Integrated Authority File
The Integrated Authority File or GND is an international authority file for the organisation of personal names, subject headings and corporate bodies from catalogues. It is used for documentation in libraries and also by archives and museums; the GND is managed by the German National Library in cooperation with various regional library networks in German-speaking Europe and other partners. The GND falls under the Creative Commons Zero licence; the GND specification provides a hierarchy of high-level entities and sub-classes, useful in library classification, an approach to unambiguous identification of single elements. It comprises an ontology intended for knowledge representation in the semantic web, available in the RDF format; the Integrated Authority File became operational in April 2012 and integrates the content of the following authority files, which have since been discontinued: Name Authority File Corporate Bodies Authority File Subject Headings Authority File Uniform Title File of the Deutsches Musikarchiv At the time of its introduction on 5 April 2012, the GND held 9,493,860 files, including 2,650,000 personalised names.
There are seven main types of GND entities: LIBRIS Virtual International Authority File Information pages about the GND from the German National Library Search via OGND Bereitstellung des ersten GND-Grundbestandes DNB, 19 April 2012 From Authority Control to Linked Authority Data Presentation given by Reinhold Heuvelmann to the ALA MARC Formats Interest Group, June 2012
Temperature is a physical quantity expressing hot and cold. It is measured with a thermometer calibrated in one or more temperature scales; the most used scales are the Celsius scale, Fahrenheit scale, Kelvin scale. The kelvin is the unit of temperature in the International System of Units, in which temperature is one of the seven fundamental base quantities; the Kelvin scale is used in science and technology. Theoretically, the coldest a system can be is when its temperature is absolute zero, at which point the thermal motion in matter would be zero. However, an actual physical system or object can never attain a temperature of absolute zero. Absolute zero is denoted as 0 K on the Kelvin scale, −273.15 °C on the Celsius scale, −459.67 °F on the Fahrenheit scale. For an ideal gas, temperature is proportional to the average kinetic energy of the random microscopic motions of the constituent microscopic particles. Temperature is important in all fields of natural science, including physics, Earth science and biology, as well as most aspects of daily life.
Many physical processes are affected by temperature, such as physical properties of materials including the phase, solubility, vapor pressure, electrical conductivity rate and extent to which chemical reactions occur the amount and properties of thermal radiation emitted from the surface of an object speed of sound is a function of the square root of the absolute temperature Temperature scales differ in two ways: the point chosen as zero degrees, the magnitudes of incremental units or degrees on the scale. The Celsius scale is used for common temperature measurements in most of the world, it is an empirical scale, developed by a historical progress, which led to its zero point 0 °C being defined by the freezing point of water, additional degrees defined so that 100 °C was the boiling point of water, both at sea-level atmospheric pressure. Because of the 100-degree interval, it was called a centigrade scale. Since the standardization of the kelvin in the International System of Units, it has subsequently been redefined in terms of the equivalent fixing points on the Kelvin scale, so that a temperature increment of one degree Celsius is the same as an increment of one kelvin, though they differ by an additive offset of 273.15.
The United States uses the Fahrenheit scale, on which water freezes at 32 °F and boils at 212 °F at sea-level atmospheric pressure. Many scientific measurements use the Kelvin temperature scale, named in honor of the Scots-Irish physicist who first defined it, it is a absolute temperature scale. Its zero point, 0 K, is defined to coincide with the coldest physically-possible temperature, its degrees are defined through thermodynamics. The temperature of absolute zero occurs at 0 K = −273.15 °C, the freezing point of water at sea-level atmospheric pressure occurs at 273.15 K = 0 °C. The International System of Units defines a scale and unit for the kelvin or thermodynamic temperature by using the reliably reproducible temperature of the triple point of water as a second reference point; the triple point is a singular state with its own unique and invariant temperature and pressure, along with, for a fixed mass of water in a vessel of fixed volume, an autonomically and stably self-determining partition into three mutually contacting phases, vapour and solid, dynamically depending only on the total internal energy of the mass of water.
For historical reasons, the triple point temperature of water is fixed at 273.16 units of the measurement increment. There is a variety of kinds of temperature scale, it may be convenient to classify them theoretically based. Empirical temperature scales are older, while theoretically based scales arose in the middle of the nineteenth century. Empirically based temperature scales rely directly on measurements of simple physical properties of materials. For example, the length of a column of mercury, confined in a glass-walled capillary tube, is dependent on temperature, is the basis of the useful mercury-in-glass thermometer; such scales are valid only within convenient ranges of temperature. For example, above the boiling point of mercury, a mercury-in-glass thermometer is impracticable. Most materials expand with temperature increase, but some materials, such as water, contract with temperature increase over some specific range, they are hardly useful as thermometric materials. A material is of no use as a thermometer near one of its phase-change temperatures, for example its boiling-point.
