A new calculator has been released to help us consider our environmental impacts. Dutch researchers have released a water footprint calculator.
According to their figures, a single apple has a footprint of 40 litres, 1 kg of soyabeans has a footprint of 1,800 litres, one kg of chicken 3,900 litres and 1 kg of cheese 5,000 litres. And, the mother of all resource consumers, it takes 16,000 litres of water to produce 1 kg of beef.
Nationally, 70% of Britain's water useage is outside of the country, compared to only 19% of the USA's and 4% of Ghana's footprint. But then, the average person uses 2,483 cubic metres of water a year in the USA compared with 1,245 in the UK and 1,293 in Ghana. So the USA is using more water per person, but more of it is nationally rather than internationally provided.
So how useful are these figures?
Well, water is clearly a scarce resource in many parts of the world and treatment of water in industrialised countries uses a lot of energy. So it makes little sense to be importing irrigated crops from developing countries with particular water problems or to waste expensive water resources in developed countries. One future scenario suggests that conflicts may occur in the future over water, and that we may have to start dealing with waterborne diseases like cholera in developed countries that eradicated them many years ago.
On the other hand, climate change models suggest that the rainfall pattern will change, not reduce. This might mean that some areas benefit from increased rainfall, whilst many other countries suffer from reduced rain.
So all water is not the same -- it depends where you live and where you're getting it from. An apple might only need 40 litres of water to grow, but if you live in an area of relative water plenty, it might have less environmental impact than if it had been grown elsewhere and shipped to you. As with all of these types of calculators, assumptions have been made and we need to be careful about how we use the conclusions.
But this underlines the wisdom of reusing our own waste water, growing our own vegetables and eating less meat.
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