Disturbing melody of melting permafrost in 'crater' called 'gateway to hell'

This remarkable footage is from the floor of the Batagaika or Batagai, a megaslump in the Siberian wilderness, where ancient permafrost is exposed to the full destructive impact of climate change.

As the August sun beats down on this Arctic odyssey, our video shows water frozen in the soil for tens of thousands of years trickle and gush away, released from its ancient clasp.

The cliffs of this vast hole, some as high as 100 metres, crumble even as you watch due to the thawing permafrost.  

Locals know this place as the doorway to the underworld, and many are frightened to approach it after hearing fearsome booms emanating from here.

These thudding sounds are probably large chunks of frozen soil cascading down the cliff sides from the unstable rim as the permafrost trench widens yet more.

The Batagai mega slump is some 650 km north of Yakutsk in Yakutia. Pictures: Alexander Gabyshev, Melnikov Permafrost Institute, The Siberian Times

This tadpole-shaped gash in the Earth's surface - around one kilometre long, and 800 metres wide - is enlarging by up to 30 metres a year because of the corrosive melting of the exposed frozen upper layers of ground, say experts.

Sergey Fyodorov, researcher at the Institute of Applied Ecology, Yakutsk, said: 'One of the most serious things we must understand looking at this slump is that its growth is not something we, humans, can stop.

'We cannot put a curtain against sun rays to stop it from thawing. 

'Even at the beginning of September, when air temperatures drop to OC, you see springs and rivers of water. 

'As you stand inside the slump on soft piles of soil that was left after ice thawed, you hear it 'talking to you', with the cracking sound of ice and a non-stop monotonous gurgling of little springs and rivers of water.' 

Watch: running water is one of the most soothing and relaxing sounds known to man, but here it signals the rapid thawing of ground frozen for thousands of years.

Fedorov said: 'It is good it happened in a remote area away from a  settlement where people live. 

'Imagine if there was a village or a city above what is now an ever-deepening depression?

'It's time for the world to wake up and pay more attention to what is happening (with melting permafrost) here in Yakutia.'

For now ithe depression represents an unparalleled natural laboratory for scientists seeking to understand the threat to permafrost due to climate change. 

Batagaika - some 650 km north of the regional capital of Yakutia, also known as the Sakha Republic - is a thermokarst depression which started to form in 1960s after a chunk of forest was cleared: the land sunk, and has continued to do so, evidently speeded by recent warmer temperatures melting the permafrost, so unbinding the layers on the surface and below. 

The Batagai slump shown as it was first noticed in 1968, and now. Pictures: Alexander Gabyshev, Melnikov Institute of Permafrost, The Siberian Times 

The director of the Research Institute of Applied Ecology of the North, Gregory Savvinov, said: 'In the 1960s there was a road between the village of Batavia and some industrial facilities. 

'The forest was cut down, and this led to the formation of the ravine. In recent years, against the backdrop of climatic changes, due to the warming, the ravine grew to the size of crater.' 

In 2009 the carcass of  an Holocene era foal - some 4,400 years old - was discovered,  and a mummified carcass of a bison calf.

Remains of ancient bison, horses, elks, mammoths, and reindeer were also found here. 

On the Yana plateau, its winter temperatures are among the coldest for inhabited places on the planet. 

The Batagai slump, all pictures The Siberian Times