Scientists warn of water woes

Demand for water in agriculture and energy production could spike in the coming decades while catastrophic floods and droughts strike more often, a water conference in Canada is to hear this week.

“At unpredictable times, too much water will arrive in some places and too little in others,” said Zafar Adeel, chair of UN Water which coordinates water-related efforts of 28 UN organisations and agencies.

Within a generation, water demand in many countries is forecast to exceed supply by an estimated 40 per cent.

In other parts of the world prone to flooding, catastrophic floods normally expected once a century could occur every 20 years instead.

Meanwhile, spending on technologies and services to discover, manage, filter, disinfect and desalinate water, improve infrastructure and distribution, mitigate flood damage and reduce water consumption by households, industry and agriculture is expected to rise to a trillion dollars annually by 2020.

Some 300 scientists, policy-makers and economists will release these and other research findings as well as proven new tools, ideas and best practices for optimising water management at the Canadian Water Network international conference in Ottawa, which kicked off yesterday and runs until Thursday.

Conference speaker Hans Schreier of the University of British Columbia in Vancouver presented research buttressing the need for flood-prone areas to brace for more frequent disasters.

He pointed to Canadian insurance data showing claims resulting from extreme weather had increased 20-fold in the past 30 years and flood-related claims now exceeding fire and wind insurance claims every year.

Mr Schreier called for improved road and street designs to minimise rainwater runoff.

“Until now, all we’ve ever done in urban environments is to drain everything into rivers and lakes,” he said.

But kerbs, drains and impermeable surfaces could be replaced where possible with grassy shoulder depressions that collect and absorb rainwater while directing excess runoff into constructed wetlands or storm water retention ponds.

This would mitigate flood damage, but also polluted runoff normally drained via pipes into lakes and rivers would instead be filtered and cleaned as it sinks through the ground, helping to compensate the extensive loss of wetlands to development.

Other low-cost innovations might include home driveway designs and materials that allow most precipitation to be absorbed instead of running onto streets and roads, he said.

Another topic to be discussed at the conference is the impact of water shortages on businesses that rely on “virtual water” or the amount of water used in production of items.

A desktop computer, for example, requires 1.5 tons (1,500 litres) of water; a pair of denim jeans up to six tons; a kilogram of wheat one ton; a kilo of chicken three to four tons; a kilo of beef 15 to 30 tons.

Nicholas Parker, chairman of the Cleantech Group, said: “What people don’t often realise is how much water there is in everything we make and buy, from T-shirts to wine.”

One proposal is to list water used on product package labels to inform consumers and encourage conservation, said Mr Adeel, noting that annual global trade in “virtual water” now exceeds 800 billion tons, the equivalent of 10 Nile Rivers.

As developing countries gain wealth, their citizens’ demands for food and energy, which both require a lot of water to produce, will skyrocket, Mr Adeel warned. “We have to be prepared for the security challenges that will arise from this,” he said.

Policy innovations to be discussed include helping farmers reuse water or tap into municipal waste water to “get a lot more bang out of your buck for the same volume of water”. Agriculture is the biggest water user by far at 71 per cent worldwide.