In physical geography, tundra is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term is a Russian word adapted from Sámi languages. There are three regions and associated types of tundra: Arctic tundra, alpine tundra, and Antarctic tundra.
Methane clathrate (CH4·5.75H2O) or (4CH4·23H2O), also called methane hydrate, hydromethane, methane ice, fire ice, natural gas hydrate, or gas hydrate, is a solid clathrate compound (more specifically, a clathrate hydrate) in which a large amount of methane is trapped within a crystal structure of water, forming a solid similar to ice. Originally thought to occur only in the outer regions of the Solar System, where temperatures are low and water ice is common, significant deposits of methane clathrate have been found under sediments on the ocean floors of the Earth (approx. 1100m below the sea level). Methane hydrate is formed when hydrogen-bonded water and methane gas come into contact at high pressures and low temperatures in oceans.
Permafrost is soil or underwater sediment which continuously remains below 0 °C (32 °F) for two years or more: the oldest permafrost had been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below a meter (3 ft), the deepest is greater than 1,500 m (4,900 ft). Similarly, the area of individual permafrost zones may be limited to narrow mountain summits or extend across vast Arctic regions. The ground beneath glaciers and ice sheets is not usually defined as permafrost, so on land, permafrost is generally located beneath a so-called active layer of soil which freezes and thaws depending on the season.
Thermokarst is a type of terrain characterised by very irregular surfaces of marshy hollows and small hummocks formed when ice-rich permafrost thaws. The land surface type occurs in Arctic areas, and on a smaller scale in mountainous areas such as the Himalayas and the Swiss Alps.
Pingos are intrapermafrost ice-cored hills, 3–70 m (10–230 ft) high and 30–1,000 m (98–3,281 ft) in diameter. They are typically conical in shape and grow and persist only in permafrost environments, such as the Arctic and subarctic. A pingo is a periglacial landform, which is defined as a non-glacial landform or process linked to colder climates. It is estimated that there are more than 11,000 pingos on Earth, with the Tuktoyaktuk peninsula area having the greatest concentration at a total of 1,350. There is currently remarkably limited data on pingos.
Yedoma is an organic-rich Pleistocene-age permafrost with ice content of 50–90% by volume. Yedoma are abundant in the cold regions of eastern Siberia, such as northern Yakutia, as well as in Alaska and the Yukon.
Drunken trees, tilted trees, or a drunken forest, is a stand of trees rotated from their normal vertical alignment.
Due to climate change in the Arctic, this polar region is expected to become "profoundly different" by 2050. The speed of change is "among the highest in the world", with the rate of warming being 3-4 times faster than the global average. This warming has already resulted in the profound Arctic sea ice decline, the accelerating melting of the Greenland ice sheet and the thawing of the permafrost landscape. These ongoing transformations are expected to be irreversible for centuries or even millennia.
Arctic methane release is the release of methane from Arctic ocean floors, lake bottoms, wetlands and soils in permafrost regions of the Arctic. While it is a long-term natural process, methane release is exacerbated by global warming. This results in a positive climate change feedback, as methane is a powerful greenhouse gas. The Arctic region is one of many natural sources of methane. Climate change could accelerate methane release in the Arctic, due to the release of methane from existing stores, and from methanogenesis in rotting biomass. When permafrost thaws as a consequence of warming, large amounts of organic material can become available for methanogenesis and may ultimately be released as methane.
The Northeast Science Station of the RAS is an Arctic research station located in Chersky, Sakha Republic in Northeast Siberia. It is one of the world's three largest Arctic stations.
Sergey Aphanasievich Zimov is a Russian geophysicist who specialises in arctic and subarctic ecology. He is the Director of Northeast Scientific Station, a senior research fellow of the Pacific Institute for Geography, and one of the founders of Pleistocene Park. He is best known for his work in advocating the theory that human overhunting of large herbivores during the Pleistocene caused Siberia's grassland-steppe ecosystem to disappear and for raising awareness as to the important roles permafrost and thermokarst lakes play in the global carbon cycle.
