Water Footprints
5 March 2009
Tim Hess
Cranfield University
Water & carbon footprints



  • Carbon footprint is the total   • Water footprint is the total
    mass of GHG that is em...
Water footprint of food

                     Production


                                  Processing




              ...
All food contains “embedded”
or “virtual water”




                               water for drinking, cleaning, etc.




...
How much water does it takes to
make a cup of tea?
                                             • Hot water 0.2 lt
       ...
If you think that’s a lot ……

                                                            Embedded or virtual water
      ...
Water required to produce 1kg



                                 litres / kg
    Meat (bovine)                 15 500
   ...
How much water do we eat?



     Basic survival                1000

     Acceptable
                                    ...
Processing


                         Rainwater          Steam



             430 mil l/d
             Mains water
      ...
Growing potatoes in
E. England


   Water to grow
                      130 l/kg
   the potatoes

    Water used in
      ...
Britain’s agricultural water footprint



      • Total agricultural water footprint 74.8 Gm3/yr
          30% of all the...
External agricultural water footprint
                                        Cocoa
   7000
                              ...
The colour of water




                      Water used at the point
   Green Water        where rain falls


           ...
Blue water / Green Water



  • Green water
      • Opportunity cost of water is low
      • Opportunity cost for land may...
Colour is important




                         250 g Peanut M&M’s ®                               575 g Dolmio® pasta sa...
Blue water abstraction in the UK

• Total water use 500 mil m3/year
• Equivalent to domestic consumption of
  9 million p...
Impact of the blue water footprint



  • Not all abstraction is harmful
      • Water that would have no other “use”
    ...
Water availability




        Water available
        No water available
        Over licensed
        Over abstracted
Opportunities to reduce impact:
Cropping


  • Relocating production / abstraction to
    less stressed catchments
    (“c...
Opportunities to reduce impact:
 Livestock production


      • Mostly for drinking, with little
        scope for savings...
Opportunities to reduce impact:
Processing industry & retail


  • Water efficiency, water recycling
      • Reduces costs...
Water & carbon footprints



  Carbon Footprint               Water Footprint

  What we put in                 What we ta...
Conclusions


  • Water footprints are important, i.e. the impact on
    the environment is important
  • But it is not al...
Water Footprints
5 March 2009
Tim Hess
Cranfield University
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2009 Water Footprint

