The South Tibetan Detachment is one of the major faults in the Himalaya Mountains.
92-578: Understanding the formation of the Himalayan mountains has been a goal of structural geologists for a long time. Many of the problems and disagreements that geologists have with each other concerning the Himalayan orogeny involve the relationship between the observed geometry, or structures, with the various rock units (different types of rock). There are three primary rock units present in the Himalaya:
184-617: A turbiditic environment, on the northern part of the Indian continental slope and in the adjoining Neotethys basin . The age of these sediments ranges from Late Permian to Eocene . The metamorphic rocks of the Himalaya can be very useful in deciphering and coming up with models of tectonic relationships. According to Kohn (2014), the exhumation of metamorphic rocks can be explained by the Main Himalayan Thrust. Although
276-403: A 70 percent probability the world population will not stabilize this century. Population, which had sort of fallen off the world's agenda, remains a very important issue." The table below shows historical and predicted regional population figures in millions. The availability of historical population figures varies by region. The following table gives estimates, in millions, of population in
368-462: A combination of these three mechanisms, it is nevertheless the last mechanism which created the high topographic relief of the Himalaya. The Himalayan tectonics result in long term deformation. This includes shortening across the Himalayas that range from 900 to 1,500 km. Said shortening is a product of the significant ongoing seismic activity. The continued convergence of the Indian plate with
460-433: A growth rate by then of zero. Other demographers predict that the human population will begin to decline in the second half of the 21st century. The total number of births globally is currently (2015–2020) 140 million/year, which is projected to peak during the period 2040–2045 at 141 million/year and then decline slowly to 126 million/year by 2100. The total number of deaths is currently 57 million/year and
552-533: A lack of accurate records. Haub (1995) estimates that around 40% of those who have ever lived did not survive beyond their first birthday. Haub also stated that " life expectancy at birth probably averaged only about ten years for most of human history", which is not to be mistaken for the life expectancy after reaching adulthood. The latter equally depended on period, location and social standing, but calculations identify averages from roughly 30 years upward. The National Institute of Corrections estimates that
644-412: A large scale. Asia is the most populous continent, with its 4.64 billion inhabitants accounting for 60% of the world population. The world's two most populated countries, India and China, together constitute about 36% of the world's population. Africa is the second most populated continent, with around 1.34 billion people, or 17% of the world's population. Europe's 747 million people make up 10% of
736-424: A low of 7.4 billion to a high of more than 10.6 billion. Projected figures vary depending on underlying statistical assumptions and the variables used in projection calculations, especially the fertility and mortality variables. Long-range predictions to 2150 range from a population decline to 3.2 billion in the "low scenario", to "high scenarios" of 24.8 billion. One extreme scenario predicted
828-532: A major rifting episode split Gondwana in two parts. The Indian continent became part of East Gondwana, together with Australia and Antarctica . However, the separation of East and West Gondwana, together with the formation of oceanic crust, occurred later, in the Callovian (160-155 Ma). The Indian plate then broke off from Australia and Antarctica in the Early Cretaceous (130-125 Ma) with
920-499: A massive increase to 256 billion by 2150, assuming the global fertility rate remained at its 1995 level of 3.04 children per woman; however, by 2010 the global fertility rate had declined to 2.52. There is no estimation for the exact day or month the world's population surpassed one or two billion. The points at which it reached three and four billion were not officially noted, but the International Database of
1012-402: A population of over 139 million in 2020. In just one hundred years, the population of Brazil decupled (x10), from about 17 million in 1900, or about 1% of the world population in that year, to about 176 million in 2000, or almost 3% of the global population in the very early 21st century. Mexico's population grew from 13.6 million in 1900 to about 112 million in 2010. Between
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#17327725087911104-454: A steady decline in population growth rate; the global population is expected to reach between 8.3 and 10.9 billion by 2050. 2003 UN Population Division population projections for the year 2150 range between 3.2 and 24.8 billion. One of many independent mathematical models supports the lower estimate, while a 2014 estimate forecasts between 9.3 and 12.6 billion in 2100, and continued growth thereafter. The 2019 Revision of
