Understanding agricultural virtual water flows in the world from an economic perspective: A long term study

The globalization process of the last half century entailed a growing trade in agricultural and food products. As a result, water has been transferred among countries, embodied in these goods. This paper studies the evolution of virtual water flows over the long term, analyzing the main driving factors through Decomposition Analysis. It contributes to the existing literature by offering a dynamic and economic interpretation of the historical changes in virtual water trade flows. In particular, this study points to a gradual increase in virtual water exchange, related to the upsurge of agricultural and food products trade in the world from 1965 to 2010. Although the origins and destinations of virtual water have changed, North America stands out as the primary net exporter of virtual water. Europe and Asia, on the other hand, with a high dependency on foreign water resources, appear as net importers of virtual water. Despite improvements in agricultural yields and the reallocation of production, the virtual water trade continues to increase globally via these significant commercial exchanges.     

基于投入产出分析的北京市虚拟水核算

城市化进程的加快与工农业的迅速发展使城市水消耗量日趋增加。水资源短缺不仅会造成居民生活质量下降,还会制约社会经济的可持续发展。从贸易和消费的角度核算虚拟水可为研究城市水资源管理提供新的视角。通过投入产出分析了构建了城市系统虚拟水核算模型,利用虚拟水直接和完全用水系数、虚拟水消费量等指标分析城市虚拟水消耗和虚拟水进出口特征。以北京市为例,利用2012年北京市投入产出表和部门的水资源消耗数据核算不同部门的用水系数、最终消费虚拟水量、虚拟水进出口贸易量及部门间虚拟水流转量。结果表明:北京市为虚拟水净进口城市,净进口虚拟水量6.77×10~9m~3,相当于北京市虚拟水用水总量(8.25×10~9m~3)的82%,农业和制造业为主要虚拟水进口部门;北京市虚拟水出口结构存在不合理之处,经济投入产出表中各部门出口总额占最终消费的79.9%,但出口产品消耗的虚拟水占了最终消费隐含虚拟水的85.04%,其中农产品消耗6.7%虚拟水但经济收益仅占1%,说明北京市出口以较大的虚拟水消耗量换取了较少的经济收益,需要减少虚拟水含量较大但经济价值不高的产品出口(如农产品);识别出的主要虚拟水流出-流入关系部门包括农业-制造业,农业-服务业和制造业-建筑业等部门的关联关系,可成为减少间接水消耗的关键路径。     

International Trade Modelling Using Open Flow Networks: A Flow-Distance Based Analysis

This paper models and analyzes international trade flows using open flow networks (OFNs) with the approaches of flow distances, which provide a novel perspective and effective tools for the study of international trade. We discuss the establishment of OFNs of international trade from two coupled viewpoints: the viewpoint of trading commodity flow and that of money flow. Based on the novel model with flow distance approaches, meaningful insights are gained. First, by introducing the concepts of trade trophic levels and niches, countries’ roles and positions in the global supply chains (or value-added chains) can be evaluated quantitatively. We find that the distributions of trading “trophic levels” have the similar clustering pattern for different types of commodities, and summarize some regularities between money flow and commodity flow viewpoints. Second, we find that active and competitive countries trade a wide spectrum of products, while inactive and underdeveloped countries trade a limited variety of products. Besides, some abnormal countries import many types of goods, which the vast majority of countries do not need to import. Third, harmonic node centrality is proposed and we find the phenomenon of centrality stratification. All the results illustrate the usefulness of the model of OFNs with its network approaches for investigating international trade flows.     

The Biophysical Performance of Argentina (1970–2009)

The biophysical features of the Argentinean economy are examined using a social metabolism approach. A material flow analysis (MFA) for this economy was conducted for the period 1970–2009. Results show that Argentina follows a resource‐intensive and export‐oriented development model with a persistent physical trade deficit. Also, Argentina's terms of trade (the average weight in tonnes of imports that can be purchased through the sale of 1 tonne of exports) show a declining trend in the period of study. Argentina's economy shows a pattern typical of countries whose economies are based primarily on exports. Comparisons between Argentina's metabolic profile and the metabolic profile of other countries in Latin America and of Australia and Spain show that the Argentinean economy presents the same pattern as other Latin American exporting economies, and its terms of trade are opposite to those of industrialized economies.     

