Global spatio-temporal change assessment in interregional water stress footprint in China by a high resolution MRIO model

Water scarcity footprint and water saving potential for large-scale green hydrogen generation: Evidence from coal-to-hydrogen substitution in China

Green hydrogen generated via water electrolysis using photovoltaics or wind has begun to scale up in the process of achieving the global net-zero goal, but there is a lack of research on its impact on the scarcity of water resources and water saving potential. A water resources impact assessment framework for green hydrogen scale-up development is established, integrating the product water footprint and regional water footprint scarcity impacts and advancing the study of the water resources impacts on green hydrogen from water conservation as well as from a sustainable context. The research framework specifies the cradle-to-gate life cycle water consumption of hydrogen production, establishes the water scarcity footprint based on the available water remaining (AWARE) model, quantifies the water saving intensity and potential of the green hydrogen alternative to traditional hydrogen production, and proposes quantitative indicators of the water saving benefit. Taking the regions of 31 provinces in China as a case study, the wind-to‑hydrogen scenario and the solar-to‑hydrogen scenario will generate approximately 68.86×108 m3 and 126.10×108 m3 water scarcity footprints, respectively. Under the coal-to‑hydrogen baseline scenario, approximately 1.68×108 m3 and - 0.57×108 m3 of water saving potential will be generated. In addition, the water saving intensity decreases from west to east. According to the adjusted quantitative indicators of water saving benefits, the wind-to‑hydrogen scenario in China can reach 40.22×108 m3eq and the water saving benefit is more obvious in northern regions such as Hebei, Ningxia and Inner Mongolia. The methodological framework can be applied to other countries or regions to assess the sustainable impacts of green hydrogen production on water resources in a given region.

Dynamic simulation of the water-land-food nexus for the sustainable agricultural development in the North China Plain

Inter-regional trade of agricultural products based on the flow of agricultural virtual resources is of great importance for sustainable agricultural development. We focused on grain crops (rice, wheat and maize) in the North China Plain (NCP), and used the Penman-Monteith equation to simulate crop water requirements. We further analyzed the flow of virtual land and virtual water associated with the grain trade using an environmentally expanded multi-regional input-output model. The coupling coordination of land, water, and food was evaluated to assess the rationality of regional agricultural production resource allocation. Between 2007 and 2017, agricultural virtual land and virtual water embodied in the grain trade between the NCP and other areas increased by 48.10 % and 34.41 %, respectively, indicating that the NCP is gradually consolidating its position as the main production area and distribution center of crops in China. Agricultural virtual resources in the NCP were mainly transported to the southeast coastal region, with an overall trend of resource movement from north to south. The total supply of agricultural land and water resources markedly increased in the NCP, whereas the transfer of virtual resources across regions showed a decreasing trend. Because of the irrational structure of crop cultivation and unevenness of regional resource allocation, the coupling coordination of the water-land-food nexus in the NCP is much lower than the national average. This study provides important information on the trade flows and coupling relationships of virtual water and land resources of three major food crops, which will help to alleviate resource pressure in agricultural production and promote sustainable agricultural development in the NCP.

Urban water resources accounting based on industrial interaction perspective: Data preparation, accounting framework, and case study

Water scarcity has become one of the serious global challenges threatening urban water security. To systematically understand the utilization of water resources in cities, this study established a novel comprehensive accounting framework of urban water resources based on three dimensions: "the entire city, sectoral level, and intersectoral interactions". To make this accounting framework that can be applied to the majority of cities, a method for compiling input-output (IO) tables at the general prefecture-level city scale was proposed to obtain the needed core data. Dongguan, a prefecture-level city in Guangdong Province, China, known for its well-developed manufacturing industries but water scarcity, was chosen as a case study to test the effectiveness of the method. The results indicated the total water use in Dongguan decreased by 7.2% during 2012-2017, which benefited from steady economic growth. Besides, the "agriculture" sector has significantly higher direct water use coefficient than other sectors, while the indirect water use coefficient of the manufacturing sector exceeded the direct water use coefficient in 2017. In addition, there are two major virtual water flow paths among sectors in Dongguan, which are helpful to water conservation. The comprehensive water resources accounting framework proposed in this study for general prefecture-level cities is applicable to water resource management, enabling not only the optimization of water resource allocation in urban areas but also the reduction of environmental pollution and ecological damage. Nevertheless, it is still necessary to further optimize the compilation of IO tables and better support the formulation of specific water-saving measures in the future research by collecting more detailed industry data and import-export data. These results of this study can provide important practical reference information for water resource management in general-scale cities similar to Dongguan in the world.