1196-400: Is currently (2015–20) 140 million/year, is projected to peak during the period 2040–45 at 141 million/year and thereafter decline slowly to 126 million/year by 2100. The total number of deaths is currently 57 million/year and is projected to grow steadily to 121 million/year by 2100. 2012 United Nations projections show a continued increase in population in the near future with
1288-631: Is divided into 4 parallel tectonostratigraphic zones and 5 thrust faults which extend across the length of Himalaya orogen. Each zone, flanked by the thrust faults on its north and south, has stratigraphy (type of rocks and their layering) different from the adjacent zones. From south to north, the zones and the major faults separating them are the Main Frontal Thrust (MFT), Subhimalaya Zone (also called Sivalik ), Main Boundary Thrust (MBT), Lesser Himalaya (further subdivided into
1380-428: Is given by the statistician Jorgen Randers, who argues that traditional projections insufficiently take into account the downward impact of global urbanization on fertility. Randers' "most likely scenario" reveals a peak in the world population in the early 2040s at about 8.1 billion people, followed by decline. Adrian Raftery, a University of Washington professor of statistics and of sociology, states that "there's
1472-405: Is measured to be approximately 17 mm/yr. This convergence is accommodated through seismic activity in active fault zones. As a result, the Himalayan range is one of the most seismically active regions in the world. This region has experienced many high magnitude earthquakes in the last 100 years, including the 1905 Kangra Earthquake , 1975 Kinnaur Earthquake , 1991 Uttarkashi Earthquake , and
1564-421: Is projected to decline further in the 21st century. The global population is still increasing, but there is significant uncertainty about its long-term trajectory due to changing fertility and mortality rates. The UN Department of Economics and Social Affairs projects between 9 and 10 billion people by 2050 and gives an 80% confidence interval of 10–12 billion by the end of the 21st century, with
1656-503: Is projected to grow steadily to 121 million/year by 2100. The median age of human beings as of 2020 is 31 years. Estimates of world population by their nature are an aspect of modernity , possible only since the Age of Discovery . Early estimates for the population of the world date to the 17th century: William Petty , in 1682, estimated the world population at 320 million (current estimates ranging close to twice this number); by
1748-536: Is sometimes referred to as the Cis-Himalayan tectonic plate in the older literature. It forms the southern foothills of the Himalayan Range and is essentially composed of Miocene to Pleistocene molassic sediments derived from the erosion of the Himalaya. These molasse deposits, known as the " Murree and Sivaliks Formations" , are internally folded and imbricated . The Sub-Himalayan Range
1840-479: Is that as agriculture advances in creating more food, the population consequently increases—the Neolithic Revolution and Green Revolution often specifically provided as examples of such agricultural breakthroughs. Furthermore, certain scientific studies do lend evidence to food availability in particular being the dominant factor within a more recent timeframe. Other studies take it as
1932-642: Is the fact that average global birth rates , as well as mortality rates , are declining rapidly, as the nations of the world progress through the stages of the demographic transition, but both vary greatly between developed countries (where birth rates and mortality rates are often low) and developing countries (where birth and mortality rates typically remain high). Different ethnicities also display varying birth rates. Birth rate and mortality rates can change rapidly due to disease epidemics , wars and other mass catastrophes, or advances in medicine and public health . The UN's first report in 1951 showed that during
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#17327725087912024-465: Is the largest language family by number of speakers. Standard Arabic is a language with no native speakers, but the total number of speakers is estimated at 274 million people. The largest religious categories in the world as of 2020 are estimated as follows: Christianity (31%), Islam (25%), Unaffiliated (16%) and Hinduism (15%). Six of the Earth's seven continents are permanently inhabited on
2116-638: Is thrust along the Main Frontal Thrust over the Quaternary alluvium deposited by the rivers coming from the Himalaya ( Ganges , Indus , Brahmaputra and others), which demonstrates that the Himalaya is still a very active orogen . The Lesser Himalaya (LH) tectonic plate is mainly formed by Upper Proterozoic to lower Cambrian detrital sediments from the passive Indian margin intercalated with some granites and acid volcanics (1840 ±70 Ma ). These sediments are thrust over
2208-417: Is unlikely that there will be another doubling of the global population in the 21st century. The total number of humans who have ever lived is estimated to be approximately 100 billion . Such estimates can only be rough approximations, as even modern population estimates are subject to uncertainty of around 3% to 5%. Kapitsa (1996) cites estimates ranging between 80 and 150 billion. The PRB puts
