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Mid-Pleistocene Transition
The Mid-Pleistocene Transition (MPT), also known as the Mid-Pleistocene Revolution (MPR), is a fundamental change in the behaviour of glacial cycles during the Quaternary glaciations. The transition happened approximately 1.25–0.7 million years ago, in the Pleistocene epoch. Before the MPT, the glacial cycles were dominated by a 41,000-year periodicity with low-amplitude, thin ice sheets and a linear relationship to the Milankovitch forcing from axial tilt. After the MPT there have been strongly asymmetric cycles with long-duration cooling of the climate and build-up of thick ice sheets, followed by a fast change from extreme glacial conditions to a warm interglacial. The cycle lengths have varied, with an average length of approximately 100,000 years. The Mid-Pleistocene Transition was long a problem to explain, as described in the article '' 100,000-year problem''. The MPT can now be reproduced by numerical models that assume a decreasing level of atmospheric carbon d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Five Myr Climate Change
5 is a number, numeral, and glyph. 5, five or number 5 may also refer to: * AD 5, the fifth year of the AD era * 5 BC, the fifth year before the AD era Literature * ''5'' (visual novel), a 2008 visual novel by Ram * ''5'' (comics), an award-winning comics anthology * ''No. 5'' (manga), a Japanese manga by Taiyō Matsumoto * The Famous Five (novel series), a series of children's adventure novels written by English author Enid Blyton Films * ''Five'' (1951 film), a post-apocalyptic film * ''Five'' (2003 film), an Iranian documentary by Abbas Kiarostami * ''Five'' (2011 film), a comedy-drama television film * ''Five'' (2016 film), a French comedy film * Number 5, the protagonist in the film ''Short Circuit'' (1986 film) Television and radio * 5 (TV channel), a television network in the Philippines (currently known as TV5 from 2008 to 2018 and again since 2020), owned by TV5 Network, Inc. * Channel 5 (British TV channel), British free-to-air television network sometim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's North Pole. Owing to Earth's axial tilt of 23.439281°, winter in the Northern Hemisphere lasts from the December solstice (typically December 21 UTC) to the March equinox (typically March 20 UTC), while summer lasts from the June solstice through to the September equinox (typically on 23 September UTC). The dates vary each year due to the difference between the calendar year and the astronomical year. Within the Northern Hemisphere, oceanic currents can change the weather patterns that affect many factors within the north coast. Such events include El Niño–Southern Oscillation. Trade winds blow from east to west just above the equator. The winds pull surface water with them, creating currents, which flow westward due to the Coriolis e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciology
Glaciology (; ) is the scientific study of glaciers, or more generally ice and natural phenomena that involve ice. Glaciology is an interdisciplinary Earth science that integrates geophysics, geology, physical geography, geomorphology, climatology, meteorology, hydrology, biology, and ecology. The impact of glaciers on people includes the fields of human geography and anthropology. The discoveries of water ice on the Moon, Mars, Europa and Pluto add an extraterrestrial component to the field, which is referred to as "astroglaciology". Overview A glacier is an extended mass of ice formed from snow falling and accumulating over a long period of time; glaciers move very slowly, either descending from high mountains, as in valley glaciers, or moving outward from centers of accumulation, as in continental glaciers. Areas of study within glaciology include glacial history and the reconstruction of past glaciation. A glaciologist is a person who studies glaciers. A glacial geologist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Events That Forced The Climate
Event may refer to: Gatherings of people * Ceremony, an event of ritual significance, performed on a special occasion * Convention (meeting), a gathering of individuals engaged in some common interest * Event management, the organization of events * Festival, an event that celebrates some unique aspect of a community * Happening, a type of artistic performance * Media event, an event created for publicity * Party, a social, recreational or corporate events held * Sporting event, at which athletic competition takes place * Virtual event, a gathering of individuals within a virtual environment Science, technology, and mathematics * Event (computing), a software message indicating that something has happened, such as a keystroke or mouse click * Event (philosophy), an object in time, or an instantiation of a property in an object * Event (probability theory), a set of outcomes to which a probability is assigned * Event (relativity), a point in space at an instant in time, i.e. a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline Of Glaciation
There have been five or six major ice ages in the history of Earth over the past 3 billion years. The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago. Within ice ages, there exist periods of more severe glacial conditions and more temperate conditions, referred to as glacial periods and interglacial periods, respectively. The Earth is currently in such an interglacial period of the Quaternary glaciation, with the last glacial period of the Quaternary having ended approximately 11,700 years ago. The current interglacial is known as the Holocene epoch.Walker, M., Johnsen, S., Rasmussen, S. O., Popp, T., Steffensen, J.-P., Gibbard, P., Hoek, W., Lowe, J., Andrews, J., Bjo¨ rck, S., Cwynar, L. C., Hughen, K., Kershaw, P., Kromer, B., Litt, T., Lowe, D. J., Nakagawa, T., Newnham, R., and Schwander, J. 2009Formal definition and dating of the GSSP (Global Stratotype Section and Point) for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleothermometer
