The remote Arctic islands of Svalbard, Norway, the northernmost settlement in the world, have been called a canary in the coal mine of climate change, warming more than two times faster than other areas of the Arctic and five to seven times faster than the rest of the planet.
Because of this warming, Svalbard offers climate researchers a preliminary look at what’s coming for the rest of the Arctic.
Research published Thursday in Nature Geoscience examines a new source of Arctic methane emissions in Svalbard coming from groundwater springs that pop up in areas uncovered by retreating glaciers.
As climate change causes more glaciers to melt it could create a feedback loop, with glacier melt from warming producing methane, a potent greenhouse gas, producing more warming. Since the Arctic warms faster than climate models predict, identifying new sources of carbon emissions can help better refine these models.
“What we found is that these groundwater springs were just completely untouched or unknown sources of methane in the Arctic, both on Svalbard and very likely across the Arctic,” said Gabrielle Kleber, a lead author on the study and a graduate student at the University of Cambridge.
Kleber said that researchers have known for years that methane seeps out of the ocean floor in areas that had glaciers thousands of years ago. But until this point no one directly studied methane seepage on land exposed by glacier retreat, she said.
When glaciers started to retreat in the past century, a gap formed between the end of the glacier and the beginning of frozen ground, known as permafrost. Groundwater that was previously trapped under glacial ice then started to bubble up out of these gaps and created a spring.
The researchers were able to identify these groundwater springs in areas recently uncovered by Arctic glaciers via satellite. Then, over the span of three winters, researchers rode snowmobiles to these frozen springs to take water samples. Over two winters researchers sampled 123 springs from 78 glaciers.
“Logistically it’s a challenge because you leave town on your snowmobile and then you’re really just completely exposed to the Arctic elements,” Kleber said. “We’ve been sampling on days when it’s minus 40 degrees and you have to sample liquid water when it’s 20 to minus 40 out.”
After analyzing the samples, researchers found that the methane concentration in this water was up to 600,000 times higher than the normal concentration in water. Most of that methane then flows into the atmosphere, where it is about 80 times more warming than carbon dioxide over a 20-year period.
“It’s just this very stark image of climate change, melting these glaciers and then releasing methane,” Kleber said.
Wei-Li Hong, an assistant professor of geochemistry at Stockholm University who was not involved in the study, said the data and analysis from the groundwater springs is “very convincing.” He said researchers have suspected that this type of process is happening, but until now there was no experimental evidence.
Evidence suggests that much of the methane coming up from the springs in Svalbard comes from rocks such as shale or coal, which are common in Svalbard and other areas in the Arctic. When these types of rock form as heat breaks down organic matter such as dead plants and animals, methane becomes trapped in the sediment. Then when glaciers move over these areas they create cracks, which allows the methane to move up through the rock. As the glacier retreats, that methane is then released with the help of the groundwater.
There is also some evidence that bacteria could also produce a portion of this methane through their metabolic process. Hong said that further research should examine how glacial retreat affects emissions of methane produced by bacteria.
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While this study only focuses on Svalbard, it’s also likely that methane emissions from these types of springs occur in other areas across the Arctic. And because Svalbard is warming so much faster than other places in the Arctic, it’s also likely that these types of emissions could become more widespread.
This study focuses on glaciers that end inland, which account for a small percentage of Arctic glaciers. Glaciers that end over water tend to be much larger and account for more glacier area in the Arctic, but as global warming leads to more glacier melt, it’s possible these glaciers will recede onto land. Of the 1,704 Arctic glaciers that terminate on land, 7 percent have receded enough in the past two decades that they’re now completely on land. Of the inland glaciers studied, nine ended over the ocean in the past century. They receded enough that now they end inland and emit methane through groundwater springs.
Kleber said this system isn’t currently creating a massive contribution to methane emissions. Svalbard’s methane emissions from this process are approximately equivalent to 8 percent of methane emissions from Norway’s oil and gas emissions.
While these groundwater springs aren’t currently emitting dangerous amounts of methane, scientists estimate that there is around twice as much organic carbon stored under Arctic glaciers and permafrost than is currently in the atmosphere. The release of methane from these groundwater springs could become “more relevant as glaciers continue to shrink in our rapidly warming climate,” Kleber said.
The Arctic is currently warming much faster than other places on the planet and Kleber said it’s also warming faster than climate models have predicted.
“And part of the reason is because there are all these kinds of invisible feedback loops that we weren’t aware of,” Kleber said. “So we have climate change, melting glaciers, and the retreat of those glaciers is then releasing methane, which will just exacerbate warming. So it’s all these hidden loops that are just perpetuating climate change that we’re just not aware of.”