Methane stored below permafrost is an unknown quantity in the Arctic greenhouse gas budget. In coastal areas with rising sea levels, much of the methane seeps into the sea and is removed before it reaches the atmosphere. However, where land uplift outpaces rising sea levels, the former seabed freezes, pressurising methane-rich groundwater beneath, which then escapes via permafrost seepages called pingos. We describe this mechanism and the origins of the methane discharging from Svalbard pingos.