Exploring the changes and driving forces of water footprints in China from 2002 to 2012: A perspective of final demand

History and future of water footprint in the Yangtze River Delta of China

Quantifying the drivers of water footprint evolution in the Yangtze River Delta is vital for the optimization of China's total water consumption. The article aims to decompose and predict the water footprint of the Yangtze River Delta and provide policy recommendations for optimizing water use in the Yangtze River Delta. The paper applies the LMDI method to decompose the water footprint of the Yangtze River Delta and its provinces into five major drivers: water footprint structure, water use intensity, R&D scale, R&D efficiency, and population size. Furthermore, this paper combines scenario analysis and Monte Carlo simulation methods to predict the potential evolution trends of water footprint under the basic, general, and enhanced water conservation scenario, respectively. The results show that (1) the expansion of R&D scale is the main factor promoting the growth of water footprint, the improvement of R&D efficiency, and the reduction of water intensity are the main factors inhibiting the increase of water footprint, and the water footprint structure and population size have less influence on water footprint. (2) The evolution trend of water footprint of each province under three scenarios is different. Compared to the basic scenario, the water footprint decreases more in Shanghai, Zhejiang, and Anhui under the general and enhanced water conservation scenario. The increase in water footprint in Jiangsu under the enhanced scenario is smaller than that of the general water conservation scenario.

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.

Crop water footprints and their driving mechanisms show regional differences

Identifying crop water footprints and their driving mechanisms is of significant importance for regional water resources management and ecological sustainability. However, there is currently a lack of comparative studies on drivers of crop water footprint among multiple regional types. In this study, based on quantifying the crop water footprints in seven regions (North China, Northeast China, East China, Central China, South China, Southwest China, and Northwest China) in mainland China from 1996 to 2020, the path analysis method was used to reveal their driving mechanisms. The results showed that the average annual agricultural water footprint was 1448.2 Gm3, with blue water, green water, and grey water accounting for 10.1 %, 66.6 %, and 23.3 %, respectively. Fruits and cereals jointly contributed 80 % of the total water footprint. The crop water footprint in East China was significantly higher than in other regions, accounting for 29.3 % of the national water footprint. The average crop production water footprint was 1080.4 mm, with the highest values observed in East China and South China, and the lowest in Northeast China and Southwest China. Except for East China, the crop production water footprint in other regions showed an increasing trend over time. Irrigation area ratio had the greatest impact on crop production water footprint except for Northeast China, while chemical fertilizer consumption significantly influenced crop production water footprints in North, East, Central, Southwest and Northwest China. Additionally, per capita GDP, per capita net income and irrigation water use efficiency also had considerable effects on crop production water footprint in Northwest China. The research findings can provide a valuable reference for the development of strategies for the efficient and sustainable utilization of agricultural water resources in different regions.

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".

How climate change affects electricity consumption in Chinese cities-a differential perspective based on municipal monthly panel data

Addressing the impacts of climate change has become a global public crisis and challenge. China is characterized by a complex and diverse topography and vast territory, which makes it worthwhile to explore the differential impacts of climate change on urban electricity consumption in different zones and economic development conditions. This study examines the differential impact of climate factors on urban electricity consumption in China based on monthly panel data for 282 prefectures from 2011 to 2019 and projects the potential demand for future urban electricity consumption under different climate change scenarios. The results show that (1) temperature changes significantly alter urban electricity consumption, with cooling degree days (CDD) and heating degree days (HDD) contributing positively to urban electricity consumption in areas with different regional and economic development statuses, with elasticity coefficients of 0.1015-0.1525 and 0.0029-0.0077, respectively. (2) The temperature-electricity relationship curve shows an irregular U-shape. Each additional day of extreme weather above 30 °C and below -12 °C increases urban electricity consumption by 0.52% and 1.52% in the north and by 2.67% and 1.32% in the south. Poor cities are significantly more sensitive to extremely low temperatures than rich cities. (3) Suppose the impacts of climate degradation on urban electricity consumption are not halted. In that case, the possible Shared Socioeconomic Pathways 1-1.9 (SSP1-1.9), SSP1-2.6, and SSP2-4.5 will increase China's urban electricity consumption by 1621.96 billion kWh, 2960.87 billion kWh, and 6145.65 billion kWh, respectively, by 2090. Finally, this study makes some policy recommendations and expectations for follow-up studies.

