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Strategies based on virtual water have become a controversial measure to alleviate pressure on the water resource in regions with scarce water. Advocates of this approach highlight its potentially low cost and high efficiency, whereas opponents criticize its over-simplification and neglect of important factors other than water. Detailed analysis of the strategy's effects on water use and socioeconomic development is essential to fully understand the strengths and weaknesses of the strategy, and to support its reasonable and scientific implementation. In the present study, we defined three virtual water strategy scenarios (i.e., reduce agricultural production, increase agricultural imports, and reduce production and increase imports simultaneously) and developed a computable general equilibrium model to simulate the effects of the scenarios. We chose China's Bohai Bay area, a rapidly developing region with scarce water, for a case study. We found that the virtual water strategy was a double-edged sword: it improved water conservation (water use decreased by 3.6%, 6.9%, and 3.2% under the three scenarios, respectively), but had negative effects on economic development, employment, and economic welfare. The scenario that only increased agricultural imports had the greatest negative impact on socioeconomic development, whereas the scenario that simultaneously decreased production and increased imports most effectively balanced the economic development and water conservation requirements. • The virtual water strategy (VWS) exerts negative effects on economic systems. • VWS produces tradeoffs between water conservation and economic development. • The dual-policy strategy could achieve a better tradeoff. [ABSTRACT FROM AUTHOR]

Carbon taxation has long been proposed to mitigate carbon emissions. Carbon tax rate determination and tax revenue recycling are two key steps to achieve a double dividend under carbon taxation. However, few research has sought to optimize the allocation proportion of tax revenue to various categories of taxpayers (households, enterprises, sectors, etc.), or to optimize the two steps synchronously based on nonlinear optimization methods. In this study, a computable general equilibrium model was established to explore the influence of carbon tax rate and tax revenue recycling shares on the economy and on carbon emissions. Meanwhile, a nonlinear optimization model was proposed, for optimizing both steps of carbon taxation synchronously, as well as for promoting GDP and CO 2 emission reduction. The Bohai Bay area, a typical area with enormous carbon emissions in China, was adopted as the study case for this research. The results showed that the optimized taxation scheme could lead to lower carbon emissions and greater economic growth, i.e., a strong double dividend was obtained. The optimized taxation scheme could lead to both cleaner air and cleaner energy and industrial structures while still promoting economic growth. • CGE model is used for effect analysis under different taxation schemes. • Carbon tax rate and revenue recycling are optimized synchronously. • Lower CO 2 emissions can be achieved without economic decline. [ABSTRACT FROM AUTHOR]

Water scarcity is a severe problem for regional environmental protection and socioeconomic development, and water footprints are effective tools for evaluating the magnitude of the water scarcity. However, water is closely intertwined with energy. Carbon taxes are an essential policy tool for managing energy use, and could therefore indirectly change the water footprint. Previous research on water footprints has revealed the historical characteristics of water footprints, but has not predicted how these characteristics would change under a carbon tax. Identifying the indirect impacts of carbon taxes on water footprints could therefore offer important information to support more effective energy and water policies. In the present study, we explored the impacts of carbon taxes on water footprints. We established a computable general equilibrium model to predict the effects of carbon taxes on the socioeconomic system, and adopted an input-output model to account for changes in the water footprint. We then used China as a case study. We found that a carbon tax could reduce the total water footprint, even though the water footprint for primary industries increased. In addition, the tax could decrease the virtual water content, and the reduction of virtual water content is the greatest for the secondary industries. • The impacts of carbon taxes on water footprints are predicted. • CGE model is used for the economic system analysis under energy tax. • A carbon tax could reduce the total water footprint. [ABSTRACT FROM AUTHOR]