2300-646: The "North Himalayan Nappes" , have also been described within this unit. An almost complete stratigraphic record ranging from the Upper Proterozoic to the Eocene is preserved within the sediments of the TH. Stratigraphic analysis of these sediments yields important indications on the geological history of the northern continental margin of the Indian sub-continent from its Gondwanian evolution to its continental collision with Eurasia . The transition between
2392-582: The 1999 Chamoli Earthquake , all of which were recorded at magnitudes equal or greater than Mw 6.6. A recent study (Parija et al, 2021) sought to quantify the Coulomb Stress Transfer in the Western Himalayas. Coulomb stress transfer is used to quantify how earthquakes release stress, identifying areas that are put under increased stress and those that have been unloaded. This study and those like it are important in understanding
2484-593: The Black Death pandemic ; it took 200 years for European population figures to recover. The population of China decreased from 123 million in 1200 to 65 million in 1393, presumably from a combination of Mongol invasions, famine, and plague. Starting in AD 2, the Han dynasty of ancient China kept consistent family registers to properly assess the poll taxes and labor service duties of each household. In that year,
2576-731: The Central Himalaya . The change of the relative speed between the Indian and Asian plates from very fast (18-19.5 cm/yr) to fast (4.5 cm/yr) at about 55 Ma is circumstantial support for collision then. Since then there has been about 2500 km of crustal shortening and rotating of India by 45° counterclockwise in the Northwestern Himalaya to 10°-15° counterclockwise in North Central Nepal relative to Asia (Fig. 4). While most of
2668-668: The Cimmerian Superterranes , was part of Gondwana and was separated from Eurasia by the Paleo-Tethys Ocean (Fig. 1). During that period, the northern part of India was affected by a late phase of the Pan-African orogeny which is marked by an unconformity between Ordovician continental conglomerates and the underlying Cambrian marine sediments . Numerous granitic intrusions dated at around 500 Ma are also attributed to this event. In
2760-659: The Ladakh region, the "Tethys Himalaya synclinorium" passes gradually to the north in a large dome of greenschist to eclogitic metamorphic rocks. As with the HHCS, these metamorphic rocks represent the metamorphic equivalent of the sediments forming the base of the Tethys Himalaya. The " Precambrian Phe Formation" is also here intruded by several Ordovician (c. 480 Ma ) granites. The Lamayuru and Markha Units are formed by flyschs and olistholiths deposited in
2852-651: The developing world have experienced extremely rapid population growth since the early 20th century, due to economic development and improvements in public health. China's population rose from approximately 430 million in 1850 to 580 million in 1953, and now stands at over 1.3 billion. The population of the Indian subcontinent , which was about 125 million in 1750, increased to 389 million in 1941; today, India, Pakistan and Bangladesh are collectively home to about 1.63 billion people. Java , an island in Indonesia , had about 5 million inhabitants in 1815; it had
South Tibetan Detachment - Misplaced Pages Continue
2944-634: The geology of Nepal . Because the Himalaya form on the leading edge of a collisional tectonic event, it stands to reason that many structural features will form in this area. The three main rock units: the LHS, GHC, and THS all have a hotly debated relationship with each other involving two main fault lines. One is the Main Central Thrust (MCT), and the other is the South Tibetan Detachment (STD). Tectonics geologists agree that
3036-456: The highest relief (8848 m at Mt. Everest Chomolangma), among the highest erosion rates at 2–12 mm/yr, the source of some of the greatest rivers and the highest concentration of glaciers outside of the polar regions . This last feature earned the Himalaya its name, originating from the Sanskrit for "the abode of the snow". From south to north the Himalaya (Himalaya orogen)
3128-533: The metamorphic equivalents of the sedimentary series forming the base of the overlying " Tethys Himalaya " . The HHCS forms a major nappe which is thrust over the Lesser Himalaya along the " Main Central Thrust " (MCT). The Tethys Himalaya is an approximately 100-km-wide synclinorium formed by strongly folded and imbricated, weakly metamorphosed sedimentary series. Several nappes, termed
3220-463: The oceanic crust was "simply" subducted below the Tibetan block during the northward motion of India, at least three major mechanisms have been put forward, either separately or jointly, to explain what happened, since collision, to the 2500 km of "missing continental crust ". Even though it is more than reasonable to argue that this huge amount of crustal shortening most probably results from
