The Virtual Water Footprint of Denmark: An Application of the Water Footprint Methodology

Abstract

Rent ferskvand er en forudsætning for alt liv, men stigende global efterspørgsel på vand og stigende forurening af vand bringer ressourcen i fare. Formålet med denne rapport er, at undersøge om vandfodsporsanalyser kan bidrage med ny viden, og derved bane vejen for en mere holistisk dansk vandforvaltning. Rapporten giver et bredere perspektiv på, hvordan vand forbruges og forurenes af Danmark og den danske livsstil. Vandfodsporsteorien inddeler vandforbrug i tre kategorier. ”Blåt vand” refererer til alt indvundet overfladevand eller grundvand, ”grønt vand” refererer til alt biologisk indvundet vand fra jorden, og ”gråt vand” refererer til det nødvendige vandvolumen for at fortynde en forureningsmængde. ”Fodspor”-definitionen implicerer, at alle produkter vil have et virtuelt vandvolumen tilknyttet, og dette er defineret som summen af alt vandforbrug og vandforurening tilknyttet fremstillingen af produktet. Teorien resulterer i en konceptuel ændring af den traditionelle vandforvaltning, eftersom enhver vandpåvirkning tildeles både forbrugeren og producenten. Dette er defineret som henholdsvis det direkte vandfodspor og det virtuelle vandfodspor. Rapporten er udelukkende udarbejdet på et nationalt niveau, og den inkluderer vand til husholdninger, institutioner, landbrug og industri. Der er tilknyttet virtuelle vandvoluminer til den nationale handel med 377 forskellige landbrugsprodukter, og den industrielle virtuelle vandhandel er beregnet for de 55 lande, der står for 98% af den danske import. Det danske vandfodspor er 35% højere end verdensgennemsnittet, og værdien har været relativ konstant over de seneste 20 år, på trods af en betydelig optimering af det direkte nationale vandforbrug. Det virtuelle vandfodspor er 14% lavere end det direkte vandfodspor, og dette skyldes den virtuelle vandeksport af svinekød, hvis omfang er på størrelse med 2/3 af alt vand forbrugt i Danmark. Vandfodsporsteorien betyder desuden, at det direkte blå vandforbrug for en gennemsnitsdansker stiger fra 123 l/dag til 480 l/dag, og vandfodsporet af hans daglige kaffeforbrug er f.eks. større end vandforbruget forbundet med bad, tøjvask, opvask og madlavning. Rapporten understreger, at enhver dansker kan sænke dit vandfodspor ved at vælge forbrugsgoder med omhu. Forskningen i denne rapport er velafprøvet og veldokumenteret, men tankegangen er ny i en dansk sammenhæng. Den åbner op for fremtidig akademisk ekstrapolering, men det overordnede resultat er, at vandfodsporsteorien kan bidrage med ny viden.

Clean fresh water is a valuable natural resource, but it is under continuous threat due to an anticipated global increase in both consumption and pollution. The objective of the study is to investigate whether water footprint assessments can provide new knowledge for the Danish water management – thus clearing the way for a more holistic management approach. The study provides a wider perspective on how water is consumed or polluted by Danish activities. The water footprint methodology divides water use into three categories; namely, blue water, water abstracted from surface waters or groundwaters; green water, water biologically abstracted from the soil matrix; grey water, the water needed to assimilate pollutants. The notion of the “footprint” implies that all products have a virtual water volume assigned; a unit equivalent to all the water consumed and polluted along the chain of production. The methodology provides a conceptual change in modern water management, since water consumption is both assigned to the consumer and the producer, respectively defined as the direct water footprint and the virtual water footprint. The study is conducted exclusively on a national level, and it includes water from households, public institutions, agriculture and industry. Virtual water bodies are assigned to the trade of 377 agricultural products, whereas industrial water trade is calculated for those 55 countries that account for 98% of all Danish imports. The Danish water footprint is 35% higher than the world average, and this value has remained rather constant for the last 20 years despite significant lowering of the direct domestic water footprint. The virtual water footprint proves to be 14% lower than the direct water footprint due to export of animal products; an export of virtual water equivalent to almost 2/3 of all water used in Denmark. When looking at an average Dane, his actual blue water use increases from 123 l/day to 480 l/day by following the water footprint methodology. His daily coffee consumption surpasses all water used for bathing, cleaning, cooking and drinking, and he can greatly impact his personal water footprint by making smarter product choices. The conducted research is built on well-tested and well-documented principles, but it is completely new in a Danish context. It opens up for much further academic extrapolation; however, the main result is that the water footprint methodology can provide new knowledge for the Danish water management.

A master thesis from Aalborg University

The Virtual Water Footprint of Denmark: An Application of the Water Footprint Methodology