A paleothermometer is a methodology that provides an estimate of the ambient temperature at the time of formation of a natural material. Most paleothermometers are based on empirically-calibrated proxy relationships, such as the tree ring or TEX86 methods. Isotope methods, such as the δ18O method or the clumped-isotope method, are able to provide, at least in theory, direct measurements of temperature. Common paleothermometers The isotopic ratio of 18O to 16O, usually in foram tests or ice cores. High values mean low temperatures. Confounded by ice volume - more ice means higher values. Ocean water is mostly H216O, with small amounts of HD16O and H218O. In Standard Mean Ocean Water (SMOW) the ratio of D to H is and 18O/16O is . Fractionation occurs during changes between condensed and vapour phases: the vapour pressure of heavier isotopes is lower, so vapour contains relatively more of the lighter isotopes and when the vapour condenses the precipitation preferentia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleoclimatology
Paleoclimatology (British spelling, palaeoclimatology) is the study of climates for which direct measurements were not taken. As instrumental records only span a tiny part of Earth's history, the reconstruction of ancient climate is important to understand natural variation and the evolution of the current climate. Paleoclimatology uses a variety of proxy methods from Earth and life sciences to obtain data previously preserved within rocks, sediments, boreholes, ice sheets, tree rings, corals, shells, and microfossils. Combined with techniques to date the proxies, the paleoclimate records are used to determine the past states of Earth's atmosphere. The scientific field of paleoclimatology came to maturity in the 20th century. Notable periods studied by paleoclimatologists are the frequent glaciations that Earth has undergone, rapid cooling events like the Younger Dryas, and the rapid warming during the Paleocene–Eocene Thermal Maximum. Studies of past changes in the environm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chibanian
The Chibanian, widely known by its previous designation of Middle Pleistocene, is an Age (geology), age in the international geologic timescale or a Stage (stratigraphy), stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. The Chibanian name was officially ratified in January 2020. It is currently estimated to span the time between 0.770 annum, Ma (770,000 years ago) and 0.126 Ma (126,000 years ago), also expressed as 770–126 ka. It includes the transition in palaeoanthropology from the Lower Palaeolithic, Lower to the Middle Palaeolithic over 300 ka. The Chibanian is preceded by the Calabrian (stage), Calabrian and succeeded by the proposed Tarantian. The beginning of the Chibanian is the Brunhes–Matuyama reversal, when the Earth's magnetic field last underwent reversal. It ends with the onset of the Eemian interglacial period (Marine Isotope Stage 5). The term Middle Pleistocene was in use as a provisional or "quasi-fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axial Tilt
In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, which is the line perpendicular to its orbital plane; equivalently, it is the angle between its equatorial plane and orbital plane. It differs from orbital inclination. At an obliquity of 0 degrees, the two axes point in the same direction; that is, the rotational axis is perpendicular to the orbital plane. The rotational axis of Earth, for example, is the imaginary line that passes through both the North Pole and South Pole, whereas the Earth's orbital axis is the line perpendicular to the imaginary plane through which the Earth moves as it revolves around the Sun; the Earth's obliquity or axial tilt is the angle between these two lines. Earth's obliquity oscillates between 22.1 and 24.5 degrees on a 41,000-year cycle. Based on a continuously updated formula (here Laskar, 1986, though since 2006 the IMCCE and the IAU recommend the P03 model), Earth's mea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Cycle
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 Quaternary glaciation. Individual pulses of cold climate within an ice age are termed ''glacial periods'' (or, alternatively, ''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, ''ice age'' implies the presence of extensive ice sheets in both northern and southern hemispheres. By this definition, Earth is currently in an interglacial period—the Holocene. The amount of anthropogenic greenhouse gases emitted into Earth's oceans and atmosphere is predicted to prevent the next glacial period for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regolith
Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestrial planets and moons. Etymology The term ''regolith'' combines two Greek words: (), 'blanket', and (), 'rock'. The American geologist George P. Merrill first defined the term in 1897, writing: Earth Earth's regolith includes the following subdivisions and components: * soil or pedolith * alluvium and other transported cover, including that transported by aeolian, glacial, marine, and gravity flow processes. * "saprolith'", generally divided into the ** ''upper saprolite'': completely oxidised bedrock ** ''lower saprolite'': chemically reduced partially weathered rocks ** ''saprock'': fractured bedrock with weathering restricted to fracture margins * volcanic ash and lava flows that are interbedded with unconsolidated material * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate Sensitivity
Climate sensitivity is a measure of how much Earth's surface will cool or warm after a specified factor causes a change in its climate system, such as how much it will warm for a doubling in the atmospheric carbon dioxide () concentration. In technical terms, climate sensitivity is the average change in global mean surface temperature in response to a radiative forcing, which drives a difference between Earth's incoming and outgoing energy. Climate sensitivity is a key measure in climate science, and a focus area for climate scientists, who want to understand the ultimate consequences of anthropogenic global warming. The Earth's surface warms as a direct consequence of increased atmospheric , as well as increased concentrations of other greenhouse gases such as nitrous oxide and methane. The increasing temperatures have secondary effects on the climate system, such as an increase in atmospheric water vapour, which is itself also a greenhouse gas. Scientists do not know exactly h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
