Tibetan Plateau
Tibetan Plateau | |
---|---|
青藏高原 (Qīng–Zàng Gāoyuán, Qinghai–Tibet Plateau) | |
Himalayan range to the south and the Taklamakan Desert to the north. (Composite image) | |
Dimensions | |
Length | 2,500 km (1,600 mi) |
Width | 1,000 km (620 mi) |
Area | 2,500,000 km2 (970,000 sq mi) |
Geography | |
Tibetan Plateau and surrounding areas above 1600 m
| |
Location | People's Republic of China (Tibet, Qinghai, Western Sichuan, Northern Yunnan, Southern Xinjiang, Western Gansu) India (Ladakh, Lahaul & Spiti, Northern Arunachal Pradesh, Northern Sikkim) Pakistan (Baltistan) Afghanistan (Wakhan Corridor) Nepal (Northern Nepal) Bhutan Tajikistan (Eastern Tajikistan) Kyrgyzstan (Southern Kyrgyzstan) |
Range coordinates | 33°N 88°E / 33°N 88°E |
The Tibetan Plateau,[a] also known as Qinghai–Tibet Plateau[b] and Qing–Zang Plateau,[c] is a vast elevated plateau located at the intersection of Central, South, and East Asia[d] covering most of the Tibet Autonomous Region, most of Qinghai, western half of Sichuan, Southern Gansu provinces in Western China, southern Xinjiang, Bhutan, the Indian regions of Ladakh and Lahaul and Spiti (Himachal Pradesh) as well as Gilgit-Baltistan in Pakistan, northwestern Nepal, eastern Tajikistan and southern Kyrgyzstan. It stretches approximately 1,000 kilometres (620 mi) north to south and 2,500 kilometres (1,600 mi) east to west. It is the world's highest and largest plateau above sea level, with an area of 2,500,000 square kilometres (970,000 sq mi) (about five times the size of Metropolitan France).[13] With an average elevation exceeding 4,500 metres (14,800 ft)[citation needed] and being surrounded by imposing mountain ranges that harbor the world's two highest summits, Mount Everest and K2, the Tibetan Plateau is often referred to as "the Roof of the World".
The Tibetan Plateau contains the headwaters of the drainage basins of most of the streams and rivers in surrounding regions. This includes the three longest rivers in Asia (the Yellow, Yangtze, and Mekong). Its tens of thousands of glaciers and other geographical and ecological features serve as a "water tower" storing water and maintaining flow. It is sometimes termed the Third Pole because its ice fields contain the largest reserve of fresh water outside the polar regions. The impact of climate change on the Tibetan Plateau is of ongoing scientific interest.[14][15][16][17]
Description
The Tibetan Plateau is surrounded by the massive mountain ranges[18] of high-mountain Asia. The plateau is bordered to the south by the inner Himalayan range, to the north by the Kunlun Mountains, which separate it from the Tarim Basin, and to the northeast by the Qilian Mountains, which separate the plateau from the Hexi Corridor and Gobi Desert. To the east and southeast the plateau gives way to the forested gorge and ridge geography of the mountainous headwaters of the Salween, Mekong, and Yangtze rivers in northwest Yunnan and western Sichuan (the Hengduan Mountains). In the west, the curve of the rugged Karakoram range of northern Kashmir embraces the plateau. The Indus River originates in the western Tibetan Plateau in the vicinity of Lake Manasarovar.
The Tibetan Plateau is bounded in the north by a broad escarpment where the altitude drops from around 5,000 metres (16,000 ft) to 1,500 metres (4,900 ft) over a horizontal distance of less than 150 kilometres (93 mi). Along the escarpment is a range of mountains. In the west, the Kunlun Mountains separate the plateau from the Tarim Basin. About halfway across the Tarim the bounding range becomes the Altyn-Tagh and the Kunluns, by convention, continue somewhat to the south. In the 'V' formed by this split is the western part of the Qaidam Basin. The Altyn-Tagh ends near the Dangjin pass on the Dunhuang–Golmud road. To the west are short ranges called the Danghe, Yema, Shule, and Tulai Nanshans. The easternmost range is the Qilian Mountains. The line of mountains continues east of the plateau as the Qinling, which separates the Ordos Plateau from Sichuan. North of the mountains runs the Gansu or Hexi Corridor which was the main silk-road route from China proper to the West.