Ecological network analysis for virtual water trade system: A case study for the Baiyangdian Basin in Northern China

Increasing inter-sectoral virtual water trade has organized the world into a huge web and different trade sectors will impact each other directly and indirectly through productions or services. It is hard to make reasonable virtual water policies before understanding the interdependency between different trade sectors in virtual water production and consumption. This paper introduces a method, named ecological network analysis, to show the independence and interaction between different trade sectors. A virtual water trade network model of the Baiyangdian Basin was built as an example of how this approach provides insights into the trade system. Control, utility, unit environ and final contribution ratio methods of network analysis were used to identify the quantitative dependency relations, distinguish the beneficiary and the contributor, detect fate of boundary input and output in any component and explore the contribution of each compartment to virtual water trade system. Results showed these methods could well depict the mutual relations in trade system and direct, observable relations may differ from integral ones. This paper revealed ways to optimize virtual water trade structure by adjusting the relationships among compartments, thereby demonstrating how ecological network analysis can be used in future basin water resources management.     

Testing environmental Kuznets curve hypothesis: The role of renewable and non-renewable energy consumption and trade in OECD countries

This paper investigates the causal relationships between per capita CO₂ emissions, gross domestic product (GDP), renewable and non-renewable energy consumption, and international trade for a panel of 25 OECD countries over the period 1980–2010. Short-run Granger causality tests show the existence of bidirectional causality between: renewable energy consumption and imports, renewable and non-renewable energy consumption, non-renewable energy and trade (exports or imports); and unidirectional causality running from: exports to renewable energy, trade to CO₂ emissions, output to renewable energy. There are also long-run bidirectional causalities between all our considered variables. Our long-run fully modified ordinary least squares (FMOLS) and dynamic ordinary least squares (DOLS) estimates show that the inverted U-shaped environmental Kuznets curve (EKC) hypothesis is verified for this sample of OECD countries. They also show that increasing non-renewable energy increases CO₂ emissions. Interestingly, increasing trade or renewable energy reduces CO₂ emissions. According to these results, more trade and more use of renewable energy are efficient strategies to combat global warming in these countries.     

Consumption‐based Material Flow Accounting

In 2007, imports accounted for approximately 34% of the material input (domestic extraction and imports) into the Austrian economy and almost 60% of the GDP stemmed from exports. Upstream material inputs into the production of traded goods, however, are not yet included in the standard framework of material flow accounting (MFA). We have reviewed different approaches accounting for these upstream material inputs, or raw material equivalents (RME), positioning them in a wider debate about consumption‐based perspectives in environmental accounting. For the period 1995–2007, we calculated annual RME of Austria's trade and consumption applying a hybrid approach. For exports and competitive imports, we used an environmentally extended input‐output model of the Austrian economy, based on annual supply and use tables and MFA data. For noncompetitive imports, coefficients for upstream material inputs were extracted from life cycle inventories. The RME of Austria's imports and exports were approximately three times larger than the trade flows themselves. In 2007, Austria's raw material consumption was 30 million tonnes or 15% higher than its domestic material consumption. We discuss the material composition of these flows and their temporal dynamics. Our results demonstrate the need for a consumption‐based perspective in MFA to provide robust indicators for dematerialization and resource efficiency analysis of open economies.     

Disparate Geography of Consumption,Production, and Environmental Impacts

International trade transfers social and environmental impacts across national borders. The consumption of forest products often takes place far away from industrial production sites, and mills procure raw material from remote forests. Finland produces about 10% of forest products that are traded internationally, with the majority of its exports destined for other European countries. Here we report and analyze data that demonstrate that international leakage, in relative terms, increased faster than the production of commodities. The international consumption of products made in Finland increased, and an increase in wood imports from Russia provided the raw material for most of the incremental production. The international consumption‐production system translated the increasing global demand for Finnish products into increased harvests in Russia, until the Russian customs duties started to increase in 2007. We argue that national and regional policies for the promotion of sustainable consumption and production must be analyzed and assessed from an international, holistic perspective.     

