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Bølling–Allerød Warming
The Bølling–Allerød interstadial (), also called the Late Glacial Interstadial, was an abrupt warm and moist interstadial period that occurred during the final stages of the Last Glacial Period. This warm period ran from 14,690 to 12,890 years before the present ( BP). It began with the end of the cold period known as the Oldest Dryas, and ended abruptly with the onset of the Younger Dryas, a cold period that reduced temperatures back to near-glacial levels within a decade. In some regions, a cold period known as the Older Dryas can be detected in the middle of the Bølling–Allerød interstadial. In these regions the period is divided into the Bølling oscillation, which peaked around 14,500 BP, and the Allerød oscillation, which peaked closer to 13,000 BP. Estimates of rise are 20–35 ppmv within 200 years, a rate less than 29–50% compared to the anthropogenic global warming signal from the past 50 years, and with a radiative forcing of 0.59–0.75 W m−2. Hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution Of Temperature In The Post-Glacial Period According To Greenland Ice Cores (Bølling-Allerød)
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or more rare within a population. The evolutionary pressures that determine whether a characteristic is common or rare within a population constantly change, resulting in a change in heritable characteristics arising over successive generations. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms, and molecules. The theory of evolution by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meltwater Pulse 1A
Meltwater pulse 1A (MWP1a) is the name used by Quaternary geologists, paleoclimatologists, and oceanographers for a period of rapid post-glacial sea level rise, between 13,500 and 14,700 calendar years ago, during which global sea level rose between and in about 400–500 years, giving mean rates of roughly /yr. Meltwater pulse 1A is also known as catastrophic rise event 1 (CRE1) in the Caribbean Sea.Blanchon, P., and J. Shaw (1995) ''Reef drowning during the last deglaciation: Evidence for catastrophic sea-level rise and ice-sheet collapse.'' Geology. 23(1):4-8. The rates of sea level rise associated with meltwater pulse 1A are the highest known rates of post-glacial, eustatic sea level rise. Meltwater pulse 1A is also the most widely recognized and least disputed of the named, postglacial meltwater pulses. Other named, postglacial meltwater pulses are known most commonly as ''meltwater pulse 1A0'' (''meltwater pulse 19ka''), ''meltwater pulse 1B'', ''meltwater pulse 1C'', ''mel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larch
Larches are deciduous conifers in the genus ''Larix'', of the family Pinaceae (subfamily Laricoideae). Growing from tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains further south. Larches are among the dominant plants in the boreal forests of Siberia and Canada. Although they are conifers, larches are deciduous trees that lose their needles in the autumn. Etymology The English name Larch ultimately derives from the Latin "larigna," named after the ancient settlement of Larignum. The story of its naming was preserved by Vitruvius: It is worth while to know how this wood was discovered. The divine Caesar, being with his army in the neighbourhood of the Alps, and having ordered the towns to furnish supplies, the inhabitants of a fortified stronghold there, called Larignum, trusting in the natural strength of their defences, refused to obey his command. So the general ordered his forces to the assault. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pine
A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts 187 species names of pines as current, together with more synonyms. The American Conifer Society (ACS) and the Royal Horticultural Society accept 121 species. Pines are commonly found in the Northern Hemisphere. ''Pine'' may also refer to the lumber derived from pine trees; it is one of the more extensively used types of lumber. The pine family is the largest conifer family and there are currently 818 named cultivars (or trinomials) recognized by the ACS. Description Pine trees are evergreen, coniferous resinous trees (or, rarely, shrubs) growing tall, with the majority of species reaching tall. The smallest are Siberian dwarf pine and Potosi pinyon, and the tallest is an tall ponderosa pine located in southern Oregon's Rogue Riv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spruce
A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfamily Piceoideae. Spruces are large trees, from about 20 to 60 m (about 60–200 ft) tall when mature, and have whorled branches and conical form. They can be distinguished from other members of the pine family by their needles (leaves), which are four-sided and attached singly to small persistent peg-like structures (pulvini or sterigmata) on the branches, and by their cones (without any protruding bracts), which hang downwards after they are pollinated. The needles are shed when 4–10 years old, leaving the branches rough with the retained pegs. In other similar genera, the branches are fairly smooth. Spruce are used as food plants by the larvae of some Lepidoptera (moth and butterfly) species, such as the eastern spruce budwo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspen
Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the ''Populus'' genus. Species These species are called aspens: *'' Populus adenopoda'' – Chinese aspen (China, south of ''P. tremula'') *''Populus davidiana'' – Korean aspen (Eastern Asia) *''Populus grandidentata'' – Bigtooth aspen (eastern North America, south of ''P. tremuloides'') *''Populus sieboldii'' – Japanese aspen (Japan) *''Populus tremula'' – Eurasian aspen (northern Europe and Asia) *''Populus tremuloides'' – Quaking aspen or trembling aspen (northern and western North America) Habitat and longevity The trembling of the leaves of the trembling aspen Aspen trees are all native to cold regions with cool summers, in the north of the northern hemisphere, extending south at high-altitude areas such as mountains or high plains. They are all medium-sized deciduous trees reaching tall. In North America, the aspen is referred to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birch
A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 to 60 known taxa of which 11 are on the IUCN 2011 Red List of Threatened Species. They are a typically rather short-lived pioneer species widespread in the Northern Hemisphere, particularly in northern areas of temperate climates and in boreal climates. Description Birch species are generally small to medium-sized trees or shrubs, mostly of northern temperate and boreal climates. The simple leaves are alternate, singly or doubly serrate, feather-veined, petiolate and stipulate. They often appear in pairs, but these pairs are really borne on spur-like, two-leaved, lateral branchlets. The fruit is a small samara, although the wings may be obscure in some species. They differ from the alders (''Alnus'', another genus in the family) in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryas Octopetala
''Dryas octopetala'', the mountain avens, eightpetal mountain-avens, white dryas or white dryad, is an Arctic–alpine flowering plant in the family Rosaceae. It is a small prostrate evergreen subshrub forming large colonies. The specific epithet ''octopetala'' derives from Greek ''octo'' 'eight' and ''petalon'' 'petal', referring to the eight petals of the flower, an unusual number in the Rosaceae, where five is the normal number. However, flowers with up to 16 petals also occur naturally. As a floral emblem, it is the official territorial flower of the Northwest Territories and the national flower of Iceland. Description The stems are woody, tortuous, with short, horizontal rooting branches. The leaves are glabrous above, densely white-tomentose beneath. The flowers are produced on stalks long, and have eight creamy white petals – hence the specific epithet ''octopetala''. The style is persistent on the fruit with white feathery hairs, functioning as a wind-dispersal agent. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salix Polaris
''Salix polaris'', the polar willow, is a species of willow with a circumpolar distribution in the high arctic tundra, extending north to the limits of land, and south of the Arctic in the mountains of Norway, the northern Ural Mountains, the northern Altay Mountains, Kamchatka, and British Columbia, Canada.Salicaceae of the Canadian Arctic Archipelago''Salix polaris''Plants of British Columbia''Salix polaris''/ref>Den Virtuella Floran/ref> Description One of the smallest willows in the world, it is a prostrate, creeping dwarf shrub, only high, and has underground branches or runners in the uppermost soil layers. The leaves are rounded-ovate, 5–32 mm long and 8–18 mm broad, dark green with entire margins. It is dioecious, with separate female and male plants. The flowers are grouped in short catkins each bearing only a few flowers. The fruit is a brownish and hairy capsule. The long runners with freely rooting stems creep in mats of mosses and lichens, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pole, with 0° at the Equator. Lines of constant latitude, or ''parallels'', run east–west as circles parallel to the equator. Latitude and ''longitude'' are used together as a coordinate pair to specify a location on the surface of the Earth. On its own, the term "latitude" normally refers to the ''geodetic latitude'' as defined below. Briefly, the geodetic latitude of a point is the angle formed between the vector perpendicular (or ''normal'') to the ellipsoidal surface from the point, and the plane of the equator. Background Two levels of abstraction are employed in the definitions of latitude and longitude. In the first step the physical surface is modeled by the geoid, a surface which approximates the mean sea level over the ocean ... [...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 Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methane Reservoirs
Methane reservoirs on Earth are mainly found in * Oil and gas reservoirs as natural gas * Coalbeds *the seabed and the Arctic and other permafrost regions as methane clathrate *the atmosphere *decaying organic material with the exact distribution so far determined by the methane cycle/carbon cycle. Methane as the main ingredient of natural gas and as an extractable fossil fuel-energy resource has limited if significant reserves. Russia, Iran, and Qatar are topping the list with together , nearly half the world's proven reserves. Methane from gas fields is an important factor in the world energy production and consumption. Methane clathrate is a potential future energy source, if it doesn't escape to the atmosphere before extraction because of global warming. In the atmosphere, it is not only unusable, but also a potent greenhouse gas, further accelerating the current climate change. But even conventional reservoirs are leaking methane (together with other gases like carbon dioxid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
