The water footprint of humanity – the global dimension of water management
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The water footprint of humanity – the global dimension of water management
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The water footprint of humanity – the global dimension of water management
- 1. The water footprint of humanity The global dimension of water management Arjen Hoekstra University of Twente, the Netherlands
- 2. The total water footprint of the average consumer in the world 3800 litre/day 3.8% of the water footprint relates to home water use 96.2% of the water footprint is ‘invisible’, related to the products bought on the market 91.5% agricultural products, 4.7% industrial products 22% of the water footprint does not lie within the country of the consumer, but other parts of the world Source: Hoekstra & Mekonnen (2012) The Water Footprint of Humanity, PNAS
- 3. Overview of presentation ► Globalization of water ► The water footprint concept ► WF of a product ► WF of nations ► WF of business ► What can we do?
- 4. Globalization of water Production Water consumption and pollution related to production for export; water is not factored into the price of traded commodities TRADE Trade Water saving, but also water dependency Consumption Source: Hoekstra & Chapagain (2008) Globalization of Water, Blackwell, Oxford, UK
- 5. Global water footprint of Dutch consumption 95% of the Dutch water footprint the Netherlands lies outside the country soybean Source: Mekonnen & Hoekstra (2011) National Water Footprint Accounts
- 6. Cotton from the Aral Sea Basin, Central Asia 2008 1989 Cotton for export Source: NASA
- 7. Source: Mekonnen & Hoekstra (2010) Mitigating the water footprint of export Flowers from Kenya cut flowers from the Lake Naivasha Basin, Water Resources Management Decline of lake level in Lake Naivasha
- 8. Number of months with blue water scarcity > 100% Blue water scarcity = blue water footprint / blue water availability Source: Hoekstra et al. (2012) Global monthly water scarcity: blue water footprints versus blue water availability, PLoS ONE ► an international water pricing protocol?
- 9. The water footprint concept
- 10. The water footprint of a product the volume of fresh water used to produce the product, summed over the various steps of the production chain. when and where the water was used: a water footprint includes a temporal and spatial dimension. Source: Hoekstra et al. (2011) The Water Footprint Assessment Manual, Earthscan, London, UK
- 11. The water footprint of a product Green water footprint volume of rainwater evaporated or incorporated into a product Blue water footprint volume of surface or groundwater evaporated or incorporated into a product Grey water footprint volume of polluted water Source: Hoekstra et al. (2011) The Water Footprint Assessment Manual, Earthscan, London, UK
- 12. Components of a water footprint Traditional water use Direct water footprint Indirect water footprint statistics Green water footprint Green water footprint Gross water withdrawal Water consumption Return flow Blue water footprint Blue water footprint = Net water withdrawal Water Grey water footprint Grey water footprint pollution Source: Hoekstra et al. (2011) The Water Footprint Assessment Manual, Earthscan, London, UK
- 13. Grey water footprint • volume of polluted freshwater that associates with the production of a product in its full supply-chain. • calculated as the volume of water that is required to assimilate pollutants based on ambient water quality standards. Source: Hoekstra et al. (2011) The Water Footprint Assessment Manual, Earthscan, London, UK
- 14. Grey water footprint Substance intake Process Substance output = Abstr × cact = Effl ×ceffl Freshwater body Critical load = R × (cmax - cnat) Load = Effl ×ceffl − Abstr × cact Load Effl × ceffl − Abstr × cact Grey water footprint = ×R = Critical load cmax − cnat Source: Hoekstra et al. (2011) The Water Footprint Assessment Manual, Earthscan, London, UK
- 15. The water footprint of a product
- 16. The water footprint of food Global average water footprint litre/kg litre/kcal starchy roots 400 0.5 cereals 1600 0.5 sugar crops 200 0.7 pulses 4000 1.1 vegetables 300 1.3 fruits 1000 2.1 pork 6000 2.2 poultry 4000 3.0 beef 15000 10.2 Source: Mekonnen & Hoekstra (2012) A global assessment of the water footprint of farm animal products, Ecosystems
- 17. The water footprint of a cow Food ► 1300 kg of grains (wheat, oats, barley, corn, dry peas, soybean, etc) ► 7200 kg of roughages (pasture, dry hay, silage, etc) 99% Water 1% ► 24000 litres for drinking ► 7000 litres for servicing Source: Hoekstra & Chapagain (2008) Globalization of Water, Blackwell, Oxford, UK
- 18. The water footprint of a hamburger Source: Hoekstra & Chapagain (2008) Globalization of Water, Blackwell, Oxford, UK
- 19. Meat versus vegetarian diet Industrialised countries: Vegetarian Meat diet kcal/day litre/kcal litre/day kcal/day litre/kcal litre/day diet Animal Animal 950 2.5 2375 300 2.5 750 origin origin Vegetable Vegetable 2450 0.5 1225 3100 0.5 1550 origin origin Total 3400 3600 Total 3400 2300 Source: Hoekstra (2013) The Water Footprint of Modern Consumer Society, Routledge, London, UK.
