Water is a scarce resource, and the agrifood industry is one of its more significant users. Food demand is expected to rise in the coming decades. Hence, taking measures to use water efficiently is a crucial requirement to secure our future food supply. Furthermore, climate change is expected to stress food production and water systems in even greater ways, so analysing sustainable indicators, such as the water footprint, is fundamental to develop a more resilient agrifood industry.
The term water footprint indicates the amount of freshwater used in any given activity or process. The Water Footprint Network developed the concept and according to them,
“The water footprint is a measure of humanity’s appropriation of fresh water in volumes of water consumed and/or polluted.”
The water footprint can be measured for a single product or a single process. For example, it can be measured for a single shirt or, or complex processes such as growing wheat or gas to heat residences, for an entire company, or a country.
Furthermore, this measurement can even be done for a specific aquifer or river basin or globally. The water footprint analysis considers both direct and indirect water used for a product, process, sector, or company; this includes water consumed and polluted during the full production cycle, from the suppliers to the end-user.
The invisible but measurable use of water
Additionally, virtual water is water that is hidden in the products, services, or processes. Virtual water is also called embedded water or indirect water; this type of water use is usually unseen by the end-user, but it is still part of our everyday water consumption. For example, water is used to prepare risotto or a loaf of bread (direct use); however, water is used in many steps along the value chain before it reaches our cupboard, including growing the grain, milling it, water used to produce the fuel needed for processing and transportation, all of these constitute virtual water uses.
The three components of the water footprint
Water footprints are composed of three different types:
- Green water footprint comes from precipitation; it is stored at the soil’s root zone and is evaporated, transpired, or incorporated by plants. This type is particularly relevant in horticultural and agricultural products.
- Blue water footprint has been sourced either from surface or groundwater resources. Domestic water use, industry and irrigated agriculture have a blue water footprint.
- Grey water footprint is the amount of fresh water needed to assimilate pollutants, so after being treated, it can meet quality standards. In the case of agriculture, this relates directly to runoff.
Water footprint in the agrifood sector
Agriculture is one of the economic sectors that use more water. On average, agriculture accounts for over 70% of all freshwater withdrawals globally. From the water used in agri-food, 78% corresponds to green water footprint, 12% blue, and 10% grey. In the US, around 80% of the country’s water use is dedicated to agriculture. In some western states, agricultural water use can even be higher than 90%.
When analyzing agricultural products, in general, animal products have a larger water footprint than crop products. On average, the water footprint per calorie of beef is 20 times larger than for starchy roots or cereals.
Among primary crops, the global average water footprint goes up from sugar crops (roughly 200 m3/ton), to vegetables (300 m3/ton), roots and tubers (400 m3/ton), fruits (1000 m3/ton), cereals (1600 m3/ton), oil crops (2400 m3/ton) to pulses (4000 m3/ton)(UNESCO-IHE, Institute for Water Education).
However, it is important to notice that this is the world average; the water footprint changes between countries and regions and each specific product. Coffee, tea, cacao, tobacco, spices, and nuts have a relatively large water footprint.
Additional data, from the UNESCO-IHE, Institute for Water Education, show that for animal products, the global average water footprint goes up from chicken egg (3300 m3/ton), cow milk (1000 m3/ton), chicken (4300 m3/ton), goat (5500 m3/ton), pig (6000 m3/ton), sheep (10400 m3/ton), to beef cattle (15400 m3/ton). The global animal production water footprint is divided into 87% green water footprint, 6% blue, and 7% grey.
When comparing water requirements for different types of proteins, milk, eggs, and chicken are about 1.5 times higher than those for pulses. When we compare with beef, a gram of meat protein has a six times larger water footprint than pulses.
Avocado’s water footprint
Avocado consumption is expanding worldwide, accompanied by greater demand, production is also rising. The production of avocado typically occurs in tropical, subtropical, and Mediterranean climates, where water consumption tends to be high, droughts frequent, and commercial-scale plantations usually require supplementary irrigation. Avocado’s green water footprint ranges from 31 m3/ton in Saint Lucia in the Caribbean to 4,494 m3/ton in Beja, Portugal. In contrast, its blue water footprint ranges from 0 m3/ton in Grenada and some Guatemala regions to 2,295 m3/ton in the north of Chile. Nonetheless, among the top avocado-producing countries, Mexico has the largest water footprint.
Banana’s water footprint
Banana production requires a large and frequent water supply to ensure good productivity and quality. As a worldwide average, bananas have a green water footprint of 600 m3/ton, while it’s blue water footprint is 97 m3/ton, and its grey water footprint is 33 m3/ton. Studies have calculated that about 99% of the water footprints correspond to the agricultural production phase, so it is key to have well-working irrigation systems. In countries such as Costa Rica, where no irrigation is needed, all the water footprint is green; in other cases, such as Peru, where there is a high dependence on irrigation -and the systems are inefficient-, 94% of the water footprint is classified as blue.
What can you do to reduce your food water footprint?
You can take several steps to reduce the water footprint embedded in your food choices; among them are eating less meat, eating more unprocessed products, reducing your food waste, and eating locally.
Water scarcity, a complex problem beyond shortages
Water scarcity can be related to availability due to physical shortage, or lack of adequate infrastructure, or access due to institutions’ failure to ensure a regular supply. Water scarcity already affects the inhabitants of every continent. UN data reveals that over 2 billion people live in countries experiencing high water stress, and 3.2 billion people live in agricultural areas with high water shortages. The Middle East and North Africa is the most water-stressed region on the world. But even in countries with low overall water stress, there are regions affected by this situation.
Ways to reduce water stress
- One of the main ways to reduce water stress is to increase agricultural efficiency. This can be done by using seeds that require less water, improving irrigation systems, by using high-precision watering techniques rather than flooding the fields.
- Investing in grey and green infrastructure, pipes and treatment plants, and healthy wetlands and watersheds can work together to increase water quantity and quality.
- Wastewater is not waste. By safely treating and reusing wastewater, we are actively creating ‘new’ water.
- Reducing food loss and waste, all the food produced requires significant quantities of water to be grown, processed, and transported. Almost a third of all the food produced is wasted; every kilogram that we can divert from the garbage constitutes litres of water saved. Among the methods to reduce food loss is to treat them with protective materials, such as coatings, to make them last longer. PolyNatural offers Shel-Life, a natural coating that reduces rot incidence and dehydration.
Climate change and a growing population will make producing enough food for everyone a challenge in the near and far future. Growing our food efficiently and sustainably is critical to ensure that enough fresh water will be available for everybody. Among the key strategies that your company can take to reduce their water footprint is to ensure that their products last for a longer time, helping in that way to reduce food waste and increasing their sustainability indicator.