In spite of these restrictions, most used practical thermometers are of the empirically based kind. It was used for calorimetry, which contributed to the discovery of thermodynamics. Empirical thermometry has serious drawbacks when judged as a basis for theoretical physics. Empirically based thermometers, beyond their base as simple direct measurements of ordinary physical properties of thermometric materials, can be re-calibrated, by use of theoretical physical reasoning, this can extend their range of adequacy. Theoretically-based temperature scales are based directly on theoretical arguments those of thermodynamics, kinetic theory and quantum mechanics, they rely on theoretical properties of idealized materials. They are more or less comparable with feasible physical devices and materials. Theoretically based temperature scales are used to provide calibrating standards for practi
Alpine tundra is a type of natural region or biome that does not contain trees because it is at high elevation. As the latitude of a location approaches the poles, the threshold elevation for alpine tundra gets lower until it reaches sea level, alpine tundra merges with polar tundra; the high elevation causes an adverse climate, too cold and windy to support tree growth. Alpine tundra transitions to sub-alpine forests below the tree line. With increasing elevation it ends at the snow line where ice persist through summer. Alpine tundra occurs in mountains worldwide; the flora of the alpine tundra is characterized by dwarf shrubs close to the ground. The cold climate of the alpine tundra is caused by adiabatic cooling of air, is similar to polar climate. Alpine tundra occurs at high enough altitude at any latitude. Portions of montane grasslands and shrublands ecoregions worldwide include alpine tundra. Large regions of alpine tundra occur in the North American Cordillera, the Alps and Pyrenees of Europe, the Himalaya and Karakoram of Asia, the Andes of South America, the Eastern Rift mountains of Africa.
Alpine tundra occupies high-mountain summits and ridges above timberline. Aspect plays a role as well; because the alpine zone is present only on mountains, much of the landscape is rugged and broken, with rocky, snowcapped peaks and talus slopes, but contains areas of rolling to flat topography. Averaging over many locations and local microclimates, the treeline rises 75 metres when moving 1 degree south from 70 to 50°N, 130 metres per degree from 50 to 30°N. Between 30°N and 20°S, the treeline is constant, between 3,500 and 4,000 metres. Alpine climate is the average weather for the alpine tundra; the climate becomes colder at high elevations—this characteristic is described by the lapse rate of air: air tends to get colder as it rises, since it expands. The dry adiabatic lapse rate is 10 °C per km of altitude. Therefore, moving up 100 metres on a mountain is equivalent to moving 80 kilometers towards the pole; this relationship is only approximate, since local factors such as proximity to oceans can drastically modify the climate.
Typical high-elevation growing seasons range from 45 to 90 days, with average summer temperatures near 10 °C. Growing season temperatures fall below freezing, frost occurs throughout the growing season in many areas. Precipitation occurs as winter snow, but soil water availability is variable with season and topography. For example, snowfields accumulate on the lee sides of ridges while ridgelines may remain nearly snow free due to redistribution by wind; some alpine habitats may be up to 70% snow free in winter. High winds are common in alpine ecosystems, can cause significant soil erosion and be physically and physiologically detrimental to plants. Wind coupled with high solar radiation can promote high rates of evaporation and transpiration. There have been several attempts at quantifying. Climatologist Wladimir Köppen demonstrated a relationship between the Arctic and Antarctic tree lines and the 10 °C summer isotherm. See Köppen climate classification for more information. Otto Nordenskiöld theorized that winter conditions play a role: His formula is W = 9 − 0.1 C, where W is the average temperature in the warmest month and C the average of the coldest month, both in degrees Celsius.
In 1947, Holdridge improved on these schemes, by defining biotemperature: the mean annual temperature, where all temperatures below 0 °C are treated as 0 °C. If the mean biotemperature is between 1.5 and 3 °C, Holdridge quantifies the climate as alpine. Because the habitat of alpine vegetation is subject to intense radiation, cold and ice, it grows close to the ground and consists of perennial grasses and forbs. Perennial herbs dominate the alpine landscape; the roots and rhizomes not only function in water and nutrient absorption but play a important role in over-winter carbohydrate storage. Annual plants are rare in this ecosystem and are only a few inches tall, with weak root systems. Other common plant life-forms include prostrate shrubs, graminoids forming tussocks, cushion plants, cryptogams, such as bryophytes and lichens. Relative to lower elevation areas in the same region, alpine regions have a high rate of endemism and a high diversity of plant species; this taxonomic diversity can be attributed to geographical isolation, climate changes, microhabitat differentiation, different histories of migration or evolution or both.
