Scientists discover huge new methane source hidden beneath Arctic glaciers

Kleber conducted extensive research over nearly three years, monitoring the water chemistry of more than a hundred springs across Svalbard. This region experiences a rapid increase in air temperatures, twice as fast as the Arctic average.

The identified springs that release methane are supplied by a concealed plumbing system beneath most glaciers. This system taps into substantial groundwater reserves within the sediment layers and bedrock beneath the ice.

As the glaciers melt and retreat, these springs emerge where the groundwater network reaches the surface.

Identifying these glacial groundwater springs can be challenging. Kleber utilized satellite images to identify areas of exposed land resulting from the retreat of 78 glaciers in Svalbard. She looked for "tell-tale blue trickles of ice," indicating leaked groundwater that froze on the surface.

Kleber visited each identified site by snowmobile to collect groundwater samples. These sites exhibited blistered ice due to pressurized water and gas buildup.

By analyzing the water chemistry from these springs, the team discovered that nearly all studied sites contained significant amounts of dissolved methane. Consequently, excess methane can escape into the atmosphere when the spring water reaches the surface.

The research findings indicate that the methane emissions from glacial groundwater springs in Svalbard could exceed 2,000 tonnes annually. This estimate represents roughly 10 percent of Norway's annual methane emissions from its oil and gas industry.

"The amount of methane leaking from the springs we measured will likely be dwarfed by the total volume of trapped gas lying below these glaciers, waiting to escape," said co-author Professor Andrew Hodson from the University Centre in Svalbard.

Additionally, "hot spots" of concentrated methane emissions were discovered, which correlated with the rock type where the groundwater originates.

Rock formations such as shale and coal contain natural gases, including methane, formed due to the decomposition of organic matter during the rock's creation. Methane can migrate upwards through cracks in the rock and enter the groundwater.

The complete study was published in Nature Geosciences.

Study abstract:

Permafrost and glaciers in the high Arctic form an impermeable ‘cryospheric cap’ that traps a large reservoir of subsurface methane, preventing it from reaching the atmosphere. Cryospheric vulnerability to climate warming is making releases of this methane possible. On Svalbard, where air temperatures are rising more than two times faster than the average for the Arctic, glaciers are retreating and leaving behind exposed forefelds that enable rapid methane escape. Here we document how methane-rich groundwater springs have formed in recently revealed forefelds of 78 land-terminating glaciers across central Svalbard, bringing deep-seated methane gas to the surface. Waters collected from these springs during February–May of 2021 and 2022 are supersaturated with methane up to 600,000 times greater than atmospheric equilibration. Spatial sampling reveals a geological dependency on the extent of methane supersaturation, with isotopic evidence of a thermogenic source. We estimate annual methane emissions from proglacial groundwaters to be up to 2.31 kt across the Svalbard archipelago. Further investigations into marine-terminating glaciers indicate future methane emission sources as these glaciers transition into fully land-based systems. Our fndings reveal that climate-driven glacial retreat facilitates widespread release of methane, a positive feedback loop that is probably prevalent across other regions of the rapidly warming Arctic.