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Hoekstra Delft 24Oct2011[1]

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    Water in relation to

    food and energy

    Arjen Hoekstra

    University of Twente / Water Footprint Network

    www.waterfootprint.org

    Overview of presentation

    - Dilemmas in freshwater allocation

    - Water footprint of Dutch consumers

    - The water footprint concept- Water for food

    The water-energy nexus

    - National water foot rints

    - What can we do?

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    Limits to freshwater use

    Freshwater consumptionAgricultural products- Food

    - Fibres cotton

    Freshwater availabilityPrecipitation on land- Evapotranspiration (green water)

    - Runoff blue water

    TRADE

    - Biofuels

    Forestry products

    - Timber

    - Paper- Firewood, charcoal

    Aquaculture products

    Industries

    Domestic water supply

    Freshwater pollutionPoint sources

    Diffuse sources

    Waste assimilation capacity- Maximum allowable concentrations

    - Decay rates

    Dilemmas in freshwater allocation

    Water allocation dilemmas- Water for consumption versus water for

    TRADE

    - Water for food versus nature

    - Water for food versus bio-energy

    What goal deserves priority?- Food security to all?

    - Allocation to highest added value?- Sustainable water use?

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    Production

    Globalization of water

    Water consumption and

    pollution related to production

    for export; water is not factored into

    the price of traded commodities

    TRADETrade

    Consumption

    Water saving, but also

    water dependency

    The total water footprint of a consumer in NL

    about 2% of the water footprint is at home.

    ,

    about 98% of the water footprint is invisible, it is relatedto the products consumers buy in the supermarket.

    3448 litre/day for agricultural products

    541 litre/da for industrial roducts

    about 95% of NLs water

    footprint lies abroad.

    [Mekonnen & Hoekstra, 2011]

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    Global water footprint of Dutch consumption

    soybean

    95% of the water footprint

    is outside its own borders

    [Mekonnen & Hoekstra, 2011]

    Coto Doana National Park, southern Spain

    raw err es or expor

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    19892008

    Former Aral Sea, Central Asia

    Cotton for export

    Calculated lake level

    without accounting for

    water abstraction

    Flowers from KenyaDecline of lake level in Lake Naivasha

    [Mekonnen & Hoekstra, 2010]

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    Soybeans, deforestation,

    Mato Grosso, Brazil

    Use of green water

    The water footprintconcept

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    the volume of fresh water used to produce the product,

    The water footprint of a 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.

    Green water footprint

    The water footprint of a product

    volume of rainwaterevaporated

    or incorporated into product

    Blue water footprint

    volume of surface or groundwater

    evapora e or ncorpora e n o pro uc

    Grey water footprint

    volume ofpolluted water.

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    Direct water footprint Indirect water footprint

    Components of a water footprint

    Green water footprint Green water footprint

    Blue water footprint Blue water footprint

    Water

    consumptionReturn flow

    Water withdrawal

    Grey water footprint Grey water footprint

    Water

    pollution

    [Hoekstra et al., 2011]

    The traditional

    statistics

    on water use

    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.

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    Applic. rate = 1 kg/ha L

    Grey water footprint related to atrazine in

    corn production in the USA

    Leaching rate = 5%

    A = 30 million ha

    cmax = 3 g/l (EPA, 2005)

    cnat = 0 g/l

    Y= 9 ton/ha Prod = 270 million ton/yr

    = . m on

    kg/yr

    = 500 109 m3/yr

    Total WFgrey of activity = (cmax cnat)

    Plane spraying pesticide on maize

    (Zea mays), California, USA

    Total renewable water resources in USA =

    3,051 109 m3/yr (AQUASTAT, 2007)

    Grey water footprint < runoffAssimilative capacity

    The environmental impact of the grey water footprint

    Full assimilativecapacity of the river

    used

    Grey water footprint = runoff

    Pollution exceeding

    the assimilative

    capacity of theenvironment

    Grey water footprint > runoff

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    Blue water footprint Blue water availability

    Blue water scarcity

    [Hoekstra & Mekonnen, 2011]

    Number of months with blue water scarcity > 100%

    [Hoekstra & Mekonnen, 2011]

