Embedded water, a hidden ecological problem
Dr Gary Robertshaw
Various forecasts predict that the worlds population will exceed 8 billion in 20 years time, increasing global demand for food and energy with the need for fresh water rising by 30 percent. In other words, unchecked population growth will place an unsustainable stress on the worlds eco-systems. This could lead to a perfect storm, a term used by the UK governments chief scientist, Professor John Beddington, to describe future shortages of energy, food and water.
What many people fail to appreciate is that consumption goes beyond simple use of water in everyday life. There is the more important embedded water – the water used to grow food. For example, embedded in an average pint of beer, is about 130 pints. That is, the total amount needed to grow the ingredients and operate all the processes necessary to create the pint of beer. Think about if for a moment, it takes 130 pints of water to create the 1 pint of beer we drink!
Coffee is even worse, consuming 246 pints of water per cup of coffee.
At the top end of the scale, it takes over 1,000 pints of water to make a single, cotton t-shirt and an eye-popping 8,500 pints of water to produce a pound of steak!
To put embedded water consumption in perspective, it is estimated that the average UK consumer uses about 85 pints of water per day, roughly the same size as a large bath. However, ten times as much is embedded in the British-made goods bought by the average UK consumer.
Once we appreciate that much more embedded water is required to create everyday food, we begin to grasp the importance of effectively managing this increasingly scarce resource.
Its all the more important because, according to the Engineering the Future alliance of professional engineering bodies, this is placing pressure on developing countries who are already using significant proportions of their water to grow food and produce goods for consumption in the West. The result is worsening water shortages in the developing world, where about one billion people lack access to clean, drinkable water.
The burgeoning demand from developed countries is putting severe pressure on areas that are already short of water, said Professor Peter Guthrie, head of the Centre for Sustainable Development at Cambridge University, who chaired the steering group. If the water crisis becomes critical, it will pose a serious threat to the UKs future development because of the impact it would have on our access to vital resources.