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Deglaciation
Deglaciation is the transition from full glacial conditions during ice ages, to warm interglacials, characterized by global warming and sea level rise due to change in continental ice volume. Thus, it refers to the retreat of a glacier, an ice sheet or frozen surface layer, and the resulting exposure of the Earth's surface. The decline of the cryosphere due to ablation can occur on any scale from global to localized to a particular glacier. After the Last Glacial Maximum (ca. 21,000 years ago), the last deglaciation begun, which lasted until the early Holocene. Around much of Earth, deglaciation during the last 100 years has been accelerating as a result of climate change, partly brought on by anthropogenic changes to greenhouse gases. The previous deglaciation took place from approximately 22 ka until 11.5 ka. This occurred when there was an annual mean atmospheric temperature on the earth that increased by roughly 5 °C, which was also accompanied by regional hig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Last Glacial Maximum
The Last Glacial Maximum (LGM), also referred to as the Last Glacial Coldest Period, was the most recent time during the Last Glacial Period where ice sheets were at their greatest extent between 26,000 and 20,000 years ago. Ice sheets covered much of Northern North America, Northern Europe, and Asia and profoundly affected Earth's climate by causing a major expansion of deserts, along with a large drop in sea levels. Based on changes in position of ice sheet margins dated via cosmogenic nuclide, terrestrial cosmogenic nuclides and radiocarbon dating, growth of ice sheets in the southern hemisphere commenced 33,000 years ago and maximum coverage has been estimated to have occurred sometime between 26,500 years ago and 20,000 years ago. After this, deglaciation caused an abrupt rise in sea level. Decline of the West Antarctica ice sheet occurred between 14,000 and 15,000 years ago, consistent with evidence for another abrupt rise in the sea level about 14,500 years ago. Glacier fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene
The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene is an interglacial period within the ongoing Ice age, glacial cycles of the Quaternary, and is equivalent to Marine isotope stages, Marine Isotope Stage 1. The Holocene correlates with the last maximum axial tilt towards the Sun of the Earth#Axial tilt and seasons, Earth's obliquity. The Holocene corresponds with the rapid proliferation, growth, and impacts of the human species worldwide, including Recorded history, all of its written history, technological revolutions, development of major civilizations, and overall significant transition towards urban culture, urban living in the present. The human impact on modern-era Earth and its ecosystems may be considered of global significance for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and greenhouse periods during which there are no glaciers on the planet. Earth is currently in the ice age called Quaternary glaciation. Individual pulses of cold climate within an ice age are termed '' glacial periods'' (''glacials, glaciations, glacial stages, stadials, stades'', or colloquially, ''ice ages''), and intermittent warm periods within an ice age are called '' interglacials'' or ''interstadials''. In glaciology, the term ''ice age'' is defined by the presence of extensive ice sheets in the northern and southern hemispheres. By this definition, the current Holocene epoch is an interglacial period of an ice age. The accumulation of anthropogenic greenhouse gases is projected to delay the next glacial period. History of research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milankovitch Cycles
Milankovitch cycles describe the collective effects of changes in the Earth's movements on its climate over thousands of years. The term was coined and named after the Serbian geophysicist and astronomer Milutin Milanković. In the 1920s, he provided a more definitive and quantitative analysis than James Croll's earlier hypothesis that variations in eccentricity, axial tilt, and precession combined to result in cyclical variations in the intra-annual and latitudinal distribution of solar radiation at the Earth's surface, and that this orbital forcing strongly influenced the Earth's climatic patterns. Earth movements The Earth's rotation around its axis, and revolution around the Sun, evolve over time due to gravitational interactions with other bodies in the Solar System. The variations are complex, but a few cycles are dominant. The Earth's orbit varies between nearly circular and mildly elliptical (its eccentricity varies). When the orbit is more elongated, there is more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryosphere
The cryosphere is an umbrella term for those portions of Earth's surface where water is in solid form. This includes sea ice, ice on lakes or rivers, snow, glaciers, ice caps, ice sheets, and frozen ground (which includes permafrost). Thus, there is an overlap with the hydrosphere. The cryosphere is an integral part of the global climate system. It also has important Climate change feedbacks, feedbacks on the climate system. These feedbacks come from the cryosphere's influence on surface energy and moisture fluxes, clouds, the water cycle, atmospheric and Ocean circulation, oceanic circulation. Through these feedback processes, the cryosphere plays a significant role in the global climate and in climate model response to global changes. Approximately 10% of the Earth's surface is covered by ice, but this is rapidly decreasing. Current reductions in the cryosphere (Effects of climate change, caused by climate change) are measurable in Ice sheet#Melting due to climate change, ice sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russell Glacier (Greenland)
