H₂O: are we in deep water?

Abstract

Wildfires in California and one billion people without access to safe drinking water: a new exhibition looks at our emerging water crisis. Janice Hopkins Tanne reports

A filmy curtain of royal blue bearing the words “water” in 17 languages greets you at the entrance to the American Museum of Natural History's exhibit “Water: H2O=Life.” You hesitate for a moment, wondering what this is, but you step through the film, because this isn't a wall but a mist of water. Like all the water in the exhibition it is recycled, a clue that the museum is trying to tell you how rare our supply of fresh water is, how it keeps us alive but sometimes gives us disease, and how careless we are in using it. The exhibition's poster shows Planet Earth floating on a life preserver.

Museum president Ellen Futter said the exhibition was timely and important when the world is facing a water crisis—drought in the US southeast, wildfires in Greece and California, mudslides in Central America, and more than a billion people without access to safe drinking water. Soon we may see water wars as nations and regions compete for this scarce resource by building dams and diverting rivers. In the spring the museum will convene an international policy panel to consider the fact that water is a finite resource.

The exhibition begins by describing the effect of water in shaping the planet through shores and canyons, giving some cultures abundant water while forcing others to struggle for a mere three gallons a day, as in Ethiopia. The United States is profligate, using 150 gallons of water per person per day, and the UK, despite its damp climate, uses a modest 31 gallons per day. Don't be proud, Britannia: the numbers reflect the higher population density in the UK.

Life on earth needs water to survive, and about 70% of water goes for irrigating the crops we eat. Sections of the exhibition show how plants and animals have adapted to scarce, salty, or abundant water; how water is distributed around the planet; how people have manipulated water supplies through dams and irrigation; the role of water in preventing or spreading disease; and restoration of ecosystems. A hands-on quiz helps visitors learn what they can do to conserve water and prevent its contamination.

The museum is good at visitor-friendly exhibits and short videos that appeal to children and teenagers. You can weigh yourself: the device won't tell the pounds but it will tell how much of your body is water. Men have a slightly higher water content than women and need about 3.7 litres per day, while women need about 2.7 litres. You don't need to drink the proverbial eight glasses of water a day because much of our water comes from the food we eat.

You'll see creatures that survive without drinking water at all, like kangaroo rats of Australia, whose kidneys recycle the water they get from eating food. Or the albatross, which has special glands that remove the salt from ocean water.

A wall of water bottles demonstrates that bottled water costs dollars to produce compared with the pennywise safe water coming out of the tap. Producing the plastic bottles is expensive, and disposing of them damages the environment. In the US, about 40% of bottled water is just filtered tap water.

Another exhibit shows how water can spread disease, presenting the famous John Snow and the Broad Street pump, and showing how in India simply pouring water through a folded-up old sari can filter out Vibrio cholerae and reduce cholera infection by about half.

Try lifting a water jar containing 25 pounds of the precious liquid. Many visitors can't, but women in developing nations do this every day, carrying it on their heads from a distant source to their homes—over and over again. Carrying water is usually women's work.

“We will never get more water than we have now, and we are always downstream from someone else,” said Dr Eleanor Sterling, curator of the exhibition. Water evaporates from rivers, oceans, and irrigated fields, rises to the sky, and falls back to earth as rain or snow.

There's not nearly as much usable water as you may have thought. Although Earth is often called the blue planet because the oceans covering two thirds of the planet make it look blue from space, less than 1% of earth's water is fresh water we can use. About 97% is in salty oceans. Of the remaining 3%, at least 2% is locked up in glaciers, deep in rocks, or in the polar ice caps.

You can see how major cities such as New York, London, Toronto, and Tokyo get their water and what they do to purify it. You'll also see their imperfect solutions for disposing of sewage and waste water. Heavy rainfall tends to overwhelm systems.

Finally, you can test yourself, measuring your own water use, and how you can be more responsible. Then you can visit the inevitable museum shop—and no, there's no bottled water on sale.

You don't need to drink the proverbial eight glasses of water a day because much of our water comes from the food we eat