The growing scarcity of that miraculous molecule we call water is one of the main indicators that we are living beyond our environmental means. Many parts of the world already have to contend with severe water shortages. The growing global population, modern patterns of consumption and less reliable rainfall patterns caused by climate change, are exacerbating the problem.

Several of the world’s major rivers no longer reach the ocean and many others carry only a fraction of their previous flow; boreholes have to go ever deeper to tap aquifers that are being depleted faster than they can replenish themselves; glaciers are retreating fast and reservoirs drying up. Already there are ‘water refugees’ in parts of Asia and Africa, while China’s premier, Wen Jiabao, has said that water scarcity threatens the very ‘survival of the Chinese nation.’

Even Britain is not immune to water shortages: parts of the country have less rainfall per capita than Dallas, and the UK recently opened its first desalination plant.

Water, water everywhere,
nor any drop to drink

Earth from outer space looks as if water scarcity could never be a problem – we’re not known as the Blue Planet for nothing – but fresh water is another matter and in surprisingly short supply. Only 2.5 per cent of all the water on Earth is fresh and two-thirds of that is frozen, either at the poles, in glaciers or in permafrost. So less than one per cent of the total water on Earth exists as liquid fresh water, and it is this fraction that supports all non-marine life forms. When you think about it in those terms, our life support system is precarious.

The water our distant ancestors used to slake their thirst when hunting and gathering is the same water that goes into the frappuccinos we pick up on the way to and from our air-conditioned offices. It therefore follows that the water resources that are stretched today, with a global population approaching seven billion, are the same resources that will have to sustain a projected global population of nine billion or more by the middle of this century.

The Green Revolution in agriculture in the twentieth century helped bring about the population explosion by dramatically improving crop yields. But farming is the thirstiest of all human activities (accounting for over 70 per cent of water use worldwide). Ironically the problem now is having enough water to produce the crops and meat to feed the Revolution’s offspring.

Water is fundamental to our health, not only in terms of growing food: it also makes up two-thirds of our bodies. Lack of clean water and adequate sanitation in developing nations is arguably the single greatest impediment to their development. Waterborne and sanitation-related diseases kill roughly five thousand people every day, most of them children.  According to a report by the United Nations Development Programme, 40 billion working hours are spent each year collecting water in sub-Saharan Africa – equivalent to a year’s labour for the entire workforce in France.

Source of friction

As the villainous Mr Greene discovered at the end of the last Bond film, whose plot revolved around control of water resources in Bolivia, you can’t drink oil (or rather, you can, but it doesn’t do you any good).

As more and more countries become water-stressed, the potential for conflict over such a crucial resource increases. In 2001 the then United Nations Secretary General, Kofi Annan, warned that ‘fierce competition for fresh water may well become a source of conflict and wars in the future.’

Access to water is a factor in the civil war in Darfur, while control of the aquifers beneath the West Bank is one of the underlying issues of the Israeli-Palestinian conflict. Potential for conflict exists in many other places too: between Turkey, Syria and Iraq over the Tigris and Euphrates; between India and Pakistan over the Indus (the dispute over Kashmir is partly about controlling the headwaters of that river); in West Africa over the Niger; and in the Horn of Africa, where Ethiopia’s dam-building projects worry its downstream neighbours.

Water, however, makes a mockery of the human habit of dividing the world into distinct political entities. It flows across and beneath borders. Optimists therefore prefer to see water’s potential to bring nations together by acknowledging their natural interdependence and cooperating to share a common resource equitably. Encouragingly, there are a growing number of forums   for dialogue where nations can peacefully resolve the hydropolitics of their respective regions such as the Nile Basin Initiative, the Niger Basin Authority and the Mekong River Commission. Europe, parts of which are increasingly reliant on groundwater, has the International Commission for the Protection of the Danube River.

Aquatic equations

The management of water resources at the level of watersheds rather than political boundaries is important to avert a worsening water crisis.  There is also a great deal we can do in terms of water’s better storage, distribution and use. In theory, there’s plenty of H2O to go around, but we need to change our habits and be far less profligate in our consumption of it.

The great challenge in agriculture is to use fewer drops to grow more crops. As the acreage under cultivation expands, so too does the amount of water lost through evaporation from fields and via the natural process of transpiration, whereby plants exhale water vapour during photosynthesis. Drip irrigation techniques that deliver water to the root of each plant rather than spraying the whole field can help, as can ploughing fields less so they retain more moisture. There are also savings to be made by matching crops to climate.

Growing thirsty crops in arid places is not a sustainable practice in today’s world. It takes a lot more water to grow a banana tree in the desert than in its natural environment – the tropics. The classic example of misguided planting was the Soviet-era determination to grow cotton in Central Asia, as a result of which the Aral Sea has all but shrivelled up and died.

Economics can reinforce common sense when it comes to intelligent allocation of water resources. The concept of ‘virtual water’ – calculating the amount of water that goes into producing a given item – is a useful tool in deciding where best to grow or manufacture something.

Removing agricultural subsidies and introducing a pricing mechanism for water that more accurately reflects its value would also help, encouraging water-intensive products and crops to be produced in wetter countries, less water-intensive ones in drier countries. But charging for water is controversial, since many consider it a fundamental human right.

At the domestic level, rainwater harvesting, which is becoming a standard feature of new buildings and could soon become mandatory in Los Angeles, can provide water for a variety of purposes that don’t require treated water: flushing loos, watering gardens, washing cars, and so on. Other low-tech solutions include fixing leaking pipes, fitting water meters and installing low-flow showers. Personal choices can also have a major impact on reducing our water footprint. For example, people living in arid climates could choose not to maintain green lawns that belong in cooler, wetter climes, and reduce their meat intake: a meat-rich diet requires at least twice the water of a vegetarian one.

A silver lining to every cloud?

A range of high-tech solutions may also solve our water problems. For several years the Chinese have been experimenting with cloud seeding technology, which involves firing silver iodide crystals into clouds to induce rainfall.

A new satellite launched by the European Space Agency in late 2009 can detect changes in the dampness of soil and increases in ocean salinity, which could help in predicting rainfall and planning agriculture.

Genetically modified, drought-resistant crops are also being developed. Research is ongoing to improve desalination technology, which is currently expensive and hugely energy-intensive. Water reclamation facilities, using similar technology to desalination plants, are another option: Namibia’s capital, Windhoek, has become the first city in the world to recycle all its water.

Then there are infrastructural ‘solutions’ to transport water across long distances, but engineering projects on this scale are spectacularly expensive and often don’t address the root problem. Libya has its Great Man-Made River, pumping water from sub-Saharan aquifers to the coast, but it is unsustainable; China and India are considering massive water transfer projects and California has its network of long-distance aqueducts.

In the end, it makes more sense to move people to water rather than spend billions battling nature by trying to do the opposite.

Overcoming the water crisis will require a combination of low-tech and high-tech solutions, economics and international cooperation.

Careful water management is a critical part of the sustainability jigsaw that societies all around the world need to piece together if we are to keep this planet hydrated.