The importance of water as a scarce resource is being reflected in the next environmental measure – water footprints:
Water footprints seem to be taking over from carbon footprints at the Water New Zealand Conference in Rotorua today.
While the production of a cup of coffee consumes a startling 140 litres of water, a pair of leather shoes consumes 8,000, the production of a single litre of bio-ethanol can consume between 1,200 and 3,000 litres of water, Professor Torkil Jonch Clausen, Chair Programme Committee, World Water Week in Stockholm and Adviser to Sweden’s Ministry of Natural Resources and Environment told the Water New Zealand conference in Rotorua this morning.
|Product||Water consumed (litres)|
|1 cup of coffee||140|
|1 glass of milk||200|
|1 litre bio-ethanol||1200 – 3000|
|1 cotton tee shirt||2000|
|1 pair leather shoes||8000|
His message to the conference was that water is an increasingly scarce world resource and those countries who are blessed with abundant supplies of water, like New Zealand, are very fortunate.
This might be good for New Zealand but no doubt the measure will be clouded by emotion rather than based on science, as carbon footprints are.
Conserving any resource is sensible but a water footprint is a blunt instrument. Using 140 litres for a cup of coffee in a desert could be more wasteful than using 8000 litres for leather shoes in a region where water is plentiful.