A quarter of all the land in the northern hemisphere is constantly frozen. But climate warming is leading to the melting of permafrost, which releases greenhouse gases that further accelerate this process. Report from the Lena delta.
Moving among 1,500 islets in the Lena Delta requires impeccable concentration: with one eye you need to look at the radar so as not to run aground, and the other to follow the coastal landmarks that dot this endless expanse of water and land. Before it flows into the Laptev Sea in northern Siberia, the river spreads so wide that its banks turn into foggy stripes on the horizon.
Samoilov Island stands out for its wooden hut located on the shore, where scientists and gamekeepers of the reserve live, which covers the mouth of the river and the slopes of the Kharaulakh ridge. Only now, slow but irreversible erosion threatens to submerge the house in the waters of the Lena. In the future, the entire island may also disappear: a strong rise in water as a result of the spring melting of ice erodes its shores.
Be that as it may, the main blow for this 5 km2 islet is the retreat of permafrost under the onslaught of climate warming. We are talking about soils, the upper layer of which thaws in the warm season, while maintaining temperatures below zero in depth for at least two consecutive years.
"The Samoilov ecosystem is threatened with potential destruction," - says an article devoted to this issue in the journal Biogeosciences. The German woman, Julia Boike, and her colleagues at the Institute for Polar and Marine Research. Alfred Wegener's (AWI) is not going to put up with such a prospect.
Every year from April to September, AWI employees and their Russian colleagues from the Arctic and Antarctic Research Institute and the Permafrost Institute travel to Samoilov Island to study changes in soil and landscape, as well as the relationship between climate warming and permafrost thawing.
Two thirds of the area of Russia
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The island on which a modern research station is located (funded by the Institute of Petroleum Geology and Geophysics) is becoming a favorite observation point: permafrost occupies 95% of Siberia and two-thirds of Russia. In general, frozen soil accounts for a quarter of the entire northern hemisphere, mainly in Alaska, Canada, Greenland, Russia and China.
Western Europe is distinguished by alpine-type permafrost, which is found in a number of mountain ranges. Its structure and geodynamics differ from frozen soils in northern latitudes, but it is also sensitive to climate change. So, on August 23, the movement of the soil as a result of the thawing of permafrost carried away eight people near the Swiss village of Bondo.
“In some places, Siberian permafrost was formed a long time ago, back in the Pleistocene (the period from 2.6 million years ago to 11,000 years ago),” says Yulia Boike. "It is very cold, about -9 ° C, and goes to a depth of almost 1,500 meters in the north of Yakutia."
“On Samoilov Island, it is relatively stable and high in organic matter with the presence of peatlands,” she adds, donning thick rubber boots, without which it is impossible to walk on the island's viscous tundra. The young scientists accompanying her go with her to the Kurungny. The neighboring island has complex ice formations, and its relief is formed by thermokarst sediments (obtained as a result of subsidence of frozen land for a long time).
The valleys, along which AWI scientists walk for six hours, are full of streams. “We want to understand if this water comes from seasonal precipitation or from ice melting when soil changes,” explains geomorphologist Anne Morgenstern. She always has a notebook ready at hand, and her backpack is full of taken water samples.
Huge freezer
Melting of permafrost in Siberia and in other regions where scientists are taking measurements is a confirmed fact. Thanks to sensors located in several wells (some were drilled to a depth of 100 meters), the Russian-German team of specialists managed to register a temperature increase of 1.5-2 ºС since 2006.
“We observe a tendency towards warming of the soil and an increase in air temperature in winter,” confirms Yulia Boike. - The change in the temperature component is reflected in the entire balance of energy flows, water and greenhouse gases. A disturbing conclusion, given that the Arctic is involved in regulating the entire earth's climate.
“The permafrost is a huge freezer,” explains Torsten Sachs of the German Geological Research Center (GFZ), which has come to the island for the eighth time. "If you leave the freezer door open, your pizza will defrost, your ice cream will melt, and microbes will begin to breed on this organic matter." Permafrost releases organic substances, which, under the influence of microorganisms, release CO2 in the presence of oxygen or methane in an anaerobic environment, for example, on the Samoilov peatlands.
These greenhouse gases contribute to higher temperatures, which in turn lead to thawing of permafrost and the release of gases. Experts call this "the retroactive process of carbon in permafrost." According to them, it contains 1,500 gigatons of carbon, which is twice as much as in the atmosphere.
Additional warming
But what are the proportions of carbon dioxide and methane emitted by soils during thawing? The latter, by the way, creates 25 times more powerful greenhouse effect. “This is one of the biggest questions for the future,” says Gerhard Krinner of the National Center for Scientific Research.
The concern is all the more serious because the models of the Intergovernmental Panel on Climate Change that have been formed so far have not taken into account the effects of permafrost thawing. "Additional warming due to permafrost thawing is about 10%," says Gerhardt Krinner. Thus, emissions of greenhouse gases from permafrost may raise the thermometer by 0.3 ºС by 2100.
In the laboratory of the research station (it is kept at a stable temperature by means of three deafening roaring generators), scientists examine graphs of greenhouse gas emissions into the atmosphere. Methane peaks occur in summer, but data analysis remains challenging at such high latitudes. The first measurement period (2002-2012) was carried out without automated equipment, which is available at the modern base put into operation in 2013.