3312-809: The "Lesser Himalayan Sedimentary Zone (LHSZ) and the Lesser Himalayan Crystalline Nappes (LHCN)), Main Central thrust (MCT), Higher (or Greater) Himalayan crystallines (HHC), South Tibetan detachment system (STD), Tethys Himalaya (TH), and the Indus‐Tsangpo Suture Zone (ISZ). North of this lies the Transhimalaya in Tibet which is outside the Himalayas. The Himalayas border the Indo-Gangetic Plain to
3404-602: The 16th century, maize and cassava have similarly replaced traditional African crops as the most important staple food crops grown on the continent. The pre-Columbian population of the Americas is uncertain; historian David Henige called it "the most unanswerable question in the world." By the end of the 20th century, scholarly consensus favored an estimate of roughly 55 million people, but numbers from various sources have ranged from 10 million to 100 million. Encounters between European explorers and populations in
3496-480: The 1920s and 2000s, Kenya's population grew from 2.9 million to 37 million. The UN estimated that the world population reached one billion for the first time in 1804. It was another 123 years before it reached two billion in 1927, but it took only 33 years to reach three billion in 1960. Thereafter, it took 14 years for the global population to reach four billion in 1974, 13 years to reach five billion in 1987, 12 years to reach six billion in 1999 and, according to
3588-616: The 20th century in Imperial Russia and the Soviet Union was marked by a succession of major wars, famines and other disasters which caused large-scale population losses (approximately 60 million excess deaths). After the collapse of the Soviet Union, Russia's population declined significantly – from 150 million in 1991 to 143 million in 2012 – but by 2013 this decline appeared to have halted. Many countries in
3680-742: The Early Carboniferous , an early stage of rifting developed between the Indian subcontinent and the Cimmerian Superterranes. During the Early Permian , this rift developed into the Neotethys ocean (Fig. 2). From that time on, the Cimmerian Superterranes drifted away from Gondwana towards the north. Nowadays, Iran , Afghanistan and Tibet are partly made up of these terranes. In the Norian (210 Ma),
3772-516: The Eurasian plate results in mega earthquakes. These seismic events can reach greater than MW 8 and result in intense damage to infrastructure. The mid-crustal ramp in the Himalayas is a key geologic feature in the history for both long-term and short-term seismic processes linked to deformation and shortening. Over the last 15 Ma, the ramp has gradually moved south due to duplexing, accretion, and tectonic undercutting. The ongoing active collision of
South Tibetan Detachment - Misplaced Pages Continue
3864-563: The European Agricultural and Industrial Revolutions , the life expectancy of children increased dramatically. The percentage of the children born in London who died before the age of five decreased from 74.5% in 1730–1749 to 31.8% in 1810–1829. Between 1700 and 1900, Europe's population increased from about 100 million to over 400 million. Altogether, the areas populated by people of European descent comprised 36% of
3956-562: The GHC, between the LHS and the THS, is between these two faults and is somehow being moved towards the surface and being exposed today. The South Tibetan Detachment is often interpreted as a low angle normal fault and can also represent extension. However, there are new interpretations about old observations that support the idea that the STD can also be a north-directed thrust fault. The main problem that
4048-520: The HHCS are of late Proterozoic to early Cambrian age, much younger metasediments can also be found in several areas, e.g. Mesozoic in the Tandi syncline of Nepal and Warwan Valley of Kistwar in Kashmir , Permian in the "Tschuldo slice" , Ordovician to Carboniferous in the " Sarchu area" on Leh-Manali Highway . It is now generally accepted that the metasediments of the HHCS represent
4140-520: The Himalayas is a record of the most dramatic and visible creations of the immense mountain range formed by plate tectonic forces and sculpted by weathering and erosion . The Himalayas , which stretch over 2400 km between the Namcha Barwa syntaxis at the eastern end of the mountain range and the Nanga Parbat syntaxis at the western end, are the result of an ongoing orogeny —
4232-420: The Indian and Eurasian continental plates challenges one hypothesis for plate motion which relies on subduction. One of the most striking aspects of the Himalayan orogen is the lateral continuity of its major tectonic elements. The Himalaya is classically divided into four tectonic units that can be followed for more than 2400 km along the belt (Fig. 5 and Fig. 7). The Sub-Himalayan tectonic plate
4324-650: The Lesser Himalayan Sequence (LHS; mainly low-grade Proterozoic metasediments , yellow in map ), the Greater Himalayan Crystalline complex (GHC; largely high-grade paragneisses and migmatite , orange in map ), and the Tethyan Himalayan Sequence (THS; dominantly low-grade late Proterozoic to Eocene shelf sediments; blue in map ) More information about these rock units can be found by reading about