The changing role of ornamental horticulture in alien plant invasions

The number of alien plants escaping from cultivation into native ecosystems is increasing steadily. We provide an overview of the historical, contemporary and potential future roles of ornamental horticulture in plant invasions. We show that currently at least 75% and 93% of the global naturalised alien flora is grown in domestic and botanical gardens, respectively. Species grown in gardens also have a larger naturalised range than those that are not. After the Middle Ages, particularly in the 18th and 19th centuries, a global trade network in plants emerged. Since then, cultivated alien species also started to appear in the wild more frequently than non‐cultivated aliens globally, particularly during the 19th century. Horticulture still plays a prominent role in current plant introduction, and the monetary value of live‐plant imports in different parts of the world is steadily increasing. Historically, botanical gardens – an important component of horticulture – played a major role in displaying, cultivating and distributing new plant discoveries. While the role of botanical gardens in the horticultural supply chain has declined, they are still a significant link, with one‐third of institutions involved in retail‐plant sales and horticultural research. However, botanical gardens have also become more dependent on commercial nurseries as plant sources, particularly in North America. Plants selected for ornamental purposes are not a random selection of the global flora, and some of the plant characteristics promoted through horticulture, such as fast growth, also promote invasion. Efforts to breed non‐invasive plant cultivars are still rare. Socio‐economical, technological, and environmental changes will lead to novel patterns of plant introductions and invasion opportunities for the species that are already cultivated. We describe the role that horticulture could play in mediating these changes. We identify current research challenges, and call for more research efforts on the past and current role of horticulture in plant invasions. This is required to develop science‐based regulatory frameworks to prevent further plant invasions.     

Fish is food--the FAO's fish price index

World food prices hit an all-time high in February 2011 and are still almost two and a half times those of 2000. Although three billion people worldwide use seafood as a key source of animal protein, the Food and Agriculture Organization (FAO) of the United Nations-which compiles prices for other major food categories-has not tracked seafood prices. We fill this gap by developing an index of global seafood prices that can help to understand food crises and may assist in averting them. The fish price index (FPI) relies on trade statistics because seafood is heavily traded internationally, exposing non-traded seafood to price competition from imports and exports. Easily updated trade data can thus proxy for domestic seafood prices that are difficult to observe in many regions and costly to update with global coverage. Calculations of the extent of price competition in different countries support the plausibility of reliance on trade data. Overall, the FPI shows less volatility and fewer price spikes than other food price indices including oils, cereals, and dairy. The FPI generally reflects seafood scarcity, but it can also be separated into indices by production technology, fish species, or region. Splitting FPI into capture fisheries and aquaculture suggests increased scarcity of capture fishery resources in recent years, but also growth in aquaculture that is keeping pace with demand. Regionally, seafood price volatility varies, and some prices are negatively correlated. These patterns hint that regional supply shocks are consequential for seafood prices in spite of the high degree of seafood tradability.     

Labor Embodied in Trade

Global production chains carry environmental and socioeconomic impacts embodied in each traded good and service. Even though labor and energy productivities tend to be higher for domestic production in high‐income countries than those in emerging economies, this difference is significantly reduced for consumption, when including imported products to satisfy national demand. The analysis of socioeconomic and environmental aspects embodied in consumption can shed a light on the real level of productivity of an economy, as well as the effects of rising imports and offshoring. This research introduces a consumption‐based metric for productivity, in which we evaluate the loss of productivity of developed nations resulting from imports from less‐developed economies and offshoring of labor‐intensive production. We measure the labor, energy, and greenhouse gas emissions footprints in the European Union's trade with the rest of the world through a multiregional input‐output model. We confirm that the labor footprint of European imports is significantly higher than the one of exports, mainly from low‐skilled, labor‐intensive primary sectors. A high share of labor embodied in exports is commonly associated with low energy productivities in domestic industries. Hence, this reconfirms that the offshoring of production to cheaper and low‐skilled, labor‐abundant countries offsets, or even reverts, energy efficiency gains and climate‐change mitigation actions in developed countries.     

