01 Marzo 2017 13:50
In Siberia there's a crater so wide and deep that it's known by locals as 'the Gateway to the Underworld'. Situated 660 kilometres north of Yakutsk, it first appeared in the 1980s after local people cut down part of the forest. Without the trees to provide shade and keep the ground cool, sunlight penetrated into the ground, leading to the melting of permafrost and the dramatic sinking of the ground.
The Batagaika crater is worrying scientists and locals because it doesn't stop growing. It is now almost a kilometre long and 100 metres deep, and people are afraid that in a few months it could reach the neighbouring valley.
A 2016 investigation revealed that during the last decade the crater has been deepening at an average rate of 10 metres a year; in especially warm years this has reached 30 metres. The big floods of 2008 increased the crater's size further, and now, as the Earth grows ever warmer due to climate change, geologists warn that the crack will grow even larger.
The rapid growth of the crater isn't just a danger to locals: the whole world could be affected. The thawing of the permafrost could lead to the release of huge quantities of greenhouse gases stored beneath the tundra.
'Global estimations of carbon stored in permafrost is the same amount as what's in the atmosphere,' Frank Günther, main author of the study, told the BBC.
The Earth would suffer from all these extra greenhouse gases being released into the atmosphere, accelerating warming further: a potentially catastrophic feedback loop.
One positive thing about the crater is that it has enabled scientists to take samples of the soil. They have found 4,400-year-old frozen remains of musk ox, mammoths and horses. One study, published last month, revealed that analysing the exposed layers further could reveal 200,000 years of climactic history, giving us clues as to what happened when permafrost thawed at the end of the last Ice Age.
'Ultimately, we're trying to see if climate change during the last Ice Age (in Siberia) was characterised by a lot of variability: warming and cooling, warming and cooling, as occurred in the North Atlantic region,' says Julian Murton, of the University of Sussex, who travelled to the area and led the study.
While there is already evidence of what happened in Greenland, China and Antarctica, the history of Siberia is unknown. Learning more about it would, scientists argue, help us to be better prepared for the future. There are plans to drill holes in the crater to analyse the sediments further and gather more data.
[Via Science Alert]