As US farmers struggling with one of the worst droughts in living memory will tell you, a scarcity of water can be crippling to jobs and livelihoods, even in the richest nation on Earth. Amid the rice paddy fields of south-eastern Texas, the situation looks especially bleak.
Last week, the Lower Colorado River Authority voted for a second year running to withhold vital water from downstream farmers, citing precariously low reservoirs and a need to protect town supplies. It was a bitter blow for Edward Sunderman, manager of the Lucy Sunderman Farm in Colorado County, who depends on water as the lifeblood of his business.
"We don't have any crop unless we got irrigation," he says in his distinctive southern drawl. "I'm worried we might lose the farm 'cause we don't have any income." Sunderman, whose family-run farm has been operating since the 1940s, believes the dearth of water will devastate regional productivity. "There's 60,000 acres of rice that won't be planted all the way from here to the Gulf of Mexico."
The food industry's reliance on water, and susceptibility to drought, of course is nothing new. According to the United Nations' Food and Agriculture Organisation, food production accounts for 70% of all the freshwater extracted from lakes, aquifers and waterways – rising to almost 95% in developing countries. Industrial usage pales in comparison at 22%.
Erratic and extreme weather, much of which is caused by climate change, only serves to highlight and exacerbate the industry's dependency problem. Yet with two-thirds of the planet predicted to live in water stressed regions by 2025, and a world population hurtling towards eight billion, competition for this precious resource is only set to grow.
Greater affluence in emerging markets and a predilection for water intensive, western-style appetites is seemingly aggravating the problem. According to the International Fund for Agricultural Development, 1,000 to 3,000 litres is generally required to produce a kilogramme of rice, while a kilogramme of grain-fed beef will sap some 15,000 litres. A tomato requires just 13 litres.
Such is the gravity of the growing water/food crisis that scientists from the Stockholm International Water Institute warned last year that unless industry and consumers drastically re-orientated toward vegetarian products by 2050, there may not be enough freshwater to feed the world's population.
"A vegetarian diet is less resource intensive not only in terms of water, but also land and energy use," says professor Jan Lundqvist, senior scientific advisor at the institute. "The problem is that a large part of the world's population is not used to only having vegetarian food." As such, Lundqvist believes businesses and consumers must also be persuaded to reduce excessive overeating and wastage.
"The amount of meat and dairy products that people are buying is much larger than they are eating. If people were more conscientious and would eat only what is necessary from a nutritional point of view, the demand for meat and dairy products could be reduced substantially," he says.
"Water scarcity and getting access to affordable, nutritious food are undoubtedly some of the biggest risks facing humankind – and they are likely to get worse in the future," says Dan Crossley, executive director of the Food Ethics Council, based in Britain. "However, it's not as simple as suggesting we all switch from food with high water footprints, like beef, to food which requires less water.
"Water's a very localised issue, and it's not just the quantity of water that's important, but also the quality."
Allegations abound of manufacturers in developing countries depleting or damaging local freshwater to produce nutritiously dubious products, but, even where operations do not impact a community's supplies, can multinationals really justify creating water intensive foodstuffs for foreign markets when so many in the source nation lack clean water?
Crossley suggests the issue is fundamentally an issue of rights. "We should not assume," he explains, "that we in the UK somehow have more of a right to the water that goes into producing our green beans or our tomatoes than those living in the [places] where they're grown."
Aware that water scarcity presents real challenges, the cohort of companies looking to find solutions is expanding. In Britain, industry body the Food and Drink Federation launched the Every Last Drop campaignto focus on the practical steps that can be taken to conserve water, including tracking usage and reducing, recycling and reusing supplies.
Food manufacturers "want to be responsible and do the right thing" insists Andrew Kuyk, the federation's director of sustainability. "What we eat in this country does affect the availability of water for domestic communities in Africa, South America, Australia or various other parts of the world – there is an inter-connectedness through global supply chains."
Around a quarter of food and drink manufacturers in England and Wales have now committed to reducing water usage by 20% by 2020. But if they want to fully protect themselves against future water crises, they need to think about the whole of their supply chain, says Kuyk. "In some parts of Africa the combination of temperature rises and water scarcity will mean that some traditional crops may not be viable in ten years time. So if you are a chocolate manufacturer you need to start thinking: what are the potential alternative sources?"
Many observers point to technological changes to help avert water crises. From genetic engineering and innovations in purification and desalination to novel changes to irrigation, recycling, piping and storage, there is reason to believe that water scarcity is not an "insoluble" problem, says Kuyk.
But as long as water is cheap, the disincentive to invest in water efficiency may be too great. "If you can turn a tap on and get water for free, why would you spend £20,000 installing a piece of machinery?"
Desperately seeking less water reliant crops, Sunderman has experimented with soy beans and sesame seeds, but to little avail. "Nothing else will grow here," he says, reflecting on Colorado County's all too changeable climate, where long periods of dry can be interrupted by short, sharp downpours.
