The invisible water in our food

What does water conservation mean to you? To the average person, this may mean showering for a shorter amount of time or not leaving the faucet running—this ‘visible’ use of water however only accounts for around 10% of our global water consumption.[1]Where is the rest of this water that is invisible to us?

World Water Day is coming this Tuesday, and this year’s theme is on making the invisible groundwater visible.

Today, 70% of global freshwater that is withdrawn is used in agriculture.[2]40% of irrigation on 40% of irrigated land is sustained by groundwater resources.[3]Meat—particularly beef—is the poster child of heavy water (and carbon) footprint. To put it into better context, it takes about as much water as showering 30-40 times to make an 8-oz. (226 g) steak.[4]

Meat-heavy diets are a notable problem with urban populations as standards of living improve. This, of course, includes Hong Kong—a city with one of the biggest appetites for meat. [5]This is reflected in a 2019 study, which found the city’s diet has a water footprint of around 4,700 litres per person per day—double than that of the average Chinese diet.[6]

It would be unfair to just blame meats however, as there are other parts of our urbanite diet that are big water guzzlers as well. Take the beloved coffee for example: that cup you are drinking right now contains 140 litres of water.[7]While it may not sound like much, a typical coffee drinker drinks more than a cup a day. The average person in Hong Kong drinks 165 cups in year, but this rises to 400 in Japan, and as much as 800 in Europe.[8]

Besides getting that caffeine rush, rising health consciousness also puts a strain on water resources. For example, almonds are popular among the middle-class Chinese, who are spending more on health foods.[9]Growing almonds however has worsened water problems in drought-prone California—the largest almond exporter.[10] It takes almost 300 litres of water to make a cup of almonds.[11]

Similar problems can be seen in Latin America with farms drawing more than their fair share of water to fuel the superfood craze for avocados.[12]

With climate change, these issues will only be exacerbated. Changes in precipitation patterns will lead to rainstorms becoming more intense but less frequent, causing excess rainwater to run off instead of replenishing groundwater. Dry seasons will become dryer as the groundwater is not replenished as quickly as it is withdrawn.

To just see how it will look like in the future, Yunnan suffered its worst drought in the decade in 2020, when hundreds of rivers, reservoirs and wells dried up. Around 1.5 million people saw drinking water shortages and some 300,000 hectares of crop were damaged as a result.[13]

Climate change will make wet regions wetter with intense rainstorm, but it will be more difficult to capture this extra rainwater. (Image source: Carbon Brief)

In the end, whether it is to reduce your water footprint or for health reasons, it is better for you and the planet to adopt a plant-heavy diet. Opting for fish only or even going fully vegetarian can cut your water footprint by 35-55%.[14]Even just eating meat less often will reduce your virtual water use by at least 11%.

There is however a need for farmers to grow crop more sustainably; and for us consumers to look at food for more than just their direct, ‘visible’ health benefits—water being just one of the many other factors. Being more aware of how food is made is certainly a start.