GEOFFREY LEAN: Freak summer or a glimpse of the future? Britain unlikely to see devastating droughts

Come with me on a journey to the future: To a Britain once characterised by grey skies, cool temperatures and copious rain – but no more.

Green fields have turned permanently brown. Food is scarce and drinking water rationed. Industry is on its knees. Blackouts are common. Wildfires rage. Pollution is growing. Diseases are spreading. And neighbours and communities are increasingly in conflict.

‘Whiskey is for drinking,’ Mark Twain once said. ‘Water is for fighting over.’ We now know he was right.

It is truly a dystopian vision. So what if this apparently freakish summer with record temperatures and drought declared in eight areas of England turned out to be a harbinger of the new normal?

Mike Rivington, a senior scientist at the James Hutton Institute in Scotland, believes: ‘We are seeing a clear signal of what the future is going to be like.’

Your first impression of that future could be favourable. The skies are blue, the sun is blazing and – though fields are parched –most trees seem in good shape, nourished by deep roots. It’s just like the Mediterranean! But look closer. Reservoirs and lakes are now baked mud and you can walk for miles along dry river beds.

Mountain torrents in the Lake District and the Scottish Highlands – normally fed by several metres of rain a year – were the first of Britain’s thousands of rivers and waterways to disappear.

Chalk streams and other rivers in the South and East lasted longer, fed by groundwater – previous rain which soaked underlying rock like sponge. But, with no replenishing rainfall, they too have dried up.

Estuaries of the Thames, the Tees and other rivers may still look full, but that is just salt water flowing back upstream from the sea.

Of course, all of this has had a devastating impact on water supplies. We used billions of litres every day, enough annually to cover the whole of Greater London to the height of a two storey building, by some estimates.

Two thirds of supplies came from reservoirs, lakes and rivers. The rest was drawn from groundwater. Now, unthinkingly turning on the tap is a thing of the past. In dry times, the lucky get water from street standpipes; others must queue for handouts of bottled water.

Agriculture and food production, which comprise the vast majority of Britain’s water demands, are suffering. On average, it takes 1,608 litres of water to produce each kilogram of bread, 3,178 litres for each kilogram of cheese, 3,300 litres for the same amount of eggs and a staggering 15,415 litres for beef. Nor can crops be planted in hard, dry ground.

Energy production, too, relies heavily on water. Power stations – whether fired by coal, gas or uranium – generate heat, which boils water, producing steam to drive turbines and generate electricity. Still more water is needed to extract fuel (it is vital in fracking) and to process it. Hence the blackouts that are a regular occurrence.

Surviving water bodies are increasingly clogged with algae as the nutrients that feed them are less diluted. Sewage, too, is more concentrated.

Disease will spread. With little water for cleaning and sanitation, diarrhoea and gastroenteritis are on the rise. So are respiratory conditions as dust, pollen and pollutants once washed away by rainfall persist in the air. Worse still, mosquitoes breed in the stagnant pools and – as the climate continues to heat up – diseases such as malaria, dengue fever and the West Nile virus will arrive. Wildfires will regularly scorch the landscape.

Internationally, shortages are sparking ‘water wars’. Ethiopia has a huge dam on the Nile, causing Egypt – which is downstream – to worry that it will suffer ‘absolute scarcity’ as a result.

Both countries have threatened military action. Other potential flashpoints include the Euphrates, which flows through Iraq, Syria, and Turkey, as well as the Jordan (Israel, the Palestinian West Bank, Jordan and Syria).

How prescient were the words of former UN secretary general Boutros Boutros-Ghali when he warned that ‘the next war in the Middle East will be fought over water, not politics’.

And, of course, in the wake of drought would come famine. There have long been fears of a ‘megadrought’ – which would last many years – in the US Midwest, whose crops help to feed more than 100 countries. That has not happened – so far.

Such is a terrifying worst-case scenario. In truth, Britain is most unlikely to see droughts on such a devastating scale. Yes, climate change is expected to bring hotter, drier summers, but warmer, wetter winters, too. But will that beneficial rainfall be enough?

Worldwide, precipitation is forecast to be more extreme. Last week, South Korea suffered its heaviest rainfall in 115 years with 10cm of rain falling hourly on Seoul, while California’s Death Valley received three-quarters of its annual rainfall in just three hours – ‘a once-in-a-1,000-year event’.

Shorter, sharper downpours are expected to increase in Britain, too. After weeks of little or no rain, the thundery showers predicted for this week risk running off the land more quickly, failing to replenish dry soils and leading to flooding.

Already London and south-east England normally get less rainfall per capita than the Sudan, Egypt or Morocco. The Environment Agency predicts they could run out of water within 20 years, without significant investment. Indeed, London is ranked ninth among the world cities most likely to run dry.

An Exeter University study has estimated that, by the end of the century, 40 per cent of the world’s population could be living outside the most suitable climate for humans – partly because of reduced rainfall – if global warming continues as at present.

So what can we do to ensure this hellish vision remains only that? In Britain water companies must stop the scandalous leakage that wastes a staggering three billion litres of water a day.

A water grid could be a better investment than HS2. So would reservoirs: We’ve not had a new one for 30 years. And it would help if we all reduced our comparatively high per capita water use.

But if we really value the rain that is so vital to our economies and our civilisation, we need to tackle global warming itself – fast.

Geoffrey Lean is a leading environmental correspondent and author.