Imbalance in the city-level crop water footprint aggravated regional inequality in China

Crop production is the main consumer of water resources. The heterogeneous water resource endowments and imbalanced crop water use exacerbate regional resource consumption inequality. In this study, we quantified the crop water footprint (CWF) of 356 cities in China from 2000 to 2020, measured the inequality between the city CWF and water resources, and identified different strategies to alleviate regional CWF inequality. We found that the average CWF from 2000 to 2020 varied widely across cities, ranging from 0.03 × 10⁸ m³ to 806.78 × 10⁸ m³, and the inequality between city CWF and local water resource endowment was increasing. China had a strong dependence on green water in crop production, and its proportion increased from 52.48 % to 67.17 %. The Gini coefficient of the green water footprint increased from 0.545 to 0.621, and the degree of inequality increased significantly. In addition, the blue water and gray water continuously showed great inequality, especially the blue water, the Gini coefficient of which was 0.724 in 2020. The results show significant disparities in CWF among cities, which have highly exacerbated regional inequality in China. Improving the utilization rate of green water is an important measure to balance the allocation between serving the natural ecosystem and meeting the basic human needs. This study revealed for the first time the inequality of city-level CWF and highlights the severe situation of inequality among regions in China. Balancing the inequality between CWF and water resource endowment at city-level is conducive to fundamentally solving the problem of unreasonable water resource allocation.

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.

Analysis of China's regional differences in water consumption based on spatial structural decomposition analysis model

Analyzing the factors that affect the spatial differences in production water consumption in China is necessary to implement its most stringent water resource management system effectively. Based on the input-output tables of 31 provinces and the water-consumption data of provinces by sectors in 2017, the water consumption-economy input-output tables of 31 provinces are constructed. The spatial structural decomposition analysis method is used to analyze the impact of technology level, economic scale, and regional characteristics on spatial differences in production water consumption. The final demand effect is then decomposed into final demand sectoral structural effect, final demand distribution structure effect, population-scale effect, and consumption-level effect. The results show that production water consumption depends on the economic scale and regional characteristics. Xinjiang, Jiangsu, Guangdong, Heilongjiang, and most provinces in the central region use more production water than the average level, while those in the Beijing-Tianjin region and most in the North-west region use less than average. The decomposition results show that the technical and the final demand effects are the main factors for the spatial differences. The impact of population-scale and consumption-level contribute the most to the final demand effect.

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

Increasingly growing consumption-based water use (WU) combined with climate change have exacerbated water stress globally and regionally, yet little is known about how the WU change is affected by metacoupled processes which involve human-nature interactions across space; within and across adjacent and distant places. This study aims to unveil the spatio-temporal pattern of China's WUs during 2007-2015 and its underlying local and non-local drivers. Results show that China's total WU exhibited an upward trend from 386.7 billion m³; in 2007 to 431.2 billion m³ in 2012 but dropped to 412.6 billion m³ by 2015. Widespread and continuous water use efficiency improvement contributed most to offsetting the increase in WU driven by the rising affluence and growing population in the context of rapid urbanization and industrialization. Economic structure drove a relatively large WU reduction (responsible for -23.7% of the WU change during 2007-2015), in line with China's ongoing transform from a capital investment-driven economy to a consumption-driven one and decoupling economic growth from environmental pressure. The population share representing the non-local factor of migration effect was large enough to be seen clearly in the changing WUs across China: the WUs of coastal areas ascended while inland areas descended, which was in accordance with migration patterns. Our findings could make a valuable contribution to decision-making in identifying hotspot areas, charting systematic courses for sustainable water use, and combining demand-oriented and supply-oriented measures.