The plateau is a high-altitude arid steppe interspersed with mountain ranges and large brackish lakes. Annual precipitation ranges from 100 to 300 millimetres (3.9 to 11.8 in) and falls mainly as hail. The southern and eastern edges of the steppe have grasslands that can sustainably support populations of nomadic herdsmen, although frost occurs for six months of the year. Permafrost occurs over extensive parts of the plateau. Proceeding to the north and northwest, the plateau becomes progressively higher, colder, and drier, until reaching the remote Changtang region in the northwestern part of the plateau. Here the average altitude exceeds 5,000 metres (16,000 ft) and winter temperatures can drop to −40 °C (−40 °F). As a result of this extremely inhospitable environment, the Changtang region (together with the adjoining Kekexili region) is the least populous region in Asia and the third least populous area in the world after Antarctica and northern Greenland.
Geology and geological history
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The geological history of the Tibetan Plateau is closely related to that of the Himalayas. The Himalayas belong to the Alpine Orogeny and are therefore among the younger mountain ranges on the planet, consisting mostly of uplifted sedimentary and metamorphic rock. Their formation is a result of a continental collision or orogeny along the convergent boundary between the Indo-Australian Plate and the Eurasian Plate.
The collision began in the Upper Cretaceous period about 70 million years ago, when the north-moving Indo-Australian Plate, moving at about 15 cm (6 in) per year, collided with the Eurasian Plate. About 50 million years ago, this fast-moving Indo-Australian plate had completely closed the Tethys Ocean, the existence of which has been determined by sedimentary rocks settled on the ocean floor, and the volcanoes that fringed its edges. Since these sediments were light, they crumpled into mountain ranges rather than sinking to the floor. During this early stage of its formation in the Late Palaeogene, Tibet consisted of a deep palaeovalley bounded by multiple mountain ranges rather than the more topographically uniform elevated flatland that it is today.[20] The Tibetan Plateau's mean elevation continued to vary since its initial uplift in the Eocene; isotopic records show the plateau's altitude was around 3,000 metres above sea level around the Oligocene-Miocene boundary and that it fell by 900 metres between 25.5 and 21.6 million years ago, attributable to tectonic unroofing from east–west extension or to erosion from climatic weathering. The plateau subsequently rose by 500 to 1,000 metres between 21.6 and 20.4 million years ago.[21]
Much of the Tibetan Plateau is of relatively low relief. The cause of this is debated among geologists. Some argue that the Tibetan Plateau is an uplifted
Environment
The Tibetan Plateau supports a variety of ecosystems, most of them classified as
Ecoregions found on the Tibetan Plateau, as defined by the World Wide Fund for Nature, are as follows:
- The Pamir alpine desert and tundra covers the western end of the Tibetan Plateau where it transitions to the Pamir Mountains
- The North Tibetan Plateau–Kunlun Mountains alpine desert covers the northwestern limits of the Tibetan Plateau along the Kunlun Mountains
- The Karakoram–West Tibetan Plateau alpine steppe covers the westernmost parts of the Tibetan Plateau and Ladakh
- The Northwestern Himalayan alpine shrub and meadows on the edges mountains bordering the extreme west of the Tibetan Plateau
- The Central Tibetan Plateau alpine steppe covers most of the central portions of the Tibetan Plateau and the eastern Changtang
- The Western Himalayan alpine shrub and meadows covers the southwestern plateau in the Garuda Valley region
- The Qaidam Basin semi-desert located in the Qaidam Basinon the northern Tibetan Plateau
- The Qilian Mountains subalpine meadows covering the Qilian Mountains in the northernmost portions of the plateau
- The Qilian Mountains conifer forests covering parts of the mountain ranges in the northeastern Tibetan Plateau
- The Tibetan Plateau alpine shrublands and meadows covering a swath of the central and northeastern Tibetan Plateau
- The Yarlung Tsangpo arid steppe in the Yarlung Tsangpo river Valley, where most of the permanent human population on the Tibetan Plateau lives
- The Eastern Himalayan alpine shrub and meadows cover the southern Tibetan Plateau on the north side of the Himalayas
- The Southeast Tibet shrub and meadows cover the southeastern and eastern parts of the plateau and are generally rainier than the other high-altitude Tibetan Plateau regions
- The Northeastern Himalayan subalpine conifer forests reach up mountain valleys in the southern plateau and contain some of the highest altitude forests in the world
- The Nujiang Lancang Gorge alpine conifer and mixed forests cover the mountain valleys that reach 500 km (310 mi) into the southeastern Tibetan Plateau
- The Hengduan Mountains subalpine conifer forests cover the southeasternmost mountain valleys on the plateau
- The Qionglai–Minshan conifer forests cover the eastern edges of the plateau and are the densest forests to be found anywhere on the Tibetan Plateau
Human history
Nomads on the Tibetan Plateau and in the Himalayas are the remainders of nomadic practices historically once widespread in Asia and Africa.[30] Pastoral nomads constitute about 40% of the ethnic Tibetan population.[31] The presence of nomadic peoples on the plateau is predicated on their adaptation to survival on the world's grassland by raising livestock rather than crops, which are unsuitable to the terrain. Archaeological evidence suggests that the earliest human occupation of the plateau occurred between 30,000 and 40,000 years ago.[32] Since colonization of the Tibetan Plateau, Tibetan culture has adapted and flourished in the western, southern, and eastern regions of the plateau. The northern portion, the Changtang, is generally too high and cold to support permanent population.[33] One of the most notable civilizations to have developed on the Tibetan Plateau is the Tibetan Empire from the 7th century to the 9th century AD.
