![](http://t3.gstatic.com/images?q=tbn:YznX29Z9_gydkM:http://media-cdn.tripadvisor.com/media/photo-s/01/25/a0/b7/methane-bubbles-up-into.jpg)
It was unclear, however, if the Arctic emissions of methane gas were new or had been going on unnoticed for centuries -- since before the Industrial Revolution of the 18th century led to wide use of fossil fuels that are blamed for climate change.
The study said about 8 million tonnes of methane a year, equivalent to the annual total previously estimated from all of the world's oceans, were seeping from vast stores long trapped under permafrost below the seabed north of Russia.
More...