RF loses annually about 11 sq. km of land due to melting permafrost

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RF loses annually about 11 sq. km of land due to melting permafrost
RF loses annually about 11 sq. km of land due to melting permafrost
Anonim

65% of Russia's territory is covered with permafrost, all construction in the Arctic, Siberia and the Far East was literally based on it. However, in recent years, its reliability has come into question due to climate change. The recently launched Big Norilsk Expedition of the Siberian Branch of the Russian Academy of Sciences (SB RAS) sets one of its tasks to test the strength of structures and the land beneath them. The director of the P. I. Melnikov SB RAS Mikhail Zheleznyak.

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What tasks does the institute set for itself in the expedition that has begun?

- In the expedition, the task of the Permafrost Institute is to characterize and assess the state of seasonal and permafrost rocks in the territory of engineering facilities, in the oil spill zone and in the territory not prone to pollution. Based on the materials that we receive during the field research, let's see how the permafrost conditions have changed. In the presence of materials of engineering and geological surveys and studies performed, we will try to give our vision of the causes of the accident.

What will the field work look like? Where are you going to take samples?

- Two researchers from our institute are participating in the expedition. We will carry out drilling operations, temperature observations in wells, perform route observations, take samples while drilling, characterize cryogenic processes. It is necessary to estimate the depth of seasonal thawing and the temperature of rocks in the background areas and at the location of the emergency structure.

What information does the Institute have about permafrost in Norilsk today? When was the last time such research was conducted there?

- Our institute has a permafrost station in Igarka, it's not so far away. The last time our colleagues worked in Norilsk was three years ago. I worked in the region in the 1980s, researching permafrost and geothermal conditions. In the 1990s, there was a laboratory of the Permafrost Institute in Norilsk, which dealt with the stability of engineering structures. In 2007 and 2013 I came to Norilsk, we discussed the problems of the sustainability of residential buildings with the city authorities. In general, permafrost conditions are familiar to us.

Immediately after the accident, there were suggestions that the melting of permafrost was to blame for the accident. Do you agree with this preliminary assessment?

- I can't say until we get the materials. After all, accidents have happened before, when there was no such warming in the Arctic. The reasons may vary. It is necessary to look at the permafrost-ground conditions, the presence of underground ice in them. Because if the soils are not ice-saturated and not subsiding, then the cause of the accident could be completely different, for example, in the state of the materials of the structures. Today they say that the cause could be the melting of the permafrost, the destruction of the concrete base, the bursting capacity from seismic vibrations that pumped the liquid in the storage, and so on. But these are all versions. You need to understand the reasons, and this can really be done.

What is the situation with permafrost in Russia? How much is it melting and decreasing in recent decades?

- Climatic changes are underway, which we all feel, and even changes in average annual air temperatures are one of the indicators, but not the only one, which says that for the Norilsk, Taimyr region over the past 40 years, the temperature has increased by one and a half degrees. In general, there are regions in Russia where the average annual temperature rose by three degrees during this period. Of course, this also affects soil conditions. On the other hand, there is the Le Chatelier-Brown principle, and the natural environment responds to external influences. That is, if the temperature rises, then there are changes in the surface conditions of heat transfer. This reaction is not the same everywhere; it depends on the landscape conditions. For example, in central Yakutia, there was intense subsidence in open, without forest, areas of the development of rocks of the ice complex, close to the surface. In forest areas, these phenomena are insignificant or not observed. That is, the response to climate change is completely different, although there is undoubtedly it. Somewhere it is weak, but somewhere in 40 years it is not visible at all. Snow cover and the regime of its accumulation have a great influence on the state of frozen soils.

How much has the area of permafrost reduced in Russia over the past decades?

- I find it difficult to say an exact estimate, because permafrost recedes in different ways in different regions. In fact, we do not know our southern permafrost boundaries clearly. In general, permafrost occupies 65% of the territory of Russia. I believe that in the southern regions of the permafrost zone, it has disappeared by 2-3% of the territory, no more. In large areas, the upper layer of summer thawing has increased, but below the frozen strata lies, it has not disappeared.

Are there any areas in Russia where there is no thawing of permafrost and climate change is not felt there?

- In central Yakutia, in some landscape zones, in certain forest communities, the air temperature rises, plant communities change, and the reaction of an increase in the depth of seasonal thawing or an increase in the temperature of rocks is not observed.

Why?

- Once every three to four years there are winters when snow, which is a good heat insulator, falls much later. Low air temperatures, the absence or low thickness of the snow cover contribute to the cooling of the soils during this period.

There are special areas in the Verkhoyansk region of Yakutia, where over the past eight years in the upper five-meter layer of the earth there has been even a decrease in temperature by two tenths of a degree. Moreover, this phenomenon was noted not at one point, but at ten different parts of the relief. This is recorded by our automatic stations, which determine the temperature four times a day and accumulate 1600 measurements per year. This allows you to assess the temperature conditions in different seasons of the year.

How many such observation stations do you have?

- There are about 60 such observation stations or sites in Eastern Siberia, where measurements are constantly carried out. However, they do not have a uniform areal distribution and do not cover all landscape conditions. Today, a program is being developed to create a monitoring system in the Arctic, and I hope that the Ministry for the Development of the Far East will support it. If you place 70 points evenly in all landscape zones, you get a good observation network.

