July 2015 Issue
Water Use and Shortages: The Environmental Impact and How RDs Can Help
By Ashley M. Colpaart, MS, RDN
Vol. 17 No. 7 P. 46
Dietitians play a unique and pivotal role in promoting food and water systems that not only optimize nutrition and health, but also advance environmental stewardship. In an unprecedented move, the 2015 Dietary Guidelines Advisory Committee convened a subcommittee on Food Sustainability and Safety to address the environmental impact of food production and consumption. The committee defined sustainable diets as "a pattern of eating that promotes health and well-being and provides food security for the present population while sustaining human and natural resources for future generations."1
As the food and nutrition experts, dietitians increasingly are tasked with understanding that eating takes place within a larger system and that the recommendations on what to eat determine how we use and care for the world. This notion is the underpinning of novelist and farmer Wendell Berry's famous quote, "Eating is an agricultural act."2
Fresh water is one of the most imperiled natural resources and is the ultimate rate-limiting step for food production. Remarkably, production of food is, in essence, the most water-intensive activity in the world. In many farming regions, including the United States, water is scarce and likely to become scarcer as trends in the world's population and household incomes rise. Coupled with the uncertainty of global climate change, the world is facing a water crisis that's a harbinger of a food crisis.
Fresh Water Withdrawals
According to AQUASTAT, the Food and Agriculture Organization's global water information system, the amount of precipitation falling on land is almost 110,000 km3 per year (1 cubic meter = 1,000 liters). Almost two-thirds of this amount evaporates from the ground or transpires from vegetation from forest, rangeland, and cropland. The remaining 40,000 km3 per year is converted to surface runoff that feeds rivers and lakes, and groundwater that feeds aquifers. These are called renewable freshwater resources.3
Water withdrawals, or the removal of surface and ground water from rivers, lakes, or aquifers by infrastructure, can be agricultural, municipal, or industrial. The United Nations World Water Assessment Programme (WWAP) states that freshwater withdrawals have tripled over the last 50 years and demand for freshwater is increasing by 64 billion km3 per year.4 At a global level, the withdrawal ratios are 70% agricultural, 11% municipal, and 19% industrial.3
However, these numbers are overstated, skewed by a few countries with very high water withdrawals, mainly in Africa, Asia, and South America.3 The average withdrawal ratios for any given country are closer to 59%, 23%, and 18% respectively.3 WWAP attributes the increased demand for water withdrawal to these key drivers:
• the world's population is growing by roughly 80 million people each year;
• changes in lifestyles and eating habits in recent years requiring more water consumption per capita;
• the production of biofuels increasing sharply in recent years, with significant impact on water demand (between 1,000 and 4,000 liters of water are needed to produce a single liter of biofuel);
• energy demand is accelerating, with corresponding implications for water demand; and
• changes in weather patterns and global climate change leading to extraordinary droughts and floods.4
Due to these trends, WWAP predicts that in 2030, 47% of the world's population will be living in areas of high water stress. Alarmingly, most population growth will occur in developing countries, mainly in regions already experiencing water stress. But the distress isn't limited to the developing world. At the end of February 2015, the Global Drought Information System reported drought intensification in the British Isles, Asia (around Mongolia and northern India), Africa (entrenched near the eastern horn), South America, and Australia. In North America, drought continues to be a concern in the Southwest and Southern Plains of the United States. The US High Plains (the Breadbasket) and California's Central Valley (the Salad Bowl) are two of the world's great agricultural regions, and the groundwater there is being pumped out at far greater rates than it can be naturally replenished.5
Irrigation and Water Exports
For thousands of years, irrigation, or the controlled application of water for agricultural purposes through manmade systems, has kept fruits, vegetables, and grains growing to feed the world's population. Many different irrigation methods are used worldwide, including center-pivot (think crop circles), drip (applied directly to the root zone of plants), flood (where the entire surface of the soil is covered by ponded water), and sprinkler irrigation. According to the US Geological Survey, almost 60% of all the world's freshwater withdrawals go toward irrigation uses.6
The Colorado River basin, covering 256,000 square miles in the western United States, provides water to 30 million people across Arizona, California, Colorado, New Mexico, Nevada, Utah, Wyoming, and Mexico. More than 90% of pasture and cropland in this arid basin relies on supplemental water to make the land viable for agriculture. The irrigated land extends across almost 3.2 million acres within the basin, but water also is exported from the basin to help irrigate another 2.5 million acres in Colorado, Utah, New Mexico, and southern California. According to the policy research organization the Pacific Institute, the irrigation of this much land consumes 70% of the basin's water supply (not including evaporation or exports), deeming the Colorado River one of America's most endangered rivers.7
Irrigators were among the first to divert and put water from the basin into agriculture, securing legal rights to the use of that water. The ownership of these water rights creates a complicated dynamic for researchers, policy makers, landowners, and environmentalists. With some of the oldest and largest water rights in the basin, irrigators face increasing pressure from urban interests to sell or relinquish some of these water rights. Growing awareness of water conservation has led to improvements such as controlling droplet size and reducing evaporation by lowering sprinklers closer to crops.8
The California Drought
According to NASA senior water scientist Jay Famiglietti, PhD, California's water storage has been at a steady decline since 2002, and has about one year's worth of water remaining in its reservoirs.9 Historically at this time of year, California's reservoirs are full of winter rains and the Sierra snowpack is at its peak, but water levels across the state are at record lows, with every major reservoir well below capacity, most less than one-half full. This past April, for the first time in 75 years, the California Department of Water Resources found no snow during its manual snowpack survey of the Phillips snow course, which traditionally averages 66.5 inches in early April.10 Reservoir levels also remain staggeringly low, with Lake Oroville, the State Water Project's principle reservoir holding 51% of its 3.5 million-acre foot capacity.10 Statewide, California has lost more than 12 million acre-feet of total water yearly since 2011, and much of that decrease can be attributed to ground water pumping, or well drilling.11 Desperate farmers continue to drill wells to provide water for crops, but many wells are starting to dry up.