Russell Glacier () is a glacier in the Qeqqata municipality in central-western Greenland. It flows from the Greenland ice sheet () in the western direction. The front of the glacier is located east of Kangerlussuaq. It is active, advancing every year, and, due to easy access from Kangerlussuaq, it remains a popular place for tourists to visit. Geography The ice sheet outflow ending in Russell Glacier is bounded on the north by the tundra highland of Isunngua and on the south by an exposed, barren, flattened ridge of Akuliarusiarsuk. Several meltwater outflow streams from the base of the glacier form the Akuliarusiarsuup Kuua river, which flows west-southwest towards Kangerlussuaq. The sandur basin of the outflow river forming the valley of the same name () is very shallow; shallow enough to form quicksand fields several kilometers long. Directly to the west of the glacier is a large lake, the 2x10km Aajuitsup Tasia. Due to the minimal height differential, its waters are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanotroph
Methanotrophs (sometimes called methanophiles) are prokaryotes that metabolize methane as their source of carbon and chemical energy. They are bacteria or archaea, can grow aerobically or anaerobically, and require single-carbon compounds to survive. Methanotrophs are especially common in or near environments where methane is produced, although some methanotrophs can oxidize atmospheric methane. Their habitats include wetlands, soils, marshes, rice paddies, landfills, aquatic systems (lakes, oceans, streams) and more. They are of special interest to researchers studying global warming, as they play a significant role in the global methane budget, by reducing the amount of methane emitted to the atmosphere. Methanotrophy is a special case of methylotrophy, using single-carbon compounds that are more reduced than carbon dioxide. Some methylotrophs, however, can also make use of multi-carbon compounds; this differentiates them from methanotrophs, which are usually fastidious ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Methane
Atmospheric methane is the methane present in Earth's atmosphere. The concentration of atmospheric methane is increasing due to methane emissions, and is causing climate change. Methane is one of the most potent greenhouse gases. Methane's radiative forcing (RF) of climate is direct, and it is the second largest contributor to human-caused climate forcing in the historical period. Methane is a major source of water vapour in the stratosphere through oxidation; and water vapour adds about 15% to methane's radiative forcing effect. The global warming potential (GWP) for methane is about 84 in terms of its impact over a 20-year timeframe, and 28 in terms of its impact over a 100-year timeframe. See Table 8.7. Since the beginning of the Industrial Revolution (around 1750), the methane concentration in the atmosphere has increased by about 160%, and human activities almost entirely caused this increase. Since 1750 methane has contributed 3% of greenhouse gas (GHG) emissions in terms of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methane Clathrate
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 (around 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. Methane clathrates are common constituents of the shallow marine geosphere and they occur in deep sedimentary structures and form outcrops on the ocean floor. Methane hydrates are believed to form by the precipitation or crystallisation of metha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equator
The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumference, halfway between the North Pole, North and South Pole, South poles. The term can also be used for any other celestial body that is roughly spherical. In three-dimensional space, spatial (3D) geometry, as applied in astronomy, the equator of a rotating spheroid (such as a planet) is the parallel (circle of latitude) at which latitude is defined to be 0°. It is an imaginary line on the spheroid, equidistant from its geographical pole, poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane (geometry), plane perpendicular to its axis of rotation and midway between its geographical poles. On and near the equator (on Earth), noontime sunlight appears almost directly o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenhouse Gas
Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. Unlike other gases, greenhouse gases absorb the radiations that a planet emits, resulting in the greenhouse effect. The Earth is warmed by sunlight, causing its surface to radiate heat, which is then mostly absorbed by greenhouse gases. Without greenhouse gases in the atmosphere, the average temperature of Earth's surface would be about , rather than the present average of .Le Treut, H., R. Somerville, U. Cubasch, Y. Ding, C. Mauritzen, A. Mokssit, T. Peterson and M. Prather, 2007:Chapter 1: Historical Overview of Climate Change. In:Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. olomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.) Cambridge University Press, Cambridge, United Kingdom and New Y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Industrial Revolution
The Industrial Revolution, sometimes divided into the First Industrial Revolution and Second Industrial Revolution, was a transitional period of the global economy toward more widespread, efficient and stable manufacturing processes, succeeding the Second Agricultural Revolution. Beginning in Kingdom of Great Britain, Great Britain around 1760, the Industrial Revolution had spread to continental Europe and the United States by about 1840. This transition included going from craft production, hand production methods to machines; new Chemical industry, chemical manufacturing and Puddling (metallurgy), iron production processes; the increasing use of Hydropower, water power and Steam engine, steam power; the development of machine tools; and rise of the mechanisation, mechanised factory system. Output greatly increased, and the result was an unprecedented rise in population and population growth. The textile industry was the first to use modern production methods, and textiles b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
