Victorian meteorologists risked their lives to collect weather readings from Scotland’s Ben Nevis. Today, their sacrifices are helping us understand the effects of climate change.

Each year, 150,000 people hike Scotland’s Ben Nevis – a former volcano and Britain’s highest mountain, at 1,345m (4,400ft) above sea level. Many opt to take the so-called tourist trail, the rocky path which winds and zigzags its way to the summit. Few realise that this path was initially carved out in 1883 for a very unique scientific expedition. Even fewer know that now, more than a century later, this site is providing UK scientists with insights into climate change.

Back in Victorian Britain, science was still largely an amateur pastime conducted by bands of self-financed enthusiasts who formed scientific societies. One was the Scottish Meteorological Society, which set up and maintained a network of weather stations across Scotland between 1855 and 1920.

At the time, a key question was how depressions, storms and other severe climatic events form in the atmosphere. By 1875 mountain observatories were being established across the US, Mexico, India, France, Germany and Russia.

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Keen to gather similar data for Britain, the Scottish Meteorological Society decided to build a weather station at the top of Ben Nevis. For a trial run, one particularly intrepid member scaled the mountain every day for four months – through blizzards, gales, and heavy storms – to record measurements at the summit. Funding to build the station and obtain the instruments was raised through a kind of 19th-Century crowdfunding initiative. Even Queen Victoria donated.

And so began a remarkable experiment in Victorian stoicism and scientific endeavour. From 1883 to 1904, a few hardy individuals lived year-round in a small stone hut, surviving on tinned food and making hourly recordings of everything from atmospheric temperature to humidity, wind speed to rainfall. In total they made almost 1.5 million observations – often going to extraordinary lengths and risking their lives to record data in the most hostile of conditions.

“Many of their scientific contemporaries were involved in planning Arctic or Antarctic expeditions but these guys were pioneering explorers of the atmosphere,” says Ed Hawkins, professor of climate science at the University of Reading.

“They were living in very severe weather conditions: 100mph winds were not uncommon, the temperature would drop to -15C (5F) at times, and they lived inside a cloud for most of the year. But on the rare occasions the cloud was below them, they got the most amazing views. So I suspect they lived for those days where they could see for miles and miles around.”

The harsh realities of life at the top of a mountain quickly became apparent during the first winter of 1883. With heavy blizzards leaving the entire summit covered in a 5ft (1.5m) layer of snow, the three weathermen found themselves snowed in to such an extent that they had to repeatedly dig tunnels just to get out.

“They were very committed to try and take these measurements every hour, working in four to eight hour shifts throughout day and night. But very occasionally they were beaten by the weather,” Hawkins says.

Rather than being thwarted by their extreme living environment, the weathermen developed ingenious solutions like building a wooden tower which allowed them to crawl out onto the roof of the observatory, tethered to a rope, to take instrument readings in adverse weather. Occasionally they even resorted to using their own bodies to lean into the wind in order to calibrate estimates of wind speed – an activity which sometimes saw them almost blown off the mountain.

“The main danger they faced was that they were very close to the edge of the cliff,” says Marjory Roy, who wrote the book The Weathermen of Ben Nevis. “The summit is a longish ride, just 200ft (61m) wide with a sheer drop on the north side of 2,000ft (610m).”

“They also used to take measurements at a place high on the mountain known as ‘the plateau of storms’, and the path there was fairly narrow. If you weren’t careful, you would disappear off the cliff completely.”

Blizzards and precarious mountain paths were far from the only scares the weathermen faced. On a couple of occasions the observatory was struck by lightning. The first time, the lightning came down the chimney and set the wooden lining of the building on fire. (The blaze was extinguished.)

During the summer and autumn months, when life was a little less arduous, the observatory attracted a number of volunteers, mostly students. One was Charles Wilson, who was inspired to study clouds by his experience at the top of the mountain. He later won the Nobel Prize in Physics for the invention of the cloud chamber, the first device to make it possible to detect radiation and subatomic particles which we cannot see with the naked eye.

“Wilson was only there for two weeks, but during that time he got the most brilliant period of anticyclonic conditions and glorious views,” Roy says. “It was those things which inspired people. There were a number of people whose experiences up there influenced them to go on and discover things which made them famous.”

By 1904, the Scottish Meteorological Society could no longer afford the observatory’s running costs. It was closed down, and the data largely has remained hidden in the dusty pages of archives ever since.

Second life

Today, we have advanced weather forecast models – which are capable of using the kind of data taken at Ben Nevis to generate three-dimensional pictures of the atmosphere. Climate scientists now hope to use these models to re-observe famously severe storms from more than a century ago, such as a 1903 storm which wreaked havoc in Ireland before passing right over the top of Ben Nevis the following day.

The first step – in a project which Hawkins is leading – is to compare the historical data from Ben Nevis to modern weather readings.

“We live in a part of the world which gets storms and we’ll always have them. But we’re trying to understand whether these storms are becoming more or less frequent, are they becoming more severe, are we getting more rain out of these storms, are they changing direction?” Hawkins says. “Going back in time and looking at the storms of that period enables us to compare with the storms of today, and look at the potential changes which have resulted from human-driven warming of the atmosphere over the past century.”

But these goals met a slight setback. Feeding the original Ben Nevis weather data into a computer model requires all the observations to be digitised. While the thousands of pages of observations were published in scientific journals in the early 20th Century and have been subsequently scanned, typing all 1.5 million into an online database would take years.

And so thousands of volunteers across Europe have helped digitise the observations over a period of just 10 weeks in autumn 2017.

As a result, Hawkins’ team is now looking at how the amount of moisture in today’s storms compares to those in the late 19th Century. “A warmer atmosphere can hold more moisture, and so when it rains in a storm today, we expect the amount of rain to be much greater compared to a storm a century ago, of the same severity,” he says. “It’s a fingerprint of how things are changing in a warmer world.”

Today, plans are underfoot to build a new modern observatory on the ruins on the former site – albeit with automatic measuring devices rather than human inhabitants. “We haven’t had any long-term observations up there for a long time now, and this would give us information straight away on how the climate at the top of the mountain has changed,” Hawkins says. “We think that the high altitude regions are some of the places where we’ve seen the largest changes in temperature.

“This could tell us a lot.”

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