The food system involves a network of interactions with our physical and biological environments as food moves from production to consumption, or from “farm to table.” Rising CO2 and climate change will affect the quality and distribution of food, with subsequent effects on food safety and nutrition.
Food- and Water-Related Threats
Across the United States, tens of millions of episodes of foodborne and waterborne illness occur every year,1,2 and more than 3,000 deaths are attributed to contaminated water and food.1,3 Climate change can exacerbate food and water safety risks in a number of ways. For instance, illnesses from pathogens such as Salmonella and Campylobacter are generally more common when temperatures are higher.4 Rapid snowmelt or extreme rainfall events can cause sporadic increases in streamflow rates; along with changes in water treatment, these increases have been linked to an increase in water-borne pathogens.4 The Great Lakes region is expected to see increased risks of waterborne illness and beach closures as climate change raises lake temperatures and increases 24-hour precipitation totals.4 Climate extremes, especially heavy precipitation and flooding, are also key drivers of food contamination and foodborne disease. Such extremes can change the level of exposure to specific contaminants and chemical residues for crops and livestock. 5,6,7 In the United States, children and the elderly are most vulnerable to serious outcomes from food- and waterborne diseases.
Exposure to pathogens and toxins occur through drinking, inhaling, or other direct contact with contaminated drinking or recreational water and through consumption of contaminated food, including fish and shellfish. Climate change impacts—including increasing temperatures, precipitation and related runoff, hurricanes, and storm surge—affect the growth, survival, spread, and virulence or toxicity of agents (causes) of water- and food-related illness.8
In addition to influencing infectious diseases, climate change is also expected to threaten the production, quality, and distribution of food. Globally, many crop yields are predicted to decline in the face of changes in rainfall, severe weather events, and increasing competition from weeds and pests. While the United States is less vulnerable to food security threats than some other countries, its food supply could still be affected in several ways:
- Americans with particular dietary patterns, such as Alaska Natives, will face shortages of key foods.
- Food insecurity increases as food prices rise. In these situations, people cope by turning to nutrient-poor but calorie-rich foods, and/or they endure hunger, with consequences ranging from micronutrient malnutrition to obesity.
- The nutritional value of some foods is projected to decline. For many crops, including barley, sorghum, and potato, protein can decrease as elevated atmospheric CO2 decreases plant nitrogen concentration.8
- Farmers are expected to need to use more herbicides and pesticides, both to cope with increasing numbers of pests and weeds and to compensate for the decreased effectiveness and duration of some of these chemicals. Farmers, farmworkers, and consumers will have increased exposure to these chemicals and their residues, which can be toxic.
For more information on this issue, see the Food Resilience topic and subtopics.
Food Access Research Atlas: Climate change is expected to affect the availability and cost of food. The USDA’s Food Access Research Atlas uses measures of supermarket accessibility to provide a spatial overview of food access for low-income and other census tracts, as well as food access data for populations within census tracts. The tool offers interactive mapping, GIS tools, and ability to download local information for community planning.
Food Environment Atlas: This USDA tool assembles statistics on food environment indicators—such as store/restaurant proximity, food prices, food and nutrition assistance programs, and community characteristics—to provide communities with an overview of their residents’ ability to access healthy food.
Virtual Beach: Climate change effects on lake and ocean ecology can result in unsafe conditions for recreation. Virtual Beach, developed by the U.S. Environmental Protection Agency, lets users generate statistical models to predict levels of disease-causing pathogens such as E. coli and enterococci at specific freshwater/saltwater beach sites. Beach managers can use the tool to decide when a beach closing is necessary to protect health, and researchers, students, engineers, and others can use it to study relationships between water quality indicators and ambient environmental conditions.
- 1. a. b. Scallan, E., P.M. Griffin, F.J. Angulo, R.V. Tauxe, and R.M. Hoekstra, 2011: Foodborne illness acquired in the United States—unspecified agents. Emerg. Infect. Dis., 17, 16–22. doi:10.3201/eid1701.P21101.
- 2. Reynolds, K.A., K.D. Mena, and C.P. Gerba, 2008: Risk of waterborne illness via drinking water in the United States. Rev. Environ. Contam. Toxicol., 192, 117–158.
- 3. U.S. Centers for Disease Control and Prevention, 2013: Surveillance for waterborne disease outbreaks associated with drinking water and other nonrecreational water—United States, 2009–2010. Morbidity and Mortality Weekly Report, 62, 714–720.
- 4. a. b. c. Luber, G., K. Knowlton, J. Balbus, H. Frumkin, M. Hayden, J. Hess, M. McGeehin, N. Sheats, L. Backer, C. B. Beard, K. L. Ebi, E. Maibach, R. S. Ostfeld, C. Wiedinmyer, E. Zielinski-Gutiérrez, and L. Ziska, 2014: Ch. 9: Human Health. Climate Change Impacts in the United States: The Third National Climate Assessment, J. M. Melillo, Terese (T.C.) Richmond, and G. W. Yohe, Eds., U.S. Global Change Research Program, 220–256. doi:10.7930/J0PN93H5.
- 5. Boxall, A.B.A., A. Hardy, S. Beulke, T. Boucard, L. Burgin, P.D. Falloon, P.M. Haygarth, T. Hutchinson, R.S. Kovats, G. Leonardi, L.S. Levy, G. Nichols, S.A. Parsons, L. Potts, D. Stone, E. Topp, D.B. Turley, K. Walsh, E.M.H. Wellington, and R.J. Williams, 2009: Impacts of climate change on indirect human exposure to pathogens and chemicals from agriculture. Environ. Health Perspect., 117, 508–514. doi:10.1289/ehp.0800084.
- 6. Strawn, L.K., E.D. Fortes, E.A. Bihn, K.K. Nightingale, Y.T. Gröhn, R.W. Worobo, M. Wiedmann, and P.W. Bergholz, 2013: Landscape and meteorological factors affecting prevalence of three food-borne pathogens in fruit and vegetable farms. Appl. Environ. Microbiol., 79, 588–600. doi:10.1128/AEM.02491-12.
- 7. Liu, C., N. Hofstra, and E. Franz, 2013: Impacts of climate change on the microbial safety of pre-harvest leafy green vegetables as indicated by Escherichia coli O157 and Salmonella spp. Int. J. Food Microbiol., 163, 119–128. doi:10.1016/j.ijfoodmicro.2013.02.026.
- 8. a. b. USGCRP, 2016: The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment. A. Crimmins, J. Balbus, J. L. Gamble, C. B. Beard, J. E. Bell, D. Dodgen, R. J. Eisen, N. Fann, M. D. Hawkins, S. C. Herring, L. Jantarasami, D. M. Mills, S. Saha, M. C. Sarofim, J. Trtanj, and L. Ziska, Eds., U.S. Global Change Research Program, 312 pp.