Virtual Water Trade to Japan and in the World

2 “Required water” …the water that is used in the production process of agricultural or industrial goods Two types of required water: Really Required Water (Real Water ; RW) water used in exporting countries for production Virtually Required Water (Virtual Water ; VW) water needed in importing countries if the same amount of products were produced domestically Really Required Water Really Required Water Virtually Required Water Virtually Required Water exporting country importing country import ! export ! What is virtual water? (Oki, et. al, 2002, IHE-UNESCO)

3 Basic Arithmetic of Virtual Water  UWR: Unit Water Requirement (VW)  ET: Evapotranspiration  BWC: Beneficial Water Consumption  L: Loss, nonbeneficial Water Consumption  D: Dry weight, W: embodied “true” water  ETR: Evapotranspiration Ratio  BE: Basin Efficiency

4  Evapotranspiration ratio (ET/D) is determined by photosynthesis efficiency of each crop.  e.g., 350 kg/kg for maize, kg/kg for rice, and 1,000 kg/kg for wheat.  UWR↓ for fresh and juicy food (D<<W)  UWR↑ for small fruit/seeds (r << 1)  UWR↑ for poor agricultural efficiency (BWC << L) Basic Arithmetic of Virtual Water

5 3,600 Unit Water Requirement of Major Crops (m 3 /t) 2,6002,500 2,0001,900 (based on crop yield in Japan 、 FAOSTAT mean ) Unit Requirement of Water --Crops-- (Oki, et. al, 2002, IHE-UNESCO)

6 Model life of a cow Dairy Cow Beef Cattle

7 (m 3 /t) Unit Water Requirement ー Meat ー Whole Beef Whole Pork Beef Poultry Whole Poultry Egg Unit Water Requirement of Major Meat (based on crop yield and the way of raising in Japan) 560 m 3 /t for milk (Oki, et. al, 2002, IHE-UNESCO)

Other:3.3 Total : 64.0 km 3 /y Virtual Water Import to Japan (for JFY in 2000) 0.3 Domestic Withdrawals in Japan: 89 km 3 /y Domestic Blue Water in Japan: 400 km 3 /y Domestic Green Water in Japan: 30 km 3 /y Blue+Green water Blue water only (Oki, et. al, 2002, IHE-UNESCO)

9 Caribbean North America Central America South America South America WestAfrica Oceania East & South East Asia SouthAsia USSR North West Africa WesternEurope MiddleEast 1~55~10 10~15 15~20 20~30 30~50 50< Importer based, over 5 km 3 /y km 3 /y (Based on Statistics from FAO etc., for 2000) “Virtual Water” flow in 2000 (cereals only)

10 7 out of top 10 importing countries are seriously poor in water resources. 7 out of top 10 exporting countries are rich in water resources. Denmark (10) and India (18) are water stressed but exporting RW in net. Virtual Water Balance in Countries (m 3 /c/y) in 2000 Blue: Exporting Red: Importing ExportingImporting

11 How Virtual Water Trade Saves the Water Resources Globally Japan 2,500m 3 Comparing the required water to produce 1 ton of soy bean in USA and Japan USA 1,700m 3 1t of Soy Bean Japan USA Trade Really required water in USA Virtually required water in Japan Export 1,700m 3 Import 2,500m 3 1t of Soybean Exporting 1t of Soy bean from USA to Japan Real Water Virtual Water 2,500-1,700 = 800m 3 Water Resources is saved by the VW trade!  Comparative advantage of water efficiency 億トン / 年 Water Productivity varies in time and space!

12 Virtually Saved Water Resources in the World Virtually Requied Water = Sum of Importing VW in each country (1), Really Requied Water = Sum of Exporting RW in each country (2), Saved = (1)-(2) In 2000 Really Required Water: 680km 3 Virtually Required Water: 1,130km 3 Saved ： 450km 3 Real Virtual Saved x0.1 km 3 /y Cf. Total Agricultural Water Usage in 2000: 3,270 km 3 RW and VW (crop & meat)

13 Water Resources Assesment Considering VW trade 22 Countries were classified into “seriously stressed” in 2000 by conventional water resources assessment.  +Virtual Water Import Rich Countries are saved by VW import Poor Countries remain Water Poor Seriously Stressed Stressed Slightly Stressed Burundi: 31m 3 /c/y Rwanda:53m 3 /c/y VW Balance Egypt:141m 3 /c/y Oman: 512m 3 /c/y Bahrain:313m 3 /c/y UAE:4,490m 3 /c/y

14 Virtual Water for What?  More appropriate water stress index for world water resources assessment considering both real and virtual water resources.  Future projection of water demand for food supply considering diet.  Examination how water is wasted.  Increasing the awareness on water of public.  Different definitions & the ways of estimation of VW may be appropriate according to the purpose and the application.  More philosophical discussions are needed.

15 Disadvantage/Limitation of the Index “Virtual Water” Trade Considers only water quantity  no considerations on:  Environmental impacts  Impacts on regional producing communities  Limiting factors other than water resources  Quantification of VWT solely cannot be used for any decision making processes.

16 Concluding Remarks  “Natural” hydrological cycle is not “Real” anymore even on global scale.  Process based numerical models are useful for quantification of natural and real water cycles.  Accuracy depends on input data.  Global dataset is there.  Accuracy depends on how the global data is estimated.  Surface monitoring network is crucial.  Modeling human activities are challenging.  From “sustainable development” to “sustainability development” on water!