In January, California Governor Jerry Brown declared a drought state of emergency and called on all Californians to voluntarily reduce water usage by 20%. New water restrictions were announced by the Water Resources Control Board in March that include limiting outdoor watering, prohibiting restaurants from offering water unless asked, and offering hotel guests the opportunity to decline freshly laundered linens.10 With the rainy season coming to a close, water restrictions and conservation campaigns will continue, but many feel that disaster is imminent.
As awareness of climate change and other global environmental challenges grow, the concept of resiliency has emerged as an important research area, particularly in understanding how to sustain local and global food systems. In his plenary presentation at the 2013 Water for Food Conference, Christo Fabricius of Nelson Mandela Metropolitan University in South Africa, described resiliency as a socioecological system's capacity to absorb disturbance and reorganize so as to retain essentially the same function, structure, and feedbacks. He continued by explaining that resilient food systems need to be integrated and that food must come from a variety of sources, recognizing that when we make a decision on moving water from one place to another, impacts are felt somewhere else.12 One project aimed at improving agriculture's capacity to adapt to climate change is the Agricultural Model Intercomparison and Improvement Project, which combines climate change projections, crop data, and economic indicators into models that forecast outcomes to support the agriculture sector in assessing adaptive strategies and on-farm decision-making.13
Many in the agricultural sector are working to better equip farmers to withstand drought and build resiliency into agriculture systems through technological advances, improved agronomic practices, and support networks. Precision management tools, such as soil moisture sensors, rain gauges, and center pivot software, are helping farmers make more informed irrigation decisions. Agronomic practices, such as planting cover crops or conservation tilling, trap soil moisture to improve water availability while also providing other ecosystem services, including increased soil organic matter and reduced soil erosion. Extension services, available through land-grant universities, also provide valuable resources, support for drought planning, and risk management solutions. However, despite these advances, the agricultural sector continues to evolve and needs continued support systems from both the public and private sectors.12
Water Footprints for Food
A concept created by Dutch water management professor Arjen Hoekstra is the term "water footprint,"14 which describes the amount of freshwater appropriated to produce a product while taking into account the amount of water consumed and polluted throughout the steps of the supply chain. "The interest in the water footprint is rooted in the recognition that human impacts on freshwater systems can ultimately be linked to human consumption, and that issues like water shortages and pollution can be better understood and addressed by considering production and supply chains as a whole," Hoekstra says, according to the website waterfootprint.org. The Water Footprint Calculator found on the website can be used to calculate your own personal water footprint based upon the water required to support your lifestyle choices. Consumption of food plays a large role in human water footprints.
