Hoekstra Delft 24Oct2011[1]

8/3/2019 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


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



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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


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


The water footprint of a hamburger



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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




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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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



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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


BIOMASS

RESIDUE

ELECTRICITY

HEAT

Production-chain bio-energy

CROP YIELD

RESIDUE

EXTRACTION

BIODIESEL

ETHANOL



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Water footprint of

biomass energy

3

] 3 water footprint of biomass [m /ton]water footprint of bio-energy [m /GJ

energy yield [GJ/ton]

33 crop water use [m /ha]water footprint of biomass [m /ton]=

crop yield [ton/ha]

Water footprint of biofuels from different crops [litre/litre]

Car driving on

bio-ethanol from

sugar beet:

40-210 litre/km



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WF of bio-energy >> WF of other forms of energy


WF bio-heat or electricity < WF biofuels

WF bio-ethanol < WF biodiesel

Sugar beet most water-efficient energy crop

Large country differences

Water footprint of humanity will increase substantially withthe increase of bioenergy

Water footprint of nations andinternational virtual water trade


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total amount of water that is used to produce the goods and services

Water footprint of national consumption

consumed by the inhabitants of the nation.

two components:

internal water footprint (inside the country).

external water footprint (in other countries).

water ootpr nt o nat ona consumpt on =

water footprint within the nation + virtual water import virtual water export

International virtual water flows

Virtual water flow (m3/yr) =

Trade volume (ton/yr) Product water footprint (m3/ton)


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Global average water footprint



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National virtual water balances


Virtual water transfers in China

52Gm3/yr

[Ma et al., 2006; Hoekstra & Chapagain, 2008]


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46

5

North

India

Virtual water flows India

9

4

2

9

22

10

8 +34

1

13

East

India

West

India

+4

South

India

[Kampman et al., 2008]

What can we do?


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Industry Agriculture

Green WF Not relevant. Decrease green water footprint

increase green water productivity (ton/m3),

The ultimate perspective

increase production from rain-fed lands

Blue WF Zero blue water footprint

recapture and recycle evaporation flow

Decrease blue water footprint

increase blue water productivity (ton/m3),

adopt better irrigation techniques and

practices

Grey WF Zero grey water footprint

zero pollution recapture chemicals and

heat from wasteflow - recycle

Reduce use artificial fertilisers & pesticides

organic farming

Towards supplementary or deficit irrigation

and application of precision irrigation techniques


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Towards full water recycling in industries:

zero blue water footprint

Make better use of green water

Increase water

productivity in

rain-fed

agriculture


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Towards organic farming: zero grey water footprint

Towards full recycling of materials and heat:

zero grey water footprint


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Water neutral urban expansion


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Hoekstra Delft 24Oct2011[1]

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