GLASGOW, Scotland — The United Kingdom's longest-lasting patch of snow, located in a remote mountain range in the Scottish Highlands, has melted away for only the eighth time in 300 years, experts have confirmed.
The snow patch, nicknamed the Sphinx, is the U.K.'s most durable, which means it typically stays frozen through the summer, even after most snow has melted across the region's upland terrain. The rare disappearance of the patch comes as Scotland plays host to the United Nations Climate Change Conference, known as COP26, during which government officials from around the world are negotiating policies to avert the worst impacts of global warming.
The Sphinx snow patch adorns the side of Braeriach, the third-highest mountain in Britain that forms part of the Cairngorms mountain range. Records indicate that the patch is previously known to have melted completely in 1933, 1959, 1996, 2003, 2006, 2017 and 2018.
Before 1933, it's estimated that the last time the snow patch disappeared was in the 1700s, according to Iain Cameron, author of "The Vanishing Ice: Diaries of a Scottish Snow Hunter."
Cameron calls himself an amateur scientist, but he has spent the past 25 years studying snow across Scotland's hills and mountains and publishes his findings on the region's snow cover in the Royal Meteorological Society's annual report.
He said it's concerning to see the patch disappear for the third time in five years, adding that global warming is likely contributing to the recent melting events.
"There's no doubt in my mind that the increased disappearance of the Sphinx is due in significant part to the changing climate," Cameron said. "The rate of disappearance is accelerating dramatically."
A report published last year on snow cover and climate change on Cairngorm mountain found rising temperatures and decreasing snow cover across the region over the past 100 years. The report, commissioned by the Cairngorms National Park Authority, used climate models to project how patterns of snow cover could change in the future.
Mike Rivington, a scientist at the James Hutton Institute in Aberdeen, Scotland, and one of the co-authors of the report, said snow's variability from year to year makes it challenging to study, but that the researchers found an overall trend toward less snow, in terms of the area it covers, and a decrease in its duration, or how long the snow stays on the ground.
"We found that once you get past 2040, there are a large number of years where the amount of snow cover decreases quite considerably," he said. "By 2080, there may be some winters where we get very little snow cover at all, which doesn't mean it won't snow but it's unlikely to stay on the ground for very long."
The models also showed that melting will likely happen more frequently in the coming years.
"What that tells us is that we're losing those very cold temperatures that help maintain snow patches," Rivington said. "And the fact that these melts are happening more frequently implies that global warming as a process is also accelerating."
Snow patches are good indicators of climate change, he said, because they tend to be sensitive to even small temperature changes. As such, what's happening in the Highlands can act as a bellwether for other parts of the country, and the world.
"The Sphinx is a keenly watched patch of snow because it has much wider implications," he said.
Changing snow cover across the Highlands could have broader consequences for mountain ecosystems, he added, and disrupt the natural hydrological process of snow gradually melting from mountains and flowing into streams.
"There's all kinds of direct consequences, ranging from aquatic ecology to the microbiology in streams," Rivington said. "But there are economic consequences as well, with things like winter sports. And in Scotland, we're the biggest whisky-producing country in the world and most of the water used comes off of those hills."