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Collapse Of The West Antarctic Ice Sheet
The West Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. It is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea. As a smaller part of Antarctica, WAIS is also more strongly affected by climate change. There has been warming over the ice sheet since the 1950s, and a substantial retreat of its coastal glaciers since at least the 1990s. Estimates suggest it added around to the global sea level rise between 1992 and 2017, and has been losing ice in the 2010s at a rate equivalent to of annual sea level rise. While some of its losses are offset by the growth of the East Antarctic ice sheet, Antarctica as a whole will most likely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Sheet
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacier, glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are the Antarctic ice sheet and the Greenland ice sheet. Ice sheets are bigger than ice shelf, ice shelves or alpine glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery. Although the surface is cold, the base of an ice sheet is generally warmer due to Geothermal activity, geothermal heat. In places, melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet — these are ice streams. Even stable ice sheets are continually in motion as the ice gradually flows outward from the central plateau, which is the tallest point of the ice sheet, and towards the margins. The ice sheet slope is low around the plate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean Stratification
Ocean stratification is the natural separation of an ocean's water into horizontal layers by Density of water, density. This is generally stable stratification, because warm water floats on top of cold water, and heating is mostly from the sun, which reinforces that arrangement. Stratification is reduced by wind-forced mechanical mixing, but reinforced by Open ocean convection, convection (warm water rising, cold water sinking). Stratification occurs in all ocean basins and also in Stratification (water), other water bodies. Stratified layers are a barrier to the mixing of water, which impacts the exchange of heat, carbon, oxygen and other nutrients. The surface mixed layer is the uppermost layer in the ocean and is well mixed by mechanical (wind) and thermal (convection) effects. Climate change is causing the upper ocean stratification to increase. Due to upwelling and downwelling, which are both wind-driven, mixing of different layers can occur through the rise of cold nutrient-ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bedrock
In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of bedrock is often called an outcrop. The various kinds of broken and weathered rock material, such as soil and subsoil, that may overlie the bedrock are known as regolith. Engineering geology The surface of the bedrock beneath the soil cover (regolith) is also known as ''rockhead'' in engineering geology, and its identification by digging, drilling or geophysical methods is an important task in most civil engineering projects. Superficial deposits can be very thick, such that the bedrock lies hundreds of meters below the surface. Weathering of bedrock Exposed bedrock experiences weathering, which may be physical or chemical, and which alters the structure of the rock to leave it susceptible to erosion. Bedrock may also experience subsur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isostasy
Isostasy (Greek wikt:ἴσος, ''ísos'' 'equal', wikt:στάσις, ''stásis'' 'standstill') or isostatic equilibrium is the state of gravity, gravitational mechanical equilibrium, equilibrium between Earth's crust (geology), crust (or lithosphere) and mantle (geology), mantle such that the crust (geology), crust "floats" at an elevation that depends on its thickness and density. This concept is invoked to explain how different topographic heights can exist at Earth's surface. Although originally defined in terms of continental crust and mantle, it has subsequently been interpreted in terms of lithosphere and asthenosphere, particularly with respect to oceanic island volcanoes, such as the Hawaiian Islands. Although Earth is a dynamic system that responds to loads in many different ways, isostasy describes the important limiting case in which crust and mantle are in static equilibrium. Certain areas (such as the Himalayas and other convergent margins) are not in isostatic equili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Civil Engineering
Civil engineering is a regulation and licensure in engineering, professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, airports, sewage systems, pipelines, structural element, structural components of buildings, and railways. Civil engineering is traditionally broken into a number of sub-disciplines. It is considered the second-oldest engineering discipline after military engineering, and it is defined to distinguish non-military engineering from military engineering. Civil engineering can take place in the public sector from municipal public works departments through to federal government agencies, and in the private sector from locally based firms to Fortune Global 500, ''Fortune'' Global 500 companies. History Civil engineering as a discipline Civil engineering is the application of physical and scientific principles for solv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snow