Disease will limit future food supply from the global crustacean fishery and aquaculture sectors

Seafood is a highly traded food commodity. Farmed and captured crustaceans contribute a significant proportion with annual production exceeding 10 M metric tonnes with first sale value of $40bn. The sector is dominated by farmed tropical marine shrimp, the fastest growing sector of the global aquaculture industry. It is significant in supporting rural livelihoods and alleviating poverty in producing nations within Asia and Latin America while forming an increasing contribution to aquatic food supply in more developed countries. Nations with marine borders often also support important marine fisheries for crustaceans that are regionally traded as live animals and commodity products. A general separation of net producing and net consuming nations for crustacean seafood has created a truly globalised food industry. Projections for increasing global demand for seafood in the face of level or declining fisheries requires continued expansion and intensification of aquaculture while ensuring best utilisation of captured stocks. Furthermore, continued pressure from consuming nations to ensure safe products for human consumption are being augmented by additional legislative requirements for animals (and their products) to be of low disease status. As a consequence, increasing emphasis is being placed on enforcement of regulations and better governance of the sector; currently this is a challenge in light of a fragmented industry and less stringent regulations associated with animal disease within producer nations. Current estimates predict that up to 40% of tropical shrimp production (>$3bn) is lost annually, mainly due to viral pathogens for which standard preventative measures (e.g. such as vaccination) are not feasible. In light of this problem, new approaches are urgently required to enhance yield by improving broodstock and larval sourcing, promoting best management practices by farmer outreach and supporting cutting-edge research that aims to harness the natural abilities of invertebrates to mitigate assault from pathogens (e.g. the use of RNA interference therapeutics). In terms of fisheries losses associated with disease, key issues are centred on mortality and quality degradation in the post-capture phase, largely due to poor grading and handling by fishers and the industry chain. Occurrence of disease in wild crustaceans is also widely reported, with some indications that climatic changes may be increasing susceptibility to important pathogens (e.g. the parasite Hematodinium). However, despite improvements in field and laboratory diagnostics, defining population-level effects of disease in these fisheries remains elusive. Coordination of disease specialists with fisheries scientists will be required to understand current and future impacts of existing and emergent diseases on wild stocks. Overall, the increasing demand for crustacean seafood in light of these issues signals a clear warning for the future sustainability of this global industry. The linking together of global experts in the culture, capture and trading of crustaceans with pathologists, epidemiologists, ecologists, therapeutics specialists and policy makers in the field of food security will allow these issues to be better identified and addressed.     

Environmental impacts of European trade: interpreting results of process-based LCA and environmentally extended input–output analysis towards hotspot identification

Purpose

Trade is increasingly considered a significant contributor to environmental impacts. The assessment of the impacts of trade is usually performed via environmentally extended input–output analysis (EEIOA). However, process-based life cycle assessment (LCA) applied to traded goods allows increasing the granularity of the analysis and may be essential to unveil specific impacts due to traded products.

Methods

This study assesses the environmental impacts of the European trade, considering two modelling approaches: respectively EEIOA, using EXIOBASE 3 as supporting database, and process-based LCA. The interpretation of the results is pivotal to improve the robustness of the assessment and the identification of hotspots. The hotspot identification focuses on temporal trends and on the contribution of products and substances to the overall impacts. The inventories of elementary flows associated with EU trade, for the period 2000–2010, have been characterized considering 14 impact categories according to the Environmental Footprint (EF2017) Life Cycle Impact Assessment method.

Results and discussion

The two modelling approaches converge in highlighting that in the period 2000–2010: (i) EU was a net importer of environmental impacts; (ii) impacts of EU trade and EU trade balance (impacts of imports minus impacts of exports) were increasing over time, regarding most impact categories under study; and (iii) similar manufactured products were the main contributors to the impacts of exports from EU, regarding most impact categories. However, some results are discrepant: (i) larger impacts are obtained from IO analysis than from process-based LCA, regarding most impact categories, (ii) a different set of most contributing products is identified by the two approaches in the case of imports, and (iii) large differences in the contributions of substances are observed regarding resource use, toxicity, and ecotoxicity indicators.

