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1500-Year Climate Cycle
Bond events are North Atlantic ice rafting events that Gerard C. Bond sought to link to climate fluctuations in the Holocene. Eight such events have been identified. Bond events were previously believed to exhibit a roughly cycle, but the primary period of variability is now put at . Gerard C. Bond of the Lamont–Doherty Earth Observatory, at Columbia University, was the lead author of the 1997 paper that postulated the theory of 1470-year climate cycles in the Late Pleistocene and the Holocene, mainly based on petrologic tracers of drift ice in the North Atlantic. However, more recent work at a single site suggested that the tracers did not provide sufficient support for 1,500-year intervals of climate change and suggested that the reported period was a statistical artifact. Furthermore, after the publication of the Greenland Ice Core Chronology 2005 (GICC05) for the North Greenland Ice Core Project ice core, it became clear that Dansgaard–Oeschger events also show no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Atlantic
The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for separating the New World of the Americas (North America and South America) from the Old World of Afro-Eurasia (Africa, Asia, and Europe). Through its separation of Afro-Eurasia from the Americas, the Atlantic Ocean has played a central role in the development of human society, globalization, and the histories of many nations. While the Norse were the first known humans to cross the Atlantic, it was the expedition of Christopher Columbus in 1492 that proved to be the most consequential. Columbus's expedition ushered in an age of exploration and colonization of the Americas by European powers, most notably Portugal, Spain, France, and the United Kingdom. From the 16th to 19th centuries, the Atlantic Ocean was the center of both an epo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilisations. Its 4.7 billion people constitute roughly 60% of the world's population. Asia shares the landmass of Eurasia with Europe, and of Afro-Eurasia with both Europe and Africa. In general terms, it is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a social constructionism, historical and cultural construct, as there is no clear physical and geographical separation between them. A commonly accepted division places Asia to the east of the Suez Canal separating it from Africa; and to the east of the Turkish straits, the Ural Mountains an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Antique Little Ice Age
The Late Antique Little Ice Age (LALIA) was a long-lasting Northern Hemispheric cooling period in the 6th and 7th centuries AD, during the period known as Late Antiquity. The period coincides with three large volcanic eruptions in 535/536, 539/540 and 547. The volcanic winter of 536 was the early phenomenon of the century-long global temperature decline. One study suggested a global cooling of . The period contributed to the decline of the Roman Empire and influenced the second wave migration period, primarily of the early Slavs. Term The term and concept were first coined and described in February 2016, in the '' Nature Geoscience'' article titled "Cooling and societal change during the Late Antique Little Ice Age from 536 to around 660 AD" by Ulf Büntgen, et al. Eruptions The existence of a cooling period was proposed as a theory in 2015, and subsequently confirmed as the period from AD 536 to about 660. Volcanic eruptions, meteorites striking the Earth's surface, and come ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Migration Period
The Migration Period ( 300 to 600 AD), also known as the Barbarian Invasions, was a period in European history marked by large-scale migrations that saw the fall of the Western Roman Empire and subsequent settlement of its former territories by various tribes, and the establishment of post-Roman kingdoms there. The term refers to the important role played by the migration, invasion, and settlement of various tribes, notably the Burgundians, Vandals, Goths, Alemanni, Alans, Huns, early Slavs, Pannonian Avars, Bulgars and Magyars within or into the territories of Europe as a whole and of the Western Roman Empire in particular. Historiography traditionally takes the period as beginning in AD 375 (possibly as early as 300) and ending in 568. Various factors contributed to this phenomenon of migration and invasion, and their role and significance are still widely discussed. Historians differ as to the dates for the beginning and ending of the Migration Period. The beginni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate Change Denial
Climate change denial (also global warming denial) is a form of science denial characterized by rejecting, refusing to acknowledge, disputing, or fighting the scientific consensus on climate change. Those promoting denial commonly use rhetorical tactics to give the appearance of a scientific controversy where there is none. Climate change denial includes unreasonable doubts about the extent to which climate change is caused by humans, its effects on nature and human society, and the potential of adaptation to global warming by human actions. To a lesser extent, climate change denial can also be implicit when people accept the science but fail to reconcile it with their belief or action. Several studies have analyzed these positions as forms of denialism, pseudoscience, or propaganda. Many issues that are settled in the scientific community, such as human responsibility for climate change, remain the subject of politically or economically motivated attempts to downplay, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kiloannus
