| The vast plains of West Siberia offer a landscape of taiga forests, lakes and bogs, inherited from the last ice age. But this glacial origin can also be traced underground. One quarter of landmasses in the Northern Hemisphere, where yearly temperature average 32°F (0°C) or below have frozen soils. The constantly frozen soils are called ‘permafrost’ in English and ‘merzlota’ in Russian. Permafrost occupies an area of 4 million square miles (10.5 million square kilometers), an area equal to the size of Europe. Composed rock or soil layers, plant debris, and ice, permafrost can be up to 5,000 feet (1,500 meters) thick and has a surface layer that may thaw during the summer months and freeze again in winter. This exposed and fragile upper layer is threatened by global warming. Before the end of this century, these soils could thaw on a depth of 10 feet (3 meters). The increasing temperatures since the beginning of the Industrial Era, even the more so in polar regions, has already altered the permafrost. In Alaska, for example, the thawing of two meters of permafrost within a 20 years period has resulted in consequences such as unstable ground, tilting buildings and trees and damaged roads. Permafrost also stores large amounts of methane, a greenhouse gas that is 25 times more potent than CO2. The melting of permafrost, ironically linked to the burning of fossil fuel such as oil, will dramatically increase the quantities of methane released into the atmosphere which could have a runaway effect on climate change.
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