- 20. Meat versus vegetarian diet Industrialised countries: Meat diet kcal/day litre/kcal litre/day Vegetarian kcal/day litre/kcal litre/day diet Animal 950 2.5 2375 Animal origin 300 2.5 750 origin Vegetable Vegetable 2450 0.5 1225 3100 0.5 1550 origin origin Total 3400 3600 Total 3400 2300 Source: Hoekstra (2013) The Water Footprint of Modern Consumer Society, Routledge, London, UK.
- 21. Water footprint of biofuels from different crops [litre/litre] Car driving on bio-ethanol from sugar beet: 20-300 litre/km ► coherent energy- water strategies? Source: Mekonnen & Hoekstra (2011) The green, blue and grey water footprint of crops and derived crop products, Hydrology and Earth System Sciences
- 22. Water footprint of nations
- 23. The spatial distribution of the water footprint of humanity Source: Hoekstra & Mekonnen (2012) The Water Footprint of Humanity, PNAS
- 24. National virtual water balances Arrows show gross virtual water flows >15 Gm3/yr Source: Hoekstra & Mekonnen (2012) The Water Footprint of Humanity, PNAS ► WTO trade rules?
- 25. Water footprint of national consumption Global average water footprint ► global water footprint ► a Kyoto protocol reduction targets? for water? Source: Hoekstra & Mekonnen (2012) The Water Footprint of Humanity, PNAS
- 26. National water footprint accounting framework Internal External Water footpr. water + water = of national Consumption footprint footprint consumption + + + Water use Virtual water Virtual + import for re- = for export export water Export export = = = Water Virtual Virtual water Focus of traditional + water use statistics footprint water = budget within nation import (and within that focus a limitation to blue water withdrawals) Production Import Source: Hoekstra et al. (2011) The Water Footprint Assessment Manual, Earthscan, London, UK
- 27. Virtual water transfers in China 52 Gm3/yr ► revisit large water transfer projects? Sources: Ma et al. (2006), Hoekstra & Chapagain (2008)
- 28. Future under growth and climate change Net virtual water import Mexico, Northern North & South Africa, Europe, Middle East, Japan Southern Europe Central Water scarcity Africa China South USA, India America Australia Net virtual water export Source: Hoekstra (2012)
- 29. The water footprint of business
- 30. The Coca Cola Company New Delhi, 4 Oct 2006
- 31. Water footprint of a Coke Water footprint of a 0.5 litre PET-bottle coke as produced in the Dongen factory, the Netherlands 0.44 litre water content 27.6 litre for sugar 5.3 litre for PET bottle and closure 3.0 litre for other ingredients & overheads ___________________ 36 litre total
- 32. Water footprint: why businesses are interested Water risks for business • Physical risk • Reputational risk • Regulatory risk • Financial risk Water opportunity for business • frontrunner advantage • corporate image Corporate social responsibility
- 33. Water footprint: what’s new for business • From focus on own operations to supply-chain thinking • From focus on water withdrawals to considering consumptive water use • From securing the ‘right to abstract’ to assessing environmental & social implications of the company’s direct & indirect water use • From meeting ‘emission permits’ to assessing the company’s contribution to pollution
- 34. What can we do?