4416-572: The Rongbuk Valley' in its assemblage of 100 'geological heritage sites' around the world in a listing published in October 2022. The organisation defines an IUGS Geological Heritage Site as 'a key place with geological elements and/or processes of international scientific relevance, used as a reference, and/or with a substantial contribution to the development of geological sciences through history.' Himalayan orogeny The geology of
4508-411: The STD is a thrust fault. The Asia-India collision is one of the most interesting tectonic events of the last 100 million years, and the Himalaya play a critical role as a laboratory to many people studying tectonic processes. The Himalaya offers many opportunities to study all factors that go into mountain building such as continental collisions, erosion, and even climatic changes. In order to understand
4600-475: The South Tibetan detachment is expected to help resolve is the method of emplacement of the GHC between the LHS and THS within the Himalaya. There are three models that help explain this emplacement: wedge extrusion, channel flow , and tectonic wedging . The wedge extrusion and channel flow models work under the assumption that the STD is a low angle normal fault, while the tectonic wedge model works as if
4692-675: The Sub-himalayan range along the Main Boundary Thrust (MBT). The Lesser Himalaya often appears in tectonic windows (Kishtwar or Larji-Kulu-Rampur windows) within the High Himalaya Crystalline Sequence. The Central Himalayan Domain forms the backbone of the Himalayan orogen and encompasses the areas with the highest topographic relief (highest peaks). It is commonly separated into four zones. Approximately 30 different names exist in
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#17327725087914784-588: The UN estimates gives the "medium variant" population as; nearly 8.6 billion in 2030, about 9.7 billion in 2050 and about 10.9 billion in 2100. In December 2019, the German Foundation for World Population projected that the global population will reach 8 billion by 2023 as it increases by 156 every minute. In a modeled future projection by the Institute for Health Metrics and Evaluation ,
4876-532: The USCB asserted that this occurred in March 2012. Since 1951, the UN has issued multiple projections of future world population, based on different assumptions. From 2000 to 2005, the UN consistently revised these projections downward, until the 2006 revision, issued on 14 March 2007, revised the 2050 mid-range estimate upwards by 273 million. Complicating the UN's and others' attempts to project future populations
4968-533: The United Nations reported that the rate of population growth continues to decline due to the ongoing global demographic transition. If this trend continues, the rate of growth may diminish to zero by 2100, concurrent with a world population plateau of 10.9 billion. However, this is only one of many estimates published by the UN; in 2009, UN population projections for 2050 ranged between around 8 billion and 10.5 billion. An alternative scenario
5060-568: The United States Census Bureau placed them in July 1959 and April 1974 respectively. The United Nations did determine, and commemorate, the "Day of 5 Billion" on 11 July 1987, and the "Day of 6 Billion" on 12 October 1999. The Population Division of the United Nations declared the " Day of Seven Billion " to be 31 October 2011. The United Nations marked the birth of the eight billionth person on 15 November 2022. As of 2020,
5152-528: The United States Census Bureau, 13 years to reach seven billion in March 2012. The United Nations, however, estimated that the world population reached seven billion in October 2011. According to the UN, the global population reached eight billion in November 2022, but because the growth rate is slowing, it will take another 15 years to reach around 9 billion by 2037 and 20 years to reach 10 billion by 2057. Alternative scenarios for 2050 range from
5244-512: The carrying capacity → faster population growth → accelerating growth of the number of potential inventors → faster technological advance → hence, the faster growth of the Earth's carrying capacity for people, and so on. The transition from hyperbolic growth to slower rates of growth is related to the demographic transition. According to the Russian demographer Sergey Kapitsa , the world population grew between 67,000 BC and 1965 according to
5336-536: The collision of the continental crust of two tectonic plates , namely, the Indian Plate thrusting into the Eurasian Plate . The Himalaya-Tibet region supplies fresh water for more than one-fifth of the world population , and accounts for a quarter of the global sedimentary budget . Topographically, the belt has many superlatives : the highest rate of uplift (nearly 10 mm/year at Nanga Parbat),
5428-437: The combined eastern and western Roman Empire in the 4th century AD. The Plague of Justinian caused Europe's population to drop by around 50% between the 6th and 8th centuries AD. The population of Europe was more than 70 million in 1340. From 1340 to 1400, the world's population fell from an estimated 443 million to 350–375 million, with the Indian subcontinent suffering the most tremendous loss and Europe suffering
