Water footprint By Elisabeth Küttim, Falko Behr, Thomas Wiedemann and Lewis Morrison.

Direct & indirect water use People use lots of water for drinking, cooking and washing, but even more for producing things such as food, paper, cotton clothes, etc. The water footprint is an indicator of water use that looks at both direct and indirect water use of a consumer or producer.

Water footprint of products

Coffee Global average water footprint: 130 litres for one cup of coffee. About litres of water are needed to produce 1 kg of roasted coffee. For a standart cup of coffee (152 ml) we requier 7 gram of roasted coffee, so that a cup coffee costs 130 litres of water. 96% green, 1% blue, 3% grey water

Chocolate When we assume that chocolate consist of 40% cocoa paste (with a water footprint of 24,000 litre/kg), 20% cocoa butter (34,000 litre/kg) and 40% cane suger (1800 litre/kg), we can calculate that chocolate has a water footprint of about 17,000 litre/kg. 98% green, 1% blue, 1% grey water

Cotton

Tomato

Beef The water footprint of meat from beef cattle (15400 litre/kg as a global average) is much lager than teh footprint of meat from sheep ( litre/kg), pig (6000 litre/kg), goat (5500 litre/kg) or chicken (4300 litre/kg). 93% green, 4% blue, 3% grey water

Beer & Bio-diesel Beer (from barley) The global average water footprint of barley is 1420 litre/kg. When we consider the amount of malted barley to produce beer, the water footprint of beer is 298 litre of water per litre of beer. This means that one glass of beer (250 ml) costs 74 litre. This excludes the water footprint of other (smaller) ingredients used in the beer production process. Bio-diesel (from soybean) The global average water footprint of soybean is 2145 litre/kg. Assuming a dry mass fraction of 92%, a fat content in the dry mass of 18%, a biodiesel yield of 1 gram per gram fat and a biodiesel density of 0.88 kg/litre, we can calculate that the water footprint of biodiesel from soybean is litre of water per litre of biodiesel.

Environmental impact of biodiesel The environmental impact of biodiesel is diverse. Greenhouse gas emissions

LCA A life-cycle assessment is a technique to assess environmental impacts associated with all the stages of a product's life from-cradle-to-grave.

LCA example Apples shipped from New Zealand are more eco-friendly than storing apples in a local place eg. Germany.

Sources rFootprintLogo cycle_assessment e