hierarchical spatial analysis framework to understand urban crime occurrence and urban neighborhood characteristics enables urban planners, stakeholders, and public safety officials to engage in more active and targeted crime-reduction strategies.

Global impacts of future urban expansion on terrestrial vertebrate diversity.

Rapid urban expansion has profound impacts on global biodiversity through habitat conversion, degradation, fragmentation, and species extinction. However, how future urban expansion will affect global biodiversity needs to be better understood. We contribute to filling this knowledge gap by combining spatially explicit projections of urban expansion under shared socioeconomic pathways (SSPs) with datasets on habitat and terrestrial biodiversity (amphibians, mammals, and birds). Overall, future urban expansion will lead to 11-33 million hectares of natural habitat loss by 2100 under the SSP scenarios and will disproportionately cause large natural habitat fragmentation. The urban expansion within the current key biodiversity priority areas is projected to be higher (e.g., 37-44% higher in the WWF's Global 200) than the global average. Moreover, the urban land conversion will reduce local within-site species richness by 34% and species abundance by 52% per 1 km grid cell, and 7-9 species may be lost per 10 km cell. Our study suggests an urgent need to develop a sustainable urban development pathway to balance urban expansion and biodiversity conservation.

Public perceptions of physical and virtual water in China.

Ensuring access to water is one of the United Nations' Sustainable Development Goals. Water demand management, which has emerged as an important approach to secure water supply, should be underpinned by a good understanding of how the public perceive their use of water. In this study, we investigated public perceptions of physical and virtual water in China through online surveys using the multi-level regression models (two-level models). Based on 3262 responses, we found that overall, participants underestimated water uses and differences between water uses (daily potable water of an adult, shower, toilet flushing, etc.). Most participants did not possess the knowledge of virtual water embedded in their daily consumed products. Individuals showed rather different perceptions in water use, which were affected by gender, age, education, resource and environmental attitude, water saving behaviors, water price and residential water source. In combination with previous findings in the United States, we concluded that despite different natural water endowment and socio-economic and cultural conditions, underestimation of water use is commonly shared by Chinese and Americans. This highlights a need of strengthening public knowledge of water use. The results are useful in informing policies to enhance the public's awareness of water use towards improved water demand management.

Observing the silent world under COVID-19 with a comprehensive impact analysis based on human mobility.

Since spring 2020, the human world seems to be exceptionally silent due to mobility reduction caused by the COVID-19 pandemic. To better measure the real-time decline of human mobility and changes in socio-economic activities in a timely manner, we constructed a silent index (SI) based on Google's mobility data. We systematically investigated the relations between SI, new COVID-19 cases, government policy, and the level of economic development. Results showed a drastic impact of the COVID-19 pandemic on increasing SI. The impact of COVID-19 on human mobility varied significantly by country and place. Bi-directional dynamic relationships between SI and the new COVID-19 cases were detected, with a lagging period of one to two weeks. The travel restriction and social policies could immediately affect SI in one week; however, could not effectively sustain in the long run. SI may reflect the disturbing impact of disasters or catastrophic events on the activities related to the global or national economy. Underdeveloped countries are more affected by the COVID-19 pandemic.

Spatial Characterization of Urban Vitality and the Association With Various Street Network Metrics From the Multi-Scalar Perspective.

In the context of rapid urbanization in developing countries, the spatial organization of cities has been progressively restructured over the past decades. However, little has been done to understand how the physical expansion affected the reorganization of socioeconomic spaces in cities. This study explores the association between various street network metrics and urban vitality and how it changes across different scales using geographic big data through a case study of Wuhan, China. Urban vitality is characterized by four components: concentration, accessibility, livability, and diversity. The new technique of spatial design network analysis (sDNA) is employed to characterize street network metrics, including connectivity, closeness, betweenness, severance, and efficiency, with 16 localized network variables. Furthermore, the stratified spatial heterogeneity between street network metrics at multiple scales and the four components of urban vitality is investigated using the Geodetector tool. First, concentration, accessibility, and diversity decline with distance from the urban center, whereas livability has a fluctuating upward trend with distance from the urban core. Second, the correlation between street network characteristics and urban vitality is sensitive to different spatial scales. Third, connectivity explains the largest amount of the variance in urban vitality (over 40%), while both betweenness and closeness explain roughly 28% of urban vitality. Efficiency and severance contribute 22 and 10% to the spatial heterogeneity of urban vitality, respectively. The study sheds light on the mechanisms between street configurations and urban vitality from the multi-scalar perspective. Some implications are provided for the improvement of the streets' urban vitality.

Conjugate evaluation of sustainable carrying capacity of urban agglomeration and multi-scenario policy regulation.

