Water demand in many countries will exceed supply by 40 per cent within 20 years due to the combined threat of climate change and population growth, scientists have warned.

A new way of thinking about water is needed as looming shortages threaten communities, agriculture and industry, experts said.

In the next two decades, a third of humanity will have only half the water required to meet basic needs, said researchers.

Crisis? Water demand in many countries will exceed supply by 40 per cent within 20 years due climate change and population growth, scientists have said

Agriculture, which soaks up 71 per cent of water supplies, is also likely to suffer, affecting food production.

Filling the global water gap by supply measures alone would cost an estimated £124billion per year, a meeting in Canada was told.

But this could be cut to between £31billion and £37billion by an approach which both raised supply and lowered demand, according to leading water economist Dr Margaret Catley-Carlson.

Around 300 scientists, policy makers, and economists attended the international meeting in Ottawa hosted by the Canadian Water Network (CWN) in the run-up to U.S. World Water Day on March 22.

Dr Catley-Carlson, a director of the CWN, which co-ordinates water research and policy in […]