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2009 Water Footprint

  1. 1. Water Footprints 5 March 2009 Tim Hess Cranfield University
  2. 2. Water & carbon footprints • Carbon footprint is the total • Water footprint is the total mass of GHG that is emitted volume of freshwater that is to produce the goods and used to produce the goods services expressed as and services expressed as carbon dioxide equivalent m 3.
  3. 3. Water footprint of food Production Processing Consumption
  4. 4. All food contains “embedded” or “virtual water” water for drinking, cleaning, etc. Water for plant growth
  5. 5. How much water does it takes to make a cup of tea? • Hot water 0.2 lt • Tea leaves 2 g 5 lt to grow the tea • Milk 0.02 lt 18 lt to grow the grass Sugar Water Tea • Sugar 8 g 9.2 lt to grow the cane Milk • Total 32.4 litres Ignores all the water used in manufacturing the cup, processing the tea, milk and sugar, producing electricity for the kettle and washing up!
  6. 6. If you think that’s a lot …… Embedded or virtual water 200 180 ater content, litres 160 140 120 100 80 Virtual w 60 40 20 0 Cup of tea Glass of Cup of Pint of Glass of wine coffee beer milk After Hoekstra & Chapagain (2007)
  7. 7. Water required to produce 1kg litres / kg Meat (bovine) 15 500 Meat (sheep) 6 000 Meat (poultry) 4 000 Rice (broken) 3 500 Eggs 3 300 Soybeans 1 700 Wheat 1 300 Maize 900 Hoekstra & Chapagain, 2007
  8. 8. How much water do we eat? Basic survival 1000 Acceptable 3500 nutritional diet Californian diet 5500 UK Domestic water 153 consumption 0 1000 2000 3000 4000 5000 6000 litres/ person/ day
  9. 9. Processing Rainwater Steam 430 mil l/d Mains water Outputs Inputs Waste water Recycling Rivers & Groundwater 260 mil l/d Food & drink industry (UK) After Defra (2007)
  10. 10. Growing potatoes in E. England Water to grow 130 l/kg the potatoes Water used in 10 l/kg processing Water used in 0.1 l/kg the home
  11. 11. Britain’s agricultural water footprint • Total agricultural water footprint 74.8 Gm3/yr  30% of all the rain that falls on the UK  3,400 litres / person / day Domestic water use = 153 litres / person/ day • 60% crops, 40% livestock • Internal = 28.4 Gm3/yr • External = 46.4 Gm3/yr Source: Chapagain & Orr (2008)
  12. 12. External agricultural water footprint Cocoa 7000 Bovine 6000 Cotton 5000 Swine Oil Palm 4000 Soybeans 3000 Coffee Livestock 2000 Milk 1000 Maize Rice 0 W heat
  13. 13. The colour of water Water used at the point Green Water where rain falls Water abstracted from rivers, Blue Water lakes and groundwater Water required to dilute Grey Water polluted return flows
  14. 14. Blue water / Green Water • Green water • Opportunity cost of water is low • Opportunity cost for land may be higher • Blue water • Taken from renewable resources • Competes for water with other uses
  15. 15. Colour is important 250 g Peanut M&M’s ® 575 g Dolmio® pasta sauce 1,153 litres 202 litres Blue 127 128 Green 987 21 Grey 39 53 Based on production in Australia – Source: Ridoutt et al., 2009. J. Cleaner Production
  16. 16. Blue water abstraction in the UK • Total water use 500 mil m3/year • Equivalent to domestic consumption of 9 million people Livestock 23% Food & Drink Industry 50% Agricultural Irrigation 27%
  17. 17. Impact of the blue water footprint • Not all abstraction is harmful • Water that would have no other “use” (including environmental flows ) • Water in excess of other requirements (e.g. winter high flows) • In water stressed catchments abstraction may have severe environmental impacts
  18. 18. Water availability Water available No water available Over licensed Over abstracted
  19. 19. Opportunities to reduce impact: Cropping • Relocating production / abstraction to less stressed catchments (“claw-back” of licences) • Encourage high-flow / rain water storage • Efficient use of water on the farm • Equipment • Scheduling • Using “appropriate” quality water
  20. 20. Opportunities to reduce impact: Livestock production • Mostly for drinking, with little scope for savings. • More prominent in the West (less stress anyway) • Savings by reducing waste and good management practices at the farm scale Thompson et al., 2007
  21. 21. Opportunities to reduce impact: Processing industry & retail • Water efficiency, water recycling • Reduces costs of water, effluent disposal and treatment (£300 million annual water bill for food & drink industry, Defra, 2007) • Reduced energy requirements & CO2 footprint • Food and Drink Federation (FDF) commitment to savings of 20% by 2020 • Food waste is water waste • Spoilage • Wastage (appearance)
  22. 22. Water & carbon footprints Carbon Footprint Water Footprint What we put in What we take out Total mass over life-cycle Total volume over life-cycle Doesn’t matter where it goes Matters where it comes from and where it goes
  23. 23. Conclusions • Water footprints are important, i.e. the impact on the environment is important • But it is not all about “size” - don’t assume that a big water footprint is “bad” • Need to consider “ecosystem impact”, which will be very case specific and includes livelihoods. • 62% of the UK’s agricultural water footprint is overseas • Work with supply chain, processors and consumers to encourage benign water use
  24. 24. Water Footprints 5 March 2009 Tim Hess Cranfield University
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