A hard, dry future for the planet

The world is wasting water on a truly colossal scale, according to the United Nations. More than 80 per cent of the used water on Earth is neither collected nor treated – the equivalent to the planet leaving the taps full on and the plugs out.

This and other equally worrying realities will be presented this week to around 35,000 people from 180 countries at the World Water Forum, a gathering held every three years, which will hear the most disturbing reports yet on the state of the world's rivers, lakes and aquifers.

Demand for water is expected to increase by 55 per cent over the next four decades, according to a new study to be presented at the forum in France. Framing the Water Reform Challenge, from the Organisation for Economic Co-operation and Development (OECD), points out that rapid urbanisation, climate change and the altering global economy are putting growing pressures on water supplies. In around 40 years' time, more than 40 per cent of the world's population – 3.9 billion people – are likely to be living in river areas in the grip of severe "water-stress". The UN warns this could also be felt in parts of Europe, affecting up to 44 million people by 2070.

Anthony Cox, head of a water programme run by the OECD, said the world is experiencing a water "crisis." He added: "More people in cities now don't have access to water than back in 1980. In developing countries, especially, there is a tremendous economic and human cost to this." Since 1900, more than 11 million people have died because of drought, according to the UN, and more than 2 billion have been affected by it – more than any other physical hazard.

The OECD is calling for "urgent reform" of water management and suggests using economic instruments, such as taxation, tariffs and transfers, to encourage greater "water efficiency".

Olcay Unver, co-ordinator of the United Nations World Water Assessment, said it would be a "game-changer" if the world could tackle environmental challenges without using water-wasting technologies, such as biofuels. "Water underpins all aspects of development," he said. "It is the only medium through which all crises can be jointly addressed. It should be seen as an explicit element in any decision-making framework."

Mr Unver is lead author of a UN report published tomorrow which warns that unprecedented growth in demand for water is threatening global development goals and will exacerbate inequality between countries, sectors and regions. Managing Water under Uncertainty and Risk shows that, while 86 per cent of the population in developing regions are expected to have improved access to safe drinking water by 2015, there are still nearly 1 billion people without such access and, in cities, the numbers are growing.

Water management can no longer be seen as a local issue, said Mr Unver; it has to be treated as a global one. "Water is not only what we drink, what we wash with, or what we use to irrigate; it is also embedded in the products that we eat, consume and use," he said. "This gives us a totally different perspective to water – it is subject to trade policies, and one nation, or one corporation, can have an impact on water shortages somewhere else."

His warning backs up analysis by the Royal Academy of Engineering, which found that Britain and other developed countries depend heavily on importing hidden or "virtual" water from places prone to droughts and shortages. In a 2010 report, the academy estimated that two-thirds of all water that Britain needs comes embedded in imported food, industrial products and clothes such as cotton. In 2008, a study published by the conservation group WWF found that about 60 per cent of Britain's water footprint is felt outside the UK.

Ashok Chapagain, WWF's senior water adviser, said: "Water scarcity affects at least 2.7 billion people in 201 river basins for at least one month a year. International trade and the globalisation of the supply chain... make water scarcity a global issue."

But the need is not expected to lessen. Increasingly, underground water sources have been tapped to respond to growing demand and, under what the UN report called a "silent revolution", this process has tripled over the past 50 years. Transnational land acquisition, where countries acquire land outside their jurisdiction to get access to water, has risen from 20m hectares in 2009 to more than 70m today.

To illustrate the political, technical and financial solutions to the world's water problems, a 400 square metre Village of Solutions will be built inside the Water Forum this year, housing a school, library, town hall, factory and bank. Different funding mechanisms and technologies will be explained.

However, the forum, organised by the French government, the World Water Council and the City of Marseille, where it is being held, has been criticised for being merely a "talking shop". "They will have the big debates there, but it's not where change happens," said Daniel Yeo, WaterAid's senior policy adviser for water security. "The real situation is that dirty water kills more kids in sub-Saharan Africa than TB, malaria and Aids combined. We have the technology to change this; what we need is the political will and the internal capacity to deliver it in developing countries."