A methane chimney or gas chimney is a rising column of natural gas, mainly methane, within a water or sediment column. The contrast in physical properties between the gas phase and the surrounding water makes such chimneys visible in oceanographic and geophysical data. In some cases, gas bubbles released at the seafloor may dissolve before they reach the ocean surface, but the increased hydrocarbon concentration may still be measured by chemical oceanographic techniques.
Pleistocene Park is a nature reserve on the Kolyma River south of Chersky in the Sakha Republic, Russia, in northeastern Siberia, where an attempt is being made to re-create the northern subarctic steppe grassland ecosystem that flourished in the area during the last glacial period.
The permafrost carbon cycle or Arctic carbon cycle is a sub-cycle of the larger global carbon cycle. Permafrost is defined as subsurface material that remains below 0o C for at least two consecutive years. Because permafrost soils remain frozen for long periods of time, they store large amounts of carbon and other nutrients within their frozen framework during that time. Permafrost represents a large carbon reservoir, one which was often neglected in the initial research determining global terrestrial carbon reservoirs. Since the start of the 2000s, however, far more attention has been paid to the subject, with an enormous growth both in general attention and in the scientific research output.
Increasing methane emissions are a major contributor to the rising concentration of greenhouse gases in Earth's atmosphere, and are responsible for up to one-third of near-term global heating. During 2019, about 60% of methane released globally was from human activities, while natural sources contributed about 40%. Reducing methane emissions by capturing and utilizing the gas can produce simultaneous environmental and economic benefits.
Susan M. Natali is an American ecologist. She is the Arctic program director and senior scientist at the Woodwell Climate Research Center, where her research focuses on the impact of climate change on terrestrial ecosystems, primarily on Arctic permafrost. She is also the project lead for Permafrost Pathways, a new initiative launched in 2022 with funding from TED's Audacious Project. On Monday, April 11, 2022, Dr. Natali gave a TED Talk introducing the Permafrost Pathways project at the TED2022 conference in Vancouver, BC.
Jill L. Bubier is a professor emerita of environmental science at Mount Holyoke College (MHC). Her research examines how Northern ecosystems respond to climate change.
Michelle Cailin Mack is an ecologist working on the connections between plants and climate in polar regions. She is a fellow of the Ecological Society of America and the American Geophysical Union. She currently holds the title of Regent's Professor at Northern Arizona University.
Merritt Turetsky is an American ecosystem ecologist and a professor at the University of Colorado Boulder. She currently serves as the Director of Arctic Security for the University of Colorado. She served as the first woman Director of the Institute for Arctic and Alpine Research (INSTAAR) from 2019-2023. Her research considers fire regimes, climate change and biogeochemical cycling in Arctic wetlands. Turetsky is a member of the Permafrost Action Team (SEARCH), a group of scientists who translate and deliver science to decision-makers.
Retrogressive thaw slumps (RTS), are a type of landslide that occur in the terrestrial Arctic's permafrost region of the circumpolar Northern Hemisphere when an ice-rich section thaws. RTSs develop quickly and can extend across several hectares modifying Arctic coastlines and permafrost terrain. They are the most active and dynamic feature of thermokarst—the collapse of the land surface as ground ice melts. They are thermokarst slope failures due to abrupt thawing of ice-rich permafrost or glaciated terrains. These horseshoe-shaped landslides contribute to the thawing of hectares of permafrost annually and are considered to be one of the most active and dynamic features of thermokarst—the "processes and landforms that involve collapse of the land surface as a result of the melting of ground ice." They are found in permafrost or glaciated regions of the Northern Hemisphere—the Tibetan Plateau, Siberia, from the Himalayas to northern Greenland, and in northern Canada's Northwest Territories (NWT), the Yukon Territories, Nunavut, and Nunavik and in the American state of Alaska. The largest RTS in the world is in Siberia—the Batagaika Crater, also called a "megaslump", is one-kilometre-long and 100 metres (330 ft) deep and it grows a 100 feet (30 m) annually. The land began to sink, and the Batagaika Crater began to form in the 1960s, following clear-cutting of a section of forested area.