5520-498: The current state of fault zones in the region, as well as their potential for rupture in the future. Localized geology and geomorphology topics for various parts of the Himalaya are discussed on other pages: World population In world demographics , the world population is the total number of humans currently alive. It was estimated by the United Nations to have exceeded eight billion in mid-November 2022. It took around 300,000 years of human prehistory and history for
5612-483: The figure at 117 billion as of 2020, estimating that the current world population is 6.7% of all the humans who have ever lived. Haub (1995) prepared another figure, updated in 2002 and 2011; the 2011 figure was approximately 107 billion. Haub characterized this figure as an estimate that required "selecting population sizes for different points from antiquity to the present and applying assumed birth rates to each period". Robust population data only exist for
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#17327725087915704-418: The following formula: where According to linear interpolation and extrapolation of UNDESA population estimates , the world population has doubled, or will double, in the years listed in the tables below (with two different starting points). During the 2nd millennium , each doubling took roughly half as long as the previous doubling, fitting the hyperbolic growth model mentioned above. However, after 2024, it
5796-562: The generally low-grade sediments of the "Tethys Himalaya" and the underlying low- to high-grade rocks of the "High Himalayan Crystalline Sequence" is usually progressive. But in many places along the Himalayan belt, this transition zone is marked by a major structure, the "Central Himalayan Detachment System" , also known as the " South Tibetan Detachment System " or "North Himalayan Normal Fault" , which has indicators of both extension and compression. See ongoing geologic studies section below. "Nyimaling- Tso Morari Metamorphic Dome" in
5888-460: The global fertility rate was estimated at 2.44 children per woman. In June 2012, British researchers calculated the total weight of Earth's human population as approximately 287 million tonnes (630 billion pounds), with the average person weighing around 62 kilograms (137 lb). The IMF estimated nominal 2021 gross world product at US$ 94.94 trillion, giving an annual global per capita figure of around US$ 12,290. Around 9.3% of
5980-587: The global sex ratio is approximately 1.01 males to 1 female. Approximately 24.7% of the global population is aged under 15, while 65.2% is aged 15–64 and 10.1% is aged 65 or over. The median age of the world's population is estimated to be 31 years in 2020, and is expected to rise to 37.9 years by 2050. According to the World Health Organization , the global average life expectancy is 73.3 years as of 2020, with women living an average of 75.9 years and men approximately 70.8 years. In 2010,
6072-490: The global population was projected to peak in 2064 at 9.73 billion people and decline to 8.79 billion in 2100. Some analysts have questioned the sustainability of further world population growth, highlighting the growing pressures on the environment , global food supplies, and energy resources. In 1975, Sebastian von Hoerner proposed a formula for population growth which represented hyperbolic growth with an infinite population in 2025. The hyperbolic growth of
6164-539: The human population to reach a billion and only 218 years more to reach 8 billion. The human population has experienced continuous growth following the Great Famine of 1315–1317 and the end of the Black Death in 1350, when it was nearly 370,000,000. The highest global population growth rates , with increases of over 1.8% per year, occurred between 1955 and 1975, peaking at 2.1% between 1965 and 1970. The growth rate declined to 1.1% between 2015 and 2020 and
6256-670: The last two or three centuries. Until the late 18th century, few governments had ever performed an accurate census. In many early attempts, such as in Ancient Egypt and the Persian Empire , the focus was on counting merely a subset of the population for purposes of taxation or military service. Thus, there is a significant margin of error when estimating ancient global populations. Pre-modern infant mortality rates are another critical factor for such an estimate; these rates are very difficult to estimate for ancient times due to
6348-480: The late 18th century, estimates ranged close to one billion (consistent with current estimates). More refined estimates, broken down by continents, were published in the first half of the 19th century, at 600 million to 1 billion in the early 1800s and 800 million to 1 billion in the 1840s. It is difficult for estimates to be better than rough approximations, as even current population estimates are fraught with uncertainties from 3% to 5%. Estimates of
6440-486: The lessening of the mortality rate in many countries by improved sanitation and medical advances , and a massive increase in agricultural productivity attributed to the Green Revolution . By 2000, there were approximately ten times as many people on Earth as there had been in 1700. However, this rapid growth did not last. During the period 2000–2005, the United Nations estimates that the world's population
