Photo: 3arabawy(flickr)

Most people have heard of the concept of a “carbon footprint," which is a measure of how much our personal, daily activities affect the environment in terms of greenhouse gases. For example, a person who bikes to work, uses energy-saving lightbulbs and recycles religiously would have a smaller carbon footprint that a person who drives a Hummer, makes overseas trips once a month and is forgetful about turning off electrical appliances.

It turns out that a carbon footprint is only one way of looking at your environmental impact. As many countries struggle with freshwater shortages, there has been a push to account for just how much water people actually consume in their day-to-day lives – in other words, a “water footprint.” Like a carbon footprint, a water footprint takes into consideration hidden environmental tolls, such as the water needed to grow grain or maintain animals in order to produce just one hamburger. Water footprints can be calculated on the individual, national and global levels.

In March 2008, a University of London scientist was honored with the Stockholm Water Prize for his work on the concept of “virtual water," which is a way of calculating how much water is used to produce a range of different commodities. For example, it takes 140 liters (about 37 gallons) of freshwater to produce one cup of coffee, which takes into account not only the water content of the drink itself, but the freshwater needed to grow, process, package and ship the coffee.

It may seem complicated to have multiple ways to measure just how much our individual actions weigh on the environment. However, in a world where one person in five has no access to freshwater, it’s a step in the right direction any time hyperconsumers in developed countries can to think about exactly how their choices affect other members of the planet.

To find out how your consumption choices add up, use Waterfootprint.org's individual water footprint calculator.