Many crop yields are expected to decline due to long-term changes in temperature and rainfall and increased climate variability. The outcome may be higher food prices, along with chronic poverty and undernutrition for farming households already battered by climate extremes such as drought and flood.

Beddington et al., 2011; Carter and Barrett, 2006

Olivier Asselin, UNICEF

Extra facts

  • Farming families may benefit from higher food prices—as long as they earn more from their crops than they spend on food. But many small-scale farmers actually spend more on food than they earn from selling food (Hertel and Rosch 2010).
  • Climate shocks like droughts and floods impact how people access food through work, trade and transfers, such as from relatives who live in other climates (Devereux 2007).
  • The causal pathways from climate change to the various aspects of food security (food availability, access, utilization and stability) are complex. For example, Tirado et al., 2010 note the following pathways:
    • Increased frequency and intensity of extreme climatic events such as heat waves, droughts, storms, cyclones, hurricanes and floods
    • Decrease of fresh water resources, and the impacts of temperature increase and water scarcity on plant or animal physiology
    • Sea-level rise and the flooding of coastal lands, leading to salinization and/or contamination of water, agricultural lands and food
    • Water and food hygiene and sanitation problems
    • Beneficial effects to crop production through CO2 ‘‘fertilization”
    • Influence on plant and livestock diseases and pest species and livestock diseases
    • Damage to forestry, livestock, fisheries and aquaculture
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Methods, caveats and issues

  • All of these physical pathways will further interact with other ongoing biophysical and socio-economic changes such as loss of biodiversity, loss of ecosystem services, the HIV/AIDS pandemic, political armed conflict, demographic changes and globalization.
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  • Beddington J, Asaduzzaman M, Fernandez A, Clark M, Guillou M, Jahn M, Erda L, Mamo T, Van Bo N, Nobre CA, Scholes R, Sharma R Wakhungu J. 2012. Achieving food security in the face of climate change: final report from the Commission on Sustainable Agriculture and Climate Change. Copenhagen: CGIAR Research Program on Climate Change, Agriculture and Food Security. (Available from
  • Carter MR, Barrett CB. 2006. The economics of poverty traps and persistent poverty: An asset-based approach. Journal of Development Studies 42:178-199.
  • Devereux S. 2007. The impact of droughts and floods on food security and policy options to alleviate negative effects. Agricultural Economics 37:47–58.
  • Hertel TW, Rosch SD. 2010. Climate change, agriculture, and poverty. Applied Economic Perspectives and Policy 32:355–85.
  • Tirado MC, Cohen MJ, Aberman N, Meerman J, Thompson B. 2010. Addressing the challenges of climate change and biofuel production for food and nutrition security. Food Research International 43:1729–1744.
  • Vermeulen SJ, Campbell BM, Ingram JSI. 2012. Climate change and food systems. Annual Review of Environment and Resources 37:195-222.
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