Mar 2021

The Mammoths Found in the Thawing Permafrost

27,000 year old cave lion cub mummy, photo by Love Dalen

Permafrost is defined as any material underlying the land surface that stays at or below zero degrees centigrade for two or more consecutive years. It can be found in the Arctic and Antarctic, high mountain areas such as the Alps and Himalayas, and even underneath the Arctic Ocean. It relies on a combination of very low temperatures and a lack of thick snow cover to be able to form.

Permafrost distribution in the northern hemisphere. Source International Permafrost Association

Arctic snow cover is crucial to keeping the planet cool, as its white surface reflects solar energy back into space. Currently, the Arctic is warming three times faster than the rest of the world. This is causing the permafrost areas to thaw, exposing a huge carbon store that scientists are struggling to accurately quantify.

In a cross-section of a permafrost landscape (left), from the surface down to 3m deep is the ‘active layer’ of soil/rock that freezes and thaws annually. Below that is a layer of permafrost which, as the name suggests, stays permanently frozen and can be up to 1.4km deep. Below the permafrost layer is unfrozen material.

A massive amount of carbon is stored below ground, locked up in the permafrost as the organic remains of plants, animals and microorganisms. Over millennia, the rate of production of organic matter has been faster than the rate of decomposition because decomposition is slowed in cold and/or wet conditions. However, as temperatures rise and the frozen land thaws, the active layer deepens and microbes can feed on previously locked up carbon in organic material, releasing it as carbon dioxide (CO2). When conditions are very wet fermentation also occurs, releasing both methane (CH4) and CO2 into the atmosphere. Methane is especially dangerous because, although it is present in the atmosphere in much lower concentrations than CO2, molecule for molecule it’s a very powerful greenhouse gas. The proportion of CO2 versus methane that is released by permafrost will depend on hydrology – the amount of water in the landscape.

Attempts to project the future of permafrost take into account planetary warming, but dramatic changes in regional weather patterns and the occurrence of fire and floods are also important. Just recently, on 27 June 2021, Lytton, British Columbia, reached 47°C, smashing Canada’s warmest temperature record, which was broken again a few days later when temperatures reached 49°C (121°F). It was a similar scenario in Siberia last year, and in some Siberian regions permafrost thaw is dramatically accelerating

Permafrost thaw and changing hydrology could play a major role in releasing CO2 and methane into the atmosphere. Current estimates suggest that there is twice as much carbon stored in permafrost than carbon dioxide and methane currently in the atmosphere. Scientists can examine existing permafrost for clues to how it responded to previous warming periods. The last warm period, 125,000 years ago, is thought to have been 4°C warmer than the present day average in some regions. Ancient changes to the landscape, plant communities and ecosystems at that time are sometimes preserved in the contemporary permafrost, but only as long as it stays frozen.

The economic impact of the permafrost carbon feedback (left) is estimated to be in the region of USD 43 trillion, between now and the end of the next century. Degrading permafrost can alter ecosystem processes, damage infrastructure and release enough CO2 and methane to influence global climate. Estimates suggest that around 120 Gigatonnes (1 Gigatonne = a billion tonnes) of carbon emissions from thawing permafrost carbon might end up in the atmosphere by 2100. This is a lot, but far less than fossil fuel emissions which could contribute seven times as much carbon (853.6 Gigatonnes) if 2012 emissions rates of 9.7 Gigatonnes of carbon per year continue unchecked until 2100.

There are powerful linkages between the cryosphere, the biosphere and the atmosphere and these matter to us all. When the ice melts in permafrost areas, the land often sinks and lakes may form; these can create new, hard-to-navigate wetlands. On the other hand, previously formed lakes can dry out as the water finds a way to drain through the decaying permafrost and disappear. This collapse of the land surface is called thermokarst. It causes changes to the local hydrology and landscape, and has a direct impact on housing and infrastructure.

Peel Plateau Thaw Slump, NWT, Canada. The slump is severalhundred metres across, and ice-rich permafrost is clearly visible in thehead-wall. This is an example of ‘thermokarst’ (image credit: Steve Kokelj).

In Siberia and North America, forests that have grown on top of permafrost can become unstable as the ground thaws, causing the trees to fall and creating a “drunken forest”. This is an early warning that the underlying ground is becoming unstable and could pose a threat to the surrounding ecosystems, from plants and animals to humans.

Nearer to home, thawing permafrost has caused problems in the Alps. As the active layer thickens it becomes unstable and causes dangerous rock falls and landslides. In August 2017 in the Val Bondasca area of Switzerland, a huge landslide of four million cubic meters of mud and rock hurtled down the mountain, killing eight people.

There are, however, some advantages to the thawing permafrost for ecological historian Professor Mary Edwards and palaeontologist Dr Tori Herridge, who have made some incredible discoveries in the thawing ice.

Mammoths and their remains have featured in human culture for a very long time. Early civilisations living in the open treeless, steppe and tundra landscapes of Asia used mammoth bones to construct their houses (pictured below).

Reconstruction of a mammoth-bone house in Ukraine (Gladkih et al 1984, Scientific American)

Through the last ice age, across parts of Siberia and Alaska-Yukon, deposition of wind-blown dust (silt) and huge ice wedges in the ground caused the gradual build-up of the land, preserving a series of ancient surfaces that included the biological remains of the ancient ecosystem in a natural “deep freeze”. These ice wedges are still visible today (see below).

Silt and ice(shining) formed in the last ice age and exposed in cliffs along the Kolyma River, NE Siberia (image: MEE)

The best place to unearth mammoth remains is near rivers and the Kolyma River in Siberia is an excellent source, not only of bones but also mummies and preserved carcasses. Professor Edwards described one of the more macabre discoveries by one of her colleagues - a human mummy, missing its head and wearing poor knitted clothing. It was an escapee from the Kolyma concentration camps, proving that many different things can be captured by the landscape and exhumed again by rivers.

