But there isn't enough water

THE world's population reached seven billion this week. The day, Monday, was marked with becoming happiness in countries that symbolically ushered in seven-billionth births. But it is the business of the United Nations Population Fund to inject realism into a statistical milestone few earthlings care about. It warns against over-consumption of resources: This was true before the fifth billion was crossed a generation ago. More optimistically, it says the crowded world could have thriving cities and productive labour that will grow economies, given the right planning and investment.

That is demanding a high threshold of proof. As 43 per cent of the seven billion are aged under 25, education and training obviously will make the difference between hope and despair.

It would have been nice if some of the increase of the past generation had been home-produced, in Singapore, for one. Or in Japan and South Korea. But what has been overlooked in the numbers lark is that falling fertility rates of the past half century - from six births per 1,000 to 2.5 - could see slower population growth than the addition of a billion every dozen years. It is possible the end-century number would be several billion short of 14-15 billion, at current rates of increase. Whatever the profile, competition for resources is the one constant that governments and the UN have to be watchful about. It is not food production. The world can feed itself. Such shortages that occur are mainly the result of questionable political choices and the machinations of food multinationals and futures markets. It is not about oil: Alternatives can be found or new industrial processes will emerge.

It is about water. Rivers cannot be transported to arid lands. 'Owners' of rich river sources and basins (China and Turkey are examples) will face increasing conflict with downstream nations as demand rises.

The World Resources Institute, a United States think-tank, calculates that water use will rise by 50 per cent in developing nations by 2025. Two representations highlight the challenges. The first: Only 2.5 per cent of the Earth's water is fresh, with two-thirds of that frozen. How soon can it be when oceans of salty water can be mined cheaply?

The second: It requires 100 litres of water to grow 1kg of potatoes, but to produce 1kg of beef takes 13,000 litres. There is scant chance of a change in eating habits when the middle-class multitudes of China and India are taking to meat-eating with gusto.

But if industry and governments would be as imaginative in seeking solutions as scientists are graphic in posing the challenge, Earth may not feel so overcrowded.