Understanding China's industrialization driven water pollution stress in 2002-2015-A multi-pollutant based net gray water footprint analysis

China produces a large amount of industrial effluent with multiple pollutants contained, along with a flourishing economy. This study aims to examine the dynamics between China's industrialization and accompanying environmental pressure based on the gray water footprint (GWF) concept. A newly proposed net GWF (NetGWF) and the decoupling index (DI) are applied to evaluate China's industrial activities during 2002-2015 in different modes considering typical, all, and individual pollutants. The NetGWF dynamics are further quantitatively decomposed into 17 effects of not only commonly assessed drivers but also industrial fixed capital formation, inventory variation, and import, using an advanced dynamic decomposition analysis approach. Results show NetGWF is an effective indicator measuring domestic water pollution stress from industrialization, with NetGWF-AllPlt (estimated using all pollutants) validated to be more reliable and sensitive than NetGWF-COD&NH3N (estimated using Chemical oxygen demand and Ammonia nitrogen). An overall decoupling between China's industrialization and wastewater pollution is identified with most of DIs less than 1.0 caused mainly by decreased (by around 40%) industrial NetGWFs for 2002-2015. Industrial fixed capital formation and export have caused main components of China's industrial GWF, with proportions of 37.3% and 30.8%, respectively, followed by urban household consumption (16.8%). Volatile phenol, Petroleum, and Ammonia nitrogen are recognized as three decisive contaminants to the industrial NetGWFs. Technological development is the dominant contributor (-50%) to decreasing China's industrial NetGWFs, while fixed capital formation (18%) and export (16%) are principal drivers increasing the NetGWFs. Based on these, we expect to provide informative findings for building a pollution-decoupled industrialization.

Water resource use and driving forces analysis for crop production in China coupling irrigation and water footprint paradigms

The crop water relationship quantification is conducive to decision-making for regional food safety and resource conservation. However, irrigation water and crop water footprint (CWF) was observed separately in previous studies, which leads to incomplete evaluation of water resource occupation in agricultural system. The crop water resource use (WRU), combining WF and irrigation water accounting, in 31 provinces of China from 1999 to 2018 was estimated in current paper. The driving forces of WRU were analyzed using the logarithmic mean divisia index (LMDI) model, based on its spatial and temporal patterns demonstration. The results showed that national WRU increased from 1051.6 Gm³ in 1999 to 1676.4 Gm³ in 2018, with an average annual growth rate of 2.48%. The provinces with high WRU were mainly distributed in North China and Northeast China. Hebei, Shandong, and Henan jointly contributed 28.9% of the national WRU. In addition, economic level was the largest contributor to promote the growth of WRU, and water use intensity was the most important contributor to inhibit the growth of WRU. Economic level, resource endowment, and population size had a promoting effect on WRU in Northeast, Northwest, North China, and Southeast provinces, while water use intensity, irrigation technique, and urbanization degree showed inhibitory effect in Northeast, Northwest, and Southwest provinces. It is meaningful to combine water footprint and irrigation water use for agricultural water management and conservation. The arid North China Plain should adopt water-saving irrigation and rainwater recycling technologies to control WRU, and the Northeast granary should reduce WRU by strengthening water pollution prevention and improving water resources scheduling to ensure food security and sustainable use of water resources.

Exploring the Spatial Network Structure of Agricultural Water Use Efficiency in China: A Social Network Perspective

The exploration of the spatial network structure of agricultural water use efficiency (AWUE) and its influencing factors for promoting water saving and improving water use efficiency in regional agricultural production is of great importance. In this paper, the modified gravity model and social network analysis methods were used to study the spatial correlation characteristics and influencing factors of AWUE in China between the years 2008 and 2019. It was found that (1) the overall trend of AWUE in China has been fluctuating and declining, and there are obvious differences in AWUE in each region; (2) the spatial network structure of AWUE in China is complex and relatively stable, with close interprovincial connections and obvious spatial spillover effects; (3) Shanghai, Beijing, Jiangsu, and Zhejiang are at the center of the network; and (4) the differences between geographical adjacency, technological development level, farmers’ income, and natural resource endowment have significant effects on the development of the AWUE network. These results provide a theoretical basis for the government to improve AWUE and promote collaborative regional development.