Conclusions

The interpretation step is crucial to unveil the main hotspots, encompassing a comparison of the differences between the two methodologies, the assumptions, the data coverage and sources, the completeness of inventory as basis for impact assessment. The main driver for the observed divergences is identified to be the differences in the impact intensities of goods, both induced by inherent properties of the IO and life cycle inventory databases and by some of this study’s modelling choices. The combination of IO analysis and process-based LCA in a hybrid framework, as performed in other studies but generally not at the macro-scale of the full trade of a country or region, appears a potential important perspective to refine such an assessment in the future.

     

中国主要农产品虚拟要素贸易网络结构特征分析

据虚拟水概念定义虚拟要素,并将其划分为虚拟资源要素和虚拟生态要素两类,选取虚拟资源要素中的耕地要素和虚拟生态要素中的化肥/农药要素为研究对象,定量分析2002—2016年以粮食贸易为载体的虚拟耕地、虚拟化肥/农药要素的贸易量,构建虚拟要素贸易网络,通过复杂网络的研究方法,结果表明:2002—2016年我国主要农产品虚拟耕地、化肥/农药要素的贸易总量呈下降趋势,降幅分别约25.51%、8.01%;虚拟耕地要素网络节点入度较大的为长江中下游、华南、西南地区,出度较大的为黄淮海和东北地区,虚拟化肥/农药要素网络与之相反;地区间节点强度的差异性大,虚拟耕地要素差值最大可达1459.56万hm~2,虚拟化肥/农药要素达61.38万t;二者网络节点度和强度的累积分布均符合幂律分布规律,其尾部的"重尾"现象揭示了节点度和强度的高可变性以及网络结构的脆弱性;虚拟耕地要素的输入区网络同配,输出区网络异配,揭示了地区间耕地要素的流动既呈集聚又有分散的态势,虚拟化肥/农药要素网络节点相关性皆为减函数,网络异配,揭示了虚拟化肥/农药要素在八大区域间联通的状况。网络结构特征分析为研究网络抗毁性特征和网络的优化调控机制奠定基础,为中国粮食贸易格局和粮价制定以及各个地区的农业种植结构调整提供理论依据。     

The Influence of Agricultural Trade and Livestock Production on the Global Phosphorus Cycle

Trends of increasing agricultural trade, increased concentration of livestock production systems, and increased human consumption of livestock products influence the distribution of nutrients across the global landscape. Phosphorus (P) represents a unique management challenge as we are rapidly depleting mineable reserves of this essential and non-renewable resource. At the same time, its overuse can lead to pollution of aquatic ecosystems. We analyzed the relative contributions of food crop, feed crop, and livestock product trade to P flows through agricultural soils for 12 countries from 1961 to 2007. Due to the intensification of agricultural production, average soil surface P balances more than tripled from 6 to 21 kg P ha⁻¹ between 1961 and 2007 for the 12 study countries. Consequently, countries that are primarily agricultural exporters carried increased risks for water pollution or, for Argentina, reduced soil fertility due to soil P mining to support exports. In 2007, nations imported food and feed from regions with higher apparent P fertilizer use efficiencies than if those crops were produced domestically. However, this was largely because imports were sourced from regions depleting soil P resources to support export crop production. In addition, the pattern of regional specialization and intensification of production systems also reduced the potential to recycle P resources, with greater implications for livestock production than crop production. In a globalizing world, it will be increasingly important to integrate biophysical constraints of our natural resources and environmental impacts of agricultural systems into trade policy and agreements and to develop mechanisms that move us closer to more equitable management of non-renewable resources such as phosphorus.     

Greenhouse gas emissions of the production chain behind consumption of products in Austria: Development and application of a product‐ and technology‐specific approach

Globalization has been one main driver affecting our whole economy. Thus, greenhouse gas emissions (GHGs) associated with imports and exports should get addressed in addition to the national emission inventory according to the United Nations Framework Convention on Climate Change (UNFCCC), which is focused on territorial emissions only. To enable a correct calculation for imports and exports and to find the most emission‐intensive products and their origin, a product‐ and technology‐specific approach would be favorable which has not been applied up to now. This article addresses this research gap in developing and applying such an approach to calculate the GHGs behind consumption of products in Austria. It is based on physical flows combined with life‐cycle‐based emission factors and emission intensities derived from sector‐ and country‐specific energy mix, for calculating all emissions behind the production chain (resources to final products) of products consumed in Austria. The results have shown that consumption of products in Austria leads to about 60% more emissions than those of the national inventory and that the main part of these emissions comes from the provision of products. The most emission‐intensive products are coming from the chemical and the metal industry. In particular, imports are the main driver of these emissions and are more emission intensive than those produced in Austria. As a result, it is necessary to look at practical measures to reduce emissions along the production chain not only in Austria, but especially abroad as well.     

