Virtual water in food is necessary for productive, sustainable food supplies. What happens when water is scarce because of drought and overuse or misuse?
Virtual water in food is an essential part of agriculture.
The connection between water and our food is a vital one, because crops need rain water or irrigation (much of which is groundwater) to survive and produce marketable fruits, vegetables, grains and pulses (beans). Some of those crops are minimally processed and then sold as whole foods. Many crops are heavily processed and then sold as new food items, and some crops become animal feed — which leads us to that hamburger we mentioned above.
In fact, many grain crops are turned into animal feed; for example, corn, sorghum, barley and oats are grown primarily for livestock feed. In the United States, corn — which is the most irrigated crop in the country — is a primary ingredient in livestock feed, in addition to alfalfa hay, which is also heavily irrigated.
As people eat higher up the food chain, the amount of water it takes to make their food — the water footprint of that food — increases, because we have to account for the water it took to grow that animal and the water it took to grow the feed the animal consumed. This is why animal products — especially beef — generally have higher water footprints than plant-based foods.
Once food products are processed, packaged and ready for transport, each step of which requires water, the water hidden in those foods is moved around the planet through global supply chains that transport food around the world. Most people don’t see the “virtual water trade” that brings food — and the water required to make it — from other locations to their plates. It could be from across the country or across the planet, and sometimes agricultural practices in those locations have damaging effects on local water resources and environments.
Climate change is making droughts worse. What happens when there’s a drought in productive agricultural regions?
There are countries in every continent except Antarctica that are being hit particularly hard right now by drought, and food supplies are being impacted in various ways. For example, Brazil is in such a severe drought that the world’s coffee supplies (among other crops) are threatened. While coffee is not a staple food item, it is an economically vital crop.
Water shortages are now affecting more than 3 billion people worldwide, and billions will face hunger and chronic food shortages as a result.
In the United States, a significant portion of the country is in the grips of an extreme drought.
Water levels in the Colorado River — which feeds seven states including Arizona, the so-called “salad bowl” of the US — have dropped after multiple years of limited precipitation and increasingly warm temperatures. Levels are so low that, in a historic move in August 2021, Colorado River Basin water managers announced for the first time ever that there wasn’t enough water in the river to meet all the demands for all agricultural users and cuts would be necessary.
Arizona and California are two states that receive Colorado River for agriculture. Both states grow a large portion of the fruits, vegetables and nuts this country consumes, and both states are currently water scarce without enough water to meet all their needs.
Given such shortages, would you ask Arizona, or California, or Brazil (or any region experiencing a severe drought, for that matter), to ship a gallon of water to you to drink from afar? Or how about a bathtub worth of water for your shower? Yet, when you drink milk from Arizona, or munch on almonds from California, or drink coffee from Brazil, without realizing it, you have asked those places to ship their precious water to you.
One reason you probably haven’t thought about it before is because the water it took to grow almonds or alfalfa or coffee beans isn’t something you can immediately see and feel.
Food’s Giant Water Footprint ALL Around the World
On a global scale, food production and consumption by far account for the largest part of humanity’s water footprint. On a smaller scale, when people measure their personal water footprint, which tallies up their tap (or direct) and virtual (or indirect) water use, their diet is often the largest part of the final tally.
Learning about the impacts of our diet is important, because, globally, the rate of water use is increasing faster than the rate of population growth. This is due primarily to our virtual water use, and particularly because more people are eating water-intensive foods — especially animal products — than ever before.
Our Water Footprint of Food Guide helps people understand how much water, on average, different food items require. Note that the actual amount of any given food item varies based on location, local climate, production methods, and so forth.
Examples of Virtual Water in Food
A closer look at several food items picked from the Water Footprint of Food Guide helps illustrate how virtual water trade works, while also highlighting the issues with producing water-intensive foods in regions that are water stressed. These popular food items illustrate how water gets moved around the country and around the world through food.
You can use what you learn to make decisions that can help lower your water footprint.
Pork from the United States
The water footprint of a 4 ounce (113 gram) serving is 180 gallons (1497 liters).
Most hogs are raised in “industrial” systems where they’re fed grain in feedlots at industrial hog facilities that can house thousands of animals. The water footprint of pork in large part comes from the water it takes to grow feed grains, most of which are rainfed, however, feed grain irrigation has steadily increased to improve productivity.