These phenomena contribute to plant diversity by introducing new flora and favoring adaptations, both of new species and the dispersal of pre-existing species. Plants have adapted to the harsh alpine environment. Cushion plants, looking like ground-hugging clumps of moss, escape the strong winds blowing a few inches a
The Republic of Sakha is a federal Russian republic. It had a population of 958,528 at the 2010 Census ethnic Yakuts and Russians. Comprising half the Far Eastern Federal District, it is the largest subnational governing body by area in the world at 3,083,523 square kilometers, its capital is the city of Yakutsk. It is known for its extreme and severe climate, with the lowest temperatures in the Northern Hemisphere being recorded in Verkhoyansk and Delyankir, regular winter averages being below −35 °C in Yakutsk; the hypercontinental tendencies result in warm summers for much of the republic. Borders: internal: Chukotka Autonomous Okrug, Magadan Oblast, Khabarovsk Krai, Amur Oblast, Zabaykalsky Krai, Irkutsk Oblast, Krasnoyarsk Krai. Water: Arctic Ocean. Highest point: Peak Pobeda, Mus-Khaya Mountain Peak Maximum N->S distance: 2,500 km Maximum E->W distance: 2,000 km Sakha stretches to the Henrietta Island in the far north and is washed by the Laptev and Eastern Siberian Seas of the Arctic Ocean.
These waters, the coldest and iciest of all seas in the Northern Hemisphere, are covered by ice for 9–10 months of the year. New Siberian Islands are a part of the republic's territory. After Nunavut was separated from Canada's Northwest Territories, Sakha became the largest subnational entity in the world, with an area of 3,083,523 square kilometers smaller than the territory of India. Sakha can be divided into three great vegetation belts. About 40% of Sakha lies above the Arctic circle and all of it is covered by permafrost which influences the region's ecology and limits forests in the southern region. Arctic and subarctic tundra define the middle region, where lichen and moss grow as great green carpets and are favorite pastures for reindeer. In the southern part of the tundra belt, scattered stands of dwarf Siberian pine and larch grow along the rivers. Below the tundra is the vast taiga forest region. Larch trees dominate in the north and stands of fir and pine begin to appear in the south.
Taiga forests cover about 47% of Sakha and 90% of the cover is larch. The Sakha Republic is the site of Pleistocene Park, a project directed at recreating Pleistocene tundra grasslands by stimulating the growth of grass with the introduction of animals which thrived in the region during the late Pleistocene — early Holocene period. Sakha Republic is the only subject of Russia. Sakha spans three time zones: Yakutsk Time Zone. Covers the republic's territory to the west of the Lena River as well as the territories of the districts located on both sides of the Lena River. Vladivostok Time Zone. Covers most of the republic's territory located between 140 ° E longitude. Districts: Oymyakonsky, Ust-Yansky, Verkhoyansky. Magadan Time Zone. Covers most of the republic's territory located east of 140°E longitude. Districts: Abyysky, Momsky, Srednekolymsky, Verkhnekolymsky. Navigable Lena River, as it moves northward, includes hundreds of small tributaries located in the Verkhoyansk Range. Other major rivers include: Vilyuy River Lena River tributary Olenyok River Aldan River Lena River tributary Kolyma River Indigirka River Alazeya River Amga River Aldan River tributary Olyokma River Lena River tributary Markha River Vilyuy River tributary Tyung River Vilyuy River tributary Maya River Aldan River tributary Anabar River Yana River Morkoka River Markha River tributary Uchur River Aldan River tributary Linde River Lena River tributary Nyuya River Lena River tributary Selennyakh River Indigirka River tributary There are over 800,000 lakes in the republic.
