Scientists have discovered a source of methane that is discharging the greenhouse gas into the Arctic Ocean off eastern Siberia, raising concerns of a "new tipping point" that could speed up the pace of global warming.

According to The Moscow Times, scientists found the potent gas bubbling from a depth of 350 meters in the Laptev Sea, with surface-level concentrations that vent into the atmosphere at between four and eight times the normal amount.

One of six monitoring points set up showed methane concentrations 400 times higher than expected under the normal air-sea equilibrium, the Russian newspaper said.

"The discovery of actively releasing shelf slope hydrates is very important, and was unknown until now. This is a new page," said Igor Semiletov, chief scientist on board the Russian research ship Akademik Keldysh. The vessel is participating in a multiyear Russian-Swedish expedition for what's known as the Siberian Shelf Study.

The discovery has prompted concerns that a new feedback loop that accelerates climate change may have already been triggered. A recent study co-authored by a member of the expedition found that the loop could be activated if the Arctic warms by just a few degrees.

"At this moment, there is unlikely to be any major impact on global warming, but the point is, that this process has now been triggered," The Guardian newspaper quoted Swedish scientist and study co-author Oerjan Gustafsson as saying.

"This East Siberian slope methane hydrate system has been perturbed and the process will be ongoing," Gustafsson said.

Preliminary findings

The scientists stressed their findings were preliminary.

The Arctic is warming twice as fast as any other place on Earth and the Guardian reported that the region is yet to begin freezing for the winter, already surpassing records for the latest date for sea ice formation after melting unusually early this spring.

At the six monitoring points over a slope area 150 kilometers in length by 10 km wide, scientists saw clouds of bubbles released from sediment.

The question of when－or even whether－the gas will be released into the atmosphere has been a matter of considerable uncertainty in climate computer models.

The scale of methane releases will not be confirmed until the scientists return, analyze the data and have their studies published in a peer-reviewed journal.

But the 60-member international scientific team on the Akademik Keldysh agreed that the discovery of a potentially destabilized slope containing frozen methane raises concerns that the pace of global warming could be hastened.

The discovery potentially identifies a third source of methane emissions from the region, The Moscow Times said.

Semiletov, who has been studying the area for two decades, has previously reported the gas is being released from the shelf of the Arctic Ocean.

"Potentially they can have serious climate consequences, but we need more study before we can confirm that," he said.