The chart below highlights the water footprint for select food products of both vegetable and animal origin. Animal products generally have a larger water footprint than crop products. The same is true when we divide out the water footprint per calorie. The average water footprint per calorie for beef is 20 times larger than for cereals and starchy roots. From a freshwater resource perspective, it's more efficient to obtain calories through crop products than animal products.15,16
Shelled almonds, which often are recommended by RDs as a perfect snack, require about 2,100 gallons of water to produce a single pound. This is because almond trees require year-round watering to survive, and any reduction in watering can reduce soil water availability, causing stress to the trees and decreasing future production.17 In the summer, farmers are forced to drill new wells to provide constant irrigation to their orchards. In the United States in 2012, there were 7,052 farms that had almond trees on their land; California accounts for 99.9% of total acres (936,248) in almond production, its largest food export.18,19 Today, the California almond industry produces more than 80% of the world's supply.20
According to the US Census of Agriculture, in 2012, sales of beef cattle in the United States totaled $29.6 billion, accounting for 7% of total US agriculture sales.20 Every state raises and sells beef cattle, but in 2012 the top five (Nebraska, Texas, South Dakota, Kansas, and Oklahoma) accounted for 43% of sales.21 Although significant advances in production efficiency have reduced resource demand, Mekonnen and Hoekstra estimate that the production of 1 lb of beef requires 1,875 gallons of water.16 It's important to understand that there's a huge variation around this global average and that the footprint of a piece of beef depends largely on production factors and origin of the feed of the cow. This is true of most animal production systems. For example, a 1993 study commonly cited by the beef industry from the University of California, Davis found it takes just 441 gallons of water to produce 1 lb of boneless beef.22 The study took into consideration the water the animal drinks, the water used to irrigate pastureland where the cattle graze, the water used to grow crops the cattle are fed, and the water used in the beef processing. On the other hand, a 2001 study, often sited by environmentalist and vegetarian activist groups, arrived at 12,008 gallons per pound.23 It's also important to understand that ranchers often are important stewards of the land, and cows raised on pastures provide unique ecosystem services through grazing.
Their chewing mouths prune plants, stimulating vegetative growth and assisting sunshine in reaching seedlings; and their trampling hooves and weight press seeds and plant matter into the ground, assisting with seed germination and plant matter decomposition. Their digestive tracts cycle nutrients, and their manure provides valuable organic matter to soil, enhancing nutrients and supporting the soil's water-holding capacity.
Putting It Into Practice
The developing world faces challenges related to water access, infrastructure, and sanitation. In response, on July 28, 2010, the United Nations adopted water as a human right. In April 2013, the Academy of Nutrition and Dietetics (the Academy) published the position paper "Nutrition Security in Developing Nations: Sustainable Food, Water, and Health," outlining the importance of developing interventions that address safe drinking water and improved sanitation facilities.24 "Access to clean, safe drinking water and proper sanitation are issues RDs should care about because they potentially affect malnutrition and maternal and newborn survival," said member Christine McCullum-Gomez, PhD, RD, a food and nutrition consultant.
The Academy's Hunger and Environmental Nutrition (HEN) Dietetic Practice Group's mission is to empower members to be leaders in sustainable, resilient, and healthful food and water systems. In 2007, the group initiated a Water Task Force and appointed its first chair, Alison Brewton-LaClaire. The task force populated the HEN member website with a comprehensive list of water-focused resources for nutrition professionals, including information from "The Water Supply; Water and Agriculture; Water Conservation Recommendations for You and Your Clients; and Water, Sanitation, and Health."
As consumers, it's important to understand that food waste is water waste. According to the environmental think tank World Resources Institute, inside the 1.3 billion tons of food wasted every year worldwide is 45 trillion gallons of water. This represents a staggering 24% of all water used for agriculture.25 In medium- and high-income countries, food is wasted largely at the consumer level, in homes, institutions, and restaurants. On the contrary, in developing countries loss occurs in the early and middle stages of the food supply chain due to poor or inadequate infrastructure.
RDs can get more involved in helping to curtail food and water waste by doing the following:
• Join the HEN Dietetic Practice Group to access resources, continuing education, and participate in discussions about complex food, agriculture, and conservation topics, including water.
• Visit the site Water Use It Wisely (http://wateruseitwisely.com), which provides a list of 100 ways to conserve in your home, office, or outdoors. When consulting or educating the public, RDs can choose from a list of 17 tips to reduce water use in the kitchen.
• Address food waste head on. Food waste is water waste. Plan menus, buy only what you need, and compost food scraps.
• Reduce meat consumption, adopt one meat-free day per week, and teach clients, patients, and the public about the Meatless Monday campaign.
• Participate by eating more seasonally and encouraging more regional agricultural production.
• Talk to a rancher about grass-fed and grass-finished beef to learn more about different production systems.
• Grow a Victory Garden in your community to ease the pressure on farmers.
• Use World Water Week and World Water Day, organized by UN Water, as an opportunity to educate yourself, clients, and the public about water issues.
— Ashley M. Colpaart, MS, RDN, is past chair of the Hunger and Environmental Nutrition Dietetic Practice Group and a doctoral candidate in interdisciplinary studies in food science and food safety at Colorado State University in Fort Collins.
1. Office of Disease Prevention and Health Promotion. Scientific Report of the 2015 Dietary Guidelines Advisory Committee. Part D. Chapter 5: Food sustainability and safety. http://www.health.gov/dietaryguidelines/2015-scientific-report/PDFs/10-Part-D-Chapter-5.pdf. Published February 23, 2015. Accessed March 21, 2015.