Radiocarbon dating has shown that many of the finds date back 20,000 - 40,000 years, and a huge variety of species have been exhumed. In 1979, Blue Babe (pictured below), an ancient bison mummy with large lion claw marks on its hide was found in a mining cut in Alaska.

Blue Babe, the bison mummy (image: University of Alaska Museum of the North)

By looking at the wear marks on exhumed woolly rhino horns, scientists discovered that the rhinoceroses used their horns to sweep away the snow and feed on the vegetation beneath.

Woolly rhinoceros (image: CBS news)    
Baby mammoth Lyuba (image: Our North,

Baby mammoth Lyuba (above right) was discovered by a reindeer herding family in 2007 and was almost perfectly preserved, allowing scientists to study her ancient DNA and reveal new information about the biology of these animals.

Dr Tori Herridge, a palaeontologist at the Natural History Museum, was part of a fascinating expedition to the Indigrika River in 2018 to work with a group of Siberian tusk hunters. Prospecting for ancient ivory, or ‘tusk hunting’, in Siberia has become the modern gold rush, with mammoth tusks selling for up to USD 50,000 in the Chinese market.

In most of Russia it is illegal to mine using water hoses for gems or ivory, but a special license is given by the Yakutian Academy of Sciences to tusk hunters. The conditions of the license are that the Academy gets first access to any discoveries that are not ivory. Some tusk hunters are single-minded and careless in their excavations, using high powered hoses to blast into the river bank (pictured below).

Tusk hunters excavating with high-powered hoses. (image: Love Dalen)

As mentioned previously, the danger with introducing such a volume of water into the permafrost is that it can release harmful greenhouse gases. The hoses also destroy many of the ancient remains, some of which pre-date the limits of radiocarbon dating, which means that where they sit in the sediment is critical and gives vital clues about when and how the animal died, as well as the ecology of the area. Without the tusk hunting industry there would be no large scale discovery of permafrost remains in this area, but it is a trade-off between the discoveries that are made and the harm that is done in the process.

Dr Herridge visited the camp of two of the most successful Siberian tusk hunters, Boris Berezhnov and Spartak Khabrov, both telecoms engineers from Yakutsk. The journey along the river bank to their camp was a palaeontologist’s gold mine, littered with Ice Age bones of bison, horse, mammoth and woolly rhino.

Boris and Spartak take particular care while prospecting because the most valuable ivory is found in the ice wedges where it hasn’t been discoloured by contact with the soil. The walls of their tunnel were packed with bones and the tusk hunters became fascinated by the fossils, slowing their work down to carefully excavate the remains.

Among their finds were a tiny, delicate, 45,000 year old moth and a horned lark (below left) that was perfectly preserved from 44,000 years ago. On the same expedition, a wolf’s head still with hair and teeth (below right) was uncovered by tusk hunters at a neighbouring camp.

44,000 year old horned lark
A wolf’s head, complete with hair and teeth (images: Love Dalen)

Most exciting of all were two mummified cave lion cubs. Initially thought to be siblings, the well-fed male nicknamed Boris was 44,000 years old, while the female, Sparta, (pictured below) was just 27,000 years old and thought to have starved to death.

‘Sparta’ a female cave lion cub believed to have died of starvation. (image: Love Dalen)

Dr Herridge says that finding carnivores is very rare, but finding a mummified one is even more rare. In the last five years in this small region, more exquisite remains have been turned up than in the past 100 years across the entirety of Siberia.

The DNA preservation is also exceptional, with the longest sequences ever discovered which has attracted the interest of a South Korean mammoth cloning project. The scientists and investors claim that reintroducing these cloned animals will help to stabilise the permafrost which traditionally relied on herds of large animals compacting the ground and snow cover. However, as these animals would be reintroduced into a warming world – potentially the original reason for their extinction - how long would they realistically survive?

James Gray MP
It’s said that the last remaining woolly mammoths were on Wrangel Island and that they are smaller than on mainland Siberia, why is that?

Dr Herridge – There is a phenomenon with elephants isolated on islands that they tend to get smaller. Fossils of 1m tall adult elephants have been found on Sicily and in Cyprus, for example. Wrangel Island mammoths were at the lower end of the average mammoth size and they still existed just 4,000 years ago. The population was becoming inbred and resources were limited at the time due to climate change, so it’s difficult to say whether it was the island environment or inbreeding that caused the smaller size.

Stanley Johnson
Is there a case for CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) regulating the trade in mammoth ivory? And, did we once have mammoths In Britain?

Dr Herridge – It was suggested that mammoths should be added to the CITES red list because of the trade in elephant ivory. Is mammoth ivory used as a front for illegal elephant ivory? Or does it offer an alternative ivory source that will protect living elephants from poaching? There is increasing demand in China for mammoth ivory since elephant ivory was banned, and it has become more accepted as an alternative, so I can’t decide myself whether the mammoth ivory trade is a good or bad thing.

Dr Herridge – Britain’s youngest mammoth fossil, the Condover Mammoth, was 14,000 years old and found in a quarry in Shropshire in a periglacial landscape which would have been a permafrost region. If you’d been there 12,000 years ago you might have had a similar experience to me coming across a permafrost mummy in Siberia!

This report was prepared by Sophie Montagne (Director, APPG for the Polar Regions Secretariat), and endorsed by James Gray MP (Chairman, APPG for the Polar Regions).

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This is not an official publication of the House of Commons or the House of Lords. It has not been approved by either House or its committees. The views expressed here are the author’s own and do not represent those of the All-Party Parliamentary Group for the Polar Regions.