Examining inequities in species loss due to land use in China from an interregional trade perspective

The escalating impact of land use pressures indicates we've exceeded the proposed safe planetary boundary. Economic shifts and increased trade drive China's demand for agricultural and forestry products, land-use changes, and subsequent biodiversity damage often occur far from where they are consumed. Given many species in China are endemic or endangered, neglecting these interconnected economic trends threatens its biodiversity conservation targets. Here, we first quantify species loss due to six land use types embodied in the life cycle at the Chinese sub-national level. Then, a Chinese high-resolution multi-regional input-output (MRIO) model was used to link threatened species to key industrial sectors in the supply chain, tracking the spatiotemporal patterns of land use species loss embodied in Chinese trade from 2007 to 2017. Our results reveal a 6% increase in aggregated species loss in China during the study period. This subtle change in species loss footprints in recent years is partially due to increases in consumption levels being offset by reductions in species loss intensity, though drivers vary by region. Notably, the Northwest and Southwest, known for their high species richness, suffer the greatest inequalities in species loss. The domestic species loss transfer most apparent in the outsourcing from the Eastern Coast to the Southwest. The Southwest registered the highest territory-based species loss, particularly for amphibians, while the highest impacts in the supply chain are associated with Forestry, logging, and related activities. Our analysis underscores the need for enhanced provincial dialogue to systematically value and monitor biodiversity, a key natural capital, and encourage its conservation. Our study effectively monitors the consumption-based species losses across China, which can further improve knowledge and dialogue on ecological challenges associated with trade.

Mapping the heterogeneity of global methane footprint in China at the subnational level

Achieving the ambitious Global Methane Pledge announced in the Glasgow Climate Pact requires collaborative efforts from both the signatory countries and China which serves as the world's largest emitter. Considering the heterogeneity of economic structures within China and the relocation of emissions between regions via the global economic network, it is vital to investigate how China's methane emissions at the subnational level are linked to global final consumption. In this paper, we mapped global methane footprint in China from 2007 to2015 at the subnational level, by nesting China's interprovincial input-output tables into global multiregional input-output accounts and upscaling grid-level methane emission data of the Edgar database to the provincial level. Our results suggested that global methane footprint in China shifted westward, and the United States, European Union, Japan, and Hong Kong were the main drivers of China's local methane emissions. By illustrating the international and interprovincial trade flows of methane emissions, this study demonstrated that southeast coastal provinces were the hotspots for global methane footprint while middle inland provinces were the emission hotspots for China's domestic demands. We also showed how China's methane emissions were distributed through the nested global economic network to different economic agents. Moreover, emission trends of key exporting sectors for China's eight economic zones were detailed discussed. The outcome of this study may be fully supportive for identifying the heterogeneous effects of global methane footprint in China and implicative for interprovincial and international collaborations towards methane emission mitigation.

Cultivated Land Demand and Pressure in Southeast Asia from 1961 to 2019: A Comprehensive Study on Food Consumption

Southeast Asia plays a crucial role in global food production and trade, yet it grapples with challenges related to food security, regional stability, and security. Cultivated land is the material foundation for ensuring food production. With the development of society and the economy, people's food consumption has undergone significant changes. This paper employs a comprehensive approach to analyze trends in food consumption, the cultivated land footprint, and associated land pressures in Southeast Asia over the period 1961-2019. The main findings are as follows: (1) Between 1961 and 2019, the total food consumption in Southeast Asia surged by 3.1 times. Notably, the proportion of livestock-based foods increased steadily from 6.62% in 1961 to 16.82% in 2019. (2) Due to advancements in agricultural productivity across Southeast Asia, the cultivated land footprint for food consumption only increased by 0.7 times, showcasing a diminishing demand for grain-cultivated land. (3) On the whole, the pressure of food consumption on cultivated land in Southeast Asia is on the decline, albeit with considerable variations among different countries. The Philippines is facing a relative undersupply, whereas Thailand has experienced the lowest cultivated land pressure. (4) Encouraging a shift towards a Mediterranean-style diet, aligned with existing dietary patterns, holds promise for reducing future pressures on cultivated land and promoting better health outcomes for the populace in Southeast Asia.

Revealing Trade Potential for Reversing Regional Freshwater Boundary Exceedance

Applying the planetary boundary for the freshwater framework at the regional level is important in supporting local water management but is subject to substantial uncertainty. Previous estimates have not fully investigated the potential of trade in mitigating regional freshwater boundary (RFB) exceedance. Here, we estimate RFB based on the average results of 15 different hydrological models to reduce uncertainty. We then propose a framework to divide the RFB exceedance/maintenance into contributions from both consumption and trade and further identify trade contribution into six types. We applied the framework to China's provinces, which are characterized by intensive interprovincial trade and a significant mismatch in water resource supply and demand. We found that the current trade pattern limits the role of trade to mitigate RFB exceedance. For the importing provinces exceeding RFBs, 78% of their imported goods and services came from other RFB exceeding provinces. Scenario analysis showed that relying on increased imports alone, even to its greatest extent, will not reverse RFB exceedance in most importing provinces. Increased imports, however, will have an aggregate effect on the trade partners, leading to the exceedance of the national freshwater boundary. We also found that promoting export of goods and services from non-RFB exceeding provinces and reducing their water intensity will help address the imbalance both locally and, in the aggregate, nationally.