Are virtual water “flows” in Spanish grain trade consistent with relative water scarcity?

Virtual water adds a new dimension to international trade, and brings along a new perspective about water scarcity and water resource management. Most virtual water literature has focused on quantifying virtual water “flows” and on its application to ensure water and food security. Nevertheless, the analysis of the potential gains from international trade, at least from a water resources perspective, needs to take into account both spatial and temporal variations of blue (groundwater and stream flow) and green (soil moisture) water, as well as the socioeconomic and policy conditions. This paper evaluates whether Spanish international trade with grains is consistent with relative water scarcity. For this purpose, the study estimates the volume and economic value of virtual water “flow” through international grain trade for the period 1997-2005, which includes 3 years with different rainfall levels. The calculations show that Spain is a net virtual water “importer” through international grain trade. The volume of net virtual water “imports” amounts to 3420, 4383 and 8415 million m³ in wet (1997), medium (1999) and dry (2005) years, respectively. Valuing blue water at its shadow price or scarcity value, blue water “exports” oscillate between 0.7 and 34.2 million Euros for a wet and dry year, respectively. Overall, grain trade is apparently consistent with relative water scarcity as net imports increase in dry years. However, the evolution of grain exports, expressed as a variation in quantity and volume, does not match the variations in resource scarcity. A disaggregated crop analysis reveals that there are other factors, such as quality, product specialization or the demand for a standardized product, which also influence trade decisions and are not included in the notion of virtual water. These facts, among others, can therefore create potential distortions in the application of virtual water to the analysis of specific trade patterns. Nevertheless, from a water resources perspective, virtual water can bring important insights across countries for improving water and land management globally, fostering adaptation strategies to climate change and to transboundary resource management.     

Agricultural impacts on water quality and implications for virtual water trading decisions

Research on the flow of virtual water associated with agricultural crop production and trade has focussed almost entirely on water quantity. It is pertinent to consider and quantify the opportunity costs in terms of reduced water quality associated with crop production. This paper investigates the impacts of water quality on virtual water trading by creating a proxy for water quality impacts by calculating the amount of water required to dilute nonpoint-source agrochemical inputs to relevant water quality guideline values. The quantity of water required for dilution of five agrochemicals (two nutrients; nitrogen and phosphorus and three insecticides; azinphos-methyl, chlorpyrifos and endosulfan) was estimated for five crops in South Africa (maize, wheat, sugar cane, citrus and cotton) and compared to consumption of irrigation water (blue water) and rainfall (green water) for the same crops. Results indicate that the volume of water required for dilution is similar to the total sum of green and blue water required for crop production, but significantly greater than blue water use (irrigation use). For all crops phosphorus losses require greater amounts of water for dilution than for nitrogen, while pesticides result in the greatest water quality use. Estimates of water quality use are based on assumptions for a number of input variables (i.e. fertilizer application rates, percentage loss of agrochemicals from cropped areas). A Monte Carlo analysis (5000 iterations) was run to randomly select input variables from within defined ranges. Water quality use was calculated and expressed as a factor of blue water use. For all crops the average factor indicated that the volume of water required for dilution of all agrochemicals was greater than that required for irrigation. The results of this study clearly indicate that the impacts of agriculture on water quality need to be considered in virtual water trading scenarios. The incorporation of a method to predict impacts on water quality provides a comparative tool which generates a more holistic frame of reference for decision making with regard to impacts on the water resource and virtual water trading.     

虚拟水及其在缓解区域水资源短缺中的应用研究

虚拟水是指生产商品和服务所需要的水资源数量。虚拟水战略是指贫水国家或地区通过贸易的方式从富水国家或地区购买水密集型农产品(粮食)来获得本地区水和粮食的安全。本文在综述前人对虚拟水研究的基础上,计算了2002年甘肃省及不同地区主要农产品虚拟水含量,并对甘肃省加强虚拟水贸易的战略进行了探讨。     

The blue, green and grey water footprint of rice from production and consumption perspectives

The paper makes a global assessment of the green, blue and grey water footprint of rice, using a higher spatial resolution and local data on actual irrigation. The national water footprint of rice production and consumption is estimated using international trade and domestic production data. The global water footprint of rice production is 784 km³/year with an average of 1325 m³/t which is 48% green, 44% blue, and 8% grey. There is also 1025 m³/t of percolation in rice production. The ratio of green to blue water varies greatly over time and space. In India, Indonesia, Vietnam, Thailand, Myanmar and the Philippines, the green water fraction is substantially larger than the blue one, whereas in the USA and Pakistan the blue water footprint is 4 times more than the green component. The virtual water flows related to international rice trade was 31 km³/year. The consumption of rice products in the EU27 is responsible for the annual evaporation of 2279 Mm³ of water and polluted return flows of 178 Mm³ around the globe, mainly in India, Thailand, the USA and Pakistan. The water footprint of rice consumption creates relatively low stress on the water resources in India compared to that in the USA and Pakistan.     