- 35. Water footprint reduction: what can we do? Industry ► Towards full water recycling in industries: zero blue water footprint ► Towards full recycling of materials and heat: zero grey water footprint Agriculture ► Make rainwater more productive: lower green water footprint ► Towards supplementary or deficit irrigation & application of precision irrigation techniques: lower blue water footprint ► Towards organic or precision farming: zero grey water footprint
- 36. Reducing humanity’s water footprint – Companies Shared terminology & calculation standards – Global Water Footprint Standard Product transparency – water footprint reporting / disclosure – labelling of products – certification of businesses Quantitative footprint reduction targets – benchmarking The Water Footprint Assessment Manual Earthscan, London, UK, 2011
- 37. International water governance ► product labeling? ► certification of industries? ► water disclosure? ► global water footprint reduction targets? ► WTO trade rules? ► an international water pricing protocol? ► coherent energy-water strategies?
- 38. The Water Footprint Network Mission: Promoting sustainable, equitable and efficient water use through development of shared standards on water footprint accounting and guidelines for the reduction and offsetting of impacts of water footprints. Network: bringing together expertise from academia, businesses, civil society, governments and international organisations.
- 39. Overview of partners Water Footprint Network Partners by category XL company 30 Large company 10 Medium company 23 Small company 33 Government 10 International organisation 9 Academic Institute 29 Civil society / ngo 25 www.waterfootprint.org
Notas do Editor
- water withdrawal for domestic water supply in NL = 31 m3/yr/cap = 85 litre/day/cap Blue wf = 10% of water withdrawal = 3.1 m3/yr/cap = 8.5 litre/day/cap Return flow = 90% of water withdrawal = 27.9 m3/yr/cap = 76.5 litre/day/cap - urban pop (77%): 99% treatment (data) - rural pop (23%): 0% treatment (assumption!) Total wf: 4000 litre/day per cap.
- International trade of water-intensive goods has consequences for both the exporting and the importing country. In the exporting country there will be revenues, but local water consumption and pollution are generally not compensated for in the price. Water resources are in most cases grossly under-priced. The importing country benefits by saving its domestic water resources (a benefit for water-scarce nations), but pays in terms of an increased dependency on foreign water supplies. Water-intensive goods: food, wood & paper, natural fibres (cotton), bio-energy
- The water footprint of a product (a commodity, good or service) is the total volume of freshwater used to produce the product, summed over the various steps of the production chain. The water footprint of a product refers not only to the total volume of water used; it also refers to where and when the water is used. Source: Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M. and Mekonnen, M.M. (2011) The water footprint assessment manual: Setting the global standard, Earthscan, London, UK. See page 195.
- Green water footprint – Volume of rainwater consumed during the production process. This is particularly relevant for agricultural and forestry products (products based on crops or wood), where it refers to the total rainwater evapotranspiration (from fields and plantations) plus the water incorporated into the harvested crop or wood. Blue water footprint – Volume of surface and groundwater consumed as a result of the production of a good or service. Consumption refers to the volume of freshwater used and then evaporated or incorporated into a product. It also includes water abstracted from surface or groundwater in a catchment and returned to another catchment or the sea. It is the amount of water abstracted from groundwater or surface water that does not return to the catchment from which it was withdrawn. Grey water footprint – The grey water footprint of a product is an indicator of freshwater pollution that can be associated with the production of a product over its full supply chain. It is defined as the volume of freshwater that is required to assimilate the load of pollutants based on natural background concentrations and existing ambient water quality standards. It is calculated as the volume of water that is required to dilute pollutants to such an extent that the quality of the water remains above agreed water quality standards. Source: Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M. and Mekonnen, M.M. (2011) The water footprint assessment manual: Setting the global standard, Earthscan, London, UK. See page 187, 189, 190.
