We might not give the water we use each day much thought, but it’s worth reconsidering that blase attitude, considering the multiple threats to the world’s fresh, clean water supplies.

What sort of threats? In honour of World Water Day, let’s look at the top five:

• Ageing infrastructure – In the US, a “significant” water line bursts every two minutes, according to a recent article in The New York Times. Some of the nation’s water and sewer systems date back to the Civil War era. The same is true across much of western Europe and in the UK, where many pipes in the water infrastructure are more than 100 years old.
• Climate change – Current climate models indicate that a warmer world will also have a more intense water cycle, but that doesn’t necessarily mean more rain for all regions. While some areas can expect more heavy downpours and, yes, even heavier snowfalls, the interior parts of continents will likely see more evaporation than precipitation, meaning a potential for “more severe, longer-lasting droughts.”
• Rising energy demands – As traditional oil sources become more expensive, energy companies are finding it profitable to extract petroleum from so-called “tar sands” or “oil sands.” In Alberta, Canada, extracting one cubic metre of crude oil from the Athabasca deposits requires between 2 and 4.5 cubic metres of water, according to a 2006 report from the Pembina Institute. Operations there are “currently licensed to divert 359 million (cubic metres) from the Athabasca River, or more than twice the volume of water required to meet the annual municipal needs of the city of Calgary.” Other energy sources — including biofuels and thermal solar — are also water-intensive.
• A growing global population – The world’s population is expected to grow from 6.8 billion today to around 9 billion by 2050. As Peter Brabeck-Letmanthe, chairman of Nestle, notes in a commentary today, “by 2030 one third of the global population, mainly concentrated in developing countries, will have only half the amount of naturally renewed water available they need.”
• Nitrogen runoff – Nitrogen-laden runoff from agricultural regions is leading to a growth in ocean dead zones devoid of oxygen. In a study published last year, researchers warned we have already pushed past the planet’s boundary of sustainability for the nitrogen cycle. (The study also identified two other areas in which we’ve passed tipping points: climate change and biodiversity loss.)

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