Sustainable conjunctive water management model for alleviating water shortage

Water shortage poses a great challenge to the health of population and environment and impedes socio-economic development. Therefore, a comprehensive model is necessary to promote the adaptation of the whole socio-economic system to limited water resources. To achieve it, a sustainable conjunctive water management model (SCWM) was developed. In SCWM, direct (physical) and indirect (virtual or embodied) water consumptions of multiple water resources in future scenarios are projected, and the sustainable performances of various water-saving scenarios are quantified from the perspectives of water resources, economy, and ecosystem under water capping policy. A case study of Shaanxi, a typical water shortage province in central-eastern China, is conducted aimed at conquering the irrational use of surface- and ground-water subjected to the constraint of future total water use quota. Key findings contain optimal possibility of adapting water shortage via saving water through increasing industrial water efficiency to 11.12 m³/10,000 CNY and reducing 40% of agricultural final demand (Summation of direct and indirect water savings of the two scenarios are 41.57 × 10⁸ m³ and 20.27 × 10⁸ m³, respectively.) and nonsynergistic effects of simultaneous decreasing final demand of multiple sectors on water consumption intensity (WCI) of total (all kinds of water) water, surface- and ground-water. To devise effective policies for conjunctive management of surface- and ground-water, positive utility, economic structure and water productivity should be heeded, and proposals emphasize trade-offs between surface water saving and groundwater conservation, water metabolic and socio-economic systems sustainability and negative interaction of multiple sectors on economy and WCI should be framed. The innovation of this study is the development of SCWM, which can provide sustainable solution for future multiple-source water saving management measures thoroughly concerning direct and indirect water and sectorial interactions. The model not only brings insights to Shaanxi's water management but also can be used for other similar arid area.

Dynamic characteristics and drivers of the regional household energy-carbon-water nexus in China

Being a node of the energy-water consumer and carbon dioxide (CO₂) emitter, the household is one key sector to pilot integrated energy-carbon-water (ECW) management. This study developed an integrated framework to explore China's provincial household ECW nexus as well as their drivers from the years 2000 through 2016. The absolute amount and growth rate of household energy use (HEU), household CO₂ emissions (HCE), and household water use (HWU) were abstracted to reveal the dynamic characteristics of the household ECW nexus. Efficiency advance, income growth, urbanization, family size, and household number were defined to explain the changes in the household ECW nexus. This study revealed that there is a huge regional heterogeneity in China's household ECW nexus. Developed regions such as Zhejiang, Jiangsu, Guangdong, and Shanghai are the most important household ECW nexus nodes with larger amounts and growth rates of household ECW. Income growth overwhelmingly increases ECW, while efficiency advance effectively curbs its growth. Comparatively, household number, family size, and urbanization have small effects. Therefore, implementing differentiated management and focusing on the synergy of socioeconomic factors are the keys to achieving integrated household ECW management. And the analytical framework can be used to analyze ECW nexus from a sector, city, or country perspective.

Chinese environmentally extended input-output database for 2017 and 2018

Environmental footprint analyses for China have gained sustained attention in the literature, which rely on quality EEIO databases based on benchmark input-output (IO) tables. The Chinese environmentally extended input-output (CEEIO) database series provide publically available EEIO databases for China for 1992, 1997, 2002, 2007, and 2012 with consistent and transparent data sources and database structure. Based on the latest benchmark IO tables for China for 2017 and 2018, here we develop the corresponding 2017 and 2018 CEEIO databases following the same method used to develop previous CEEIO databases. The 2017 and 2018 CEEIO databases cover 44 and 28 types of environmental pressures, respectively, and consider multiple sector classifications including ones consistent with previous CEEIO databases and ones following the 2017 China's national economy industry classification standard. A notable improvement in the 2017 and 2018 CEEIO databases is the comprehensive inclusion of CO2 emissions from additional industrial processes. This work provides a consistent update of the CEEIO database and enables a wide range of timely environmental footprint analyses related to China.