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    14000

    16000

    m3/sIndus River Basin Natural

    runoff

    4000

    6000

    8000

    10000

    12000

    Environmental

    flow requirement

    Bluewaterfootprint

    0

    2000

    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

    Bluewateravailability

    The water footprintof food

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    sugar crops 200 litre/kg

    global averages

    The water footprint of food products

    vegetables 300 litre/kg

    starchy roots 400 litre/kg

    fruits 1000 litre/kg

    cereals 1600 litre/kg

    pulses 4000 litre/kg

    poultry 4000 litre/kg

    pork 6000 litre/kg

    beef 15000 litre/kg

    [Mekonnen & Hoekstra, 2010]

    The water footprint of a cow

    Food

    1300 kg of grains

    [Hoekstra & Chapagain, 2008]

    (wheat, oats, barley, corn, dry peas, soybean, etc)

    7200 kg of roughages

    (pasture, dry hay, silage, etc)

    Water

    24000 litres for drinking

    7000 litres for servicing.

    99%

    1%

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    The water footprint of beef

    [Hoekstra & Chapagain, 2008]

    The water footprint of a hamburger

    [Hoekstra & Chapagain, 2008]

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    Meat versus vegetarian diet

    Meat diet kcal/day litre/kcal litre/day Vegetarian

    dietkcal/day litre/kcal litre/day

    Industrial

    countries n ma

    origin950 2.5 2375

    n ma

    origin300 2.5 750

    Vegetable

    origin2450 0.5 1225

    Vegetable

    origin3100 0.5 1550

    Total 3400 3600 Total 3400 2300

    Developing

    coun r es

    origin350 2.5 875

    origin200 2.5 500

    Vegetable

    origin2350 0.5 1175

    Vegetable

    origin2500 0.5 1250

    Total 2700 2050 Total 2700 1750

    Meat versus vegetarian diet

    Meat diet kcal/day litre/kcal litre/day Vegetarian

    dietkcal/day litre/kcal litre/day

    Industrial

    countries n ma

    origin950 2.5 2375

    n ma

    origin300 2.5 750

    Vegetableorigin

    2450 0.5 1225 Vegetableorigin

    3100 0.5 1550

    Total 3400 3600 Total 3400 2300

    Developing

    coun r es

    origin350 2.5 875

    origin200 2.5 500

    Vegetable

    origin2350 0.5 1175

    Vegetable

    origin2500 0.5 1250

    Total 2700 2050 Total 2700 1750

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    Meat versus vegetarian diet

    Meat diet kcal/day litre/kcal litre/day Vegetarian

    dietkcal/day litre/kcal litre/day

    Industrial

    countries n ma

    origin950 2.5 2375

    n ma

    origin300 2.5 750

    Vegetable

    origin2450 0.5 1225

    Vegetable

    origin3100 0.5 1550

    Total 3400 3600 Total 3400 2300

    Developing

    coun r es

    origin350 2.5 875

    origin200 2.5 500

    Vegetable

    origin2350 0.5 1175

    Vegetable

    origin2500 0.5 1250

    Total 2700 2050 Total 2700 1750

    The water-energy nexus

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    The water sector is becoming more energy-intensive.

    Water - energy nexus

    pumping deeper groundwater

    large-scale (inter-basin) water transfers

    The energy sector is becoming more water-intensive.

    biomass

    increasin water use in minin fossil fuels

    Primary energy carriers Global average water

    footprint (m3/GJ)

    Water footprint of energy

    Non-renewable Natural gas 0.11

    Coal 0.16

    Crude oil 1.06

    Uranium 0.09

    Renewable Wind ener 0.00

    Solar thermal energy 0.27

    Hydropower 22

    Biomass energy 70 (range: 10-250)

    [Gerbens-Leenes, Hoekstra & Van der Meer, 2008]

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    Source examples

    Energy from biomass

    Starch crops barley, cassava, maize, paddy rice, potato,

    sorghum, rye, wheat

    Sugar crops sugar beet, sugarcane

    Oil crops soybean, rapeseed, jatropha

    Trees poplar

    [Gerbens-Leenes, Hoek

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