Snow consists of individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout its life cycle, starting when, under suitable conditions, the ice crystals form in the atmosphere, increase to millimeter size, precipitate and accumulate on surfaces, then metamorphose in place, and ultimately melt, slide, or Sublimation (phase transition), sublimate away. Snowstorms organize and develop by feeding on sources of atmospheric moisture and cold air. Snowflakes Nucleation, nucleate around particles in the atmosphere by attracting supercooling, supercooled water droplets, which Freezing, freeze in hexagonal-shaped crystals. Snowflakes take on a variety of shapes, basic among these are platelets, needles, columns, and Hard rime, rime. As snow accumulates into a snowpack, it may blow into drifts. Over time, accumulated snow m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate Engineering
Geoengineering (also known as climate engineering or climate intervention) is the deliberate large-scale interventions in the Earth’s climate system intended to counteract human-caused climate change. The term commonly encompasses two broad categories: large-scale carbon dioxide removal (CDR) and solar radiation modification (SRM). CDR involves techniques to remove carbon dioxide from the atmosphere and is generally considered a form of climate change mitigation. SRM aims to reduce global warming by reflecting a small portion of sunlight (solar radiation) away from Earth and back into space. Although historically grouped together, these approaches differ substantially in mechanisms, timelines, and risk profiles, and are now typically discussed separately.IPCC (2022Chapter 1: Introduction and FramingiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pine Island Glacier
Pine Island Glacier (PIG) is a large ice stream, and the fastest melting glacier in Antarctica. responsible for about 13% of Antarctica's ice loss. The glacier flows west-northwest along the south side of the Hudson Mountains into Pine Island Bay, part of the Amundsen Sea. The area drained by Pine Island Glacier comprises about 10% of the West Antarctic Ice Sheet. Satellite measurements have shown that the Pine Island Glacier Basin has a greater net contribution of ice to the sea than any other ice drainage basin in the world and this has increased due to recent acceleration of the ice stream. In recent years, the flow of the glacier has accelerated and the grounding line has retreated. Since 2015, the calving of very large icebergs from the Pine Island Glacier has become a roughly annual event. The largest such iceberg, Iceberg B-46, had an initial size of . The glacier is extremely remote, but scientists have surveyed the ice with radar, GPS, and seismic sensors. Most of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thwaites Glacier
Thwaites Glacier is an unusually broad and vast Antarctic glacier located east of Mount Murphy, on the Walgreen Coast of Marie Byrd Land. It was initially sighted by polar researchers in 1940, mapped in 1959–1966 and officially named in 1967, after the late American glaciologist Fredrik T. Thwaites. The glacier flows into Pine Island Bay, part of the Amundsen Sea, at surface speeds which exceed per year near its grounding line. Its fastest-flowing grounded ice is centered between east of Mount Murphy. Like many other parts of the cryosphere, it has been adversely affected by climate change, and provides one of the more notable examples of the retreat of glaciers since 1850. Thwaites Glacier is closely monitored for its potential to elevate sea levels. Since the 1980s, Thwaites and Pine Island Glacier have been described as part of the "weak underbelly" of the West Antarctic Ice Sheet, in part because they seem vulnerable to irreversible retreat and collapse even under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isostatic Rebound
Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound and isostatic depression are phases of glacial isostasy (glacial isostatic adjustment, glacioisostasy), the deformation of the Earth's crust in response to changes in ice mass distribution. The direct raising effects of post-glacial rebound are readily apparent in parts of Northern Eurasia, Northern America, Patagonia, and Antarctica. However, through the processes of ''ocean siphoning'' and ''continental levering'', the effects of post-glacial rebound on sea level are felt globally far from the locations of current and former ice sheets.Milne, G.A., and J.X. Mitrovica (2008) ''Searching for eustasy in deglacial sea-level histories.'' Quaternary Science Reviews. 27:2292–2302. Overview During the last glacial period, much of northern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eemian
The Last Interglacial, also known as the Eemian, was the interglacial period which began about 130,000 years ago at the end of the Penultimate Glacial Period and ended about 115,000 years ago at the beginning of the Last Glacial Period. It corresponds to Marine Isotope Stage 5e. It was the second-to-latest interglacial period of the current Ice Age, the most recent being the Holocene which extends to the present day (having followed the last glacial period). During the Last Interglacial, the proportion of in the atmosphere was about 280 parts per million. The Last Interglacial was one of the warmest periods of the last 800,000 years, with temperatures comparable to and at times warmer (by up to on average 2 degrees Celsius) than the contemporary Holocene interglacial, with the maximum sea level being up to 6 to 9 metres higher than at present, with global ice volume likely also being smaller than the Holocene interglacial. The Last Interglacial is known as the Eemian in nort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