Quantifying the influences of natural and human factors on the water footprint of afforestation in desert regions of northern China

To mitigate desertification and alleviate soil erosion, a wide range of ecological restoration initiatives have been implemented in arid and semi-arid areas, the water consumption of ecological projects and driving mechanisms received increasing attention to balance economy development and ecology restoration at different scales. In this study, the water footprint (WF) was employed as an indicator of water consumption by afforestation, and trend analysis, texture classification and geographical detector methods were used to identify the afforestation area and assess the influences of natural and human factors on the afforestation WF in the desert regions of northern China. The results revealed four major findings. (1) The afforestation area increased by 73,764.31 km², from 2003 to 2017, accounting for 2.42% of the study area. (2) On average, the afforestation WF increased from east to west, ranging from 0 to 58.9 m³/gC, indicating its high spatial heterogeneity. (3) Potential evapotranspiration was the dominant factor influencing the afforestation WF, explaining 20.4% of the variation in afforestation WF. (4) The explanatory power of natural and human factors was disparate at the different scales and the interactions between different factors had higher impact than that of single factors. These findings could provide valuable information to support more sustainable ecological restoration science and interventions in arid and semi-arid areas.

Driving Forces of Food Consumption Water Footprint in North China

The water footprint (WF) vividly links water resources with virtual water of food, providing a novel perspective on food demand and water resources management. This study estimates the per capita WF of food consumption for six provinces in North China. Then, the study applies the logarithmic mean Divisia index method to decompose the driving forces of their WF changes. Results show that the per capita WF of food consumption in Beijing, Tianjin, and Inner Mongolia increases significantly in 2005–2017, whereas that in the other three provinces in North China varies slightly. All provinces have shown the same trend of food structure changes: the grain decreased, whereas the meat increased. In general, the urban effect was positive, and the rural effect was negative for all regions. The urban effects in Beijing and Tianjin played a leading role, whereas the rural effects in the other four provinces played a leading role from 2005–2009. However, the urban effects in all provinces played a leading role in 2010–2017. The WF efficiency increased in each province, and the effect in urban areas is stronger due to the higher water use efficiency. For most provinces, the consumption structure was positive because the diet shifted toward more meat consumption. The food consumption per capita effect was the major driving force in Beijing and Tianjin due to the increased consumption level, whereas the population proportion effect exerted a weak effect. To alleviate the pressure on water resources, further improving water use efficiency in food production and changing the planting structure should be emphasized for all regions in North China.

Dynamic assessment of ecological sustainability and the associated driving factors in Tibet and its cities

With the general decline of the life support system on earth, it is of great value to carry out ecological sustainability research. This study used the improved ecological footprint (EF) model to calculate the EF of Tibet and its cities (prefecture-level administrative regions) from 2005 to 2017, quantified its ecological sustainability, and analyzed its driving factors using the logarithmic mean divisia index method. The study found that: (1) The EF of Tibet is steadily increasing, yet its distribution among cities is extremely uneven. The size of the internal sub-footprints is different and the distribution is extremely uneven in each city; (2) The ecology of Tibet and other cities is in a safe state, except for Lhasa that is in a completely unsafe state. The ecological footprint diversity index of Tibet, Lhasa, Qamdo, and Shannan showed a downward trend, while the other cities are the opposite. The coordination is deteriorating between the ecological and economic systems of Lhasa and Ngari, while the opposite is for Tibet and other cities; (3) The EF growth of Tibet and its cities is mainly driven by per unit of GDP, population size and footprint structure. The footprint intensity is a decisive factor in slowing down the growth of EF. This research is helpful for actors at all levels to identify the appropriate strength and type of policies to achieve ecologically sustainable development.

