Time to rethink the food systems for a sustainable diet Martine Padilla CIHEAM-IAMM/UMR MOISA
Food production and distribution => 30% of GHG emissions of the planet 20% to 30% of acidification, eco-toxicity and human toxicity more than 50% of eutrophication [EIPRO, 2006].
T of Eq CO2 emissions per person/year 0 1 2 3 4 5 6 Different diets, different impacts GHG emissions Conventional (mainly meat) Conventional (standard) Conventional (mainly plant based) Organic (mainly plant based) Organic (plant based) Organic semi-autarkic Aubert C. 2008
Have we enough space? Ecological Footprint of our Food Type of Food Vegetarian Food Dominant vegetarian Food Western diet Mainly meat diet Area required 500 m2 700 m2 4000 m2 7000 m2 [FAO 2006]
Is there enough Earth? On the total surface, 12 billion ha (/51 billion of soil and water) are bioproductive (Global Footprint Network) Bio-productive surface per person: 1,9 hag (global hectar) An European needs 4,8 hag => 2,5 planets An American = 5,2 planets A Bresilian = 1,3 planet A Chinese = 1 planet An Indian = 0,4 planet A South Mediterranean = 0,8-1 planet Living Planet Report 2012
Is there enough water? 96% of water is used for food [Marsily, 2010] We need about 1 liter of water to produce 1 final Kcal [Molden et al, 2007]. At production level, Horticultural crops require less water than staple food crops per kilo: 150 l of water to produce 1kg tomatoes, 1000 l for pulses and 1500 l for cereals [Chapagain and al, 2008] On an average, to feed himself a human being consumes 1240 m3 (USA=2480 m3, China=700m3) [Hoekstra et Chapagain, 2006] A «western» consumer uses 4000 l/day A vegetarian = 1500 l/day [FAO, 2003]
Do we really need a complex Food System? Food energy used in the Food system in France Field Transport Storage Processing Transport Supermarket Transport Storage Cooking In 1975 (CNEEMA) 10 Kcal 1 Kcal Thirty years later (Solagro) 20 Kcal 1 Kcal Only 10 plants (corn, wheat, rice, potatoes, cassava, soybean, palm nuts, sugar cane, tomatoes and bananas) and 3 animal products (cow's milk, meat pork and poultry) assured about ¾ of food supply in volume in 2009.
Complex Food System alter nutrients At production stage, genetics influence nutrient content more than production methods. Ex: tomatoes -> the vitamin C content of different varieties grown in same conditions can vary from 8.3 to 32.6 mg/100g. For a single variety, the vitamin C content of fruits placed in different conditions ranges from 26.2 to 32.2 mg/100g. At the logistics stage, the longer the product is stored at high temperature or low temperature, the less vitamin C will remain. Ex: tomatoes, losses reach 50% after 8 days at 25 C and 40% after 16 days at 4 C [Sablani et al., 2006]. At the industrial processing stage, peeling highly affects nutrients. Ex: tomatoes, the skin and seeds contribute on average 53% of all polyphenols, including 52% of flavonoids, 48% of lycopene and 43% of ascorbic acid [Toor and Savage, 2005].
We must reduce food losses and waste FAO, 2011
How can we assure a Sustainable Food System? Should we replace animal products with vegetable products? Should we chose organic or conventional food? In season or out of season production? Local food or imported food? Short or long food supply chains?
1- Animal products or vegetable products? Livestock - is responsible for 18% of GHG emissions (>transport) - uses 78% of agricultural surface and pastureland and 38% of cultivated surface - 8% of the whole world s water consumption BUT: [Livestock s long shadow; FAO, 2006] Fruit and vegetables produced at 600 Km from the sale point have a higher environmental impact than locally produced and consumed milk [Wallon et al., 2004]
2- Organic products or conventional products? GHG emissions by group of Foods and recommended levels (organic and conventional products) Freyer, 2008
3 - In season products or products throughout the year? Imported food Energetic cost of green beans from Kenya and UK (Production + packaging + transport to supermarket [Blanke, Burdick, 2005] = 4,7 to 5,3 MJ/Kg for UK products 62,5 to 63,5 MJ/Kg for Kenyan products BUT: What about local Products grown in greenhouses? Greenhouse vegetables = more pollution and much more energy than open field vegetables : CO2 emissions are 4 times higher [Jungbluth N., Faist Emmenegger M. 2004] A German study showed that in winter it makes more sense to import salad from Spain than to produce it locally in greenhouses as energy consumption and the carbon footprint for the latter are twice as high as the former [Müller-Lindenlauf et Reinhardt, 2010].
4- Local Products or imported products? - A local product is not necessarily preferable [Schlich and Fleissner, 2005] - Mass transport, even over long distances, can offer ecological advantages? - High level of natural resources depletion (such as heated greenhouses to produce vegetables and cold storage for fruit) - Moreover local products have to integrate the industrial supply chains - It is important not to confuse sustainable with local, alternative, speciality, traditional product [Ilbery et Maye, 2005].
5 - Short or long supply chains? It may have environmental, economic and social advantages of short supply chains BUT : A sustainable Food System is linked -To organization of the logistics -To the production methods (more than transport) Difficult to conclude whether short supply chains are always preferable to long supply chains
Conclusion Beyond nutrition education, which often bear the responsibility for the situation in the sole consumer, it's time to rethink the food systems. Acting on different levels of food chain can improve the availability and nutritional density of the products. Further research is needed to contextualize and to inform decisionmakers.