6532-422: The literature to describe this unit; the most frequently found equivalents are "Greater Himalayan Sequence" , " Tibetan Slab " and "High Himalayan Crystalline" . It is a 30-km-thick, medium- to high-grade metamorphic sequence of metasedimentary rocks which are intruded in many places by granites of Ordovician (c. 500 Ma) and early Miocene (c. 22 Ma) age. Although most of the metasediments forming
6624-425: The long-standing trend on all inhabited continents, as well as in most individual states. During the 20th century, the global population saw its greatest increase in known history, rising from about 1.6 billion in 1900 to over 6 billion in 2000 as the whole world entered the early phases of what has come to be called the " demographic transition ". Some of the key factors contributing to this increase included
6716-432: The lower plate tore off into the mantle leading to high amounts of rebound. The second model states that the rocks got to a certain point in subduction and then were forced back up through the channel they came down due to a space problem. The third model states that the thick continental crust of India further exacerbated the space problem and caused the corner flow of those rocks back up the channel. The fourth model includes
6808-510: The mechanism of emplacing higher grade metamorphic rocks on top of lower grade metamorphic rocks still strongly debated, Kohn believes that it is due to long periods of transportation of higher grade metamorphic rocks on the Main Himalayan Thrust. Essentially, the longer the higher grade rocks were spatially interacting with the thrust, the farther they were transported. The exhumation of eclogite and granulite rocks can be explained by several different models. The first model includes slab tear where
6900-491: The number of people who have ever lived will rise to 121 billion by 2050, 4 billion more than their 2021 estimate. Individuals from a wide range of academic fields and political backgrounds have proposed that, like all other animal populations, any human population (and, by extension, the world population) predictably grows and shrinks according to available food supply, growing during an abundance of food and shrinking in times of scarcity. This idea may run counter to
6992-499: The opening of the "South Indian Ocean" (Fig. 3). In the Late Cretaceous (84 Ma), the Indian plate began its very rapid northward drift covering a distance of about 6000 km, with the oceanic-oceanic subduction continuing until the final closure of the oceanic basin and the obduction of oceanic ophiolite onto India and the beginning of continent-continent tectonic interaction starting at about 65 Ma in
7084-513: The past. The data for 1750 to 1900 are from the UN report "The World at Six Billion" whereas the data from 1950 to 2015 are from a UN data sheet. Using the above figures, the change in population from 2010 to 2015 was: Long-term global population growth is difficult to predict. The United Nations and the US Census Bureau both give different estimates – according to the UN, the world population reached seven billion in late 2011, while
7176-443: The period 1950–55 the crude birth rate was 36.9/1,000 population and the crude death rate was 19.1/1,000. By the period 2015–20, both numbers had dropped significantly to 18.5/1,000 for the crude birth rate and 7.5/1,000 for the crude death rate. UN projections for 2100 show a further decline in the crude birth rate to 11.6/1,000 and an increase in the crude death rate to 11.2/1,000. The total number of births globally
7268-820: The popular thinking that, as population grows, food supply must also be increased to support the growing population; instead, the claim here is that growing population is the result of a growing food supply. Notable proponents of this notion include: agronomist and insect ecologist David Pimentel , behavioral scientist Russell Hopfenberg (the former two publishing a study on the topic in 2001), anthropologist and activist Virginia Abernethy , ecologist Garrett Hardin , science writer and anthropologist Peter Farb , journalist Richard Manning , environmental biologist Alan D. Thornhill, cultural critic and writer Daniel Quinn , and anarcho-primitivist John Zerzan . Scientists generally acknowledge that at least one significant factor contributing to population growth (or overpopulation)
7360-507: The population of Western Han was recorded as 57,671,400 individuals in 12,366,470 households, decreasing to 47,566,772 individuals in 9,348,227 households by AD 146, towards the end of the Han dynasty . From 200 to 400, the world population fell from an estimated 257 million to 206 million, with China suffering the greatest loss. At the founding of the Ming dynasty in 1368, China's population
7452-421: The population of the world at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Even earlier, genetic evidence suggests humans may have gone through a population bottleneck of between 1,000 and 10,000 people about 70,000 BC, according to the now largely discredited Toba catastrophe theory . By contrast, it is estimated that around 50–60 million people lived in
