David Yawson @FTF2013


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  • “ The green revolution has won a temporary success in man’s war against hunger and deprivation; it has given man a breathing space.
  • Physiological level: increase transpiration, CO2 effectiveness and harvest index
  • Three ways to shift the curve from G3 towards G4: CO2 concentrating mechanisms, increased mesophyll conductance to CO2, increased Rubisco specificity factor.
  • David Yawson @FTF2013

    1. 1. virtual water: a missing piece in the water-foodsecurity puzzle?David YAWSONd.o.yawson@dundee.ac.uk
    2. 2. outline:::food security: a wicked problem?water for food security: a challengeoptions for food securityvirtual water: the missing piececoncluding remarks
    3. 3. food security pressures – wicked problem?scarce water for allBio-enginesa warmer worldOur daily BREADaffluence9 billion mouthspeak phosphorus peak oil
    4. 4. water for food security: a challenge
    5. 5. water for food security: a challengeSource: World Water Councilwhy is uselessdiamond moreexpensive thanESSENTIAL water?[Aristotle]“Water is the next petroleum” – Goldman Sachs(Sunday Times, June 8, 2008)
    6. 6. water for food security: a challengeSource: World Water Council
    7. 7. water for food security: a challengeFinitewaterresources Domestic, urbanand industrialEcosystem services(environmental flows)Foodproduction
    8. 8. water for food security: a challenge• Agriculture (70% global water use)(Rockstrom, 2003)2000:6,800 km3yr-12050:12,600 km3yr-1
    9. 9. maintaining food security underwater scarcitysome optionsmanaging ‘the limits to growth’
    10. 10. Green revolution? in water-scarceregions?Norman Borlaug (1914-2009)Green Revolution
    11. 11. food security optionswater productivity,efficiency & breedingwater productivity,efficiency & breedingWatersupplyWatersupplyFooddemandoptions:1. Agronomy:•Improve water productivity-minimize unproductive water losses-maximize water retention in root zone-sustainable intensification???options:2. Physiology & Breeding:-water productivity (physiological level)-drought tolerance (genetic level)•Social:-reducing food waste-dietary shifts
    12. 12. Source: Parry et al. (2005)NB: Selection forphysiological WUE iscounterproductivefood security options
    13. 13. virtual water: the missing piecewater productivity,efficiency & breedingwater productivity,efficiency & breedingWatersupplyWatersupplyFooddemandvirtual water(food trade)virtual water(food trade)Virtual water is the volume ofwater consumptively used toproduce a unit crop that is traded
    14. 14. • water scarcity & food insecurity arelocalized• agriculture has low return oninvestment• food insecurity  upheavals• the entire food system is a businessvirtual water: the missing piece
    15. 15. Net virtual water flows (>2 Gm3yr-1) associated with wheattrade (1996-2005). Source: Mekonnen and Hoekstra (2010).virtual water: the missing piece
    16. 16. Global crop consumptive blue and green water use (km3yr-1)Source: Hoff et al. (2010).  Blue  water (irrigation)Green water1  Green water2  Green water3 GCWM 1180-1448* 4586-4772* 5505-5731* 9823(PM)GEPIC 927 - 4987 6371H08 1530 4700 5550 9540IMPACT 1425 3272 4975 -LPJmL 1364 5088 5469 -waterGap 1300 - - 8290WBM 1301 - - 9406* For different PET calculationsPMPET calculated by Penman-Monteith equation1rain-fed cropland, cropping period2rain-fed and irrigated cropland, cropping period3rain-fed and irrigated cropland, full yearvirtual water: the missing piece
    17. 17. summary & concluding remarks• future food security is a ‘wicked problem’• a wicked problem has one solution: suite of solutions• water scarcity: slowable, inevitable, irreversible• known options for food security worth pursuing • BUT virtual water (food trade) is a missing piece in the suite of solutions to the water-food security puzzle• virtual water: - a soft-path approach to offset effect of water scarcity on food security-opportunity for rethinking sustainable investment in agriculture and agro-environmental governance-potentially effective & efficient path to food security-needs to be promoted to the water-food security policy arena
    18. 18. take home message“…famine can be caused not only by insufficient food production but also by socioeconomic dynamics and failure of public action” [Amartya Sen].virtual water can help avert future catastrophe!
    19. 19. supervisors1. Dr Tom Ball (Geography, Univ. of Dundee)2. Dr Barry Mulholland (ADAS UK Ltd)3. Prof. Philip White (James Hutton Institute) 4. Dr Sushil Mohan (Economic Studies, Univ. of Dundee)
    20. 20. for low virtual water content