Corn is the primary feed grain in the United States. More than 90 million acres of corn planted represent more than 95 percent of total feed grain produced and used in the country. Feed corn crop farming causes water pollution when the fertilizers and/or pesticides used on the crops leach into and pollute surrounding waterways like groundwater, streams and lakes.
Likewise, industrial hog facilities cause water pollution when the huge amount of manure generated by the hogs leaches out of containment facilities and seeps into groundwater or washes away with rains. Nutrients from the manure and chemicals used in livestock production leach into local waterways.
There is also a water footprint associated with processing, packaging and transporting pork products.
Pork production in the United States has increased over time, and in recent years, has grown to meet export demand for the Chinese market. The United States is now the leading pork exporter to China, and China, in turn, also imports US-produced corn and soy to feed their domestically produced hogs. In other words, we’re sending the limited water resources it took to grow the feed and the hogs to China. Here’s why.
In the United States, corn is grown primarily in the Heartland region, such as Illinois, Iowa and Indiana, and also in the Great Plains region, such as Montana, North Dakota, South Dakota. As states in the Heartland and Great Plains regions increasingly experience drought, more and more farmers irrigate and many of them pump water without regard to the health of the aquifers from which they pump.
The Ogallala Aquifer, for example, was once thought to be an endless water supply. Now, overpumping has caused wells in parts of the aquifer — for example, in the Texas Panhandle — to run dry, forcing some farmers to make tough decisions about their future farming efforts.
This is why the water footprints of meat and dairy products, in general, are higher than those of plant-based foods. In essence, eating grain-fed meats like pork also means consuming large amounts of precious water resources.
Coffee from Brazil
The water footprint of an 8 fluid ounce (237 milliliter) serving is 66 gallons (249 liters).
Top coffee producing countries include Brazil, Vietnam, Columbia and Indonesia. In the United States, coffee is grown in Hawaii, California and Puerto Rico (which has a thriving coffee industry).
Coffee beans are typically grown one of two ways – they are either sun-grown or shade-grown, both of which have implications for coffee’s water footprint. Coffee has traditionally been almost exclusively rainfed, although more coffee growers have turned to irrigation as coffee production methods have changed and precipitation patterns have shifted from the effects of climate change.
Sun-grown plantations produce higher yields and profits, but have adverse effects on the ecosystem (like deforestation, monocropping and required irrigation) as well as on coffee quality. Shade-grown plantations are the more traditional approach that mimics the natural way coffee used to grow, underneath a forest canopy. This method has fewer ecological impacts, and doesn’t compromise ecological diversity the way sun-grown coffee does. In addition, shade-grown orchards typically do not require irrigation.
The water footprint of coffee is also impacted heavily by the way it is processed — how the seed or bean is removed from the fruit. When coffee is processed by washing (where the fruit and seed are separated before the seed is dried) as opposed to natural processing (where the seed is separated from the fruit after the entire berry is dried), it uses a substantial amount of water, and can create pollution by poor management of wastewater that results in chemicals being released into local waterways.
Brazil, one of the world’s biggest coffee growing and exporting countries, primarily produces arabica beans in irrigated, sun-grown orchards. It is also experiencing an extreme drought. Without water to irrigate, many farmers have experienced crop losses that range from 30 percent to total loss. If the drought continues, they will be faced with difficult decisions. Some farmers will be able to prune damaged trees, but many more will have to rip out their trees and plant new ones, which take three to four years to become productive.
As we sip our morning lattes, it might be easy to miss how complex the forces are that brought that coffee to our cups, however, the reality and harshness of drought is glaringly apparent for the farmers.
Quinoa from the Andes Mountains
The water footprint of a 4 ounce (113 gram) serving is 135 gallons (1,128 liters).
Quinoa is an ancient crop native to the semi-arid Andes Mountains of South America. Its evolution as an international crop gives insight into how communities can be altered by global trade. Top quinoa producing countries are Peru, Bolivia and Ecuador, and the crop is grown in locations that are considered to have high levels of water stress. Although it is produced (with limited success) commercially in Colorado and Nevada, most quinoa consumed in the United States is imported.
