Post on 28-Jun-2015
description
www.waterfootprint.orgwww.waterfootprint.org
Water Footprint:Water depletion/Affordability of food
Presented @ Metrics of Sustainable Diets
and Food Systems – Expert Workshop
Agropolis InternationalMontpellier,
France
4-5 Nov 2014
Ashok Kumar ChapagainScience Director
Water Footprint Network
www.waterfootprint.orgwww.waterfootprint.org
What is the water footprint?
The ‘water footprint’ is a measure of human’s appropriation of freshwater resources.
[Hoekstra et al., 2011]
► Water footprint is a measurement of the volume of water consumed (evaporated or otherwise not returned) or assimilation capacity used.
► The water footprint is a geographically & temporally explicit indicator.
► The water footprint is an indicator of water use that looks at both direct & indirect water use of a consumer or producer.
► A water footprint can be calculated for a process, a product, a consumer, group of consumers (e.g. municipality, province, state or nation) or a producer (e.g. a private enterprise, public organization).
www.waterfootprint.orgwww.waterfootprint.org
[Hoekstra et al., 2011]
Water footprint components
Green water footprint
Blue water footprint
Grey water footprint
www.waterfootprint.orgwww.waterfootprint.org
Cotton for export
Mekonnen & Hoeksrta., 20]2
Water Footprint Assessment: Phase 2 - Accounting
Global average WF
www.waterfootprint.orgwww.waterfootprint.org
sugar crops 200 litre/kg
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
global averages
www.waterfootprint.org[Hoekstra & Chapagain, 2008]
Food► 1300 kg of grains
(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%
The water footprint of a cow
www.waterfootprint.orgwww.waterfootprint.org
≠
www.waterfootprint.orgIndustrial systems
Mixed systems
Grazing systems Water footprint: • mostly green• local
Water footprint:• green-blue-grey• partly imported
Water footprint:• green-blue-grey• local
www.waterfootprint.org
Water footprint of an animal product
The two major factors
www.waterfootprint.org
The two major factors
► feed conversion improves from grazing to industrial systems.
► but at the cost of more high-nutrient concentrate feed with a larger water footprint than roughages.
[Mekonnen & Hoekstra, 2010]
www.waterfootprint.org
► Water footprint of animal production is 29% of the total water footprint of the global agricultural sector.
► Water footprint of the agricultural sector is 92% of the total water footprint of humanity.
The water footprint of animal products
[Mekonnen & Hoekstra, 2010]
www.waterfootprint.org
The water footprint of animal versus vegetal products
Food item
Water footprint
Litre per kg Litre per kcal Litre per gram protein Litre per gram fat
Sugar crops 197 0.69 0.0 0.0
Vegetables 322 1.34 26 154
Starchy roots 387 0.47 31 226
Fruits 962 2.09 180 348
Cereals 1644 0.51 21 112
Oil crops 2364 0.81 16 11
Pulses 4055 1.19 19 180
Nuts 9063 3.63 139 47
Milk 1020 1.82 31 33
Eggs 3265 2.29 29 33
Chicken meat 4325 3.00 34 43
Butter 5553 0.72 - 6.4
Pig meat 5988 2.15 57 23
Sheep/goat meat 8763 4.25 63 54
Bovine meat 15415 10.19 112 153
[Mekonnen & Hoekstra, 2010]
www.waterfootprint.org
► The water footprint of any animal product is larger than the water footprint of a wisely chosen crop product with equivalent nutritional value.
The water footprint of animal versus vegetal products
[Mekonnen & Hoekstra, 2010]
www.waterfootprint.org
Meat versus vegetarian diet
Meat diet kcal/day litre/kcal litre/day Vegetarian diet
kcal/day litre/kcal litre/day
Industrial countries Animal
origin 950 2.5 2375 Animal origin 300 2.5 750
Vegetable origin 2450 0.5 1225 Vegetable
origin 3100 0.5 1550
Total 3400 3600 Total 3400 2300
Developing countries Animal
origin 350 2.5 875 Animal origin 200 2.5 500
Vegetable origin 2350 0.5 1175 Vegetable
origin 2500 0.5 1250
Total 2700 2050 Total 2700 1750
www.waterfootprint.org
Challenges
• Local data – though intensive work, can be tackled in the long run
• Supply chain data – Increasingly becoming more complex and very challenging
• Water footprint must always be measured in terms of green [use of rain-fed crops], blue [consumption of surface and ground water] and grey [use of assimilation capacity of fresh water].
• Measuring in time and space is critical for a meaningful interpretation of results
www.waterfootprint.org
Thank you
Ashok ChapagainScience DirectorWater Footprint Network
@A_Chapagain
Ashok.Chapagain@waterfootprint.org