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Megan Konar's Talk on Water and Food
- 1. Network Analysis of Virtual Water Trade Megan Konar Civil & Environmental Engineering Princeton University
- 2. Global DistribuKon of Water on Earth From space, Earth is a “Blue Planet”
- 3. Global DistribuKon of Water on Earth SURFACE WATER 0.34% UNDERGROUND 30% FRESH WATER 3% FROZEN 70% OCEANS 97% Water available for plant use is less than 0.34% of all fresh water
- 4. Water for Food Water and food security are inextricably linked. Water and food systems face increasing pressures from global populaKon growth, economic development, and climate change. How are water and food systems linked through internaKonal trade?
- 5. Sources of Water The vast majority (80%) of irrigaKon (i.e. “blue”) water resources goes to agriculture. Most food (60-‐70%) is actually rainfed, or produced using “green” water resources. Green Water Blue Water
- 6. ProducKon Chain 0.16 0.47 Cotton seed oil 1.07 1.00 Cotton seed oil, refined Co`on Cotton seed Hulling/ extraction 0.51 0.33 Cotton seed cake 0.63 0.18 0.10 0.20 Cotton linters Harvesting Cotton plant Seed-cotton Ginning 0.05 0.35 0.10 Garnetted stock 0.82 1.00 Cotton, not Carding/ Cotton lint 1.00 carded or combed Spinning 0.95 Cotton, carded or 0.99 combed (yarn) Knitting/ weaving 0.95 0.05 0.99 0.10 Grey fabric Yarn waste Wet processing 1.00 1.00 Fabric Legend Finishing 0 .35 Product fraction 1.00 1.00 0 .82 Value fraction Final textile Hoekstra, 2009
- 8. Crop Water Use Varies In Both Space and Time Virtual Water Content [-‐] Hanasaki, 2010 H08 Global Hydrologic Model ½₀ x ½₀ SpaKal ResoluKon
- 9. Water, Food, and Trade The water embodied in the internaKonal food trade is referred to as “virtual water trade”. Virtual water trade is driven by underlying economic system and climaKc factors.
- 10. Water, Food, and Trade The water embodied in the internaKonal food trade is referred to as “virtual water trade”. Virtual water trade is driven by underlying economic system and climaKc factors. This complex system can be represented as a network. NODES: Countries parKcipaKng in internaKonal food trade. LINKS: Weighted by water volumes, directed by trade.
- 11. What is a network? …Quick Intro
- 12. Unweighted & Undirected Weighted & Undirected Node Link Unweighted & Directed Weighted & Directed 4 4 1 1 8 2 2 6 3
- 13. Network ProperKes Undirected Directed Degree k out = 0 k in = 1 k =2 Strength 4 1 s out = 3 2 s in = 10 6 s =7
- 14. Network ProperKes Unweighted Weighted Nearest Neighbor Clustering
- 15. Virtual Water Trade Network
- 16. Regional Networks Crops and Livestock Crops Livestock All Water Green Water Blue Water
- 17. Regional Networks Crops and Livestock Crops Livestock All Water Green Water Blue Water
- 18. Regional Networks Crops and Livestock Crops Livestock All Water EnKre network is Green driven by the trade Water of rain-‐fed crops Blue Water
- 19. Network ProperKes Node Degree k out = 0 k in = 1 ExponenKal export degree distribuKon Node Strength Data 4 1 Fit s out = 3 2 s in = 10 6 Stretched-‐exponenKal strength distribuKon
- 20. Power Law RelaKonship Volume of virtual water traded vs. number of trade partners follows a power law relaKonship Data Fit This relaKonship is parKcularly strong for food import, indicaKng that the more import trade partners a country has, the much more virtual water it imports.
- 21. Evidence of Rich Club Nearest-‐Neighbor Degree Clustering Coefficient Unweighted Unweighted Weighted Weighted Weights break down disassortaKve structure
- 22. Network Dynamics Over Time 1986 2007 % Change from 1986 Green Water Blue Water Volume of virtual water embodied in trade has more than doubled from 1986-‐2007, parKcularly for green water. Dalin et al, 2012; Konar et al, In Review
- 23. Global Water Savings from Trade Savings = 238 km3 yr-‐1 Equivalent to 9% of global agricultural water use Dalin et al, 2012
- 24. Blue and Green Networks Save Water . Pos. Links [%] . Blue Water Green Water Global Water Savings [m3] <VWC Gap> Crop Trade [%] What is driving this increased water saving over Kme?
- 25. IntensificaKon of Trade on Water-‐Efficient Links . . Blue Water Green Water
- 26. Thank You QuesKons?