7544-611: The rest of the world often introduced local epidemics of extraordinary virulence. According to the most extreme scholarly claims, as many as 90% of the Native American population of the New World died of Old World diseases such as smallpox , measles , and influenza . Over the centuries, the Europeans had developed high degrees of immunity to these diseases, while the indigenous peoples had no such immunity. During
7636-488: The rocks being transported along the Main Himalayan Thrust. ISZ, also called Indus-Yarlung suture zone , Yarlung-Zangpo Suture Zone or Yarlung-Tsangpo Suture Zone, defines the zone of collision between the Indian Plate and the Ladakh Batholith (also Transhimalaya or Karakoram-Lhasa Block ) to the north. This suture zone is formed by: The modern day rate of convergence between the Indian and Eurasian plates
7728-650: The south, Pamir Mountains to the west in Central Asia , and the Hengduan Mountains to the east on the China–Myanmar border . From east to west the Himalayas are divided into 3 regions, Eastern Himalaya , Central Himalaya, and Western Himalaya, which collectively house several nations and states . During Late Precambrian and the Palaeozoic , the Indian subcontinent , bounded to the north by
7820-563: The structural complexity of the Himalaya orogen, understanding the South Tibet detachment is critical to figuring out the exact time and processes involved in the emplacement of rock units there. In respect of it being 'the place where the highest regional scale low-angle normal fault of the Earth can be directly observed', the International Union of Geological Sciences (IUGS) included 'The South Tibetan Detachment System in
7912-684: The world population live in extreme poverty , subsisting on less than US$ 1.9 per day; around 8.9% are malnourished . 87% of the world's over-15s are considered literate . As of January 2024, there were about 5 billion global Internet users, constituting 66% of the world population. The Han Chinese are the world's largest single ethnic group, constituting over 19% of the global population in 2011. The world's most-spoken languages are English (1.132B), Mandarin Chinese (1.117B), Hindi (615M), Spanish (534M) and French (280M). More than three billion people speak an Indo-European language, which
8004-420: The world population observed until the 1970s was later correlated to a non-linear second-order positive feedback between demographic growth and technological development. This feedback can be described as follows: technological advance → increase in the carrying capacity of land for people → demographic growth → more people → more potential inventors → acceleration of technological advance → accelerating growth of
8096-676: The world's population as of 2020,while the Latin American and Caribbean regions are home to around 653 million (8%). Northern America, primarily consisting of the United States and Canada, has a population of around 368 million (5%), and Oceania, the least populated region, has about 42 million inhabitants (0.5%). Antarctica only has a very small, fluctuating population of about 1200 people based mainly in polar science stations . Approximately 4.6 billion people live in these ten countries, representing around 57% of
8188-531: The world's population as of July 2023. The UN estimates that by 2023 India will have overtaken China in having the largest population. The tables below list the world's most densely populated countries, both in absolute terms and in comparison to their total populations, as of November 2022. All areas and populations are from The World Factbook , unless otherwise noted. [REDACTED] Palestine Population size fluctuates at differing rates in differing regions. Nonetheless, population growth has been
8280-660: The world's population in 1900. Population growth in the Western world became more rapid after the introduction of vaccination and other improvements in medicine and sanitation . Improved material conditions led to the population of Britain increasing from 10 million to 40 million in the 19th century. The population of the United Kingdom reached 60 million in 2006. The United States saw its population grow from around 5.3 million in 1800 to 106 million in 1920, exceeding 307 million in 2010. The first half of
8372-561: Was growing at an annual rate of 1.3% (equivalent to around 80 million people), down from a peak of 2.1% during the period 1965–1970. Globally, although the population growth rate has been steadily declining from its peak in 1968, growth still remains high in Sub-Saharan Africa . In fact, during the 2010s, Japan and some countries in Europe began to reduce in population , due to sub-replacement fertility rates. In 2019,
8464-475: Was reported to be close to 60 million; toward the end of the dynasty in 1644, it may have approached 150 million. England's population reached an estimated 5.6 million in 1650, up from an estimated 2.6 million in 1500. New crops that were brought to Asia and Europe from the Americas by Portuguese and Spanish colonists in the 16th century are believed to have contributed to population growth. Since their introduction to Africa by Portuguese traders in
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