Three years earlier, during a visit to Samoilov Island, President Vladimir Putin felt that Russian-German cooperation on permafrost deserved better infrastructure. Until that moment, AWI employees (their first expedition to the island took place back in 1998) had to be content with the minimum: sleep in tents, warm themselves with firewood (from the forest descending along the Lena) and use the hut of the rangers as their headquarters.
Process pace
Wintering was then impossible. “We simply couldn't collect data in the winter,” says Torsten Sachs. "It was necessary to add fuel to the external generator every three days at a temperature of -40 ° C on a polar night." Other difficulties with data interpretation look much more familiar. Ten years is too short a period to detect changes in gas flow trends in the long term. In addition, it is necessary to increase the number of observation posts, which is by no means so easy to achieve in Siberia, which is more than 20 times larger in area than France.
At a decent distance from the station painted in the colors of the Russian flag, the AWI team is completing the construction of an igloo, which will house the computer and electronic equipment of the new weather tower in 2018. The fiberglass cocoon should create the necessary conditions for stable measurements, providing shelter from the fierce winds and blizzards of the Siberian winter. Like other buildings on the island, the igloo stands on stilts so as not to be affected by soil movement. So, at the first meteorological tower, the earth sank by 10 centimeters in a year.
"There is no longer any doubt about the link between climate warming and melting permafrost," notes engineer Peter Schreiber, who is assembling the igloo. "The question now is how fast the permafrost will continue to melt and how nature will react to this process."
Nature is the main manager in the conditions of the changes taking place in Siberia, Fyodor Selliakhov notes. The head of the research station admits the changes that have taken place around: “For example, 20 years ago there was not a single tree here, but only vegetation typical of the tundra. On a trip to the delta last year, I saw 2 meters high trees."
Be that as it may, this native of Yakutia from the Vilyui shores does not believe in the anthropological causes of climate change. “This is the cycle of nature. It was warm here 100 years ago, then it became cold, and now another period of warming is beginning,”he says in his office, which is decorated with fossils found in the vicinity.
Mammoth tusk
As for the permafrost, "it is probably melting, but slowly." “When we take a mammoth tusk out of the soil, we realize that the other end is still in the ground, still frozen. This is a sign that the permafrost remains very cold,”he continues. An unexpected consequence of the thawing of soils in the far north was the development of hunting for ancient remains.
Günter Stoof, nicknamed "Molo", understands the attitude of his Russian friends. “Nature decides, not man,” says this AWI technician who has spent the longest time on the island. Now 65 years old, he vows that this season will be the last of his career (48 expeditions to the Arctic and Antarctica). The East German native was the youngest member of a nearly two-year Soviet expedition (1975-1977) tasked with building a base in Antarctica. He had a chance to visit the polar regions more than once, both alone and in groups.
His life path reflects a different history, cooperation between the GDR and the USSR during the Cold War. After the fall of the Berlin Wall, a scientific committee was formed, which was entrusted with determining the program of scientific research for a united Germany. He recommended keeping the polar direction and building it around the AWI research group in Potsdam. “It included experts such as Molo and Christine Siegert, who had 20 years of experience in studying permafrost thanks to their joint work with the USSR,” explains Anna Morgenstern.
The study of frozen soils became widespread in Russia at the beginning of the 20th century in accordance with the strategic decisions of Moscow. The policy of developing the eastern and northern regions rich in hydrocarbons and other natural resources could not be implemented without the construction of the Trans-Siberian Railway. Be that as it may, for the implementation of this project, it was initially required to form an engineering science about the ubiquitous permafrost here.
At the end of the 1930s, the Permafrost Institute was established in Moscow. In 1960 he was moved to Yakutsk. This large East Siberian city also stands on the frozen ground. Two underground galleries (at a depth of 4 and 12 meters) at the base of the institute provide “direct” access to the permafrost. The sandy layers tell about the geological history of the city, which was built on the alluvial deposits of the Lena.
Anthrax and hollows
Heavy doors keep temperatures below freezing. “The melting of permafrost is a threat to the planet, but on the scale of Yakutia, everything is still quite stable,” explains the director of the institute Mikhail Grigoriev. "At the same time, the consequences of melting are more noticeable in other regions, especially in Yamal."
After the abnormally warm summer of 2016, an anthrax epidemic began on the peninsula (the first case since 1941, according to the Moscow Institute of Epidemiology) due to the thawing of the permafrost in which the pathogen was located. In addition, the newspapers again started talking about the Yamalo-Nenets Autonomous Okrug after the discovery of large depressions. They also became the result of permafrost thawing. “The region is rich in gas. When the soil melts, it emits gas bubbles, which explain these explosions,”says Mikhail Grigoriev.
At the same time, not a single case of this kind has yet been reported on Samoilov Island, Alaska or northern Canada. The global permafrost monitoring network collects data from over 250 sites. Its goal is to “pool knowledge and also validate new climate models,” says AWI employee Hugues Lantuit.
In addition, research on alpine permafrost is gaining momentum. The June 2018 European Conference on Permafrost is due to report on this work, which is actively developed in Switzerland but is still in its infancy in France.
Coastal erosion and its socio-economic consequences are becoming another source of concern: a third of the world's coastline is in the permafrost zone. In the Laptev Sea and the Beaufort Sea (North America), coastal erosion can reach eight meters per year, which makes nearby villages think about moving houses. On Samoilov Island, the coastal wooden hut is still in place. But how long will it last?
Simon Roger