Local and non-local drivers of consumption-based water use in China during 2007-2015: Perspective of metacoupling

China's strictest water policy: Reversing water use trends and alleviating water stress

Growing water problems have promoted the Chinese government to implement the strictest water resources management system (SWRMS), the first national policy that puts into practice the concept of "safe operating space" for human water use. Here, we investigate the impact of the SWRMS on China's water use and water stress based on a newly compiled high-resolution and multi-sectoral water use dataset. Results indicate that China's total water use (TWU) increased significantly from 549 km3 yr-1 to 610 km3 yr-1 between 2000 and 2012 (i.e., the pre-SWRMS period), but decreased remarkably in the post-SWRMS period (2012-2020), reaching 565 km3 yr-1 by the year 2020. The decline in TWU was attributed to the improvements of irrigation and industrial water use efficiency (WUE), which were strictly controlled by the SWRMS at various administrative levels of China. The improved WUE has yielded about ∼90 km3 of water savings per year, freeing 17 prefectures from extreme water stress that affects 6% of China's population and 10% of its GDP. Although the improved WUE caused a significant decrease in TWU, the reduction in China's average water stress was insignificant due to the considerable influence of water availability. We further identified hotspots with great potential for water stress reduction, mainly in northwestern China, and hotspots at high risks of water security, primarily on the North China Plain. This study underscores the crucial role of the SWRMS in addressing China's water shortage and provides valuable insights to other countries grappling with water problems in defining their own "safe water operating spaces".

Leveraging the metacoupling framework for sustainability science and global sustainable development

Sustainability science seeks to understand human-nature interactions behind sustainability challenges, but has largely been place-based. Traditional sustainability efforts often solved problems in one place at the cost of other places, compromising global sustainability. The metacoupling framework offers a conceptual foundation and a holistic approach to integrating human-nature interactions within a place, as well as between adjacent places and between distant places worldwide. Its applications show broad utilities for advancing sustainability science with profound implications for global sustainable development. They have revealed effects of metacoupling on the performance, synergies, and trade-offs of United Nations Sustainable Development Goals (SDGs) across borders and across local to global scales; untangled complex interactions; identified new network attributes; unveiled spatio-temporal dynamics and effects of metacoupling; uncovered invisible feedbacks across metacoupled systems; expanded the nexus approach; detected and integrated hidden phenomena and overlooked issues; re-examined theories such as Tobler's First Law of Geography; and unfolded transformations among noncoupling, coupling, decoupling, and recoupling. Results from the applications are also helpful to achieve SDGs across space, amplify benefits of ecosystem restoration across boundaries and across scales, augment transboundary management, broaden spatial planning, boost supply chains, empower small agents in the large world, and shift from place-based to flow-based governance. Key topics for future research include cascading effects of an event in one place on other places both nearby and far away. Operationalizing the framework can benefit from further tracing flows across scales and space, uplifting the rigor of causal attribution, enlarging toolboxes, and elevating financial and human resources. Unleashing the full potential of the framework will generate more important scientific discoveries and more effective solutions for global justice and sustainable development.

Driving forces and variation in water footprint before and after the COVID-19 lockdown in Fujian Province of China

The COVID-19 outbreak has injured the global industrial supply chain, especially China as the world's largest manufacturing base. Since 2020, China has implemented a rigorous lockdown policy, which has sternly damaged sectoral trade in export-oriented coastal areas. Fujian Province, which mainly processes imported materials, has a more profound influence. Although the COVID-19 lockdown has had some detrimental consequences on the world economy, it also had some favorable benefits on the global ecology. Previous studies have shown that the lockdown has altered the physical water quantity and quality, but the lack of total, virtual, and physical water research that combines water quantity and water quality simultaneously to pinpoint the subject and responsibility of water resources consumption and pollution. This research quantified the physical, virtual, and total water consumption and water pollution among 30 sectors in Fujian Province based on the theory of water footprint and the Economic Input-Output Life Cycle Assessment model. SDA model was then used to investigate the socioeconomic elements that underpin variations in the water footprint. The results show that after the lockdown, the physical water quantity and the physical grey WF in Fujian Province decreased by 2.6 Gm3 (-6.7%) and 0.4 Gm3 (-1.3%) respectively. The virtual water quantity decreased by 2.3 Gm3 (-4.5%), whereas the virtual grey WF rose by 1.5 Gm3 (4.3%). The total water quantity dropped by 3.3 Gm3 (-4.9%), while the grey WF increased by 1.2 Gm3 (2.5%), i.e. the COVID-19 lockdown decreases physical water quantity and improves local water quality. More than 50% of the water comes from virtual water trade outside the province (virtual water is highly dependent on external), and around 60% of the grey WF comes from physical sewage in the province. The COVID-19 lockdown reduced water outsourcing across the province (paid nonlocally decrease) but increased pollution outsourcing (paid nonlocally increase). And gross capital formation's contribution to the growth in water footprint will continue to rise. As a result, this study suggested that Fujian should take advantage of sectoral trade network to enhance the transaction of green water-intensive intermediate products, reduce the physical water consumption of blue water-intensive sectors, and reduce the external dependence on water consumption. Achieving the shared responsibility of upstream and downstream water consumption and reducing the external dependence on water in water-rich regions is crucial to solving the world's water problems. This research provides empirical evidence for the long-term effects of COVID-19 lockdown on the physical and virtual water environment.

The impacts of China's crops trade on virtual water flow and water use sustainability of the "Belt and Road"

Since the "Belt and Road" initiative was put forward, the trade of crops between China and the countries have increased markedly. Agriculture is the most water-consuming sector, the trade of crops could influence national water availability via virtual water embodied in the products. In order to gain an in-depth understanding of the water use of crops traded in countries along the "Belt and Road", from the perspective of import and export of China's crops, based on the characteristics and driving factors of virtual water trade, we proposed the Water Use Potential Index (WUPI) to assess sustainability of countries and their crops, and constructed a more comprehensive virtual water trade research framework. Results showed that the import and export of virtual water in 64 countries was dominated by green virtual water content from 2001 to 2017, and China was in a virtual water trade surplus. The Association of South-East Asian Nations was China's leading importer and exporter. The level of agricultural available water resources, the proportion of the agricultural population, the scale of agricultural production and the virtual water intensity could promote the growth of virtual water trade in crops between China and countries along the "Belt and Road", while economic model and the population structure played a restraining role. In terms of water use potential, China and Kazakhstan had great sustainable water use potential for crops, and the trade structure of other countries still needed to be further optimized. Understanding the virtual water trade in crops can provide a reference for the rational planning of crop cultivation and water resource conservation.