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Global Water Program

Cracking the Code of "Hidden Water"

How can it possibly take more than 30 gallons* – or 140 litres – of water to produce a cup of coffee? Scientists have estimated that’s how much it takes to grow, wash and process the coffee beans. Add cream and sugar and your water tally skyrockets: think of the water needed to grow the sugar cane and the grain that the cow eats to produce cream. Some of that water comes directly via rain on the crops; some via irrigation pipes that pull from rivers, lakes, and aquifers.

In fact, nearly 70 percent** of the water extracted from nature worldwide is used by agriculture and industry as they produce the food and goods we need and want. Since our drinking water usually comes from the very same sources, it’s vital that we help industry use as little water as truly necessary.

But first we have to track down this “hidden water."

Conservancy scientists are innovating new research methods to do that. Nature.org spoke with Brian Richter, director of the Global Freshwater Program, about how he’s using this new science to help large corporations like Coca-Cola determine their “water footprint” – and why that’s key to keeping more water available for people, plants and animals.


"We have to work faster and smarter — and we have to engage directly with the biggest water users and help them find ways to use less. "

Brian Richter, Conservancy director of Freshwater Conservation

Nature.org:

Why would a corporation want to know their water footprint?

Brian Richter:

First, let’s distinguish between water footprint accounting – which is usually applied in estimating how much water goes into the production of a consumer good, such as a soft drink, cotton shirt, or a can of beer – and a sustainability assessment, which looks much more closely at the places where water is being used in the production process, and asks, “is that water footprint sustainable?”

Many companies are deeply concerned about whether there will be enough clean water available in the future for their operations. They also know that when a river or lake is getting overused, the company can get blamed for problems like causing the river to go dry or killing fish that people need to eat.

A sustainability assessment tells the company whether it is at risk of running out of water because of overuse in the watershed, or whether their water use might be causing undesirable ecological or social impacts that could put a company’s reputation at risk.

Nature.org:

Is a “water footprint” like a “carbon footprint”?

Brian Richter:

It’s the same idea, but with an important distinction. With carbon, a reduction of carbon emissions anywhere in the world helps to reduce the problems caused by those emissions, such as climate change. By comparison, water problems are localized. The same level of water use might not be causing any problems in one watershed, but it might be sucking a river dry in the watershed next door.

For that reason, if we’re going to talk about sustainable water use, we have to deal with water footprints in local watersheds.

It’s also important to emphasize that it’s not just the amount of water that’s important. If a water source is polluted, it’s the same as being sucked dry because it’s unusable. That’s why water footprints account for both water quantity and water quality.

Nature.org:

There are critics who have called into question the accuracy of figures like 30 gallons of water for a cup of coffee. How exact can you get with “water footprinting”?

Brian Richter:

There have been some exciting breakthroughs in estimating water availability and use. Because of increasingly accurate satellite data, we can identify what type of crop is being grown on each patch of ground, and use available climate information to develop an accurate estimate of how much water that crop is consuming. This means that we can use computer models to estimate, for any watershed, how much water is available and how much is being used, and then gain insights into the sustainability of water use in each place.

Nature.org:

You’re a freshwater scientist talking about business risk. How did that happen?

Brian Richter:

Because when it comes to water, what constitutes business risk for a corporation is likely the same problem the Conservancy is trying to solve for nature and people: the prospect of not enough clean water to live and to thrive for generations to come. So we’re finding common ground with the business sector.

Our water footprinting work with corporations began when Coca-Cola asked for our help in quantifying how much water was being saved in community conservation projects funded by the company. This has now grown into a much larger effort to assess key elements of their water footprint and the sustainability of that water use. They came to the Conservancy because of our reputation for sound science, and our understanding of how to get conservation accomplished on the ground and in the water.

The bottom line is that our rivers and lakes are in serious trouble around the world. Freshwater plants and animals are being decimated and experts predict that on our current course more than two-thirds of the world’s population could face water shortages by 2025***.

We have to work faster and smarter – and we have to engage directly with the biggest water users and help them find ways to use less. We simply cannot solve our water problems solely through local projects.

By partnering with a company like Coca-Cola we can have a big impact on water use in places around the world, benefiting both our water security and the health of nature we care about.


*Food and Agriculture Organization of the United Nations(.PDF)
**International Water Resources Association: Water International, Volume 25, March 2000
***United Nations World Water Development Report: Water in a Changing World, 2007


Brian Richter
 Brian Richter directs the Conservancy's Freshwater Conservation Program. He has been involved in river science and conservation for more than 20 years and travels worldwide helping governments, academic institutions, non-governmental organizations and private firms understand the need for and feasibility of sustainable water-management practices. He has also consulted on more than 90 river projects worldwide and has developed numerous scientific tools and methods to support river restoration efforts.

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