Water down the drain

By Michael Richardson, For The Straits Times

SINGAPORE has done an excellent job in stretching its limited fresh water supplies by recycling. But improved urban water management can for now contribute in only a small way to alleviating Asia's looming water crisis, although the advanced techniques being pioneered here for distributing water and controlling its consumption in cities will become more important as the continent urbanises.

In terms of water consumption, the dominant force in Asia is agriculture. Of the estimated 319 billion cubic metres of water used in South-east Asia each year, 86 per cent goes to agriculture, 8 per cent to industry and just 6 per cent to towns and cities. Agriculture's share is even higher in South Asia (90 per cent) and Central Asia (95 per cent). It is a bit lower (69 per cent) in North-east Asia.

The world's demand for water, chiefly to grow food, has been rising sharply for over a century as the population increases and material living standards improve. In 2000, half a billion people lived in countries that were chronically short of water, out of a global population of around six billion. By 2050, the number of people living in conditions of water shortage is projected to grow to four billion, in a population of about nine billion.

To continue to thrive - or perhaps just to survive - as the demand for water intensifies while climate change brings erratic rainfall, Asia and its farmers will have to use less water to produce more food. This is a major challenge.

Irrigated agriculture and other improvements in farm productivity since the Green Revolution of the 1960s have boosted food output and cut poverty, providing a basis for political order and economic modernisation. Indeed, rural resilience has been the foundation of Asia's growth. This is often forgotten today. Instead, there is massive under-investment in agriculture.

Though only 17 per cent of the world's arable land is irrigated, it produces over one-third of the world's food supply. A reliable supply of water allows farmers to grow two or even three crops a year.

As a recent report by the International Water Management Institute (IWMI) and the United Nations Food and Agriculture Organisation (FAO) shows, Asia is the heartland of global irrigation. It contains 70 per cent of the world's 277 million hectares of irrigated land. While accounting for only 34 per cent of Asian arable land, the irrigated zone produces 60 per cent of the continent's rice, wheat and other staple food grains.

However, there is a dangerous downside. As currently practised, irrigated farming is water-intensive, especially for growing rice. Asia uses some 73 per cent of the 2,664 cubic kilometres of water the world uses annually for agriculture.

There is massive wastage of water. Many of the canals, channels and other parts of the irrigation system are old and inefficient. So millions of small-holders have bought pumps and drilled bore holes to extract water from rivers, lakes, underground aquifers and their own storage ponds whenever they choose.

Surface water is being sucked dry in major river basins in India, China and Indonesia. Recent surveys show that water tables and aquifer levels below ground are also falling, as water is being withdrawn faster than it can be replenished.

Yet the demand for food, and the water to grow it, is rising as more and more Asians migrate from the countryside to cities. By 2025, 52 per cent of South-east and North-east Asians are predicted to be living in urban centres. For South and Central Asia, the ratio is expected to be 45 per cent.

As people join the urban middle classes and become richer, they tend to eat less cereal. Instead, they will consume more fruit, vegetables, milk and meat. Meat consumption in China has more than doubled in the past 20 years and is expected to double again by 2030.

For Asian farmers on irrigated land, these trends have generally been good. However, growing more profitable niche crops (including food for animals) to satisfy urban consumers, especially those on increasingly meat-based diets, often takes much more water.

A kilogram of potatoes requires just 500 litres of water to produce. The same amount of rice needs 1,900 litres. But 1kg of poultry absorbs 3,500 litres, while beef gulps 15,000 litres.

An estimated five billion people will live in Asia by 2050, 1.5 billion more than now. The continent has three broad options to meet its food needs: Import large quantities of cereals from abroad, improve and expand rain-fed agriculture, or focus on irrigated farmlands.

Many governments attach a high priority to food security. So there is an understandable reluctance to rely on foreign supplies. Of course, small countries like Singapore will continue to depend on imports for the bulk of their food.

However, South-east Asia as a whole is better placed than other parts of Asia to expand irrigated land. There is a large gap between the potential area of 44 million hectares of land considered suitable for irrigation and the currently irrigated area of 17 million hectares.

For the rest of Asia, the IWMI-FAO report suggests that the main thrust of future investment in agriculture should be directed towards improving irrigation systems.

The writer is a visiting senior research fellow at the Institute of Southeast Asian Studies.