Are Siberia's mysterious craters caused by climate change?

Four new mysterious giant craters have appeared in the Siberian permafrost in northern Russia, sparking fears that global warming may be causing gas to erupt from underground.

Scientists spotted the new holes, along with dozens of other smaller ones, in the same area as three other enormous craters that were spotted on the Yamal Peninsula last year.

The craters are thought to be caused by eruptions of methane gas from the permafrost as rising rising temperatures causes the frozen soil to melt.

One of new craters, surrounded by at least 20 smaller holes, is just six miles from a major gas production plant.

Experts have predicted there could be up to 30 more are waiting to be discovered.

Scientsts, however, are still largely baffled by the exact processes causing the craters.

Professor Vasily Bogoyavlensky, deputy director of the Moscow-based Oil and Gas Research Institute, part of the Russian Academy of Sciences, has called for 'urgent' investigation of the new phenomenon amid safety fears.

Until now, the existence of only three Siberian craters had been established when great caverns in the frozen landscape were spotted by passing helicopter pilots.

'We know now of seven craters in the Arctic area,' Professor Bogoyavlensky told The Siberian Times.

'Five are directly on the Yamal peninsula, one in Yamal Autonomous district, and one is on the north of the Krasnoyarsk region, near the Taimyr peninsula.

'We have exact locations for only four of them.

'The other three were spotted by reindeer herders.

'But I am sure that there are more craters on Yamal, we just need to search for them. I would compare this with mushrooms.

'When you find one mushroom, be sure there are few more around. I suppose there could be 20 to 30 craters more.'

Two of the newly-discovered large craters - also known as funnels to scientists - have turned into lakes, revealed Professor Bogoyavlensky.

'It is important not to scare people, but this is a very serious problem.

'We must research this phenomenon urgently to prevent possible disasters.

We cannot rule out new gas emissions in the Arctic and in some cases they can ignite.' 

Professor Bogoyavlensky said that the parapet of the craters suggested an eruption of gas from a shallow underground reservoir. 

The first hole was spotted in 2013 by helicopter pilots 20 miles from a gas extraction plant at Bovanenkovo, on the Yamal Peninsula.

An examination of the area using satellite images, comparing landscapes in the past with the present day, has alerted Russian experts to the prospect that the phenomenon is more widespread than first thought.