TASS, August 12. The recent warming in the Arctic has reduced the permafrost’s area by 2-3% in its southern part, at the same time ground temperatures in Yakutia’s certain districts tend to fall, Director of the Melnikov Permafrost Institute of the Russian Academy of Sciences’ Siberian Branch Mikhail Zheleznyak said in an interview with TASS.
One of the tasks of the current Big Norilsk Expedition, organized by the Russian Academy of Sciences’ Siberian Branch, is to examine the conditions of buildings and ground underneath them. “As part of this expedition, the Permafrost Institute’s task is to assess seasonal soils and permafrost rock masses under engineering facilities, as well as in the oil contamination area and environmentally clean areas. We will use materials, collected during the field studies, to see how freezing conditions have changed. Based on the results of the engineering and geological studies and the research conducted, we will try to establish the reasons for the [recent] accident,” he said.
65% of Russia’s territory
The recent climate changes seem evident to everyone, he continued. Even changes of annual air temperatures. It is a criterion, not the only one though, which shows that in Norilsk or on Taimyr the air temperature has risen by 1.5 degrees over the 40 years. “If you take Russia, there are regions, where the annual temperature has grown by three degrees. This change clearly has an impact on soils. On the other hand, we are aware of the Le Chatelier-Braun principle and that the environment responds to external influences. This means, higher temperatures cause different surface heat exchange conditions. The reaction differs throughout different landscapes. For example, in Central Yakutia we have registered intensive thawing of layers close to the surface in open areas without forests. Inside forests, such changes are either insignificant or do not happen at all. Thus, the reaction to the climate changes is absolutely different, though, for sure, it does exist. In some areas it is insignificant, and in others over the 40 years it has not been observed at all. Conditions of the perennially frozen ground depend greatly on the snow cover, on how it accumulates,” the scientist said.
At the same time, the expert would not provide exact figures on how much permafrost had shrunk in Russia over recent decades, “because the permafrost tends to retreat differently in different regions.”
“We do not know precisely the southern borders of the permafrost,” he continued. “The perennially frozen ground takes 65% of Russia’s territory. My opinion is that in the southern regions of the cryolithozone it has lost 2-3% of the territory, not more. In many territories we have registered bigger areas of summer thawing, but anyway underneath remains the thick frozen layer, it has not disappeared.”
In Yakutia’s central part, where in certain landscapes and in certain woodlands air temperatures rise, the fauna has changed, but scientists do not register deeper thawing or higher ground temperatures. “Every three-four years, we have winters, when snow, a good insulator, covers the ground later than normally. Low air temperatures, absence or thin snow cover favor the soil’s cooling. In Yakutia’s Verkhoyansk District, over the eight years temperatures inside the upper five-meter layer have even dropped by 0.2 degrees. Noteworthy, this phenomenon has been registered at a dozen places with different landscapes. This difference has been recorded by our automatic stations, which take measures four times a day and which over a year record 1,600 measurements. Thus, we are able to see temperature conditions in different seasons,” the institute’s director said.
How perennial is it?
The permafrost’s age is comparable to an eternity for people, the expert said. “In some places the permafrost has remained frozen for almost two million years. Like, for example, in the Kolyma Lowland in northern Yakutia. It is 500-600 meters deep there. In warmer seasons, it could thaw from the top and from the bottom, but its middle part has remained frozen for more than 1.9 million years,” he added.
And yet, every year Russia loses its territory because of the thawing permafrost. “Our institute’s experts have been watching the permafrost in the Arctic Ocean’s shelf zone as well as processes on the coast. The coastline retreats by 1-2 to 30 meters a year, depending on the coast’s structure. The average speed of the coastline’s retreat in the Laptev and East-Siberian seas is 0.8 meters a year, and the coastal territory lost is 10.7 square kilometers a year,” he said, stressing that a few islands – the Semenovsky, Vasilyevsky and Figurnin – had disappeared during his lifetime.
New technologies for Far North
Scientists are aware of areas, where the permafrost has retreated to the extent it cannot hold construction piles. Such places are known in the Trans-Baikal Region, in Chita. “There were foundations designed for frozen ground conditions. Presently, in some places the permafrost has degraded,” he said.
The scientist mentioned new materials and new forms of piles, like, for example, corrugated piles, which have a bigger surface of freezing into the ground, and widely used insulation materials.
“Apparently, one approach is not applicable to all districts in the Far North, as climate and soil conditions differ. While 40 years ago in Yakutsk builders used 10-meter piles, which were considered to be very deeply installed, nowadays piles go down 15 or 16 meters, depending on weights. By having a bigger area of freezing between piles and ground, we minimize the risk of destruction. Another important aspect in construction in the North is concrete, which crumbles from significant temperature fluctuations. In piles and other reinforced concrete structures iron fittings rust, which is very dangerous. Russia has been working on new grades of concrete,” the scientist said. “In road construction, specialists have been using plasticizers and other additional substances so that materials could resist severe conditions and big temperature fluctuations.”