When do you expect to receive the program?

- The program should be submitted to the government in December 2020. Further, the question will be decided who will carry out it, drill, monitor. It is planned that this will be a state-owned network. The question is, in whose jurisdiction? Subsoil users, ecologists, geologists, meteorologists? I think that it will take ten years to create an observing system in the entire permafrost zone.

What we have are scientific stations that are set up to solve some problem, often for promising mineral deposits. However, not all subsoil users are ready or allow the creation of such observation platforms on their territories. We participate in scientific grants and, if we win, we use funds to purchase equipment and create observation sites. In the budget for science today there is no finance for the creation of normal stations.

Are there places where the thickness of the permafrost layer has decreased and no longer allows keeping construction piles?

- Of course, there are such examples, for example, in Transbaikalia, in Chita. There were foundations projected on frozen ground. At present, in some areas, this permafrost has degraded. But to be honest and frank, the greater impact on the stability of buildings and structures is exerted not by the permafrost, but by the operating conditions. The construction of engineering structures creates a specific natural and technical system. If, for example, in Yakutsk the average annual soil temperature is now about 2, 5–3 degrees, then under properly functioning ventilated underground houses on piles, the soil temperature is minus 3, 5–4 degrees. That is, a properly functioning ventilated underground is itself an engineering cooling system.

As for Norilsk, there are different conditions. Ventilated undergrounds work ineffectively due to significant snow accumulation, which does not allow cold air to circulate under the building in winter.

Do the rise in average annual temperature and thawing of permafrost require changes in building rules and regulations?

- The current change in climatic conditions for a number of regions, including Yakutsk, does not have catastrophic consequences if these engineering systems are normally operated and provided with control of the state of the subgrade. Buildings and structures are designed for a certain service life. For example, a stone dwelling house is for 50–70 years. If there is a system of normal control over an engineering structure, then in the event of a change in the control parameters, preventive protective measures can be taken, which will allow maintaining operating conditions for a certain period. But, unfortunately, there is often no such control. For example, the media reports that a house in Yakutsk collapsed due to thawing of permafrost. In fact, the reason for this destruction is different - mismanagement, which is associated with improper operation of the ventilated underground (in the summer there is an accumulation of water, in the winter - the formation of ice) and, as a result, the destruction of the supporting structures. Often, the foundations of some houses are in a depression between the foundations of other structures raised around them, a drainage hollow is formed, which is also poorly ventilated in summer, and in these conditions a talik zone is formed. The increased humidity under these structures affects the structures, piles, beams, which collapse, cease to bear the planned loads - collapse occurs. Permafrost is a "conservative environment" and allows us to have time to think, if we control what is happening, and do not wait for the building to collapse. There is no need to do tragedies from the melting of permafrost, you need to keep an eye on the structures.

How do you assess the deterioration of infrastructure in the Far North?

- Probably, it will be better done by services that monitor wear and tear. I know different numbers that professional people call. They believe that the deterioration of buildings and structures has reached about 60%. Someone thinks that the wear is higher. It is better to evaluate a specific city or village. Depreciation depends on the rules of operation and obsolescence of buildings. After all, each building is designed for a certain period. Some buildings may exist for one and a half time allotted for their operation. This is due to the correct operating conditions.

Have new materials and technologies appeared in construction that are not afraid of permafrost thawing?

- There are new materials and development of new pile designs. Began to use corrugated piles, which have a large area of freezing to the ground at the same depth as smooth piles, various heat-insulating materials are widely used. It is quite obvious that one and the same structure cannot be used for the entire Far North, because climatic and soil conditions are different. This is taken into account in the design decisions for each territory. Today multi-storey buildings are being built. If in Yakutsk 40 years ago, ten-meter piles were considered deep, now the piles are buried 15-16 m, which depends on the load. By creating a margin of safety, by increasing the freezing area of the hanging piles, we are avoiding the danger of buildings being destroyed. One of the serious problems of construction in the North is, of course, concrete, which begins to crumble from significant temperature fluctuations. In piles and other reinforced concrete structures, iron reinforcement is exposed, which begins to rust, which, in turn, leads to their destruction. Today new concrete grades appear and are being developed. In road construction, plasticizers and additives are beginning to be used to withstand harsh conditions with high temperature ranges.

How permafrost is permafrost? Are there any estimates of her age?

- For a person, her age is comparable to eternity. There are areas where permafrost has not thawed for almost 2 million years. This is the Kolyma lowland in the north of Yakutia. Its thickness there is 500–600 m. During periods of warming, it thawed above and below, but in the middle part it survived for more than 1.9 million years.

How dangerous is the melting of permafrost for the coast of the Arctic Ocean, where the coast, crumbling, is retreating? How much land is our country losing?

- Employees of our institute are monitoring permafrost in the shelf zone of the Arctic Ocean and coastal processes. The coastal retreat rates range from one to two to 30 m per year and depend on the coastal structure. The average rate of retreat of the shores of the Laptev and East Siberian Seas is 0.8 m per year, and the area of land lost in the modern period is 10.7 square meters. km per year.

On the old royal maps you can see islands that no longer exist …

- Quite right. There are such islands. Even in my life, several islands have disappeared - these are the islands of Semenovsky, Vasilievsky, Figurnin.

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