Isn’t Japan a water-poor country?  日本も実は“水貧国”?―世界取り巻く水環境の危機―


Photo by BIEZ Graphics Free Photos
Photo by BIEZ Graphics Free Photos

A crisis situation of the global water environment and related problems facing Japan were taken up for discussion at an international symposium held at Chuo University’s Korakuen campus on April 22. Prof. Saburo Matsui from the school’s Research and Development Initiative (RDI) and other water specialists spoke on their studies at the second such forum hosted by the university.




According to a report on world water development published by the United Nations Educational, Scientific and Cultural Organization (UNESCO) and introduced at the symposium, approximately 2.4 billion people suffer from chronic water shortage, with 7 billion people in 60 countries expected to face the same situation in the worst scenario by the middle of this century. Epidemics resulting from water poverty prevail in many developing countries, requiring an urgent effective response.




The seriousness of the issue does not draw national attention in Japan where people have easy access to clean and safe water. However, the symposium has made clear that future prospects do not allow Japan to stay complacent and optimistic. In other words, Japan can hardly see its future as a problem for someone else.




Japan’s low food self-sufficiency rate /低い食料自給率がもたらす水問題

The annual precipitation in Japan is 1,700 mm or twice as much as the world average. It has one of the best water supply and sewerage systems in the world. This may make you think that Japan has nothing to do with a water crisis. However, seen from the viewpoint of food that is indirectly related to water, you may get a grip of the dismal situation Japan faces. A latest annual report from the Ministry of Agriculture, Forestry and Fisheries puts Japan’s food self-sufficiency rate at about 40%, one of the lowest among developed countries. You may wonder how food self-sufficiency is related to water. Significant in this respect is the concept of “virtual water”. According to Kazunari Yoshimura, a water consultant who is deeply associated with global water issues, virtual water is the amount of water that will be needed when imported foods are produced in Japan.




Japan depends on imports for nearly 60% of its annual food supply, which is equivalent to about 30 million tons of grain. Now 2,000 tons of water is said to be necessary to produce every ton of grain. This means that Japan annually consumes more than 60 billion tons of virtual water. On the other hand, it consumes 80 billion tons of water annually for agricultural and daily living. Put differently, it relies on virtual water equivalent in volume to 40% of its annual water consumption. Does not this imply that Japan is one of “water-poor” countries where living is hardly possible with its own water resources?



Does Japan make efficient use of its water resources? /水資源を有効的に活用していない日本

According to a report on “water resources and water circulation in 2012” published by the Ministry of Land, Infrastructure, Transport and Tourism, the maximum volume of water resources Japan can theoretically use is about 420 billion cubic meters (cbm) per year on the average. The report is based on statistics available from 1976 to 2004. This amount looks sufficient enough for a country with a narrow land space like Japan. But it translates into a per-capita volume of only 3,300 cbm, less than half the global average of 8,600 cbm. So, you cannot necessarily see Japan as a country rich in water resources. Moreover, the 80 billion tons (80 billion cbm) of water Japan consumes annually, as seen above, barely represents 20% of the maximum volume available to it. This illustrates an intriguing fact that Japan does not make an efficient use of its water resources.



The discussions at the symposium pointed to the strong possibility that Japan may plunge into a water crisis in the future. Particularly, the current global food shortage stemming from the scarcity of water could directly threaten Japan’s food security. The government needs to address the matter without taking much time. Japan that looks to be a water-rich country on the surface may essentially be not.



Written By :  Hideki Kato