Climate Change and Agriculture: Building Resilience Through Better Water Management in Southern Africa
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Climate Change and Agriculture: Building Resilience Through Better Water Management in Southern Africa

Climate Change and Agriculture: Building Resilience Through Better Water Management in Southern Africa

David Molden
International Water
Management Institute

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Climate Change and Agriculture: Building Resilience Through Better Water Management in Southern Africa Climate Change and Agriculture: Building Resilience Through Better Water Management in Southern Africa Presentation Transcript

  • Climate Change and Agriculture: Building Resilience Through Better Water Management in Southern Africa David Molden International Water Management Institute
  • One liter of water produces one calorie on average Food Supply in Calories One liter of water produces  one calorie on average
  • Diets and water Between 2,000 and 5,000 liters per person per  day – depending on type and amount of food  eaten and how it is produced
  • Drivers of Water Use Other Water Pressures Urbanization ‐ Cities are projected to use 150%  more water in 2025 Land Degradation – limits further productivity  increases Climate Change – Shifting patterns of water  availability – potential yields decline in Africa Energy – Production and use by agriculture is in  competition with hydropower
  • How can water be developed and  managed to end poverty and hunger?  A question posed to 700  researchers and  practitioners who put  together the  Comprehensive  Assessment of Water  Management in  Agriculture.
  • Investing in Irrigation 2.5 320 World Bank lending for irrigation 280 2.0 Irrigated Area 240 200 1.5 160 1.0 Food price index 120 Living Planet Index Freshwater Species 80 0.5 40 Africa Irrigation 0 0 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
  • Limits – reached or breached • River basins closed – Colorado, Murray Darling,  Yellow, Indus, Amu Darya, Orange ‐ 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
  • Water Scarcity 2000 1/3 of the world’s population live in basins that have to deal with water scarcity
  • WHAT OF THE FUTURE?
  • Per Capita Meat Demand (kg/cap/yr) 140 data projections 120 Meat consumption kg/cap/yr 100 USA 80 60 China 40 World 20 India Southern Africa 1961 2003 2050
  • Food demand doubles over the next 50 years because of diet and population growth Water Needs (ET) will double – without water productivity gains How much more cereals?
  • Climate Change Mitigation is about gases. Adaptation is about water.
  • Climate Change in Africa According to IPCC  (2007) Temperature and precipitation changes over Africa from the MMD‐A1B simulations. Top  row: Annual mean, DJF and JJA temperature change between 1980 to 1999 and 2080 to  2099, averaged over 21 models. Lower row: fractional change in precipitation. 
  • Variability in Precipitation Thornton et al 2006 likely to increase with climate change
  • Observed Trends in River Flow mean daily flow (annual averages) in Niamey (Niger) 1600 1400 1200 1000 [m3/s] 800 600 400 200 0 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 year
  • Unmitigated Rainfall and Hydrological Variability Impacts Economic Growth and Stability Impact of rainfall variability on GDP and Agricultural GDP growth 80 25 20 60 15 40 20 10 5 Rainfall and GDP growth 0 in Ethiopia and in SSA % 0 -5 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 -20 -10 -40 -15 rainfall variability -20 -60 GDP growth -25 -80 Ag GDP growth -30 year 12 10 ag grow th GDP grow th 8 6 SSA GDP depends  Annual growth rate 4 2 (%) on agriculture 0 1970 1975 1980 1985 1990 1995 2000 -2 -4 -6
  • Water storage mitigates variability Water Storage Mitigates Climate Variability 6150 But need to re‐ 7,000 4729 think water  Cubic meters per capita 6,000 storage: role of  5,000 3255 2486 4,000 groundwater and  1406 3,000 1287 soil moisture.  746 2,000 43 And beyond:  1,000 4 0 insurance, local  China Ethiopia Brazil Laos Thailand South Kenya America Africa Australia trade North Source: World Bank data from ICOLD
  • Lake Chad Large  Dams  in   Nile Southern  Africa Congo (DRC) Congo N.B. Large dam: Wall height > 15 m and/or Volume > 2 million m3 Tanzania (ICOLD, 1999) • Africa has a total of 1,269 Angola Rovuma large dams; 827 (65%) of Zambia Mozambique these are in the SADC Kunene Zambezi countries Cuvelai Zimbabwe Malawi • SADC dams hold 37% of Pungué Buzi Africa’s impounded(#11) and South Africa water Okavango/ Makgadikgadi Save-Runde Botswana Limpopo • South Africa ((#11) are listed Zimbabwe #20) and Namibia amongst the top twenty Zimbabwe (#20) are listed Incomati Umbeluzi amongst the top the world in countries in twenty Orange Maputo countries of the world in terms terms in the numbers of South Swaziland dams built (WCD 2000) of the numbers of dams built Africa Thukela N 0 250 500 Lesotho Sources: AQUASTAT Database (FAO, 2005); Kilometres WCD, 2000
  • Policy Agenda – Where is there hope?
  • Get water to poor people, use it better Around 70% of the  world’s under‐ nourished live in  rural areas where  non‐agricultural  livelihood options  are limited. Improve and Safeguard  Water Access Access to Technologies
  • Consider A Range of Agricultural Water  Management Options Fish, Livestock, Crops, Ecosystem Services
  • A range of options  Water sources in Krishna basin  Krishna river basin 24 major reservoirs 6100 small reservoirs High groundwater use
  • Adapt yesterday’s irrigation to tomorrow’s needs 1. To reduce rural poverty 2. To improve performance of many systems,  3. To keep up with changing food demand 4. To adapt to changes – water scarcity,  competition, climate change, energy 5. To increase multiple benefits and ecosystem  services, while reducing negative impacts
  • Manage Water in Rainfed Landscapes
  • Upgrade Water Management in  Rainfed  Landscapes • Even if area irrigated doubles, the contribution to  food production for SSA from irrigation would  change from 5 to 11% • Rainfed areas, especially in the semi‐arid tropics,  have the highest potential for poverty reduction  and water productivity gains.
  • Small Reservoirs The Small Reservoirs Project
  • … Newly prepared half-moon at the inception of rain …. Half-moon with millet crop …. Tied- ridges
  • Increase Water Productivity • Physical Water Productivity – more crop per  drop – To reduce future water needs – For food production increases • Economic Water Productivity – more value  per drop – For more income, growth – Integrated, multiple use systems
  • Productivity United States Maize yield  (tons/hectare) China Latin  America Sub‐Saharan  Africa
  • Importance of Fish and Livestock for Economic  Water Productivity
  • Make difficult choices  now, not later; Try to increase the pie – share  the benefits But difficult choices remain: • Water storage for agriculture – water for environment • Upstream – Downstream • Productivity ‐ Equity • This generation – the next one  (GW decline) 
  • Reform the policy reform  process • Poverty, hunger, gender inequality,  and ecosystem degradation continue  ‐ not because of technical failings but  because of political and institutional  failings  Africa’s diversity is it’s wealth:  • Diversity is a key to resilience • No blueprints ‐ need to craft local  solutions
  • Thank You ! “Anyone who can solve the problems of water will be worthy of two Nobel Prizes – one for peace and one for science” John F Kennedy