I TRAVEL a lot for work, and everywhere I go people talk about rain. I was in Uganda last November and heard grumbles that the rainy season had failed to arrive. In Albania in March, I read about plans to export water to drought-stricken Italy. I visited Saudi Arabia in June and was told about an unexpected torrential downpour in the desert.
It is easy to shrug at all this. After all, we already know climate change is disrupting the weather. And the rain will fall eventually because water is infinitely renewable. It falls from the sky as rain, variably but reliably. Doesn’t it?
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The answer, increasingly, is no. “We’ve allowed ourselves to think that water is simply something that comes back every year and there’s a stable water cycle and we can trust it,” says at the Potsdam Institute for Climate Impact Research in Germany. But that is changing as a result of human activity. “We must recognise that – oh my God – we’re actually not able to trust the source any more.”
This isn’t vague scaremongering. Rockström has just carried out a serious analysis of our water systems and concluded that they are broken. So how bad is the damage? And is there anything we can do as individuals or as a society? Broadly, the answers are that the damage runs deep, but it is still fixable – just.
The hydrological cycle is a complex, interconnected system that circulates freshwater between rivers, lakes, wetlands, groundwater, ice, water vapour in the atmosphere, clouds and precipitation. It has been extremely stable during the Holocene, or the past 11,700 years, during which temperate climatic conditions have allowed humans to thrive. But geologists are on the cusp of declaring that we are now in a new, human-influenced geological epoch called the Anthropocene. Part of our impact is that we increasingly suck the system dry, extracting ever-more water for agriculture, industry and use in our homes. Until recently the hydrological cycle could cope, but there are signs that the taps are about to turn off.
In March, in recognition of a looming crisis, the United Nations convened a Water Conference in New York, only the second in its history. The first was in 1977, in Mar del Plata in Argentina, where 118 countries agreed that there should be universal supply of water and sanitation by 1990. “We are now in 2023 and we know how far away we are still from that,” says , chair of the Global Water Partnership, a network that includes thousands of water-related agencies.
But it is even worse than that. The word on everyone’s lips at this year’s conference was “crisis”. Not only do 2 billion people lack adequate access to clean water, the entire hydrological cycle is being thrown out of its comfort zone by the double whammy of climate change and land degradation. Some places are getting wetter, others drier. The net result is that the largely stable distribution of rainfall in which humans evolved and flourished is no longer. “There is simply not enough fresh water left any more,” Hungarian diplomat Csaba Kőrösi, president of the 77th session of the UN General Assembly, told the conference.
Planetary boundaries
In 2009, Rockström, who was then at the Stockholm Environment Institute in Sweden, pioneered, with others, the concept of “planetary boundaries“, nine global life-support systems that we must keep within certain limits to maintain a habitable Earth. One of them was freshwater use, which Rockström and his colleagues decided – unlike climate change, biodiversity loss and the nitrogen cycle – was still well within safe limits. They defined the boundary as consumption of no more than 4000 cubic kilometres of fresh water per year, and said that actual consumption was 2600 cubic kilometres per year. But they warned that, under a business-as-usual scenario, the boundary would be approached by mid-century. They reviewed this position in 2019 and concluded that, again, freshwater use was within safe limits.
Now, however, the situation has taken a dramatic plunge. The original planetary boundaries analysis only considered the extraction of fresh water. In a new paper, Rockström and his colleagues did a . They created two new freshwater boundaries: flow alteration of surface water and extraction of groundwater. The former is key to freshwater biodiversity, drinking water and the fisheries upon which millions of people depend; the latter contributes to flows in river systems and sustains wetlands and plants.
We are breaching both. For flow alteration, they set the boundary as a 20 per cent decrease or increase over the natural flow. “Once we start altering flow regimes by more than 20 per cent, we start to see significant impact to freshwater systems and the essential services that they provide [to humans],” says , a co-author of the paper who is at the Australian Rivers Institute at Griffith University, Brisbane. Globally, we are within the boundary, but a third of land areas, which are home to half the world’s population, have exceeded it.
The situation for groundwater is even worse. For this, the researchers defined the boundary as extraction not exceeding replenishment. By that reckoning, 47 per cent of the world’s groundwater basins are in decline. This is enough to push us over the global boundary. It was recently reported that humanity has extracted so much groundwater that the planet has shifted on its axis. The water is still there, but has been redistributed from below to above ground, causing .
Green water
That conclusion is made even more alarming by a separate study, also conducted by Rockström and his colleagues and published last year. It proposed a . This refers to moisture in the soil and atmosphere, which comprises around two-thirds of all fresh water on Earth. Surface water such as that in rivers, lakes and reservoirs is classed as blue water, as is that within aquifers.
Green water is the lifeblood of the water cycle. “It powers all biomass production on Earth, secures food security and is the basis also for large parts of livelihoods and economic development,” says Rockström. Around half of all rainfall comes from the venting of green water vapour into the atmosphere from trees and other plants, a process called transpiration. The vapour will often travel long distances in the atmosphere before eventually falling as rain. Some of the UK’s rainfall, for example, originates in the forests of central Europe.
The criterion Rockström and his colleagues set to assess this precious, but long-neglected resource is the percentage of ice-free land in which soil moisture in the part of the ground where we find plant roots significantly deviates from its normal baseline for a whole month. Soil moisture is a good indicator of the state of green water as it is directly affected by changes in the two fundamental processes of the water cycle, precipitation and evaporation. They further calculated that if more than 10 per cent of ice-free land gains or loses excessive amounts of soil moisture, the green water boundary is a busted flush.
The estimate of Rockström and his colleagues, based on pre-existing soil moisture data, is that this boundary has been exceeded across 18 per cent of ice-free land, meaning that it has been “considerably transgressed”.
