Water demand will exceed supply by 40% within 20 years, warn scientists

Scientists have warned that water demand in many countries will outstrip supply by 40% within 20 years due to the combined threat of climate change and population growth.

Experts said a new way of thinking about water is needed as looming shortages threaten communities, agriculture and industry, reports the Daily Mail.

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

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

Filling the global water gap by supply measures alone would cost an estimated £124 billion per year. But this could be cut to between £31 billion and £37 billion by an approach that both raised supply and lowered demand, said leading water economist Margaret Catley-Carlson.
 
Carlson of the World Economic Forum Global Agenda Council on Water Security, said, “We need to brace for what could easily be humanity's greatest short-term challenges.”

Nicholas Parker, of international environmental technology consultants Cleantech Group, highlighted the vast amount of 'virtual water' used in farming and industry.

Manufacturing a desk top computer, for example, requires 1.5 tonnes, or 1,500 litres of water while a pair of denim jeans used up six tonnes, a kilogram of wheat one tonne, a kilogram of chicken three to four tonnes, and a kilogram of beef 15 to 30 tonnes.

“What people don't often realise is how much water there is in everything we make and buy, from T-shirts to wine,” said Parker.

Nicholas Ashbolt, from the US Environmental Protection Agency (EPA) said water conservation measures could 'easily' reduce household demand in developed countries by 70%.

Other innovations described at the meeting included roads, pavements and home driveways redesigned to collect and absorb rainwater.

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 the US World Water Day on March 22.