Major lakes and reservoirs include: Lake Mogotoyevo Lake Nedzheli Lake Nerpichye Vilyuyskoye Reservoir Sakha's greatest mountain range, the Verkhoyansk Range, runs parallel and east of the Lena River, forming a great arc that begins in the Sea of Okhotsk and ends in the Laptev Sea. The Chersky Range has the highest peak in Sakha, Peak Pobeda; the second highest peak is Peak Mus-Khaya reaching 3,011 m. The Stanovoi Range borders Sakha in the south; the Republic's extensive coastline contains a number of peninsulas. The soil contains large reserves of oil, coal, gold, tin and many others. Sakha p
A glacier is a persistent body of dense ice, moving under its own weight. Glaciers deform and flow due to stresses induced by their weight, creating crevasses and other distinguishing features, they abrade rock and debris from their substrate to create landforms such as cirques and moraines. Glaciers form only on land and are distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets in the polar regions, but glaciers may be found in mountain ranges on every continent including Oceania's high-latitude oceanic island countries such as New Zealand and Papua New Guinea. Between 35°N and 35°S, glaciers occur only in the Himalayas, Rocky Mountains, a few high mountains in East Africa, New Guinea and on Zard Kuh in Iran. Glaciers cover about 10 percent of Earth's land surface. Continental glaciers cover nearly 13 million km2 or about 98 percent of Antarctica's 13.2 million km2, with an average thickness of 2,100 m.
Greenland and Patagonia have huge expanses of continental glaciers. Glacial ice is the largest reservoir of fresh water on Earth. Many glaciers from temperate and seasonal polar climates store water as ice during the colder seasons and release it in the form of meltwater as warmer summer temperatures cause the glacier to melt, creating a water source, important for plants and human uses when other sources may be scant. Within high-altitude and Antarctic environments, the seasonal temperature difference is not sufficient to release meltwater. Since glacial mass is affected by long-term climatic changes, e.g. precipitation, mean temperature, cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level. A large piece of compressed ice, or a glacier, appears blue, as large quantities of water appear blue; this is. The other reason for the blue color of glaciers is the lack of air bubbles. Air bubbles, which give a white color to ice, are squeezed out by pressure increasing the density of the created ice.
The word glacier is a loanword from French and goes back, via Franco-Provençal, to the Vulgar Latin glaciārium, derived from the Late Latin glacia, Latin glaciēs, meaning "ice". The processes and features caused by or related to glaciers are referred to as glacial; the process of glacier establishment and flow is called glaciation. The corresponding area of study is called glaciology. Glaciers are important components of the global cryosphere. Glaciers are categorized by their morphology, thermal characteristics, behavior. Cirque glaciers form on the slopes of mountains. A glacier that fills a valley is called a valley glacier, or alternatively an alpine glacier or mountain glacier. A large body of glacial ice astride a mountain, mountain range, or volcano is termed an ice cap or ice field. Ice caps have an area less than 50,000 km2 by definition. Glacial bodies larger than 50,000 km2 are called continental glaciers. Several kilometers deep, they obscure the underlying topography. Only nunataks protrude from their surfaces.
The only extant ice sheets are the two that cover most of Greenland. They contain vast quantities of fresh water, enough that if both melted, global sea levels would rise by over 70 m. Portions of an ice sheet or cap that extend into water are called ice shelves. Narrow, fast-moving sections of an ice sheet are called ice streams. In Antarctica, many ice streams drain into large ice shelves; some drain directly into the sea with an ice tongue, like Mertz Glacier. Tidewater glaciers are glaciers that terminate in the sea, including most glaciers flowing from Greenland, Antarctica and Ellesmere Islands in Canada, Southeast Alaska, the Northern and Southern Patagonian Ice Fields; as the ice reaches the sea, pieces break off, or calve. Most tidewater glaciers calve above sea level, which results in a tremendous impact as the iceberg strikes the water. Tidewater glaciers undergo centuries-long cycles of advance and retreat that are much less affected by the climate change than those of other glaciers.
Thermally, a temperate glacier is at melting point throughout the year, from its surface to its base. The ice of a polar glacier is always below the freezing point from the surface to its base, although the surface snowpack may experience seasonal melting. A sub-polar glacier includes both temperate and polar ice, depending on depth beneath the surface and position along the length of the glacier. In a similar way, the thermal regime of a glacier is described by its basal temperature. A cold-based glacier is below freezing at the ice-ground interface, is thus frozen to the underlying substrate. A warm-based glacier is above or at freezing at the interface, is able to slide at this contact; this contrast is thought to a large extent to govern the ability of a glacier to erode its bed, as sliding ice promotes plucking at rock from the surface below. Glaciers which are cold-based and warm-based are known as polythermal. Glaciers form where the accumulation of ice exceeds ablation. A glacier originates from a landform called'cirque' – a armchair-shaped geological feature (such as a depressio
Siberia is an extensive geographical region spanning much of Eurasia and North Asia. Siberia has been a part of modern Russia since the 17th century; the territory of Siberia extends eastwards from the Ural Mountains to the watershed between the Pacific and Arctic drainage basins. The Yenisei River conditionally divides Siberia into two parts and Eastern. Siberia stretches southwards from the Arctic Ocean to the hills of north-central Kazakhstan and to the national borders of Mongolia and China. With an area of 13.1 million square kilometres, Siberia accounts for 77% of Russia's land area, but it is home to 36 million people—27% of the country's population. This is equivalent to an average population density of about 3 inhabitants per square kilometre, making Siberia one of the most sparsely populated regions on Earth. If it were a country by itself, it would still be the largest country in area, but in population it would be the world's 35th-largest and Asia's 14th-largest. Worldwide, Siberia is well known for its long, harsh winters, with a January average of −25 °C, as well as its extensive history of use by Russian and Soviet administrations as a place for prisons, labor camps, exile.
