Spitsbergen’s glaciers release methane from the subsoil

by Heiner Kubny

10/21/2026

Silje Waaler takes a water sample from the glacial stream at the end of the Svalbreen glacier on Spitsbergen. Researchers have found elevated concentrations of methane in such meltwater. The methane originates mainly from ancient rock layers beneath the ice and is transported out of the glacier with the meltwater. (Photo: Gabrielle Kleber / UiT, iC3)

Hidden beneath Spitsbergen’s glaciers lies a previously underestimated source of the greenhouse gas methane. A new study shows that meltwater absorbs methane from the rock beneath the ice and transports it to the surface. As glacial melt increases, this process could become more significant.

An international research team analysed meltwater from 19 valley glaciers in central Spitsbergen. A total of 148 water samples were taken. The result: the scientists found elevated methane concentrations in the outflows of all the glaciers studied. In some cases, these concentrations were up to 425 times higher than the equilibrium value with the atmosphere.

The Ragna Mariebreen on Spitsbergen with its widely branching meltwater outflow in front of the glacier tongue. The glacier is one of the sites investigated in the new methane study. Meltwater beneath the ice can absorb methane from the geological subsurface and transport it to the surface via glacial streams. (Photo: Leonard Magerl / UiT, iC3)

The origin of the gas is particularly noteworthy. Isotope analyses, as well as the detection of ethane and propane, show that a large proportion of the methane is not produced by microorganisms beneath the ice. It consists predominantly of old, thermogenic methane that was formed in organically rich rock layers in the subsurface.

The way the glacier rests on its bed appears to be a crucial factor as well. Particularly where the glacier base is not completely frozen and the ice lies over shale-rich, organic rock layers, meltwater can circulate beneath the glacier. In doing so, it absorbs methane and transports it to the surface via glacial streams.

For Svalbard, this mechanism could become increasingly significant as the glaciers continue to retreat. Around 60 per cent of the archipelago is covered by glaciers, whilst methane-rich rock layers are present in large parts of the subsoil. Additional meltwater pathways could mobilise further trapped gas in the future.

Schematic representation of methane transport beneath a glacier on Svalbard. Meltwater circulates along the glacier bed, predominantly absorbing thermogenic methane from organically rich rock layers and transporting it to the surface via subglacial channels. The methane can then escape into the atmosphere via the glacial stream. The illustration is based on the findings of a new study of 19 glaciers on Svalbard. (Illustration: PolarJournal)

However, it is still unclear just how significant these methane emissions are in total. The researchers do not regard this as a dominant source of methane, but rather as a process that has received little attention to date and which may also occur in other glaciated regions.

The findings were published on 8 September 2026 in the journal Nature Communications under the title ‘Subglacial geology and thermal conditions regulate methane emissions from Svalbard glaciers’.

Heiner Kubny, PolarJournal