日本財団 図書館


Chapter 1

Pupulation and Water Resources

- Urbanization and Industrialization -

 

Kenichi Furuya

Vice President

Japan Family Care Association

 

1. Changes in the Situation of Water Resource

 

According to measurements by the United Nations, the total water resources for the world population, i.e., the total river flow obtained by subtracting evaporated and absorbed water from rainfall, is 43 trillion cubic meters, or 7,000 m3 per capita. The resource has been maintained at a stable level for a long period, apart from some aberrations caused by the recent changes in the global environment.

Of the resource, the river flows relatively easily available to the population is 9 trillion m3 plus 3.5 trillion m3 of storage in dams, etc., making 12.5 trillion m3. However, it is said that only about half of this figure is actually used. Further, taking into consideration the increase in world population, the per-capita available amount has declined by 40% in the quarter of a century between 1970 and 1995. Of course the 40% drop is not an actual decrease in the used water amount and does not exactly reflect the volume of water shortage, since the loss is more or less recouped by more efficient use. I would also point out that 50% of the resource is, globally, left still unused.

Another critical feature of water as a resource is its unevenly distributed locations. There is only 2% of the resource in the arid regions that occupy 40% of the land area of the Earth. Such regional difference in availability of water have diverse consequences, and the effective utilization of water resource has historically depended on human development and the level of civilization in the region.

Such uneven regional distribution of water resource and population generate the reality that in Asia the total volume of river flow is greatest in the world while that per capita is the smallest. As the monsoon zone, Asia is blessed with sufficient rainfall, but per-capita rainfall is substantially below the world average of 26,871m3; for example, 5,907m3 in China, 5,160m3 in Japan and 5,061m3 in India. On the other hand, 13,985m3 in Thailand and 12,738m3 in Philippines denote affluent rainfall, but do not necessarily mean more effective use of water than in the three former nations.

 

 

 

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