流域人类活动净氮输入量的估算、不确定性及影响因素

人类活动使得大量的氮素进入流域生态系统,大量氮的盈余导致了一系列生态环境问题的出现。为了评估人类活动对流域生态系统的影响,Howarth等于1996年提出了人类活动净氮输入(NANI)的概念。综述了当前人类活动净氮输入的估算方法、不确定性及影响因素,并得到以下结论:导致NANI估算结果的不确定性原因主要有:内涵分歧、数据来源、尺度转换、估算方法的分歧。影响NANI的主要因素包括:各输入项、人口密度、土地利用组成;对于各输入项而言,化肥施用是最主要的氮素输入来源,占人类活动净氮输入总量的79.0%,其次为作物固氮,占17.6%,食品/饲料氮净输入量占-14.5%,大气沉降占15.7%;对于人口密度,NANI随着人口密度的增大而增大,当人口密度高于100人/km2,人口密度对NANI的影响趋于稳定,其他因素起主导作用。对于土地利用组成:NANI与森林面积比例成负相关,而与耕地面积比例成正相关。     

Virtual water and water footprints do not provide helpful insight regarding international trade or water scarcity

Many authors have estimated the virtual water content of good and services traded internationally, and many have calculated national water footprints that account for the volumes of virtual water imported and exported. Some authors have suggested that international trade of virtual water has been harmful to selected exporting countries with limited water endowments. Some suggest also that current patterns of international trade should be rearranged to make better use of global water resources. Yet, countries do not actually trade in virtual water. They trade in goods and services for which water is one of many inputs. Wise choices regarding water resources and smart strategies regarding international trade cannot be determined by focusing on water alone. The notions of virtual water and water footprints are not helpful indicators of optimal strategies regarding water resources, particularly when considering issues such as water scarcity or international trade. I describe four perspectives regarding virtual water and water footprints, with the goal of demonstrating the inadequacies of these notions in policy discussions and in efforts to determine the optimal allocation and use of water resources. The four perspectives are: (1) international trade should not be modified or regulated to reflect the virtual water content of traded commodities or water footprints in the countries of trading partners, (2) countries do not save water by engaging in virtual water trade, (3) consumers in one country cannot alleviate water scarcity or improve water quality in other countries, and (4) water footprints are not analogous to carbon or ecological footprints.     

Recent non‐native invertebrate plant pest establishments in Great Britain: origins,pathways, and trends

1 An appraisal of non‐native invertebrate plant pest establishments in Great Britain, between 1970 and 2004, was carried out to improve our understanding of current invasion processes by non‐native plant pests, and to assist national strategies in managing the risks they pose. 2 A total of 164 establishments, comprising 50 natural colonists and 114 human‐assisted introductions, were recorded across 13 major taxonomic groups. 3 The mean rate of establishment was 22.1 species per 5‐year period: 19.1 and 3.0 species outside and inside protected cultivation, respectively. Despite the continuing rapid growth in international trade and a general perception that rates of pest invasions are accelerating, no significant temporal trends in the rate of establishments in Great Britain were detected, either for natural colonists or human‐assisted introductions, or for pests of plants grown indoors or outside. 4 The plant trade, particularly in ornamental plants, accounted for nearly 90% of human‐assisted introductions; apiculture, biological control, timber imports, transport stowaways and intentional releases each contributed less than 5%. Only eight (4.9%) of the establishments could be considered as having no direct potential economic impact because all other species have been recorded as feeding on cultivated plants. A greater proportion of establishments by both natural colonists and human‐assisted introductions occurred on non‐native, woody plants. 5 The present study confirms previous work in other European countries that highlight the predominant role of the ornamental plant trade in introducing new plant pests to the European continent, mainly from Asia and North America.