Climate Change and Food Security

Erin SchlicherJRN 473

December 6, 2010

Overview

• Global climate change will impact agricultural production

• Increases in population have increased food demand

• The combined effects of climate change and population growth are likely to decrease global food security

Agricultural Production

• Temperature• CO2 levels• Precipitation

Temperature

• Longer growing seasons or multiple planting cycles per season in mid-latitudes

• Extension of crop production toward the poles

• Heat stress to crops and livestock• Increased water loss through transpiration• Increased range of insects, weeds, and

disease• Decrease in soil quality, nutrient limitations• Grain filling and vernalization

CO2 Levels

• Increased CO2 levels can increase photosynthesis rates and improve water use efficiency by limiting transpiration

• Weeds may become more invasive• Many crops, such as maize, sorghum,

millet, and sugar cane, do not benefit from increased CO2 levels

Precipitation

• Climate scientists expect more extremes in precipitation: longer dry spells and brief, heavy downpours– Drought stress on crops– Soil erosion– Increased risk of flooding– Reduction in water available for

irrigation

Population Growth

Population Growth

• Increased production on limited amount of arable land– More intensive application of fertilizers and

pesticides– Land clearing and development of wetlands

for agriculture contribute about 20% of annual greenhouse gas emissions

• Increased water scarcity– Higher demands in population centers

diverts water from agricultural uses

Food Security

• The world did see a food crisis in 2007-2008– Will such crises become more frequent in

the future?

• Most scientists believe climate change will pose a significant risk to food security on a global basis

• Not all food systems are equally vulnerable. The poorest countries are likely to be the most affected

The three components of food systems with their main elements shown in italics.

Gregory P et al. Phil. Trans. R. Soc. B 2005;360:2139-2148

©2005 by The Royal Society

• Food Access– A more volatile climate will pose more

risks to crop production, leading to increased prices

• Food Availability– Poor farmers may not have the

resources or technology to adapt to a changing climate, causing decreased production in poorer, more vulnerable countries

Sources

Chartres, Colin J, and Samyuktha Varma. Out of Water: From Abundance to Scarcity and How to Solve the World's Water Problems. Upper Saddle River, N.J: FT Press, 2011. Print.

Gregory, P.J., J.S.I. Ingram, and M. Brklacich. Climate Change and Food Security. Philosophical Transactions of The Royal Society. Oct. 2005. 2139-2148.

Michon, Heather K. “Food Production.” Encyclopedia of Global Warmingand Climate Change. 2008. SAGE Publications. 4 Dec. 2010. http://www.sage-ereference.com/globalwarming/Article_n256.html.

Swaminathan, Monkombu S, and Norman E. Borlaug. Science and Sustainable Food Security: Selected Papers of M S Swaminathan. Singapore: World Scientific, 2010. Print.