Sea of methane sealed beneath Arctic permafrost could trigger climate feedback loop if it escapes 

 A sea of migrating methane discovered below the permafrost in Svalbard may eventually escape its icy prison if the permafrost continues to thaw due to climate change. 

https://cdn.mos.cms.futurecdn.net/DmStp8kr4U3K7S4GRWxrCm.jpg

https://www.space.com/methane-beneath-arctic-permafrost-climate-feedback-loop