You're looking at 140 litres of water

If your lunch today is a quarter-pound burger with cheese, a side plate of chips, a cup of coffee and an apple, would you consider washing that down with a 2,369-litre drink of water? That, according to scientists, is the staggering volume of fresh water needed to bring this simple midday meal to the table. And while consumers might have assuaged their enviro-guilt in the past by tallying their carbon footprints, they may not have considered the ecological stress that a burger bun, beef mince, slice of cheese, potato, coffee and piece of fruit can put on the planet's water resources.

Called a "water footprint", it is an emerging method by which eco-campaigners are measuring the world's total fresh water use in the face of shrinking resources. The UAE is already known as the world's third-largest water consumer per capita - the average resident's 550 litres a day for drinking and washing are more than triple the world average - but the invisible or "virtual water" used in the production of goods packs a bigger wallop, and has yet to be measured for the Emirates.

Take one kilogram of beef, which taps 16,000 litres of virtual water, for instance. That includes water to grow the grain feed, water for the cattle to drink, water to wash its stall, water to process the meat, even water for the ink on the price tag of the package in the chiller. "Comparing the volume to the size of the product, that's about 16,000 times more water than the weight of the beef itself," said Arjen Hoekstra, the University of Twente professor who created the water footprint.

"The amounts of water used for the production of goods and services are big amounts. In fact, it's scary." Speaking from The Netherlands, where he is scientific director of the Water Footprint Network, Prof Hoekstra said the idea to quantify water usage and export came out of his research in 2002 on the relationship between water resources management and trade. "Once you realise that water is a global resource and not - like many people think, a local resource - you realise that people do leave something like a water footprint, which is the amount of water that you use but not necessarily at home."

An apple might tap 70 litres of the planet's water, according to the Water Footprint Network. A cotton shirt maybe 2,500 litres. That morning cup of coffee as much as 140 litres, taking into account the water used to harvest, process and ship the beans. Calculating water footprints surprises many consumers. The World Wildlife Fund (WWF) in 2008 released a Living Planet Report, listing for the first time the water footprints of more than 100 countries. Data for the UAE was not available and is still not known, said Prof Hoekstra.

"Definitely, it will be beyond the global average, which is about 1,200 cubic metres per capita per year." (One cubic metre of water equals 1,000 litres of water). Sarfraz Dairkee, who heads the technical committee of the Emirates Green Building Council in Dubai, believes the UAE's water footprint may rank among the highest in the Middle East. The average Saudi soaks up about 1,263 cubic metres a year while the typical Qatari uses about 1,087 and the typical Omani about 1,606, according to the WWF.

"I think the UAE would be even higher because you can consider the lifestyle to be more water-intensive in comparison," Mr Dairkee said. Given the lack of rainfall, coffee-drinking culture and meat-eating habits of UAE residents, he expected the local water footprint to be deep and wide. "Coffee is a high-consumption item in this part of the world, one cup is a lot of water consumed to grow the beans, process them, clean your cups and bring everything to your table," he said. "You have to think about all of that."

The breakneck pace of infrastructure development is another consideration. The 828 metre Burj Khalifa in Dubai required 330,000 cubic metres of concrete and 39,000 tonnes of reinforced steel, both materials that need large volumes of water for processing. Even greater, Mr Dairkee said, is the amount of water needed to maintain cooling systems on a day-to-day basis in the country's towers. "The Burj Khalifa's operational water footprint is much higher than the virtual footprint because it's a continuous process," he said. "You have to work out how much water it will take to cool that building continuously."

Interestingly, household water use in general amounts to only "about two or at most five per cent" of the total water footprint. Irrigation is the major use of water worldwide. Irrigation in the agriculture sector accounts for 60 per cent of the UAE's water consumption, according to Dr Mohammed Dawood, the manager of the water resources department at the Environment Agency-Abu Dhabi. "One issue here is we are relying on unconventional water resources, which actually are very expensive and need a lot of energy to treat Gulf water to become potable," Dr Dawood said.

The UAE's dependence on desalination plants also presents an "interesting case", Prof Hoekstrom said. The process of obtaining drinking water from brackish water might at first appear to be a solution to the problem of fresh water scarcity. "People sometimes tell me, in the end, isn't all the world's water problems really an energy problem? Because you can just desalinate salt from freshwater." But swapping a scarce resource for a shrinking one is no solution, Prof Hoekstra argued.

"That's really energy-intensive, so in fact using desalination has a very large carbon footprint." With the growing trend of "eco-chic" carbon-footprint product labels making their way into stores, he predicted that water-footprint labels could be next. He stopped short of promoting the idea, however, acknowledging that such labels were sometimes just marketing gimmicks. "What I think is important is product transparency and not labelling," he said. "Labelling can be one way of achieving product transparency, but it may not be suitable in many cases."

Still, businesses have taken notice. Levi Strauss & Co, known for making the Levis brand of jeans, began auditing its water footprint in 2008 and found that the life cycle of a medium-sized pair of stonewashed Levis 501 jeans - from growing the cotton to milling it into denim to multiple washes of the trousers - can consume as much as 3,480 litres. That is roughly equivalent to taking 53 showers or flushing a toilet 575 times, said John Anderson, the Levis chief executive.

All this is not a cue to shun blue jeans, meat and coffee, even though a vegetarian diet would use roughly a thirtieth of the water required to put meat on another consumer's plate. "It's very difficult to give that message of not eating meat, not buying cotton, not drinking coffee," Prof Hoekstra said. "What's more important is product transparency because one cotton is not the other cotton; one beef is not the other beef. We can choose to buy the better cotton or the better beef if we know the difference and have better information."

For more information on how to calculate your water footprint, go to www.waterfootprint.org. mkwong@thenational.ae