The gap of water supply-Demand and its driving factors: From water footprint view in Huaihe River Basin

Climate change, population growth, the development of industrialization and urbanization are increasing the demand for water resources, but the water pollution is reducing the limited water supply. In recent years, the gap between water supply and demand which shows water scarcity situation is becoming more serious. Clear knowing this gap and its main driving factors could help us to put forward water protection measures correctly. We take the data of Huaihe River Basin from 2001 to 2016 as an example and use ecological water footprint to describe the demand, with the water carrying capacity representing the supply. We analyze the water supply-demand situation of Huaihe River Basin and its five provinces from footprint view in time and space. Then we apply the Logarithmic Mean Divisia Index model to analyze the driving factors of the ecological water footprint. The results show that: (1) the supply and demand balance of Huaihe River Basin was only achieved in year 2003 and 2005. There is also a large difference between Jiangsu province and other provinces in Huaihe River basin, most years in Jiangsu province per capital ecological footprint of water is more than 1 hm2/person except the years of 2003, 2015, and 2016. But other provinces are all less than 1 hm2/person. (2) Through the decomposition of water demand drivers, we concluded that economic development is the most important factor, with an annual contribution of more than 60%. Our study provides countermeasures and suggestions for the management and optimal allocation of water resources in Huaihe River Basin, and also provides reference for the formulation of water-saving policies in the world.

Income impacts on household consumption's grey water footprint in China

Urbanization is accompanied by growing household consumption and changing consumption patterns, with both having impacts on the life-cycle water pollution generated. This study uses the indicator of grey water footprint (GWF) within an Input-Output framework to examine the decadal change from 2002 to 2017 of the life-cycle water pollution change for household consumption in China, where rapid urbanization has particularly posed looming environmental challenges. Against the background of enlarging inequality, the results also shed light on the impacts of households within different income groups. From 2002 to 2017, GWF required by urban household consumption has increased significantly from 1586 to 2195 km³ while that for rural households have decreased slightly from 1139 to 964 km³ during the same period. Total Nitrogen required the largest GWF throughout the whole period and throughout all different income groups. Food consumption dominated the GWF for household consumption. However, the share of GWF for food consumption decreases with income increases, from 83% for extremely poor rural households to 71% for very rich urban households in 2012. Urbanites on average require higher GWF for their consumption than their rural counterparts. An average person from the highest income rural households required 2033 m³ GWF for household consumption, which is higher than a person from a very poor urban household (1685 m³) but lower than that of a person from poor urban household (2149 m³). While household consumption volume increase has been the primary driver for GWF increase, pollution intensity reduction has offset such impacts. Household consumption pattern change's impacts differ by household income and by pollutant considered.

Decomposition of Water Footprint of Food Consumption in Typical East Chinese Cities

Water scarcity has put pressure on city development in China. With a particular focus on urban and rural effects, logarithmic mean Divisia index decomposition (LMDI) was used to analyze the water footprint per capita (WFP) of food consumption in five East China cities (Beijing, Tianjin, Shanghai, Qingdao, and Xiamen) from 2008 to 2018. Results show that the WFP of food consumption exhibited an upward tendency among all cities during the research period. Food consumption structure contributed the most to the WFP growth, mainly due to urban and rural residents’ diet shift toward a livestock-rich style. Except in Beijing, the food consumption level mainly inhibited the WFP growth due to the decrease in food consumption level per capita in urban areas. Urbanization had less influence on WFP growth for two megacities (Beijing and Shanghai) due to the strictly controlled urban population inflow policy and more positive effects for other cities. The water footprint intensity effect among cities was mainly due to uneven water-saving efficiency. Meanwhile, Beijing and Tianjin have achieved advancement in water utilization efficiency.

Integrated virtual water trade management considering self-sufficient production of strategic agricultural and industrial products

The uneven distribution of water on earth causes its scarcity in many countries, hindering economic and human development. Virtual water trading takes place by the export and import of agricultural and industrial products whose production involves water and, so, is one of the methods to cope with water scarcity. This work investigates the integrated management of the virtual water trade of strategic agricultural and industrial products with the goals of maximizing economic revenue and minimizing the consumption of virtual water. Bi-objective optimization is performed with the non-dominated sorting genetic algorithm (NSGA)-II algorithm under two scenarios. One of the scenarios applies production constraints to ensure a minimum of internal or domestic production of agricultural and industrial goods, thus providing a degree of self-sufficiency. This paper applies its methodology to Iran and establishes that the imports of industrial products should be terminated and exports of these products should increase. The results show that the export amount of iron ore increases by 71% due to the application of the self-sufficiency constraint, which shows the profitability of this product in addition to its low water consumption. This paper demonstrates that the optimal solutions for agricultural products (except for potatoes and tomatoes) is achieved by producing at least 50% of the domestic demand, but rarely calls for a higher level of production. This work illustrates through the case study that it is possible to increase economic revenue under water scarcity by proper management of the virtual water trade.