虚拟水贸易在解决中国和全球水危机中的作用

水资源短缺已经威胁到中国一些地区的社会经济发展和生态安全,经济的发展将会进一步加剧水危机。近年来,农产品贸易中的虚拟水引起了全世界的关注,被看做是一种缓解水资源压力的手段。本文利用虚拟水的概念和方法分析了中国1996～2001年间的粮食贸易,发现:这些年间中国通过粮食贸易净进口了3.28×1 010m3虚拟水;通过粮食进口,中国相当于节省了1.86×1011 m3的水资源;中国的粮食贸易由于基本符合水利用效率的比较优势,因而给全球节省了1.01×1011m3的水资源。中国通过虚拟水贸易不能完全解决国内水危机问题,但是可以节省国内水资源,缓解农业区的水危机状况,提高全球水资源利用效率。尽管当前中国采取虚拟水进口策略会遇到很多问题,但是虚拟水的概念给我们理解粮食贸易和调水工程提供了全新的角度。     

The water footprint of coffee and tea consumption in the Netherlands

A cup of coffee or tea in our hand means manifold consumption of water at the production location. The objective of this study is to assess the global water footprint of the Dutch society in relation to its coffee and tea consumption. The calculation is carried out based on the crop water requirements in the major coffee and tea exporting countries and the water requirements in the subsequent processing steps. In total, the world population requires about 140 billion cubic metres of water per year in order to be able to drink coffee and tea. The standard cup of coffee and tea in the Netherlands costs about 140 l and 34 l of water respectively. The largest portions of these volumes are attributable to growing the plants. The Dutch people account for 2.4% of the world coffee consumption. The total water footprint of Dutch coffee and tea consumption amounts to 2.7 billion cubic metres of water per year (37% of the annual Meuse runoff). The water needed to drink coffee or tea in the Netherlands is not Dutch water. The most important sources for the Dutch coffee are Brazil and Colombia and for the Dutch tea Indonesia, China and Sri Lanka. The major volume of water to grow the coffee plant comes from rainwater. For the overall water need in coffee production, it makes hardly any difference whether the dry or wet production process is applied, because the water used in the wet production process is a very small fraction (0.34%) of the water used to grow the coffee plant. However, the impact of this relatively small amount of water is often significant. First, it is blue water (abstracted from surface and ground water), which is sometimes scarcely available. Second, the wastewater generated in the wet production process is often heavily polluted.     

A study of virtual land trade between China and ASEAN based on material flow analysis model

In this paper,based on the material flux analysis model（MFA） and its corresponding theories and algorithms of ＂virtual land＂ virtual land contents of five primary agricultural products are calculated and＂Virtual land trade＂hidden in those imported and exported products are also obtained through analyzing the primary agricultural product trade between China and ASEAN. In the process of calculationl following the thought of Changing agricultural products to ＂Virtual land trade＂land content, trade condition and spatiai distribution of agricultural products Were integratedly considered. indicate that China exported 73;057 km^2 of virtual land area to ASEAN by tea, vegetables; maize and grain, ASEAN exported： 57.332 km^2 to China by natural rubber from 2002 to 2005. It obvious; that china has lost 15,725 km^2 arable land through agricultural product trade, Additionally, in order to process： of calculation Virtual land trade, Thailand taker as an example to analyze its international trade of rice and Wheat from 1991 to 2005 and Calculate their ＂Virtual land trade＂ 2001 through 2005. According to and calculation, it is not difficult to conclude that ＂Virtual land trade＂ very important and could be used for China to guide agricultural export or import Structure and maintain Sustainable use of land resources.     

我国省域水资源的可持续利用初探*——以辽宁山东等省供水量指标为基础数据

水资源承载力的确定是经济可持续发展决策的前提。本文通过相对水资源承载力的动态分析方法,透析辽宁、山东等省份水资源短缺和超负载的现状,揭示可控因子,进而提出水资源可持续利用的对策。     

日本对外贸易保险分析及借鉴

随着国际经济一体化趋势的进一步增强 ,各个国家或经济体之间的联系越来越紧密 ,任何一方的政治或经济动荡都会在一定程度上波及其它国家或地区 ,而这也对国际贸易的安全性提出了更大的挑战。在本文中 ,我们以日本对外贸易保险为研究对象 ,对它的制度、组织形式及具体运作特点加以分析并期望能对中国的贸易保险提供一定的借鉴作用。     

