Water is rapidly becoming one of the defining crises of the 21st century. Climate change is making its availability increasingly uncertain. And we are using ever more of the stuff.
In the past three decades the human population has doubled but human use of water has tripled – largely because, tonne-for-tonne, modern ‘high-yielding’ crop varieties often need more water than the old crops.
A typical Westerner consumes, directly and through thirsty products like food, about a hundred times their own weight in water every day. That is why some of the great rivers of the world, such as the Nile, Indus, Yellow River and Colorado, no longer reach the sea in any appreciable volume. All their water is taken.
Many parts of the world, notably the Middle East, are running out of water to feed themselves. In response, a vast global trade is emerging. Not in water itself, but in thirsty crops like grains and sugar and cotton. Effectively the UK imports 45 cubic kilometres of water every year embodied in such crops – much of it from poor and arid lands.
Economists call this the ‘virtual water trade’. Many countries would starve without it. But as more and more countries run short of water, the trade will be disrupted. And the threat of wars over water will grow.
Already water shortages are at the heart of many injustices. Ever since Israel took control of the West Bank in 1967, it has refused to let Palestinians sink new boreholes there. It says this policy is necessary to protect the underground water reserves, which are already being over-used. That is true. But the reality is that Israel takes most of the water, and the limits only apply to Palestinians.
Israeli settlers in their hilltop compounds on the West Bank have swimming pools and sprinklers on their lawns, while down below, their Palestinian neighbour go thirsty. Literally, in some cases. Some farmers I met there spend three hours every day carrying pots on their donkeys to get water for their children and animals.
Israel’s relations with its other neighbours are poisoned by its insistence on controlling the watershed of the River Jordan, its main source of water. The 1967 Six Day War was, according to former prime minister Ariel Sharon’s memoirs, fought as much for control of the River Jordan as for land. Israel hangs onto the Golan Heights less for military reasons than because it is where the river rises.
Scour the ‘in briefs’ in the broadsheets and you will see a constant drip-drip of stories about water riots in Pakistan, Mexico, India, China, Indonesia and elsewhere. The world is awash too with disputes over international rivers that threaten to become full-blown wars as water shortages grow. A disturbing number are legacies of British imperial rule.
The 1947 partitioning of India split control of the River Indus. Now India and Pakistan are at odds over a new Indian hydroelectric plant that, Pakistan claims, threatens its British-built irrigation schemes, which supply most of the country’s food. India’s control over the Ganges causes both floods and droughts in downstream Bangladesh.
In Africa, Britain left behind a Nile treaty that gives all the waters of a river that flows through ten countries to the two most downstream: Egypt and Sudan. Egypt now threatens to wage war on anyone upstream -- such as Ethiopia - who takes so much as a pint pot of water from the river.
Other festering disputes concern Chinese dams being built on the Mekong in Southeast Asia, and complex conflicts in central Asia, where upstream hydroelectric dams that keep the people of Tajikistan and Kyrgyzstan warm in winter disrupt water supplies for the huge cotton plantations of downstream Uzbekistan and Kazakhstan.
One of the first items on the agenda of a future functioning Iraqi government will be to contest Turkish dams upstream on the Tigris and Euphrates.
A major problem in many of these disputes is that there are no internationally agreed ground rules for how nations should cooperate over shared rivers. One of the first foreign policy acts of the Blair government back in 1997 was to try and rectify this by sponsoring a Watercourses Convention at the UN. And yet a decade later, the government hasn’t got round to ratifying the convention in parliament. And partly as a result, the treaty languishes without sufficient signatures to enter into force.
This seems bizarre when successive Labour foreign secretaries, notably Margaret Beckett, have stressed the security threat posed by disputes over international rivers. And when former defence secretary John Reid recently warned that our armed forces needed to prepare for future "water wars".
Asked to explain Britain’s failure to sign a piece of paper it helped draft and recommended to the world, then international development secretary Hilary Benn told parliament in early 2007: "We do not believe that any potential domestic benefits justify the resources that would be required." And: "We need to ensure this does not just place a further burden on governments in our partner countries."
What resources? What burdens? Which "partner countries"? And what has changed since 1997 when this government saw no such impediment?
This article will appear in the World Development Movement magazine, Action. The World Development Movement has launched a campaign ‘Stop Water Wars’ calling on people to sign an online petition  to Gareth Thomas, Minister for Water