- Water footprint – The water footprint is an indicator of freshwater use that looks at both direct and indirect water use of a consumer or producer. Green water footprint – Volume of rainwater consumed during the production process. This is particularly relevant for agricultural and forestry products (products based on crops or wood), where it refers to the total rainwater evapotranspiration (from fields and plantations) plus the water incorporated into the harvested crop or wood. Blue water footprint – Volume of surface and groundwater consumed as a result of the production of a good or service. Consumption refers to the volume of freshwater used and then evaporated or incorporated into a product. It also includes water abstracted from surface or groundwater in a catchment and returned to another catchment or the sea. It is the amount of water abstracted from groundwater or surface water that does not return to the catchment from which it was withdrawn. Grey water footprint – The grey water footprint of a product is an indicator of freshwater pollution that can be associated with the production of a product over its full supply chain. It is defined as the volume of freshwater that is required to assimilate the load of pollutants based on natural background concentrations and existing ambient water quality standards. It is calculated as the volume of water that is required to dilute pollutants to such an extent that the quality of the water remains above agreed water quality standards. As an indicator of ‘water use’, the water footprint differs from the classical measure of ‘water withdrawal’ in three respects: 1. It does not include blue water use, in so far as this water is returned to where it came from. 2. It is not restricted to blue water use, but also includes green and grey water. 3. It is not restricted to direct water use, but also includes indirect water use. Source: Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M. and Mekonnen, M.M. (2011) The water footprint assessment manual: Setting the global standard, Earthscan, London, UK. See page 3.
- The grey water footprint of a product of freshwater pollution that can be associated with the production over its full supply chain. It is defined as the volume of freshwater to assimilate the load of pollutants based on natural background and existing ambient water quality standards. It is calculated water that is required to dilute pollutants to such an extent the water remains above agreed water quality standards. Photo: China
- Livestock products typically require more water per kilogram (or per calorie) than crop products.
- The water footprint of a beef cow is 3,100,000 litres. In an industrial beef production system, it takes in average three years before the animal is slaughtered to produce about 200 kg of boneless beef. The animal consumes nearly 1300 kg of grains (wheat, oats, barley, corn, dry peas, soybean meal and other small grains), 7200 kg of roughages (pasture, dry hay, silage and other roughages), 24 cubic meter of water for drinking and 7 cubic meter of water for servicing. This means that to produce one kilogram of boneless beef, we use about 6.5 kg of grain, 36 kg of roughages, and 155 litres of water (only for drinking and servicing). Producing the volume of feed requires about 15300 litres of water in average.
- The major part of the water footprint of a hamburger refers to the water needed to make the feed for the cow.
- Since food consumption gives the most important contribution to the water footprints of people, even in industrialised countries, dietary habits greatly influence the associated water footprint. In industrialised countries the average calorie consumption today is 3400 kcal per day; roughly 30% of that comes from animal products. When we assume that the average daily portion of animal products is a reasonable mix of beef, pork, poultry, fish, eggs and dairy products, we can estimate that 1 kcal of animal product requires roughly 2.5 litres of water on average. Products from vegetable origin, on the other hand, require roughly 0.5 litre of water per kcal, this time assuming a reasonable mix of cereals, pulses, roots, fruit and vegetables. Under these circumstances, producing the food for one day costs 3600 litres of water. In developing countries, the average consumption is lower: about 2700 kcal per day per person, only 13% of which is of animal origin. Such diet costs 2050 litres of water per day. These numbers are averages over averages, because, first, total caloric intakes and meat fractions assumed vary between and within nations, and, second, the water requirements actually vary across production regions and production systems. The averages shown here mainly function to make a comparison between the water footprints of a meat-based versus a vegetarian diet. A vegetarian diet has a smaller fraction of animal origin (not zero, because of dairy products still consumed). For industrialised countries, this reduces the food-related water footprint by 36%. In the case of developing countries, the switch to vegetarian diet saves 15% of water. Consumers can reduce their water footprint through reducing the volume of their meat consumption. Alternatively, or in addition, consumers can reduce their water footprint by being more selective in the choice of which piece of meat they pick. Chickens are less water-intensive than cows and beef from one production system cannot be compared in terms of associated water impacts to beef from another production system. Source: Hoekstra, A.Y. (2010) The water footprint of animal products, In: D'Silva, J. and Webster, J. (eds.) The meat crisis: Developing more sustainable production and consumption, Earthscan, London, UK, pp. 22-33.