A year is a unit of time based on how long it takes the Earth to orbit the Sun. In scientific use, the tropical year (approximately 365 solar days, 5 hours, 48 minutes, 45 seconds) and the sidereal year (about 20 minutes longer) are more exact. The modern calendar year, as reckoned according to the Gregorian calendar, approximates the tropical year by using a system of leap years. The term 'year' is also used to indicate other periods of roughly similar duration, such as the lunar year (a roughly 354-day cycle of twelve of the Moon's phasessee lunar calendar), as well as periods loosely associated with the calendar or astronomical year, such as the seasonal year, the fiscal year, the academic year, etc. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by changes in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the planet, four seasons are generally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Before Present
Before Present (BP) or "years before present (YBP)" is a time scale used mainly in archaeology, geology, and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Because the "present" time changes, standard practice is to use 1January 1950 as the commencement date (epoch) of the age scale, with 1950 being labelled as the "standard year". The abbreviation "BP" has been interpreted retrospectively as "Before Physics", which refers to the time before nuclear weapons testing artificially altered the proportion of the carbon isotopes in the atmosphere, which scientists must account for when using radiocarbon dating for dates of origin that may fall after this year. In a convention that is not always observed, many sources restrict the use of BP dates to those produced with radiocarbon dating; the alternative notation "RCYBP" stands for the explicit "radio carbon years before present". Usage The BP scale is s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outlier
In statistics, an outlier is a data point that differs significantly from other observations. An outlier may be due to a variability in the measurement, an indication of novel data, or it may be the result of experimental error; the latter are sometimes excluded from the data set. An outlier can be an indication of exciting possibility, but can also cause serious problems in statistical analyses. Outliers can occur by chance in any distribution, but they can indicate novel behaviour or structures in the data-set, measurement error, or that the population has a heavy-tailed distribution. In the case of measurement error, one wishes to discard them or use statistics that are robust statistics, robust to outliers, while in the case of heavy-tailed distributions, they indicate that the distribution has high skewness and that one should be very cautious in using tools or intuitions that assume a normal distribution. A frequent cause of outliers is a mixture of two distributions, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology (journal)
''Geology'' is a peer-reviewed publication of the Geological Society of America (GSA). GSA stated (in 2006) (ISSN 0091-7613) that it is the most widely read scientific journal in the field of earth science. It is published monthly, with each issue containing 20 or more articles. One of the goals of the journal is to provide a forum for shorter articles (four pages each) and less focus on purely academic research–type articles. According to the ''Journal Citation Reports'', the journal had a 2020 impact factor of 5.399. The journal is indexed in Scopus and SCImago The SCImago Journal Rank (SJR) indicator is a measure of the prestige of scholarly journals that accounts for both the number of citations received by a journal and the prestige of the journals where the citations come from. Etymology SCImag .... See also * List of scientific journals ** List of earth and atmospheric sciences journals References External links *Geology — Browse Issues [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinrich Event
A Heinrich event is a natural phenomenon in which large groups of icebergs break off from the Laurentide ice sheet and traverse the Hudson Strait into the North Atlantic. First described by the marine geologist Hartmut Heinrich, they occurred during five of the last seven glacial periods over the past 640,000 years. Heinrich events are particularly well documented for the Wisconsin glaciation, during the Last Glacial Period, but notably absent from the Penultimate Glacial Period. The icebergs contained rock mass that had been eroded by the glaciers, and as they melted, the material was dropped to the sea floor as ice rafted debris and formed deposits called Heinrich layers. The icebergs' melting caused vast quantities of fresh water to be added to the North Atlantic. Such inputs of cold and fresh water may well have altered the density-driven, thermohaline circulation patterns of the ocean, and often coincide with indications of global climate fluctuations. Various mechanisms hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle East
The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western European nations in the early 20th century as a replacement of the term Near East (both were in contrast to the Far East). The term "Middle East" has led to some confusion over its changing definitions. Since the late 20th century, it has been criticized as being too Eurocentrism, Eurocentric. The region includes the vast majority of the territories included in the closely associated definition of West Asia, but without the South Caucasus. It also includes all of Egypt (not just the Sinai Peninsula, Sinai) and all of Turkey (including East Thrace). Most Middle Eastern countries (13 out of 18) are part of the Arab world. The list of Middle Eastern countries by population, most populous countries in the region are Egypt, Turkey, and Iran, whil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
