Browsing by Author "Lowe, Benjamin H."

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    Comparing the economic value of virtual water with volumetric and stress-weighted approaches: a case for the tea supply chain
    (Elsevier, 2020-03-30) Lowe, Benjamin H.; Oglethorpe, David R.; Choudhary, Sonal
    In this paper, we employ a new approach to assessing the impact and efficiency of virtual water use along the supply chain. This approach involves estimating the economic value of virtual water flows. A realistic tea supply chain case study is presented to test this new approach and compare it with alternative volumetric and stress-weighted methods. The case study is used to highlight the total value of the blue and grey water used to produce 1 tonne of tea as a finished good ($224). The case study also illustrates how variations in the relative unit value of water between geographies, in this case between multiple locations where crops are cultivated (India $0.08 m3, Indonesia $0.09 m3 and Kenya $0.27 m3), can be used to inform supply chain optimisation and allocative efficiency. Indeed, the case study suggests that taking into account the economic value of virtual water may provide differing prescriptions for the sustainable management of supply chains when compared to the traditional volumetric water footprint, and the stress-weighted water footprint used in LCA.
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    Dataset on the in-stream and off-stream economic value of water
    (Elsevier, 2020-03-16) Lowe, Benjamin H.; Oglethorpe, David R.; Choudhary, Sonal
    This dataset contains 706 estimates of the economic value of water; it has been compiled from published sources. Economic values are provided for three off-stream uses (agriculture/irrigation, industry, and municipal) and three in-stream ecosystem services (recreation, waste assimilation, and wildlife habitat). The dataset covers per period and capitalised asset values. All value estimates have been standardised in USD (2014) per acre-foot. The data accompany the research article entitled “Shifting from volume to economic value in virtual water allocation problems: a proposed new framework and methodology” [1]. The dataset can be used to facilitate benefits (or value) transfer.
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    Estimating the economic value of green water as an approach to foster the virtual green-water trade
    (Elsevier, 2022-02-17) Lowe, Benjamin H.; Zimmer, Yelto; Oglethorpe, David R.
    Green water – precipitation that is stored in the soil as moisture and consumed in the production of biomass – provides the main source of water for crop cultivation, pasturelands, forestry, and terrestrial ecosystems. At a local level, green water is land-bound and cannot be easily allocated between uses. However, at the global level, agricultural commodities and their embodied virtual water are traded between countries. This trade typically sees the cultivation of crops in water abundant rainfed locations exported to regions that would otherwise have employed local irrigation resources. The result is a global saving of irrigation water and the negative environmental externalities associated with irrigation. In addition, scarce blue water resources are freed up for other (often higher valued) uses. Here we assess whether there is an economic rationale for the virtual green-water trade and the increased and intentional allocation of crop cultivation to water abundant rainfed locations. We model a realistic case study of maize cultivation on representative farms in 16 major maize producing regions (across four continents) and provide the first spatially variable estimates of the economic value of the green water employed. These economic values are contrasted with the economic value of blue water used for irrigation. We find that the volume of green water employed in the cultivation of maize varies between 409 m3/tonne and 1547 m3/tonne; the estimated economic value of green water varies between $ −0.04 m3 and $0.12 m3. We demonstrate how these economic value estimates can inform crop allocation decisions in favour of green water-based cultivation and inform decisions regarding the intensification and horizontal expansion of rainfed agriculture. In so doing, we aim to provide a further rationale for the green water-based measures that have been identified in the literature as the principal means of providing the additional fresh water needed to address pressing global challenges beyond the case study.
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    Shifting from volume to economic value in virtual water allocation problems: a proposed new framework and methodology
    (Elsevier, 2020-04-08) Lowe, Benjamin H.; Oglethorpe, David R.; Choudhary, Sonal
    The water footprint provided a full methodology to operationalise the virtual water concept (the volume of water used along a supply chain to produce products and services). A key theme in the water footprint literature is the efficient allocation of water resources at the global scale given the feasibility of trading water intensive commodities from water rich to water poor areas: this is an economic problem of resource allocation between alternative and competing demands, albeit with a novel international component. Moreover, given that price signals indicating relative scarcity are usually either absent or distorted for water, it is also a problem that can be seen through the lens of environmental (or non-market) valuation. However, to date environmental valuation has not been used to inform the efficient use and allocation of water within and between the different locations encompassed by international supply chains.