Britain’s official rainfall records now go back to the year before Queen Victoria ascended the throne, thanks to the efforts of thousands of volunteers who, cooped up at home during Covid, were brought together by their passion for a very British preoccupation: the weather.
It began when Ed Hawkins, a climate scientist at the University of Reading in England, put out a call for help transcribing more than 65,000 handwritten logs of monthly rainfall, spanning three centuries, from across Britain and Ireland.
The writing in the records was too irregular to be read by machine; human eyes were needed. More than 16,000 people answered Dr. Hawkins’s request, and together they chewed through the task in a little over two weeks.
That was two years ago, during Britain’s first coronavirus lockdown. Now, the nation’s weather agency, the Met Office, has processed 3.3 million data points from the transcribed pages and added them to its national rainfall statistics, enriching the official record with many more observations and extending it back to 1836. Among the newly digitized information is fresh detail on the curious weather of 1852, when an exceptionally dry spring was followed by severe flooding in November and December.
“If the weather that conspired to bring us so much rain in 1852 happened again, it would probably be putting more rain onto our island because we live in a warmer world,” Dr. Hawkins said in an interview from Reading. Having better information on past extremes can help buttress our defenses against future ones, he said.
Dr. Hawkins and a team of volunteers and other researchers lay out how they processed and cleaned up the data in a study published on Friday in Geoscience Data Journal.
“We’ve hardly scratched the surface” of what there is to learn from Britain’s climate archives, he said. “The U.S. has enormous archives as well, at NOAA, which haven’t yet been explored as fully as they might be,” he added, referring to the National Oceanic and Atmospheric Administration.
The Met Office knew the value of the data in the old rainfall logbooks when it scanned them in 2019, said Catherine Ross, an archivist at the agency and an author of the new study. But it was only because of volunteers during the 2020 lockdown, Dr. Ross said, that the ornately, sometimes idiosyncratically, handwritten information was made useful for scientific analysis.
The records start in 1677 with measurements from scattered observers. By 1860, data collection was being coordinated by the British Rainfall Organization, which would later become part of the Met Office. More people got involved: ordinary citizens, clergymen, wealthy landowners who entrusted the task to gardeners and groundskeepers. This last category apparently included the royals: Among the archives are rainfall readings from Buckingham Palace, Kensington Palace and Sandringham House.
“It’s the Victorian Age: People want to control, measure, understand statistically far more in detail,” Dr. Ross said. “There’s this increased understanding of, ‘We can collect observations and do something with them.’”
In notes they kept with the rainfall logs, the record-keepers reveal the care they invested in the task, and some of the challenges. Rev. W. Borlase, in the village of Ludgvan, Cornwall, added this footnote to his reading for October 1770: “Receiver quite full. Might have run over. Don’t know.”
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The observers documented various indignities that were visited upon their rain gauges: vandalism by children; obstruction by birds’ nests; damage by tourists, lawn mowers and ponies. The monks at Belmont Abbey, in Herefordshire, noted a bullet hole in their gauge in 1948. At one psychiatric hospital, record-keeping was on hold for more than two years in the 1950s because the gauge had been “hidden by inmates.”
As World War II raged, one log from 1944 notes that a rain gauge was “destroyed by enemy action.” In the village of West Ayton, the record-keeper ended readings in 1949 with the comment “too old to bother now.”
Once the records were transcribed, the data had to be organized by precise location. This presented its own challenges. The notes for one rain gauge in Scotland describe it only as being “in a glen among the hills.”
Dr. Hawkins is perhaps best known for creating the climate stripes, a way of visualizing global warming. He is now involved with another online project to transcribe weather observations made by mariners traversing the globe in the mid-19th century. It is part of a larger initiative, GloSAT, that aims to extend records of worldwide surface temperatures — on land, ocean and ice — back to the 1780s. At the moment, most global temperature records start in the 1850s.
The additional information could help scientists better understand the Earth’s climate before the Industrial Revolution and the accompanying large-scale carbon emissions from human activity. It could also reveal more about how the climate reacted to several huge volcanic eruptions in the early 19th century, including the one at Mount Tambora, in what is now Indonesia, that chilled the planet and caused the so-called “year without a summer.”
“We haven’t had a really big one probably since Tambora in 1815,” Dr. Hawkins said. “We’re probably overdue one. And so understanding the consequences of an eruption like that ahead of time would probably be quite useful.”