water use
All the foods we consume require water, not only as a direct ingredient (> 90% for most vegetables) but also to allow the food to be grown or cultivated, processed and delivered. Consequently a humble 125 ml cup of coffee actually requires about 140 litres of water to grow the coffee tree and beans, pick, transport, dry and grind the coffee.
Obviously, the water used in delivering that cup of coffee is not "consumed" in the same way that e.g. wood is consumed when it is logged and converted into furniture, as nearly all the water required to make the cup of coffee is recycled well before we drink the coffee. However, the amount of water required to deliver a given quantity of a particular food is a good measure of the "water intensity" of the food, which in turn is a reasonable measure of the energy and environmental effort required to deliver the food. Water use for food shows significant variation from food to food.
By comparing e.g. the water use to deliver a kilogram of apples to the table (approximately 700 litres) versus the water requirement to deliver a kilogram of beef to the table (approximately 16,000 litres) we can see that the water intensity of the apple is much lower than that of the beef, and we can reasonably conclude that the energy and environmental effort required for the beef is an order of magnitude greater.
| Data source: www.waterfootprint.org | ||
A 250 ml Glass of beer? 75 litres |
A 200 ml glass of milk? 200 litres |
A 125 ml Cup of Coffee? 140 litres |
A 250 ml cup of tea? 35 litres |
A glass of orange juice? 170 litres |
A 125 ml glass of wine? 120 litres |
A bag of crisps? 185 litres |
A pair of leather shoes? 8000 litres |
A hamburger? 2400 litres |
A 30g slice of bread with 10g cheese? 70 litres |
A 100 g Apple? 70 litres |
A tomato? 13 litres |
An egg? 135 litres |
A kilogram of beef? 16000 litres |
A kilogram of maize? 900 litres |
A cotton T-shirt? 2000 litres |
One kg of rice? 3400 litres |
One A4 sheet of paper? 10 litres |