This is due to climate change, but also alterations in land use, says Rockström. “When we have deforestation, we lose the green water flow,” he says. In the Brazilian Amazon, for example, tree loss has greatly lowered the amount of water vapour entering the atmosphere, reducing rainfall across the region. Deforestation of the Congo river basin is depriving Nigeria and other countries in West Africa of their once-reliable rainy seasons. Similar things are happening across the world, as formerly intact ecosystems are deforested and degraded. Add this all up and we are facing a completely new magnitude of global water crisis, says Rockström. “We are taking colossal risks with the future of civilisation.”
It seems, then, like we need to engage in a wholesale recalibration of the way we use water. I wondered to what extent our personal water use is to blame for the crisis. To find out, I decided to take a look at my own water footprint.
I live alone in London, and according to the bill from my water supplier, I use 110 litres a day on average. This is less than is typical for a single-person household, which is 150 litres a day. But it still seems an awful lot, about half a bathtub. I drink maybe 2 litres a day and use another 30 to 40 in the shower (yes, I measured it). The bulk comes from running my washing machine and dishwasher, flushing the toilet and watering the garden during our increasingly parched summers.
Water footprint
That is just my direct use of water, though. All of us also use vast quantities indirectly, in the sense that more or less everything we use and buy – from food to clothes and the packaging they come in – requires water to produce. According to Rockström, the average person needs 3000 litres a day to support their basic needs when you consider both indirect and direct usage. That is 1200 cubic metres per person per year, about what is needed to fill three 25-metre swimming pools.
I estimated my own combined consumption online using the created by the Water Footprint Network, a collaboration between companies, organisations and individuals. I discovered that I use roughly 430 m3 per year, or 1180 litres a day. That is fairly low, but I don’t eat meat, I avoid dairy and I don’t have a car to wash.
By far the biggest component of my water footprint comes from the food I buy: 30 m3 per year from vegetables, 61 from fruit and a shocking 153 from coffee. I don’t drink half a swimming pool of coffee a year – half a litre a day at most – but the crop is water-intensive. The UN estimates that . I had no idea. I just throw a bag of coffee beans in my supermarket trolley without a moment’s thought. Getting to know your water footprint can be a shock, but it does at least offer the opportunity to change (see “How to cut your water footprint”). If I switched to tea, that part of my footprint would fall by 53 per cent. But I much prefer coffee.
I guess my reluctance to swap coffee for tea makes me part of what Rockström says is the fundamental problem with our relationship with water. He says that the world has got used to exploiting it as an effectively infinite resource. “It’s incredible that somehow the modern world has been allowed to take water for free and for granted.”
The action we need to take to rectify this goes way beyond personal choices. We also need systemic changes – and fast. “We broke the hydrological cycle,” says , the Netherlands’ special envoy for international water affairs. “Now we have to bring it back again. There’s a possibility for that.”
The most obvious fixes involve getting to grips with deforestation and keeping global warming to a minimum. But another crucial step, according to a report by the newly-formed Global Commission on the Economics of Water, of which Rockström is a member, is to rather than a national commodity to be profited from and squabbled over. Yet that is easier said than done. “The truth is that we don’t have a proper economics of the common good,” says commission member Mariana Mazzucato at University College London.
A good start would be to bring green water into the reckoning. “In water policy, we tend to only focus on the blue water,” says Rockström. Adding green water would allow neighbouring countries to agree how to co-manage their shared rainfall, much as they often do with blue water.
Farming is a huge consumer of water, accounting for around 75 per cent of global use. That is partly driven by more than $500 billion a year in subsidies that drive overproduction and overconsumption of water-intensive products in water-scarce regions, says commission member , director-general of the World Trade Organization. Global trade can help, she says, with thirsty crops grown in wet countries and dry-tolerant crops in drier ones, and then exported.
Investing in smart irrigation systems can reduce agricultural water use massively and this pays for itself in one to three years, says commission member Tharman Shanmugaratnam, until recently the senior minister of Singapore, one of the most water-stressed countries in the world. Ditto water use in industry and mining. “We need innovation around recycling industrial waste water,” says Mazzucato. “We waste an immense amount of water in how we do industry.”
Domestic water supplies are also massively wasteful, and not just because they leak. The UK, for instance, mostly has a mixed sewage system that combines rainwater and human waste and treats them together. “It is absolutely bonkers to take perfectly good rainwater, intentionally mix it with sewage, put a huge amount of effort to get it somewhere, put energy into separating it again, and then flush our toilets with the fresh water,” says Andy Mitchell, CEO of Tideway, a water company that is building London’s new “super sewer”. What’s needed is to create a whole new infrastructure to treat rainwater and sewage separately and use “grey water” from washing machines and dishwashers to flush toilets, he says, but that will take decades.
Yet these efficiency gains will amount to a drop in the ocean unless we fix the fundamental problems. “If you want to be sure you have any water to operate efficiently with, then you need to secure the source, and the source has to be secured by managing the climate and nature,” says Rockström.
How to cut your water footprint
Want to reduce your water consumption? There are changes you can make to the way you use water directly at home, such as installing a water butt if you have a garden or turning off the taps when you brush your teeth. But, perhaps surprisingly, you can have a far greater impact by changing your consumer habits.
Take fashion. Cotton is an especially thirsty crop: it takes about . Eschewing fast fashion or buying second-hand is a huge water saver.
Dietary changes can also have a big impact. Some of the foods that take a lot of water to produce (see top 10, below) aren't so surprising. Animals clearly drink a lot of water as they are reared, so it makes sense that meat has a vast water footprint. But I hadn't previously thought about how much water it takes to grow luxuries like coffee, chocolate and vanilla. Reducing our consumption of these most-thirsty foods could be a big win.
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