Climate change signals in the historical water footprint of wheat production in Zimbabwe

Climate change has been posited as the biggest threat to crop productivity in agro-systems, yet its impact on the water footprints of crop production for many regions remains uncertain. This study sought to determine evidence of historical climate change (1980-2010) and its resultant impact on the blue water footprint of winter wheat production in Zimbabwe. The analysis involved assessing the impact of climate change on wheat yield and crop water requirements, the key factors determining the blue water footprint. The CROPWAT model and the global water footprint assessment (WFA) standard were used to calculate the blue water footprint. Multiple linear regression was used to correlate climate variables to wheat yield, crop water requirements and the blue water footprint. Results show a significant (p < 0.05) warming of temperatures in the country's main wheat growing areas. Crop water requirements for winter wheat decreased by 4.88%, due to positive and negative trends in humidity and wind speed respectively. Between 1980 and 2000 the coupled effects of solar radiation at anthesis and maximum temperatures in July, August and September reduced wheat yields by 6.65%. The cumulative effects of climate change on crop water requirements and wheat yields increased the blue water footprint by 4%. The results of the study suggest that climate change and agricultural management factors might be equally responsible for the increase in the blue water footprint.

Clarifying Demographic Impacts on Embodied and Materially Retained Carbon toward Climate Change Mitigation

Modern lifestyles demand a number of products derived from petroleum-based sources that eventually cause carbon emissions. The quantification of lifestyle and household consumption impacts upon carbon emissions from both the embodied CO₂ (EC) and materially retained carbon (MRC) viewpoints is critical to deriving amelioration policies and meeting emission reduction goals. This study, for the first time, details a methodology to estimate both EC and MRC for Japan, focusing on petrochemicals and woody products utilizing the time series input-output table, physical value tables and the national survey of family income and expenditure, leveraging time series input-output-based material flow analysis (IO-MFA), and structural decomposition analysis (SDA). Findings elucidated hot spots of deleterious consumption by age of householder and the critical factors which underpin them including intensity effects, pattern effects, and demographic shifts over time. Although demographic shifts associated with an aging, shrinking population in Japan decreased EC and MRC, the negative effect reduced in size over time during 1990-2005. Policy implications identify the potential to mitigate approximately 21% of required household emission reductions by 2030 through strategies including recycling initiatives and the recovery of carbon from products covered within current recycling laws and hot spot sectors which are not currently considered such as apparel.

Identifying the environmental footprint by source of supply chains for effective policy making: the case of Spanish households consumption

Household consumption has been identified to have an essential role in influencing ultimately the environmental pressures generated by human activities. This study assesses the indirect environmental footprint of the Spanish households applying a combination of consumer expenditure surveys with environmentally extended multi-regional input-output analysis. A total of fourteen environmental impact categories are studied from 2006 to 2015. All the impact categories present a similar trend, particularly affected by the economic crisis. The impacts decreased from 2008 to 2013 and finally slightly started rising again from 2014 to 2015. Results show that the dominant categories influencing the indirect environmental footprint in 2015 are (1) food and beverages, (2) housing, and (3) furnishings. From the intensity perspective, housing, transport, and food and beverages appear to be the most intensive consumption clusters in the Spanish household indirect environmental footprint. In relation to the indirect water impacts embodied in the Spanish households' imports, the largest amount is from European countries and the highest virtual water (59%) corresponds to food and agriculture, in particular from wheat, fruit, vegetables, and dairy products. The findings obtained in relation to the sources generating indirect impacts from household consumption could aid the implementation of future mitigation policies.