Glacier-fed rivers in central Svalbard carried methane at up to 425 times atmospheric equilibrium
Gabrielle E. Kleber's team at UiT the Arctic University of Norway in Tromsø analysed 148 river samples from 19 valley glaciers in central Svalbard. Methane peaked at 425 times atmospheric equilibrium. Nature Communications published the paper on 8 September 2026; land-terminating glaciers are scaled at 182 to 368 tonnes of methane in 2023.
Science··Evening
A Tromsø team sampled 19 valley glaciers in central Svalbard
Gabrielle E. Kleber and colleagues at the Department of Geoscience, UiT the Arctic University of Norway, Tromsø, analysed 148 river samples from 19 valley glaciers in central Svalbard. The samples were taken along each river, beginning as close as possible to the glacier terminus. Co-authors include Silje Waaler and Leonard Magerl. The peer-reviewed paper, Subglacial geology and thermal conditions regulate methane emissions from Svalbard glaciers, was published in Nature Communications on 8 September 2026 (DOI 10.1038/s41467-026-77190-z). On selected glaciers the team used ground-penetrating radar to map the extent of temperate ice at the bed, the condition that lets meltwater contact the rock.[1]
Methane peaked at 425 times atmospheric equilibrium
All sampled meltwaters were supersaturated with methane, with peak concentrations up to 425 times atmospheric equilibrium. Carbon isotopic compositions of the methane, together with ethane and propane in the samples, indicate a largely thermogenic origin. The largest acquisition is recorded where organic-rich, shale-dominated geological formations meet extensive temperate ice at the glacier bed. A discharge-weighted-mean methane concentration applied to land-terminating glacial runoff on Svalbard yields 368 tonnes of methane in 2023. A glacier-area-weighted-mean mass flux yields 182 tonnes of methane in 2023.[1]
The 2023 upscaling is a first-order estimate for Svalbard
The 182 and 368 tonne figures are first-order upscaling for Svalbard's land-terminating glaciers in 2023, not a measured archipelago total. Sampling was conducted primarily during mid-summer, so it does not capture the early-season pulse flushed at the onset of the melt season. Some of the most upstream sampling points were not always directly at the glacier terminus, and methane lost from the river upstream of those termini is uncounted. The field survey itself covers 19 valley glaciers in central Svalbard. The paper reports both the discharge-weighted and the area-weighted methods.[1]
