RESUMEN

Agriculture accounts for 61 % of fresh water consumption in China. Although population and diet have a significant impact on water consumption, little is known about the reasons for and extent of their influence. Changes in the blue and green water footprint of 20 agricultural sectors in 31 Chinese provinces were estimated in 5 scenarios by applying the environmentally expanded multi-regional input-output model. The water footprint network is strongly interconnected, with over 50 % of the provinces characterized as net importers of the blue water footprint, 70 % of the total blue and green water footprint imports in developed provinces, and 65 % of the total blue and green water footprint exports in developing provinces, with the flow distribution driven and dominated by economically developed provinces. The findings also highlighted that the impact of population change on the water footprint is insignificant, contributing 0.51 % and 5.78 % to the reduction of the water footprint in 2030 and 2050, respectively. The impact of simultaneous changes in the population and dietary structure on the water footprint was higher than population changes and lower than dietary structure changes. The main force driving changes in the water footprint was changes in the dietary structure, which resulted in a two-fold effect on the water footprint. First, it has increased the blue and green water footprint by 33 % and 12 %, respectively, thus aggravating the coercive impact on water resources on the production side. Second, it has led to a change in the main contributing sectors for the blue and green water footprint from cereals to fruits, vegetables, and potatoes. Therefore, when the population is changing and optimizing its dietary structures, a greater focus must be placed on threats and pressures to water resources. This will result in better scientific management and more efficient use of water resources.

RESUMEN

The United Nations Sustainable Development Goal 6 aims for clean water and sanitation for all by 2030, through eight subgoals dealing with four themes: (i) water quantity and availability, (ii) water quality, (iii) finding sustainable solutions and (iv) policy and governance. In this opinion paper, we assess how soils and associated land and water management can help achieve this goal, considering soils at two scales: local soil health and healthy landscapes. The merging of these two viewpoints shows the interlinked importance of the two scales. Soil health reflects the capacity of a soil to provide ecosystem services at a specific location, taking into account local climate and soil conditions. Soil is also an important component of a healthy and sustainable landscape, and they are connected by the water that flows through the soil and the transported sediments. Soils are linked to water in two ways: through plant-available water in the soil (green water) and through water in surface bodies or available as groundwater (blue water). In addition, water connects the soil scale and the landscape scale by flowing through both. Nature-based solutions at both soil health and landscape-scale can help achieve sustainable future development but need to be embedded in good governance, social acceptance and economic viability. This article is part of the theme issue 'The role of soils in delivering Nature's Contributions to People'.

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RESUMEN

Despite the perception of being one of the most agriculturally productive regions globally, crop production in Alberta, a western province of Canada, is strongly dependent on highly variable climate and water resources. We developed agro-hydrological models to assess the water footprint (WF) of barley by simulating future crop yield (Y) and consumptive water use (CWU) within the agricultural region of Alberta. The Soil and Water Assessment Tool (SWAT) was used to develop rainfed and irrigated barley Y simulation models adapted to sixty-seven and eleven counties, respectively through extensive calibration, validation, sensitivity, and uncertainty analysis. Eighteen downscaled climate projections from nine General Circulation Models (GCMs) under the Representative Concentration Pathways 2.6 and 8.5 for the 2040-2064 period were incorporated into the calibrated SWAT model. Based on the ensemble of GCMs, rainfed barley yield is projected to increase while irrigated barley is projected to remain unchanged in Alberta. Results revealed a considerable decrease (maximum 60%) in WF to 2064 relative to the simulated baseline 1985-2009 WF. Less water will also be required to produce barley in northern Alberta (rainfed barley) than southern Alberta (irrigated barley) due to reduced water consumption. The modeled WF data adjusted for water stress conditions and found a remarkable change (increase/decrease) in the irrigated counties. Overall, the research framework and the locally adapted regional model results will facilitate the development of future water policies in support of better climate adaptation strategies by providing improved WF projections.

RESUMEN

Proper management of blue and green water resources is important for the sustainability of ecosystems and for the socio-economic development of river basins such as the Athabasca River Basin (ARB) in Canada. For this reason, quantifying climate change impacts on these water resources at a finer temporal and spatial scale is often necessary. In this study, we used a Soil and Water Assessment Tool (SWAT) to assess climate change impacts on fresh water resources, focusing explicitly on the impacts to both blue and green water. We used future climate data generated by the Canadian Center for Climate Modelling and Analysis Regional Climate Model (CanRCM4) with a spatial resolution of 0.22°×0.22° (~25km) for two emission scenarios (RCP 4.5 and 8.5). Results projected the climate of the ARB to be wetter by 21-34% and warmer by 2-5.4°C on an annual time scale. Consequently, the annual average blue and green water flow was projected to increase by 16-54% and 11-34%, respectively, depending on the region, future period, and emission scenario. Furthermore, the annual average green water storage at the boreal region was expected to increase by 30%, while the storage was projected to remain fairly stable or decrease in other regions, especially during the summer season. On average, the fresh water resources in the ARB are likely to increase in the future. However, evidence of temporal and spatial heterogeneity could pose many future challenges to water resource planners and managers.

RESUMEN

Future water scarcities in the face of an increasing population, climate change and the unsustainable use of aquifers will present major challenges to global food production. The ability of water footprints (WFs) to inform water resource management at catchment-scale was investigated on the Steenkoppies Aquifer, South Africa. Yields based on cropping areas were multiplied with season-specific WFs for each crop to determine blue and green water consumption by agriculture. Precipitation and evapotranspiration of natural vegetation and other uses of blue water were included with the agricultural WFs to compare water availability and consumption in a catchment sustainability assessment. This information was used to derive a water balance and develop a catchment WF framework that gave important insights into the hydrology of the aquifer through a simplified method. This method, which requires the monitoring of only a few key variables, including rainfall, agricultural production, WFs of natural vegetation and other blue water flows, can be applied to inform the sustainability of catchment scale water use (as opposed to more complex hydrological studies). Results indicate that current irrigation on the Steenkoppies Aquifer is unsustainable. This is confirmed by declining groundwater levels, and suggests that there should be no further expansion of irrigated agriculture on the Steenkoppies Aquifer. Discrepancies between in- and outflows of water in the catchment indicated that further development of the WF approach is required to improve understanding of the geohydrology of the aquifer and to set and meet sustainability targets for the aquifer. It is envisaged that this 'working' framework can be applied to other water-stressed aquifers around the world.