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Growing Enough Food Without Enough Water David Molden
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About IWMI IWMI is one of 15 research centers supported by the Consultative Group on International Agricultural Research (CGIAR). Mission: To improve the management of land and water resources for food, livelihoods and the environment. Where we work: Headquarters: Colombo, Sri Lanka In Africa : Ghana, Southern Africa, Ethiopia In Asia: India, Pakistan, Nepal, Laos, Vietnam, Central Asia, Syria
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Water Scarcity 2000 1/3 of the world’s population live in basins that have to deal with water scarcity
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Other Water Pressures Population & Diet – food grain production projected to increase by 100% by 2050 Urbanization - Cities are projected to use 150% more water in 2025, encroach on ag land Energy – Hydropower and biofuels compete for water and land Climate Change – Shifting patterns of water availability Drivers of Land & Water Use
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Land degradation – limits productivity River basins closed – Colorado, Murray Darling, Yellow, Indus, Amu Darya ……… no additional water left Groundwater overdraft – in agricultural breadbaskets Fisheries – ocean and freshwater at a limit, aquaculture will become more prevalent Livestock – limit on extent of grazing land, more will come from mixed and industrialized production Limits – Reached or Breached
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Some areas will be wetter, others drier, more rainfall variability, all hotter Source: Arnell, 2003 – IWMI, FAO, ADB report on revitalizing irrigation.
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Water Scarcity and Climate Change Some areas wetter, some areas drier
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Will there be enough water?
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One liter of water produces one calorie on average Food Supply in Calories One liter of water produces one calorie on average
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USA projections data 2003 1961 2050 China India 140 20 120 100 40 60 80 World Meat consumption kg/cap/yr Per capita meat demand (kg/cap/yr) More meat and milk requires more feed grain, requiring more water
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More People – 6.5 to 9 billion people by 2050 More calories & more meat, fish, milk More food production – need to double grain production by 2050 More water for food – if practices don’t change, double water needs This equation doesn’t work – something has to change Will there be enough water? More people – 6.5 to 9 billion people by 2050 More calories & more meat, fish, milk More food production – need to double grain production by 2050 More water for food – if practices don’t change, water needs for agriculture will double Something has to change
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Solutions Water Management
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Major Pathways to Meet Future Food & Water Demands 1.Improve water productivity (more food/water) –Irrigation systems –Rainfed systems 2.Expand irrigated & rainfed agriculture 3.Promote trade from highly productive to less productive regions 4.Manage demand, consume and waste less
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Grow more food per unit of water
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Productivity of Water at 40 Irrigation Systems: There is ample scope for improvement. Source : Sakthivadivel et al, 1999
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Range of water productivities in biological, economical and nutritional terms for selected commodities a Includes extensive systems without additional nutritional inputs to superintensive systems Source: Muir, 1993; Verdegem, Bosma, and Vereth 2006; Renault and Wallender 2000; Oweis and Hachum 2003; Zwart and Bastiannsen 2004 Product Water Productivity Kilograms per cubic meter ET Dollars per cubic meter ET Protein grams per m 3 ET Calories per m 3 ET Wheat ($0.2 per kilogram) 0.2-1.20.04-0.3050-150660-4,000 Rice ($0.31 per kilogram) 0.15-1.60.05-0.1812-50500-2,000 Maize (0.11 per kilogram) 0.30-2.000.03-0.2230-200 1,000- 7,000 Beef ($3.0 per kilogram)0.03-0.10.09-0.310-3060-210 Fish (aquaculture) a 0.05-1.00.07-1.3517-34085-1,750
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WP for Livestock and Fish Beef0.03 to 0.1 kg/m 3 (ET) Fish0.05 to 1.0 kg/m 3 (ET) Rapid increase in consumption of fish, meat, milk, with income Huge scope for improvement – feed source, and animal husbandry important
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Reasons for Caution
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740km 3 90% Accounting for Water Use at Chistian, Pakistan Often problem is overuse, not low efficiency Low water productivity is the real waste
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Breeding: optimism or caution? Biophysical limit on biomass/transpiration Harvest index already maximized – limit on marketable produce per unit transpiration Hard to foresee a big jump except in underutilized, understudied crops But helpful in reducing damage from weeds, insects, minimizing impacts of drought
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Water productivity rises faster at lower yields and levels off at higher yields Source: Adapted from Zwart and Bastiaanssen 2004 In Water for Food, Water for Life, Earthscan Publishing
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Water productivity is subject to diminishing returns Source: Based on the yield-water productivity relationship for rainfed cereals in Rockström (2003) In Water for Food, Water for Life, Earthscan Publishing Area of Greatest Potential Areas with high poverty
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Opportunities in Rainfed Agriculture Largest opportunities to build resilience and improve water productivity are in rainfed landscapes – low productivity, high poverty Technology – water harvesting, supplemental irrigation – Field water conservation to reduce nonproductive evaporation – Improved nutrients – Drought resistance varieties Expand “water” to include policies and practices for upgrading rainfed systems
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Irrigation potential developed: Egypt, Morocco, Somalia, South Africa > 75% Botswana, Sudan, Zimbabwe, Madagascar, Mali, Malawi, Uganda 50-75% Rest < 50% % Irrigated Land INDIA: ~50 SSA: 5
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Rain = 1745 km 3 Rainfed ET – 190 km 3 Irrigated ET – 67 km 3 Outflow – 10 to 30 km 3 Limited options to expand irrigation – but gets attention Ample options to upgrade agriculture on rainfed lands – gets little attention A green-blue view Irrigated Pastoral Rainfed Wetlands
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Consider A Range of Agricultural Water Management Options Fish, Livestock, Crops, Ecosystem Services
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Transforming Agricultural Water Management We know what to do – we need to know HOW?
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- Use of wells and dug-outs - Small-scale: labour-intensive manual irrigation - Few commercial farmers : motor pumps - Irrigation during dry season Crops: Mainly tomato, pepper, local vegetables Shallow Groundwater Irrigation
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Millions of pumps in operation in S-Asia In India >70% of irrigated production High demand in SSA Spontaneous uptake Privately owned Enormous impact on farmer & landless income But: Small pumps are inefficient (50%) Still quite expensive sales price and running Technical knowledge gap 6% GHG emission in India Resource sustainability No women ownership? Solutions 1.Affordable & efficient pump for smallholders 2.Alternative energy sources (solar) 3.Ban import tax on ag equipment (cost of pump <$100 in India, $140 in Togo, $300 in Ghana). Zambia recently abolished 4.Extension training Motorized pumps: extreme demand – extreme opportunity for change Easy to transport: * individual * scattered plots * rent-out
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Accra Market Queen
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Making it Happen – beyond technologies Access to technology, seeds, fertilizers? Is there enough money or credit to buy them? Are markets available to sell? Financially viable? Water and land resources available? Is it sustainable – financial, ecological? Supportive policies? “Mind mobilization” Matsepo Khumbane
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Summary – Water, Food & Livelihood Agenda 1.Enhance & safeguard water access for the poor 2.Increase water productivity 3.In doing so enhance ecosystem services & resilience 4.Transform water governance and management
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Water access, productivity, and ecosystems for livelihoods 1.Upgrade rainfed areas – manage water & soils 2.Revitalize irrigation 3.Sustainable groundwater management 4.Reuse wastewater safely 5.Transform water governance and management 6.Support with information systems
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