From Guy Cox, Sydney, Australia
Your story on the breakdown of the water cycle states that one cup of coffee requires 140 litres of water to produce. I have tried to reverse-engineer this claim using rainfall data and crop yields, and this is only explicable on the basis that every drop of rain that falls on a plantation is somehow taken out of circulation. Clearly, it isn’t (26 August, p 36).
Coffee is a crop like any other, and some of the rain that falls will be taken up by the bushes and transpired (so is still in the water cycle) and the rest will run off into streams and rivers. Since all we are harvesting are the “cherries” – the bushes are perennial – what we are taking out of the system is tiny. We would take out more by growing cabbages, as we eat the whole thing.