The origin of the name is unknown. Some sources say that "Siberia" originates from the Siberian Tatar word for "sleeping land". Another account sees the name as the ancient tribal ethnonym of the Sirtya, an ethnic group which spoke a Paleosiberian language; the Sirtya people were assimilated into the Siberian Tatars. The modern usage of the name was recorded in the Russian language after the Empire's conquest of the Siberian Khanate. A further variant claims; the Polish historian Chyliczkowski has proposed that the name derives from the proto-Slavic word for "north", but Anatole Baikaloff has dismissed this explanation. He said that the neighbouring Chinese and Mongolians, who have similar names for the region, would not have known Russian, he suggests that the name might be a combination of two words with Turkic origin, "su" and "bir". The region has paleontological significance, as it contains bodies of prehistoric animals from the Pleistocene Epoch, preserved in ice or in permafrost. Specimens of Goldfuss cave lion cubs and another woolly mammoth from Oymyakon, a woolly rhinoceros from the Kolyma River, bison and horses from Yukagir have been found.
The Siberian Traps were formed by one of the largest-known volcanic events of the last 500 million years of Earth's geological history. Their activity continued for a million years and some scientists consider it a possible cause of the "Great Dying" about 250 million years ago, – estimated to have killed 90% of species existing at the time. At least three species of human lived in Southern Siberia around 40,000 years ago: H. sapiens, H. neanderthalensis, the Denisovans. In 2010 DNA evidence identified the last as a separate species. Siberia was inhabited by different groups of nomads such as the Enets, the Nenets, the Huns, the Scythians and the Uyghurs; the Khan of Sibir in the vicinity of modern Tobolsk was known as a prominent figure who endorsed Kubrat as Khagan of Old Great Bulgaria in 630. The Mongols conquered a large part of this area early in the 13th century. With the breakup of the Golden Horde, the autonomous Khanate of Sibir was established in the late 15th century. Turkic-speaking Yakut migrated north from the Lake Baikal region under pressure from the Mongol tribes during the 13th to 15th century.
Siberia remained a sparsely populated area. Historian John F. Richards wrote: "... it is doubtful that the total early modern Siberian population exceeded 300,000 persons."The growing power of Russia in the West began to undermine the Siberian Khanate in the 16th century. First, groups of traders and Cossacks began to enter the area; the Russian Army was directed to establish forts farther and farther east to protect new settlers from European Russia. Towns such as Mangazeya, Tara and Tobolsk were developed, the last being declared the capital of Siberia. At this time, Sibir was the name of a fortress at Qashlik, near Tobolsk. Gerardus Mercator, in a map published in 1595, marks Sibier both as the name of a settlement and of the surrounding territory along a left tributary of the Ob. Other sources contend that the Xibe, an indigenous Tungusic people, offered fierce resistance to Russian expansion beyond the Urals; some suggest. By the mid-17th century, Russia had established areas of control; some 230,000 Russians had settled in Siberia by 1709.