The scientific evaluation of carrying capacity and the formulation of adaptive regulation policies are powerful ways to achieve sustainable development goals. In order to quantitatively and accurately diagnose the sustainable development state of urban agglomeration, this paper responds to the "Future Earth" framework; takes the carrying capacity as the breakthrough point; embeds the conjugate thought; considers the elements of the resources, the environment, the ecology, and the development; and establishes the conjugate evaluation model and the evaluation index system of sustainable carrying capacity. In order to solve the actual bottleneck problem of urban agglomeration, this work identifies the key obstacle factors, constructs the multi-scenario dynamic coupling (MSDC) model, recognizes the sensitivity policies, and proposes the adaptive regulation polices. Taking the urban agglomeration on the northern slope of the Tianshan Mountains (UANSTM) in arid areas as a case study, it was found that from 2007 to 2017, the carrying capacity gradually increased, and the sustainable development showed a benign transformation trend in the UANSTM. It will also be in a transitional stage of growth from now to 2035, and the steady development of the economy and the society and the good maintenance of the resources, the environment and the ecology are equally important. The policies on population intervention and on the management of water resources play a vital role, and the speed of economic development should be controlled throughout the whole process. The study confirms that the effective regulation is necessary for the sustainable development of the urban agglomeration in the future, and the key lies in improving technological progress and governance policy support. It is expected that this new and complete research framework for the conjugate evaluation of the sustainable carrying capacity of urban agglomeration and multi-scenario policy regulation can be applied to other regions or urban agglomerations in developing countries and can make a possible breakthrough in promoting the theoretical exploration and practice of sustainable development.

The influence of environmental efficiency on PM2.5 pollution: Evidence from 283 Chinese prefecture-level cities.

Environmental inefficiency caused by the extensive economic growth pattern is considered a critical driver of the unprecedented PM2.5 (fine particulate matter) pollution in China. However, the nexus between environmental efficiency and PM2.5 concentrations has rarely been examined. We used a recently developed data envelopment analysis method to measure environmental efficiency, environmental total factor productivity, and their compositions in China at the prefecture level from 2003 to 2013 and examined the effects of environmental efficiency on PM2.5 pollution. The results indicated that improvements in environmental efficiency significantly ameliorated PM2.5 pollution. The effect of technological progress on PM2.5 reduction is limited, but the pure efficiency and scale efficiency promoted by enhanced management level and optimized production scale strongly contribute to PM2.5 mitigation. The significant spatial spillover of environmental efficiency and PM2.5 pollution introduces challenges and opportunities for lowering PM2.5 emissions. The impact of environmental efficiency on PM2.5 pollution exhibits significant spatiotemporal heterogeneity, and the strength of influence tends to increase with PM2.5 concentration and become more pronounced over time. Furthermore, several socioeconomic factors are related to PM2.5 pollution, which implies that PM2.5 control is a complex system and requires a comprehensive policy mix.

Assessing environmental performance of eco-industrial development in industrial parks.

While driving the regional economy, industrial parks also pose great threats to natural environment due to large quantities of resource consumption and intensive pollutants emissions. Eco-industrial development, including cleaner production, bioproducts or waste interchange, and infrastructure sharing, is key to improving the parks' environmental quality and sustainability. However, how to measure the performance of eco-industrial development is an essential and hard work since the material and energy flows are complex and cannot be compared in various units. The water and non-renewable resources which are very vital materials to sustain industrial activities in the industrial parks were rarely considered in the previous traditional ecological footprint analysis. Therefore, our research depicts a real picture of all the resources including water and non-renewable resources to illustrate the actual environmental impact of a national high technology industrial development zone-Jiangyin high technology Park, using energy based ecological footprint method. Results show that the emergy-ecological footprint deficit and emergy-ecological footprint intensity of the study park decreased by 16.75% and 16.74% due to the implementation of eco-industrial development. In detail, minerals made the largest reduction, 2.00E + 2 ha/capita, followed by fossil fuels with a reduction of 1.01E + 2 ha/capita, and the resources from cropland and pasture did not make a contribution in reducing emergy ecological footprint. Policy implications such as further replenishing and improving the ecological industry chains are proposed based on this survey. This study provides a basis to improve the environmental management and performance of industrial parks.

Dynamics of the surface thermal landscape (STL) in northern slope of central Tianshan mountains, Xinjiang, NW China from 2000 to 2018.

Using the 2000-2018 MODIS Land Surface Temperature (LST) data and taking 11 cities (counties) in the northern slope of the central Tianshan Mountains in northwestern China as the study area, the spatial-temporal characteristics, landscape indices, centroid, and geo-information Tupu (carto-methodology in geo-information, CMGI) of surface thermal landscape (STL) were analyzed, and the paper draws the following results: (1) There are great differences in the diurnal and seasonal STL. The higher thermal levels are distributed more northerly in spring, summer, and autumn, and more southerly in winter. (2) In terms of class type level and landscape level, different landscape indices show different characteristics in diurnal and seasonal thermal landscapes. (3) Centroids at different thermal levels during the daytime are more dispersed than at nighttime in spring and summer, while the opposite is found in autumn. In winter, centroids of different thermal levels are concentrated in the southern and central-southern regions. During the period of 2000-2018, centroids of different thermal levels tend to move with the varying of STL. (4) The whole STL in same seasons changed little, transition usually happens between adjacent thermal levels. Overall, compared with the eastern monsoon area, there are similarities and differences in the characteristics of the STL.