Researchers conducted field studies in 2021 on Vallåkrabreen, a 20 km² valley glacier in central Svalbard, to measure methane levels in meltwater and groundwater. Their results revealed methane concentrations in the glacial river of up to 3,170 nanomolar (nM)—nearly 800 times higher than atmospheric equilibrium levels. Isotopic analysis confirmed that the methane was of thermogenic origin, likely released from ancient organic material trapped beneath the glacier.
The study found that methane is mobilized in two ways:
During the 2021 melt season, the research team estimated that 1.0 metric tons of methane was emitted from the catchment, with approximately two-thirds originating from subglacial sources.
This study presents a growing concern for Arctic methane emissions. Previous research focused on permafrost thaw and wetland emissions as primary Arctic methane sources. However, these findings suggest that glacial meltwater rivers and forefields should also be considered in climate models.
With Svalbard hosting over 1,400 land-terminating glaciers, the cumulative methane emissions from glacial melt rivers across the region could represent a substantial seasonal source of methane. As Arctic warming intensifies, methane release from these newly identified sources may accelerate, further amplifying global climate change.
The discovery of methane emissions from glacial meltwater underscores the complex and evolving dynamics of Arctic greenhouse gas emissions. As glacier retreat continues, it is crucial to integrate these findings into climate projections and mitigation strategies. Future research will be essential to quantify the full extent of methane emissions from other Arctic glacial regions and to assess their potential impact on global warming.