2. Berry W. The pleasures of eating. In: What Are People For? New York, NY: North Point Press; 1990:145-152.
3. AQUASTAT database. Food and Agriculture Organization of the United Nations website. http://data.fao.org/database?entryld=75f7d9c5-57ab-4a62-88d3-91e47fb50c45. Updated March 20, 2014. Accessed March 21, 2015.
4. United Nations World Water Assessment Programme. The United Nations World Water Development Report 2015: Water for a Sustainable World. Paris, France: United Nations Educational, Scientific and Cultural Organization; 2015.
5. Current conditions. National Integrated Drought Information System website. http://www.drought.gov/gdm/current-conditions. Accessed March 21, 2015.
6. Irrigation water use. US Geological Survey website. http://water.usgs.gov/edu/wuir.html. Updated March 17, 2014. Accessed March 21, 2015.
7. Cohen M, Christian-Smith J, Berggren J. Pacific Institute. Water to supply the land: irrigated agriculture in the Colorado River Basin. http://www.pacinst.org/wp-content/uploads/2013/05/pacinst-crb-ag.pdf. Published May 2013. Accessed March 21, 2015.
8. Schaible GD, Aillery MP. Water Conservation in Irrigated Agriculture: Trends and Challenges in the Face of Emerging Demands. Washington, DC: US Department of Agriculture, Economic Research Service; 2012. EIB-99.
9. Famiglietti JS. The global groundwater crisis. Nat Clim Chang. 2014;4:945-948.
10. Sierra Nevada snowpack is virtually gone; water content now is only 5 percent of historic average, lowest since 1950. California Department of Water Resources website. http://www.water.ca.gov/news/newsreleases/2015/040115snowsurvey.pdf. April 1, 2015. Accessed May 7, 2015.
11. Famiglietti JS. California has about one year of water stored. Will you ration now? Los Angeles Times website. March 12, 2015. http://www.latimes.com/opinion/op-ed/la-oe-famiglietti-drought-california-20150313-story.html.
12. Too hot, too wet, too dry: building resilient agroecosystems. Proceedings of the 2013 Water for Food Conference. Lincoln, Nebraska: University of Nebraska Robert B. Daugherty Water for Food Institute; 2014.
13. Rosenzweig C, Elliott J, Deryng D, et al. Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison. Proc Natl Acad Sci U S A. 2014;111(9):3268-3273.
14. Hoekstra AY. The water footprint of food. University of Twente website. http://doc.utwente.nl/77216/1/Hoekstra08waterfootprintFood.pdf
15. Mekonnen MM, Hoekstra AY. The green, blue and grey water footprint of crops and derived crop products. Hydrol Earth Syst Sci. 2011;15:1577-1600.
16. Mekonnen MM, Hoekstra, AY. A global assessment of the water footprint of farm animal products. Ecosystems. 2012;15:401-415.
17. Almonds. University of California Drought Management website. http://ucmanagedrought.ucdavis.edu/Agriculture/Crop_Irrigation_Strategies/Almonds/. Accessed March 21, 2015.
18. 2012 California almond acreage report. California Department of Food and Agriculture, California Agricultural Statistics Service website. Updated April 25, 2013. Accessed March 21, 2015. http://www.nass.usda.gov/Statistics_by_State/California/Publications/
19. Quick stats: almonds. United States Department of Agriculture, National Agricultural Statistics Service website. http://quickstats.nass.usda.gov/results/
20. Morecraft B. How the U.S. almond industry exported its way to domination of the world market. United States Department of Agriculture website. http://www.usda.gov/oce/forum/past_speeches/2013_Speeches/Morecraft.pdf. Accessed May 7, 2015.
21. 2012 Census of Agriculture Highlights. United States Department of Agriculture, National Agricultural Statistics Service website. http://www.agcensus.usda.gov/Publications/2012/Online_Resources
22. Beckett JL, Oltjen JW. Estimation of the water requirement for beef production in the United States. J Anim Sci. 1993;71(4):818-826.
23. Goodland R, Pimentel D. Environmental sustainability and integrity in the agriculture sector. In: Pimentel D, Westra L, Noss RF, ed. Ecological Integrity: Integrating Environment, Conservation and Health. 2nd ed. Washington, DC: Island Press; 2000:121-138.
24. Nordin SM, Boyle M, Kemmer TM, Academy of Nutrition and Dietetics. Position of the Academy of Nutrition and Dietetics: nutrition security in developing nations: sustainable food, water and health. J Acad Nutr Diet. 2013;113(4):581-595.
25. Lipinski B, Hanson C, Waite R, Searchinger T, Lomax J, Kitinoja L. Reducing food loss and waste: creating a sustainable food future, installment two. World Resources Institute website. http://www.wri.org/publication/reducing-food-loss-and-waste. Updated June 2013.