Hou Dongmin: Where's the water for more people to drink

Beijing's population is close tolion and increasing by 1 million every two years. This is cause for worry and begs the question: Is such population growth in cities like Beijing sustainable?

Those who answer in the affirmative may cite metropolises such as Tokyo and Seoul as examples. But compared with those cities Beijing lacks one basic resource to sustain life: water.

The utilization ratio of water resources in any place should be kept below 40 percent to ensure ecological balance. If the per capita per year water resources in a place is below 1,000 cubic meters, it's a sign of water scarcity. If we use these two critical yardsticks, the situation in Beijing is alarming, because its utilization ratio is above 90 percent and its per capita per year water resources are below 200 cubic meters.

For the past few years, Beijing has been trying desperately to ensure adequate water supply to its ever-increasing population and ever-expanding industries by reducing the use of water for ecological purposes, and over-exploiting reservoir and groundwater. Plus, upstream and already water-scarce areas in Hebei province have to reduce their water consumption to ensure the capital gets enough supply.

But even these measures have not been enough. Beijing has, off and on, considered diverting water from the often-dry Yellow River and pins its last hope on the South-to-North Water Diversion Project. The latest scientific expedition to the project's resource area in Southwest China, however, has yielded pessimistic results, because rivers and lakes there are also shrinking.

Adding other uncertainties to the problem is the impact of global warming and the frequent droughts in southern and western provinces. All this has made the project's prospects gloomy.

Beijing's annual water resource is about 3.7 billion cubic meters. After completion, the South-to-North Water Diversion Project is expected to add another 1 billion cubic meters. But even then Beijing's per capita per year water resource would be only 250 cubic meters. Remember that is calculated on Beijing's current population and is far below the standard 1,000 cubic meters.

As for groundwater, according to a survey conducted by the Beijing bureau of geological and mineral exploration, the city's groundwater reserve between the ground surface and 150 meters is 60 billion cubic meters. In the 1960s, wells hardly 10 meters deep used to have water. Today, even 100-meter-deep wells are being discarded. New wells are been dug to depths of 150 meters, almost reaching bedrock.

Some may argue that water is not the only factor that determines whether a city can take in more newcomers, and other aspects such as the economy, land and traffic should be taken into account to make the right judgment. The population density of Tokyo is 6,000 per square kilometer and that of Shanghai 3,000 per square kilometer. At 1,200, Beijing's population density is optimistically low, prompting some experts to say the city still has plenty of room to absorb more newcomers.

But this logic is misleading, for Tokyo, Shanghai and Seoul are in regions that have abundant water resources and get ample rainfall. With its dwindling water resources, Beijing cannot sustain a larger population. Instead, it should make serious efforts to control the population, if not reduce it.

But then population control is a controversial issue, especially for Beijing because a large part of its population is migrants. Since the city's population has risen rapidly because of the economic growth model followed by the government, efforts should now be made to raise people's standard of living and manage the market.

Beijing's efforts to strengthen population management have failed because they did not focus on the cause of population growth, which is unlimited market access to enterprises.

From 2004 to 2008, between the city's first economic and second census, the number of industrial units grew from 2.9 million to 4.4 million. No government policy can stop such an increase in enterprises from attracting larger crowds of job seekers to the city. Though free market access to enterprises has helped Beijing a lot in expanding its economy, it has slowed the pace of improvement in industrial efficiency.

Hence, checking the unfettered growth of industrial units should now be at the core of the battle to ease Beijing's population growth and water scarcity. It might slow the city's GDP growth but would be a wise choice for all.

Hou Dongmin is a professor at the Population Development Studies Center, Renmin University of China. These are excerpts from his interview with China Daily's He Bolin.