Substance of the Year 2010






Water (two hydrogen atoms bonded to an atom of oxygen: H2O) is one of the most ubiquitous substances: it covers 70% of the Earth’s surface, comprises 65% of the human body, and is essential to all forms of life.

For some time, reports have warned of an imminent ‘water crisis’ – but only in recent years has this threat been taken seriously at a policy level. At the World Water Forum in March 2009, government representatives signed the Istanbul Water Consensus, pledging to ‘shift water security higher in national and international policy priorities’, while the UN Under-Secretary-General stressed the urgent need to make water security a priority at the December 2009 climate change talks in Copenhagen.


The total quantity of water on Earth remains constant at 1·4bn km3. However, water demand increased six-fold during the C20th as a consequence of population growth, industrialisation, and urbanisation. Climate change has also threatened water security – drying up supplies in some areas while deluging others in ‘extreme water events’. The UN estimates that 700m people currently live in ‘water stressed’ countries; by 2025, this number could reach 3bn.


The increased burden on water resources is evident around the world: in China, the three rivers that supply half the country’s water (the Hai, Huai, and Huang) are being depleted at twice their rate of replenishment; in America, seven states have been haggling over the rights to the dwindling Colorado River; in Mexico City, buildings are sinking as aquifers below the capital become over-exploited; in Australia, the Murray-Darling Basin is in the midst of a seven-year drought; and along the Nile, diversions for irrigation mean that this mighty river no longer reaches the sea.


The tension between finite supply and insatiable demand has led many to predict ‘water wars’. Famously, in 1995, the World Bank’s Ismail Serageldin warned: ‘Many of the wars of the c20th were about oil, but wars of the c21st will be over water’. That said, a 2001 study of 1,831 international water-related events since 1948 found only 37 examples of violent conflict (30 involved Israel). And co-operation will be key to managing future water scarcity, whether via trade or through technological fixes such as desalination or wastewater recycling.


It is tempting for ‘first worlders’ to see water shortages as a foreign problem; images of Africans carrying well-water spring easily to mind. But few of us are aware of how much water we use – in the UK, 150 litres a day each, just for household washing and drinking. Fewer still would be able to survive for longer than a day or so if the taps ran dry.