Quinoa is primarily rainfed but its productivity is enhanced when it receives a small amount of irrigation water, and farming it can cause water pollution when fertilizer and/or pesticides run off into local waterways. There is also a water footprint associated with processing, packaging and transporting quinoa.
As quinoa has risen in popularity internationally and its price has substantially increased, smallholder farmers have increased production of monocropped varieties, which has further degraded lands and created social and environmental justice issues in places where it has been traditionally grown. In addition, quinoa is taking its place beside corn and soy as a rapidly growing part of livestock feed.
Oftentimes, the majority of the crop is exported, leaving little for local consumption and shifting traditional dietary patterns to crops that aren’t as easily produced on marginal lands with minimal water resources, like wheat and rice. In effect, quinoa consumers are essentially “taking” the already limited water resources away from the places where quinoa is grown, increasing the stress on communities in those regions as they replace their own quinoa supplies with more water-intensive crops.
Avocados from Mexico
The water footprint of a 4 ounce (113 gram) serving is 35 gallons (293 liters).
While the top avocado producing states in the United States are California, Florida and Hawaii, most avocados consumed in the US are imported from Mexico.
Avocado production is water intensive. Avocado plantations are primarily rainfed and require a significant amount of supplemental irrigation where they’re grown in drier regions.
Avocado farming can cause water pollution if fertilizers and/or pesticides are used, because the chemicals can run off into local waterways like streams and lakes. There is also a water footprint associated with processing, packaging and transporting avocados.
Mexico is a top avocado producing country, and most of the avocados there are grown in the water-stressed state of Michoacán. Orchards there have edged into protected areas like the Monarch Butterfly Biosphere Preserve. Lately, orchards have been increasingly established in the state of Jalisco, which, according to the WRI Water Risk Atlas, faces extreme water risk because 80 percent or more of the available water supply is withdrawn every year.
Concern over the water footprint of avocados has caused a group of chefs in London to take avocados off their menus, citing the high water footprint as one of the reasons. The avocados have been replaced with fava beans, and some chefs in Canada have followed suit. The World Avocado Organization points out that fava beans can also have a high water footprint and the chefs’ menus still include meat dishes, which, of course, have some of the highest water footprints.
The concern is warranted, as explained above, but the controversy has shone a light on how complex our food system and virtual water trade really is. Just about every food product has an impact on the environment and replacing one food for another based on reduced impacts can often be tricky.
Lettuce from Arizona
The water footprint of a 4 ounce (113 gram) serving is 7 gallons (59 liters).
More than half of all lettuce in the world is grown in China, followed by the US. California and Arizona dominate US lettuce production growing 71 and 20 percent of the country’s lettuce, respectively. In Arizona, lettuce is the top crop grown, and it comes mostly from the Yuma County area.
In Arizona lettuce is typically irrigated because there is limited rain, which drives up the water footprint. Lettuce farming can cause pollution when the fertilizers and pesticides that are applied to fields runoff into local waterways and leach into groundwater, streams and lakes.
Although lettuce is a thirsty crop in a dry state that is facing cuts to its irrigation water, surprisingly, lettuce farmers in Yuma County won’t face any cuts due to the way water rights in the west work, because Yuma County farmers hold senior water rights.
Undoubtedly, if the drought continues, those farmers will eventually face cuts and will have to find alternative water sources or stop farming, but the situation is complicated and demands reflection. Why are we growing water-intensive crops in dry places like the middle of the desert?
We used to eat seasonally, which means that if you lived in a place where lettuce was only grown during certain times, for the rest of the year, you didn’t eat lettuce. Now, just like with avocados, quinoa and coffee, virtual water trade allows us to eat (almost) what we want (almost) whenever we want it. The demand creates the impetus for the supply, and water availability makes meeting the demands possible.
Reducing our demand — perhaps through a return to eating seasonally or locally — is a ready-made solution to lowering the call on water from the Colorado River or other potentially far off locales, in order to satisfy our ever expanding palates. Do we need avocados from Mexico, coffee from Brazil or lettuce from Yuma, Arizona (when we live elsewhere)? Maybe, but we need water even more.
By Robin Madel
Image: Virtual water balance per country and direction of gross virtual water flows related to trade in agricultural and industrial products over the period 1996–2005. Only the biggest gross flows (>15 Gm3∕y) are shown. From Hoekstra and Mekonnen, (2011).