- Since food consumption gives the most important contribution to the water footprints of people, even in industrialised countries, dietary habits greatly influence the associated water footprint. In industrialised countries the average calorie consumption today is 3400 kcal per day; roughly 30% of that comes from animal products. When we assume that the average daily portion of animal products is a reasonable mix of beef, pork, poultry, fish, eggs and dairy products, we can estimate that 1 kcal of animal product requires roughly 2.5 litres of water on average. Products from vegetable origin, on the other hand, require roughly 0.5 litre of water per kcal, this time assuming a reasonable mix of cereals, pulses, roots, fruit and vegetables. Under these circumstances, producing the food for one day costs 3600 litres of water. In developing countries, the average consumption is lower: about 2700 kcal per day per person, only 13% of which is of animal origin. Such diet costs 2050 litres of water per day. These numbers are averages over averages, because, first, total caloric intakes and meat fractions assumed vary between and within nations, and, second, the water requirements actually vary across production regions and production systems. The averages shown here mainly function to make a comparison between the water footprints of a meat-based versus a vegetarian diet. A vegetarian diet has a smaller fraction of animal origin (not zero, because of dairy products still consumed). For industrialised countries, this reduces the food-related water footprint by 36%. In the case of developing countries, the switch to vegetarian diet saves 15% of water. Consumers can reduce their water footprint through reducing the volume of their meat consumption. Alternatively, or in addition, consumers can reduce their water footprint by being more selective in the choice of which piece of meat they pick. Chickens are less water-intensive than cows and beef from one production system cannot be compared in terms of associated water impacts to beef from another production system. Source: Hoekstra, A.Y. (2010) The water footprint of animal products, In: D'Silva, J. and Webster, J. (eds.) The meat crisis: Developing more sustainable production and consumption, Earthscan, London, UK, pp. 22-33.
- Source: Mekonnen, M.M. and Hoekstra, A.Y. (2011) The green, blue and grey water footprint of crops and derived crop products, Hydrology and Earth System Sciences , 15(5): 1577-1600. Mekonnen, M.M. and Hoekstra, A.Y. (2010) The green, blue and grey water footprint of crops and derived crop products, Value of Water Research Report Series No.47, UNESCO-IHE. Source of estimate litre/km for sugar beet-based ethanol: Gerbens-Leenes, W. and Hoekstra, A.Y. (2011) The water footprint of biofuel-based transport, Energy & Environmental Science, 4(8): 2658-2668.
- Virtual water balance per country and direction of gross virtual water flows related to trade in agricultural and industrial products over the period 1996-2005. Only the biggest gross flows (> 15 Gm3/yr) are shown; the fatter the arrow, the bigger the virtual water flow. Source: Hoekstra, A.Y. and Mekonnen, M.M. (2012) The water footprint of humanity, Proceedings of the National Academy of Sciences , 109(9): 3232–3237. Mekonnen, M.M. and Hoekstra, A.Y. (2011) National water footprint accounts: the green, blue and grey water footprint of production and consumption, Value of Water Research Report Series No.50, UNESCO-IHE, Delft, the Netherlands.
- Source: Hoekstra, A.Y. and Mekonnen, M.M. (2012) The water footprint of humanity, Proceedings of the National Academy of Sciences , 109(9): 3232–3237. Mekonnen, M.M. and Hoekstra, A.Y. (2011) National water footprint accounts: the green, blue and grey water footprint of production and consumption, Value of Water Research Report Series No.50, UNESCO-IHE, Delft, the Netherlands.
