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Climate change in africa impacts on agriculture


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Presentation by Mr. Eric Yao, co-ordinator of The Africa Centre, Dublin, and a farmer in Ghana, on the effects that a changing climate has had on his business.

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Climate change in africa impacts on agriculture

  1. 1. Climate Change in Africa: Impacts on Agriculture Prof. John Sweeney, Department of Geography NUI MAYNOOTH Ollscoil na Éireann Má Nuad Food Security & Climate Change in Africa – A community solution. 20 th May 2010
  2. 3. Thomas Malthus on Population and Resources
  3. 4. Malthusian Theory of Population <ul><li>Malthus argued that population increased geometrically while resources increased only arithmetically. </li></ul><ul><li>He predicted that, eventually, population growth would outstrip resources and calamities (starvation, diseases, wars) would produce a population crash which would bring population back to balance supply of resources. </li></ul>
  4. 5. The Green Revolution First green revolution (developed countries) Second green revolution (developing countries) Major International agricultural research centres and seed banks
  5. 6. Heavier heads required: more fertilizer, water, hybrids with shorter stalks (to prevent lodging) Higher density plantings required: more fertilizer, constant water, hybrids with smaller root system More plantings per year required: more fertilizer, year round water, pesticides
  6. 7. Total World Grain Production 2,000 1,500 1,000 500 0 Grain production (millions of tons) 1950 1960 1970 1980 1990 2000 2010
  7. 8. 400 350 300 250 150 Per capita grain production (kilograms per person) 1950 1960 1970 1980 1990 2000 2010 Per Capita World Grain Production 200
  8. 9. Population Growth 2000-2080 Source: Lutz et al., 2001
  9. 10. Africa by 2050 will have a population equivalent to that of Europe, Australasia and the Americas combined
  10. 11. Global Food production <ul><li>Yields still increasing but rate declining </li></ul><ul><li>800 million undernourished (hungry) with no money to buy available food </li></ul><ul><li>3 billion malnourished </li></ul><ul><li>Many countries not self-sufficient in food </li></ul><ul><li>Total calorie production has kept pace with population growth thanks to oil crops, but… </li></ul><ul><li>per capita grain production has fallen for past two decades (380 to 330 kgs/person) </li></ul>
  11. 12. Compounding Impacts of Climate Variability
  12. 13. Climate variability has huge impacts on poverty & livelihoods Relationship holds even in diverse middle income economies with substantial water storage infrastructure e.g. Morocco
  13. 15. (Source: Le Houérou et al, 2006)
  14. 17. Rainfall trends in the Sahel 147 241 Tombouctou 97 210 Agadez 116 178 Khartoum 54 92 Atbara 1970-1984 (mm) 1950-1959 (mm)
  15. 19. <ul><li>Global Food production needs to double to meet the needs of an additional 3 billion people in the next 30 years </li></ul>Climate change is projected to decrease agricultural productivity in Africa for almost any amount of warming
  16. 24. Assessing Agricultural Impacts requires two sometimes contradictory effects to be considered <ul><li>The (Direct) beneficial effect to most plants of having more CO2 in the atmosphere to aid photosynthesis </li></ul><ul><li>The (Indirect) effect, positive or negative, which a particular change of climate may have on the productive capacity of the plant itself. </li></ul>
  17. 25. C3 and C4 Plants <ul><li>C3 Plants </li></ul><ul><ul><li>Wheat, Rice, Barley, Oats, Pea, Bean,Potato </li></ul></ul><ul><ul><li>Soya Bean, Coconut, Banana, Cassava, Sugar Beet </li></ul></ul><ul><li>C4 Plants </li></ul><ul><ul><li>Maize, sorghum, Millet,Sugar cane </li></ul></ul><ul><ul><li>Most grasses </li></ul></ul>
  18. 26. C3 crops outperform C4 crops with higher CO2 concentrations
  19. 27. Crop yield response to temperature change IPCC WG-II (2007) Without adaptation With adaptation
  20. 28. Cereal production in developed and developing countries
  21. 29. Projected changes in crop yields
  22. 30. Suitability for rainfed cereals 1961-90 Suitability for rainfed cereals 2080’s A1FI
  23. 31. Suitability for coffee in Uganda IPCC WG-I (2007)
  24. 32. Indirect Effects <ul><li>As well as stimulating the crop directly, the increases in CO2 will also stimulate weed growth. </li></ul><ul><li>Many weeds are C3 plants </li></ul>
  25. 33. Indirect Effects <ul><li>Temperature increases may extend the range of some pests currently limited by temperature, especially at high latitudes </li></ul><ul><li>No of generations per year may increase </li></ul><ul><li>Earlier appearance in the growing season </li></ul>
  26. 35.                                                                                                                                                                                                  
  27. 36. Vulnerability to climate change (A2) in 2050 Without adaptation With adaptation
  28. 37. The State of Food Insecurity (Source: FAO, 2001)
  29. 38. Source: Fischer et al., 2002 Number of People at Risk of Hunger projected for different IPCC economic development paths AFRICA SOUTH, SOUTHEAST and EAST ASIA
  30. 39. What needs to be done <ul><li>Improve our understanding of the effects of climate change on specific cropping systems and the possibilities for adapting to change </li></ul><ul><li>Improve institutional capacities (research, advisory systems, on-farm experimentation, farmer education) </li></ul><ul><li>Investment in the development of improved seeds and cultivars in terms of tolerance to high temperatures and drought </li></ul><ul><li>Improved strategies to tackle biological constraints including those pertaining to pests and diseases </li></ul><ul><li>Improve efficiency of irrigation systems </li></ul><ul><li>Improve strategies for soil and land use management systems to make them more resilient to flooding and droughts </li></ul><ul><li>Ensure that sufficient financial and human capital is available to make timely investments in adaptation and overcome recognised socio-economic-constraints . </li></ul>
  31. 40. Climate effects on crop yields Yield Climate Temperature + Rainfall Growth duration Water availability Resource use efficiencies Soil Weeds, Pests, diseases Freshwater
  32. 41. Adaptation Yield Climate Temperature + Rainfall Growth duration Water availability Resource use efficiencies Soil Weeds, Pests, diseases Freshwater Microclimate modification Change crops Irrigation Soil management Cropping system diversity
  33. 42. Teleconnections in Sahel
  34. 45. Greenhouse gas emissions
  35. 46. Climate Change Impacts and Carbon Dioxide Emissions ECHAM4, 2080s Fairness and Equity? Greenhouse gas emissions since 1950: 75% from developed countries, 25% from developing countries
  36. 47. Probability of occurrence Average Hot Cold - “mean” effect - “variance” effect combined “mean + variance” Climate change effects on extreme temperatures Current climate After Timbal,B and McAvaney, B. Very Hot More record hot weather More record hot weather More record hot weather More record cold weather Future climate