Siberia was a destination for sending exiles. The first great modern change in Siberia was the Trans-Siberian Railway, constructed during 1891–1916, it linked Siberia more to the industrialising Russia of Nicholas II. Around seven million people moved to Siberia from European Russia between 1801 and 1914. From 1859 to 1917, more than half a million people migrated to the Russian Far East. Siberia has extensive natural resources. During the 20th century, large-scale exploitation of these was developed, industrial towns cropped up throughout the region. At 7:15 a.m. on 30 June 1908, millions of trees were felled near the Podkamennaya Tunguska River in central Siberia in the Tunguska Event. Most scientists believe this resulted from the air burst of a comet. Though no crater has been found, the landscape in the area still bears the scars of this event. In the early decades of the Soviet Union (
Last Glacial Maximum
The Last Glacial Maximum was the most recent time during the Last Glacial Period when ice sheets were at their greatest extent. Vast ice sheets covered much of North America, northern Europe, Asia; the ice sheets profoundly affected Earth's climate by causing drought, a large drop in sea levels. The ice sheets reached their maximum coverage about 26,500 years ago. Deglaciation commenced in the Northern Hemisphere at 20 ka and in Antarctica at 14.5 ka, consistent with evidence for an abrupt rise in the sea level at about 14.5 ka. The LGM is referred to in Britain as the Dimlington Stadial, dated by Nick Ashton to between 31 and 16 ka. In the archaeology of Paleolithic Europe, the LGM spans the Gravettian, Magdalenian and Périgordian; the LGM was followed by the Late Glacial. According to Blue Marble 3000, the average global temperature around 19,000 BC was 9.0 °C. This is about 6.0 °C colder than the 2013-2017 average. The figures given by the Intergovernmental Panel On Climate Change estimate a lower global temperature than the figures given by the Zurich University of Applied Sciences.
However, these figures are open more to interpretation. According to the IPCC, average global temperatures increased by 5.5 ± 1.5 °C since the last glacial maximum, the rate of warming was about 10 times slower than that of the 20th Century. It appears that they are defining the present as sometime in the 19th Century for this case, but they don’t specify exact years, or give a temperature for the present. Berkeley Earth puts out a list of average global temperatures by year. If you average all of the years from 1850 to 1899, the average temperature comes out to 13.8 °C. When subtracting 5.5 ± 1.5 °C from the 1850-1899 average, the average temperature for the last glacial maximum comes out to 8.3 ± 1.5 °C. This is about 6.7 ± 1.5 °C colder than the 2013-2017 average. This figure is open to interpretation because the IPCC does not specify 1850-1899 as being the present, or give any exact set of years as being the present, it does not state whether or not they agree with the figures given by Berkeley Earth.
According to the United States Geological Survey, permanent summer ice covered about 8% of Earth's surface and 25% of the land area during the last glacial maximum. The USGS states that sea level was about 125 meters lower than in present times; when comparing to the present, the average global temperature was 15.0 °C for the 2013-2017 period. About 3.1% of Earth's surface and 10.7% of the land area is covered in year-round ice. The formation of an ice sheet or ice cap requires both prolonged precipitation. Hence, despite having temperatures similar to those of glaciated areas in North America and Europe, East Asia remained unglaciated except at higher elevations; this difference was. These anticyclones generated air masses that were so dry on reaching Siberia and Manchuria that precipitation sufficient for the formation of glaciers could never occur; the relative warmth of the Pacific Ocean due to the shutting down of the Oyashio Current and the presence of large'east-west' mountain ranges were secondary factors preventing continental glaciation in Asia.
All over the world, climates at the Last Glacial Maximum were cooler and everywhere drier. In extreme cases, such as South Australia and the Sahel, rainfall could be diminished by up to 90% from present, with florae diminished to the same degree as in glaciated areas of Europe and North America. In less affected regions, rainforest cover was diminished in West Africa where a few refugia were surrounded by tropical grasslands; the Amazon rainforest was split into two large blocks by extensive savanna, the tropical rainforests of Southeast Asia were affected, with deciduous forests expanding in their place except on the east and west extremities of the Sundaland shelf. Only in Central America and the Chocó region of Colombia did tropical rainforests remain intact – due to the extraordinarily heavy rainfall of these regions. Most of the world's deserts expanded. Exceptions were in what is now the western United States, where changes in the jet stream brought heavy rain to areas that are now desert and large pluvial lakes formed, the best known being Lake Bonneville in Utah.
This occurred in Afghanistan and Iran, where a major lake formed in the Dasht-e Kavir. In Australia, shifting sand dunes covered half the continent, whilst the Chaco and Pampas in South America became dry. Present-day subtropical regions lost most of their forest cover, notably in eastern Australia, the Atlantic Forest of Brazil, southern China, where open woodland became dominant due to drier conditions. In northern China – unglaciated despite its cold climate – a mixture of grassland and tundra prevailed, here, the northern limit of tree growth was at least 20° farther south than today. In the period before the Last Glacial Maximum, many areas that became barren desert were wetter than they are today, notably in southern Australia, where Aboriginal occupation is believed to coincide with a wet period between 40,000 and 60,000 years Before Present. During the Last Glacial Maximum, much of the world was cold and inhospitable