- The internal water footprint is the water use within the country in so far it is used to produce goods and services consumed by the national population. The external water footprint of a country is the annual volume of water resources used in other countries to produce goods and services imported into and consumed in the country considered. It is equal to the virtual-water import into the country minus the volume of virtual-water exported to other countries as a result of re-export of imported products. The virtual-water export consists of exported water of domestic origin and re-exported water of foreign origin. The virtual-water import will partly be consumed, thus constituting the external water footprint of the country, and partly be re-exported. The sum of virtual water import and water use within a country is equal to the sum of the virtual water export and the country ’ s water footprint. This sum is called the virtual-water budget of a country. Source: Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M. and Mekonnen, M.M. (2011) The Water Footprint Assessment Manual: Setting the Global Standard, Earthscan, London, UK.
- A large volume of water is used in the (water-scarce) North to produce crops that are traded to the (more water-abundant) South. Sources: Ma, J., Hoekstra, A.Y., Wang, H., Chapagain, A.K. and Wang, D. (2006) Virtual versus real water transfers within China, Phil. Trans. R. Soc. Lond. B. 361 (1469): 835-842. Hoekstra, A.Y. and Chapagain, A.K. (2008) Globalization of water: Sharing the planet's freshwater resources, Blackwell Publishing, Oxford, UK.
- For many companies, fresh water is a basic ingredient for their operations, while effluents may lead to pollution of the local water system. Initially, public pressure has been the most important reason for sustainability initiatives in businesses. Today, however, many companies recognize that failure to manage the issue of fresh water raises different sorts of business risk, including damage to the corporate image, threat of increased regulatory control, financial risks caused by pollution, and insufficient freshwater availability for operations. A number of multinationals recognise now that proactive management can avoid risks and contribute to their profitability and competitiveness. Business water footprint accounting is increasingly regarded as an essential part of sustainable corporate performance accounting. An increasing number of businesses recognize that not only their operations, but also their supplies depend and impact on natural water systems.
- • Companies have traditionally focused on water use in their operations, not in their supply chain. The water footprint does take an integrated approach. Most companies will discover that their supply chain water footprint is much larger than their operational water footprint. As a result, companies may conclude that it is more cost-effective to shift investments from efforts to reduce their operational water use to efforts to reduce their supply chain water footprint and associated risks. • Companies have traditionally looked at reduction of water withdrawals. The water footprint shows water use in terms of consumption rather than it terms if withdrawal. Return flows can be reused, so it makes sense to specifically look at consumptive water use. • Companies make sure that they have a water use right or licence. Possessing that is not sufficient to manage water-related risks. It is useful to look into the spatiotemporal details of a company ’ s water footprint, because details on where and when water is used can be used as input to a detailed water footprint sustainability assessment, to identify the environmental, social and economic impacts and to find out associated business risks. • Companies have traditionally looked at meeting emission standards (effluent standards). The grey water footprint looks at the required water volume for assimilating waste based on ambient water quality standards. Meeting emission standards is one thing, but looking at how effluents actually result in reduced assimilation capacity of ambient freshwater bodies and at business risks associated to that is another. Meeting effluent standards (which are formulated in terms of concentrations) can easily be done by taking in more water in order to dilute the effluent before disposal. Diluting effluents may be helpful in meeting effluent standards, but not in reducing the grey water footprint, because the latter is related to the total load of chemicals added to the environment, not the concentration of chemicals in the effluent. Source: Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M. and Mekonnen, M.M. (2011) The water footprint assessment manual: Setting the global standard, Earthscan, London, UK. Page 66.
- Source: Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M. and Mekonnen, M.M. (2011) The Water Footprint Assessment Manual: Setting the Global Standard, Earthscan, London, UK. Page 106-108.
- Source: Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M. and Mekonnen, M.M. (2011) The Water Footprint Assessment Manual: Setting the Global Standard, Earthscan, London, UK. Page 109.
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