Water, water everywhere?

Could a famously rainy country like the UK really run low on water? Through a combination of climate change and population growth—it might.

Tuesday, May 19, 2020,
By Jon Heggie
Where our Water goes - United Kingdom
Where our Water goes - United Kingdom
National Geographic photographer Charlie Hamilton James heads across the UK to find out how our famously wet country could be facing water shortages in the next 25 years.

Almost wherever you were across the British Isles, March 2019 was particularly wet. As precipitation hit 140 percent of the monthly average, rain caused road accidents in Scotland, rivers burst their banks in Yorkshire, snow stopped traffic in Cumbria, railway lines were washed away in Wales, shoppers waded through the streets of Manchester, storms lashed London and the southeast, and there were landslides in Kenton and flooding in Northern Ireland. The idea that we could run low on water seemed incredible—there was too much water, not too little. But as Britain pulled on its wellies and opened its umbrellas that March, Sir James Bevan, the CEO of the Environment Agency, was painting a very different picture: in 25 years England would not have enough freshwater to meet demand. 

His stark warning reflected a wider projection that Britain as a whole could experience significant water shortages in coming decades. The key drivers of future water stress in England, notably climate change contributing to a decrease in water supply and population growth causing an increase in demand, would also affect Wales, Scotland, and Northern Ireland. With increasing pressure being placed on our water sources, projections are that water shortages will begin to affect all parts of the UK. For a famously damp country, the future is looking much drier than we might imagine.

But the UK is not actually as wet as we think. While our temperate climate brings frequent rain, an average of 133 days totalling 885 millimetres, our notoriously variable weather means that dry spells can come at any time of year. This unpredictability is partly due to Britain’s geographical location in the mid-latitudes, where warm and dry tropical air from the south collides with cold and wet polar air from the north; whichever air mass gains dominance will dictate our weather. At the same time, warm moist air from the sea is driven by our prevailing south westerly winds onto our western uplands where it rises over the mountains, cools, condenses, and releases rain. This not only makes the west wetter, it also keeps the east drier: the UK’s highest peaks can receive 5,100 millimetres of rain, but the Thames estuary and London might receive just 10 percent of this. In fact, despite all the stereotyping, London gets just 106 days of rainfall a year, and only around 600 millimetres of rain—about half the average rainfall of Sydney, Australia. Although it certainly rains in the UK, it doesn’t rain everywhere all of the time. 

While there’s no denying that the UK is currently a wet place, our weather is also notoriously unpredictable. Dry spells can hit at any time, and statistics suggest that we could actually run low on freshwater in the next 25 years.
Photograph by Charlie Hamilton James

And climate change is altering our weather. In the last two decades we have had nine of our ten warmest years on record; in summer 2019, after three dry years, river levels dropped so much that some waterways disappeared. There could be worse summers to come. By 2040, more than half our summers could be hotter than some of the hottest heatwaves the UK has already experienced, river levels could drop by as much as 80 percent, and water shortages could be significant. The pattern of rainfall is also shifting: winters will be generally wetter and summers would be much drier. While more winter rain sounds like a boon, it will likely fall in intense downpour events during which rain is difficult to capture: a winter flood won’t necessarily assuage a summer drought. 

Drought occurs during an extended period of unusually dry weather when evaporation and transpiration by plants exceeds precipitation. In the UK, it is specifically defined as a period of at least 15 consecutive days in which rainfall doesn’t exceed 0.2 millimetres. Although droughts are a temporary natural phenomenon that have always been a feature of the UK climate, the southeast is particularly susceptible to drought; East Anglia has been officially classified as semi-arid and receives even less rain than many parts of Italy. But droughts are not restricted to our drier areas―even Yorkshire and Scotland have experienced droughts in recent decades. Across the UK, climate change projections are for more frequent, more severe, more widespread, and longer-lasting droughts that will contribute to UK water stress—and water shortages. 

Climate change and a growing population are primary concerns for our future water supply— warmer weather will likely bring the rain down in intense cascades that are hard to capture, while more people consuming water will stress a decreasing supply.
Photograph by Charlie Hamilton James

The rain that we famously complain about is really the water that we rely on to come out of our taps. Water authorities take water from our rain-fed rivers, reservoirs, and aquifers, treat it, and then pump it into our homes through some 208,000 miles of pipes. Our wastewater is then collected, treated, and discharged back into rivers and the sea, where it evaporates, rises, and condenses to form clouds, and so the cycle continues. Water stress occurs when demand increases in relation to supply; a country using more than 40 percent of its available water is considered dangerously vulnerable to drought and water stress. In the UK, climate change could mean less water will be entering our water system at the same time that more water is being drawn out, significantly straining our water supply. 

By 2050 the UK is projected to have an extra 12 million people increasing demand on a what could very well be a diminishing water supply; the majority of this growth will occur in the already water-vulnerable southeast. Across the UK we currently use around 143 litres per person per day for hygiene, cooking, cleaning, and drinking. As temperatures rise, so does demand for water: heatwaves can increase domestic water use by nearly a third as people drink more, water gardens, and fill paddling pools. Climate change would most likely mean an increase in water demand in the agriculture sector. The UK is unusual in that it uses less of its water for farming compared to the global average. But hotter and drier weather could significantly increase the need for irrigation to keep crops alive. With projections likening London’s climate in 2050 to Barcelona’s today, the corresponding increase in water demand for agriculture could seriously impact―and strain―our water supply. 

However much water we think we have, the reality is that we might not have enough. The warnings issued by Sir James Bevan couldn’t be clearer: in his March 2019 speech, he cautioned that the country is facing “an existential threat” and reaching “the jaws of death … we will not have enough water to meet our needs.” To counter the combined challenges of climate change and population growth he called for a dual approach of increasing supply and reducing demand. Through sweeping improvements from building more reservoirs to making water waste socially unacceptable, he remained positive that this is a challenge we can overcome. Businesses and local authorities have their part to play, both in ensuring the integrity of the UK’s water infrastructure and making the public more aware of what they can do on a consumer level. The Environment Agency, for example, works with policy developer Water UK to create ‘Love Water’—a campaign designed to increase the general public’s awareness of their water use along with measures they can take to help reduce it. 

As Sir James has laid down the water-saving gauntlet to everyone across the country, it’s certainly clear that water conservation must begin to seep into public consciousness, especially if we want to ensure the UK’s water future.

LEARN MORE

Read More