虚拟水、虚拟水贸易理论研究综述

相对于水价和用水技术能够提高水资源在当地的配置效率,虚拟水贸易则可以提高水资源在全球范围内的配置效率。虚拟水从水资源生产率较高的国家流向水资源较低的国家意味着在全球层次上水资源的节约。因此,国家之间、洲际之间虚拟水贸易被看作提高全球水资源利用效率和缺水国家获得水安全的一个有力工具。     

水资源可持续利用及其管理制度的创新

本文以资源可持续利用与制度安排之间的关系为基础，联系我国目前水资源的现状和在管理中存在的问题，分析了我国水资源未实现可持续利用的主要原因：一是在市场经济条件下未形成合理的水价机制，二是未形成集中统一，具有权威的管理机构，三是水资源保护意识不强，污水处理措施不得力，最后针对这些问题从制度创新的角度提出建议。     

产业用水分析的水资源投入产出模型研究

设计出一种具有实际可操作性的水资源投入产出表编制方法,依据水资源投入产出表建立产业直接用水系数、完全用水系数和用水乘数的计算模型,选择缺水较为严重的宁夏地区进行实证研究。计算结果表明,产业间接用水具有极强的隐蔽性,分析产业用水时,不能简单以直接用水系数衡量产业发展对水资源的需求,应正确区分产业用水性质,为缺水地区制定合理的产业发展策略提供决策支持。     

The water footprint of energy from biomass: A quantitative assessment and consequences of an increasing share of bio-energy in energy supply

This paper assesses the water footprint (WF) of different primary energy carriers derived from biomass expressed as the amount of water consumed to produce a unit of energy (m³/GJ). The paper observes large differences among the WFs for specific types of primary bio-energy carriers. The WF depends on crop type, agricultural production system and climate. The WF of average bio-energy carriers grown in the Netherlands is 24 m³/GJ, in the US 58 m³/GJ, in Brazil 61 m³/GJ, and in Zimbabwe 143 m³/GJ. The WF of bio-energy is much larger than the WF of fossil energy. For the fossil energy carriers, the WF increases in the following order: uranium (0.1 m³/GJ), natural gas (0.1 m³/GJ), coal (0.2 m³/GJ), and finally crude oil (1.1 m³/GJ). Renewable energy carriers show large differences in their WF. The WF for wind energy is negligible, for solar thermal energy 0.3 m³/GJ, but for hydropower 22 m³/GJ. Based on the average per capita energy use in western societies (100 GJ/capita/year), a mix from coal, crude oil, natural gas and uranium requires about 35 m³/capita/year. If the same amount of energy is generated through the growth of biomass in a high productive agricultural system, as applied in the Netherlands, the WF is 2420 m³. The WF of biomass is 70 to 400 times larger than the WF of the other primary energy carriers (excluding hydropower). The trend towards larger energy use in combination with an increasing contribution of energy from biomass will enlarge the need for fresh water. This causes competition with other claims, such as water for food.     

基于投入产出法的浙江省虚拟水贸易实证分析

基于"虚拟水"理论,利用2005年和2007年浙江省的投入产出表(延长表)和各产业部门的用水数据,采用投入产出分析法构建价值型-实物型水资源投入产出模型,计算并分析了2005年和2007年浙江省各产业部门的虚拟水贸易量。结果表明:浙江省通过商品贸易向他省和国外输出的虚拟水主要集中在纺织、缝纫及皮革产品制造业和机械设备制造业;通过商品贸易向省内输入的虚拟水集中在农业、化学工业、金属冶炼及加工制造业、采掘业和食品制造和烟草加工业;从虚拟水贸易结构来看,农业和重工业为净输入虚拟水贸易行业,轻工业为净输出虚拟水贸易行业。     

虚拟水贸易及其影响因素研究

由于水资源的分布不均和大量消耗,水资源短缺成为很多国家和地区经济社会发展的约束。虚拟水贸易作为一种解决水资源短缺的方式被提出,成为水资源研究领域的热点。以农产品的国际贸易为主体的虚拟水国际贸易也不仅仅涉及水资源的平衡问题,还涉及到很多政治、经济等因素。本文从政治、经济、社会、生态四方面对虚拟水贸易的影响因素进行分析,从而对虚拟水贸易展开研究。     

我国农业水权制度改革探讨

通过对我国农业用水现状的经济学分析和国外水权制度安排的研究,指出中国作为农业大国在引进水市场机制的过程中,更应重点关注农业水权制度的改革和切实保障农民利益;同时在借鉴国外水权制度的基础上结合我国农业水权的实际,提出了我国农业水权制度改革的若干思考和建议。