Date:

Caves point to thawing of Siberia

Frost crystals at the entrance of Ledyanaya Lenskaya Cave. Photo: Vladimir V Alexioglo

- Advertisement -

Evidence from Siberian caves suggests that a global temperature rise of 1.5 degrees Celsius could see permanently frozen ground thaw over a large area of Siberia, threatening release of carbon from soils, and damage to natural and human environments.

A thaw in Siberia’s permafrost (ground frozen throughout the year) could eventually release over 1,000 giga-tonnes of the greenhouse gases carbon dioxide and methane into the atmosphere, potentially enhancing global warming.

The data comes from an international team led by Oxford University scientists studying stalactites and stalagmites from caves located along the ‘permafrost frontier’, where ground begins to be permanently frozen in a layer tens to hundreds of metres thick. Because stalactites and stalagmites only grow when liquid rainwater and snow melt drips into the caves, these formations record 500,000 years of changing permafrost conditions, including warmer periods similar to the climate of today.

Records from a particularly warm period (Marine Isotopic Stage 11) that occurred around 400,000 years ago suggest that global warming of 1.5 degrees Celsius compared to the modern (pre-industrial) climate is enough to cause substantial thawing of permafrost far north from its present-day southern limit.

This has huge implications for ecosystems in the region, and for aspects of the human environment. Dr Anton Vaks

A report of the research is published in this week’s Science Express. The team included scientists from Britain, Russia, Mongolia and Switzerland.

- Advertisement -

‘The stalactites and stalagmites from these caves are a way of looking back in time to see how warm periods similar to our modern climate affect how far permafrost extends across Siberia,’ said Dr Anton Vaks of Oxford University’s Department of Earth Sciences, who led the work. ‘As permafrost covers 24% of the land surface of the Northern hemisphere significant thawing could affect vast areas and release giga-tonnes of carbon.

‘This has huge implications for ecosystems in the region, and for aspects of the human environment.  For instance, natural gas facilities in the region, as well as power lines, roads, railways and buildings are all built on permafrost and are vulnerable to thawing. Such a thaw could damage this infrastructure with obvious economic implications.’

The team used radiometric dating techniques to date the growth of cave formations (stalactites and stalagmites). Data from the Ledyanaya Lenskaya Cave – near the town of Lensk, at a latitude of 60 degrees North – in the coldest region showed that the only period when stalactite growth took place occurred about 400,000 years ago, during a period with a global temperature 1.5 degrees Celsius higher than today. Periods when the world was 0.5-1 degrees Celsius warmer than today did not see any stalactite growth in this northernmost cave, suggesting that around 1.5 degrees Celsius is the ‘tipping point’ at which the coldest permafrost regions begin to thaw.

Dr Vaks said: ‘Although it wasn’t the main focus of our research our work also suggests that in a world 1.5 degrees Celsius warmer than today, warm enough to melt the coldest permafrost, adjoining regions would see significant changes with Mongolia’s Gobi Desert becoming much wetter than it is today and, potentially, this extremely arid area coming to resemble the present-day Asian steppes.’

A report of the research, entitled ‘Speleothems reveal 500 kyr history of Siberian permafrost’, is published this week online in Science Express. The work was carried out by scientists from Oxford University, Russian Academy of Sciences, Swiss Federal Institute of Technology Zurich, Mongolian Academy of Sciences, and Arabica Speleological Club. The research was supported by the UK’s Natural Environment Research Council (NERC), The Royal Society and the Russian Foundation for Basic Research.

Contributing Source : University of Oxford

HeritageDaily : Natural Science News : Natural Science Press Releases

- Advertisement -
spot_img
Mark Milligan
Mark Milligan
Mark Milligan is multi-award-winning journalist and the Managing Editor at HeritageDaily. His background is in archaeology and computer science, having written over 8,000 articles across several online publications. Mark is a member of the Association of British Science Writers (ABSW), the World Federation of Science Journalists, and in 2023 was the recipient of the British Citizen Award for Education, the BCA Medal of Honour, and the UK Prime Minister's Points of Light Award.
spot_img

Mobile Application

spot_img

Related Articles

Archaeologists find a Bronze Age purple dye workshop

Archaeologists have uncovered a Bronze Age purple dye workshop on the Greek island of Aegina.

Celtic ritual lake discovered in Poland

Archaeologists from the University of Warsaw have discovered a ritual lake associated with the Celtic peoples.

Ancient Syrian diets are similar to the modern “mediterranean diet”

A study of agropastoral and dietary practices of people living in ancient Syria has revealed that they lived on a diet similar to the modern “mediterranean diet”.

Evidence of twin-children sacrificial practices at Chichén Itzá

A genome study has uncovered evidence of male-twin-sacrifices at the Maya city of Chichén Itzá.

Trove of Roman objects linked to feasting found at Ostia antica

Archaeologists have uncovered a trove of Roman objects linked to ritual feasting at Ostia antica.

Scholars uncover rare papyrus fragment from the Infancy Gospel of Thomas

The Infancy Gospel of Thomas is an apocryphal gospel that describes the early life of Jesus. 

Labyrinthine structure discovered from the Minoan civilisation

Archaeologists have discovered a monumental labyrinthine structure on the summit of Papoura Hill in Crete.

Dragon sculpture found on the Jiankou section of the Great Wall of China

Archaeologists conducting restoration works on the Jiankou section of the Great Wall of China have discovered an ornate dragon sculpture.