As fossil fuel pollution cranks up global temperatures, no place on Earth is warming faster than the Norwegian archipelago of Svalbard. There, temperatures are rising five to seven times faster than the global average rate, and for residents of Longyearbyen, that could mean their water supply is in danger.
Longyearbyen, with its population of roughly 2,400, is the capital and largest settled area of Svalbard. It’s also one of the world’s northernmost settlements, located just 800 miles (1,300 kilometers) from the North Pole. Today, Longyearbyen’s economy is largely driven by tourism, but in the 1900s it was a coal mining town. Thanks to climate change, the local geology that allowed this industry to thrive now threatens a dammed lake called Isdammen, the town’s only source of drinking water.
In September 2025, an analysis of treated drinking water from Isdammen found dangerously high levels of manganese, a heavy metal that can be neurotoxic in high doses or as a result of prolonged exposure. For the past year, local authorities have advised Longyearbyen residents not to drink the tap water. Instead, they can refill containers at the supermarket, where Svalbard Brewery now supplies a tank of free, purified drinking water.
Manganese levels have declined since September 2025 and are no longer considered a health concern, but they are still above the safe limit—as are sulfate and nickel levels. Because of this, the local government still recommends avoiding tap water.
Researchers investigating the source of the contamination believe it stems from rapid permafrost melt, which could be exposing bedrock and allowing metals to leach into Isdammen.
“The combination of the thawing permafrost and the shale bedrock, which contains a mineral called pyrite, or fool’s gold, is causing contamination of its water supply,” Marjolaine Verret, a permafrost expert and associate professor in Arctic geology at the University Centre in Svalbard, told The Guardian.
Permafrost in peril
To be clear, pyrite is not the direct source of this metal contamination. But when this mineral comes into contact with water and oxygen, it undergoes a reaction called oxidation that produces acid, Verret explained.
“The acid produced can now leach heavy metals from these rocks into the waterways,” she said. “The issue we’ve been having here in Longyearbyen is manganese, but other contaminants can be leached out from the rocks,” as showcased by elevated sulfate and nickel levels.
This pathway seems likely, but understanding where Isdammen’s water actually comes from will be key to confirming the source of the metal pollution. Scientists at SINTEF, a major independent research organization, are working to answer that question.
“We don’t know for sure how the water channels and water quality will change as the permafrost thaws,” SINTEF research manager Hanne Kvitsand said in a blog post published earlier this year. “We need to investigate this thoroughly,” she said.
If permafrost melt is the culprit, Verret believes Longyearbyen’s water crisis could be a preview of what’s to come for other Arctic communities. The region is warming four times faster than the rest of the world, and experts believe permafrost in the Arctic Circumpolar Permafrost Region could decline 42% by 2050.
“These ingredients [bedrock rich in pyrite and heavy metals] and thawing permafrost are present in other parts of the Arctic so this could be a first example of how climate change can impact freshwater, for example in northern Canada and Alaska,” Verret said.
