The concept of virtual water Virtual water is

The concept of ‘virtual water’ Virtual water is the water ‘embodied’ in a product, not in real sense, but in virtual sense. It refers to the water needed for the production of the product. Global trade in goods and services brings along global trade in ‘virtual water’

► The Water Footprint of a product is the volume of fresh water used to produce the product, summed over the various steps of the production chain.

► The Water Footprint of a product is the same as its ‘virtual water content’, but includes a temporal and spatial dimension: when and where was the water used.

► The Water Footprint consists of three components: BLUE wf + GREEN wf + GREY wf

► Assessing the Water Footprint of a product requires analysis of the full production chain.

Production chain cotton

2500 litres of water for 1 cotton shirt

The water footprint of products global averages 1 kg wheat 1 m 3 water 1 kg rice 3 m 3 water 1 kg milk 1 m 3 water 1 kg cheese 5 m 3 water 1 kg pork 5 m 3 water 1 kg beef 15 m 3 water [Hoekstra & Chapagain, 2008]

40 litres of water for 1 slice of bread

1500 litres of water per kg refined sugar

1 egg = 135 litres water

= 140 litres of water

2400 litres of water for 100 gram of chocolate

10 litres of water for 1 sheet of A 4 -paper

► The Water Footprint is spatially explicit. Examples for coffee and cotton.

Water footprint of Dutch coffee consumption [Hoekstra & Chapagain, 2008]

Water footprint of EU’s cotton consumption blue water + green water + gray water [Hoekstra & Chapagain, 2008]

► The Water Footprint of a nation is the total amount of water that is used to produce the goods and services consumed by the inhabitants of the nation.

► National Water Footprint = national water use + virtual water import – virtual water export

Water footprint per capita [Hoekstra & Chapagain, 2008]

Water dependency of nations Many countries have net import of water in virtual form and a significant external water footprint: : n n n most of Europe North Africa Middle East Japan Mexico

Consumer perspective Reduction of the direct water footprint: n water saving toilet, shower-head, etc. Reduction of the indirect water footprint: substitution of a consumer product that has a large water footprint by a different type of product that has a smaller water footprint; n substitution of a consumer product that has a large water footprint by the same product that is derived from another source with smaller water footprint. n Ask product transparency from businesses and regulation from governments