Impact on other regions
Role in monsoons
Monsoons are caused by the different amplitudes of surface temperature seasonal cycles between land and oceans. This differential warming occurs because heating rates differ between land and water. Ocean heating is distributed vertically through a "mixed layer" that may be 50 meters deep through the action of wind and buoyancy-generated
In winter, the land cools off quickly, but the ocean maintains the heat longer. The hot air over the ocean rises, creating a low-pressure area and a breeze from land to ocean while a large area of drying high pressure is formed over the land, increased by wintertime cooling.
Glaciology: the Ice Age and at present
Today, Tibet is an important heating surface of the atmosphere. However, during the Last Glacial Maximum, an approximately 2,400,000 square kilometres (930,000 sq mi) ice sheet covered the plateau.[36][37][38] Due to its great extent, this glaciation in the subtropics was an important element of radiative forcing. With a much lower latitude, the ice in Tibet reflected at least four times more radiation energy per unit area into space than ice at higher latitudes. Thus, while the modern plateau heats the overlying atmosphere, during the Last Ice Age it helped to cool it.[39]
This cooling had multiple effects on regional climate. Without the thermal low pressure caused by the heating, there was no monsoon over the Indian subcontinent. This lack of monsoon caused extensive rainfall over the Sahara, expansion of the Thar Desert, more dust deposited into the Arabian Sea, and a lowering of the biotic life zones on the Indian subcontinent. Animals responded to this shift in climate, with the Javan rusa migrating into India.[40]
In addition, the glaciers in Tibet created meltwater lakes in the Qaidam Basin, the Tarim Basin, and the Gobi Desert, despite the strong evaporation caused by the low latitude. Silt and clay from the glaciers accumulated in these lakes; when the lakes dried at the end of the ice age, the silt and clay were blown by the downslope wind off the Plateau. These airborne fine grains produced the enormous amount of loess in the Chinese lowlands.[40]
Frozen biological samples
Ice of the plateau provides a valuable window to the past. In 2015, researchers studying the Plateau reached the top of the Guliya
Climate change
The Tibetan Plateau contains the world's third-largest store of ice. Qin Dahe, the former head of the China Meteorological Administration, issued the following assessment in 2009:
Temperatures are rising four times faster than elsewhere in China, and the Tibetan glaciers are retreating at a higher speed than in any other part of the world. In the short term, this will cause lakes to expand and bring floods and mudflows. In the long run, the glaciers are vital lifelines for Asian rivers, including the
Indus and the Ganges. Once they vanish, water supplies in those regions will be in peril.[43]The Tibetan Plateau contains the largest area of low-latitude glaciers and is particularly vulnerable to global warming. Over the past five decades, 80% of the glaciers in the Tibetan Plateau have retreated, losing 4.5% of their combined areal coverage.[44]
This region is also liable to suffer damages from permafrost thaw caused by climate change.
Outside of the Arctic,power lines, and 580 km of railways.[45] There are also 9,389 km of roads, and around 30% are already sustaining damage from permafrost thaw.[46] Estimates suggest that under the scenario most similar to today, SSP2-4.5, around 60% of the current infrastructure would be at high risk by 2090 and simply maintaining it would cost $6.31 billion, with adaptation reducing these costs by 20.9% at most. Holding the global warming to 2 °C (3.6 °F) would reduce these costs to $5.65 billion, and fulfilling the optimistic Paris Agreement target of 1.5 °C (2.7 °F) would save a further $1.32 billion. In particular, fewer than 20% of railways would be at high risk by 2100 under 1.5 °C (2.7 °F), yet this increases to 60% at 2 °C (3.6 °F), while under SSP5-8.5, this level of risk is met by mid-century.[45]See also
- Annexation of Tibet by the People's Republic of China
- Bayan Har block
- Central Tibetan Administration
- Geography of Tibet
Geology of the Himalaya- Tibet (1912–1951)
- Tibetan culture
- Tibetan sovereignty debate
- Tibetan diaspora
Notes
References
Citations
- ^ Wang, Zhaoyin; Li, Zhiwei; Xu, Mengzhen; Yu, Guoan (30 March 2016). River Morphodynamics and Stream Ecology of the Qinghai-Tibet Plateau. CRC Press.
- ^ Jones, J.A.; Liu, Changming; Woo, Ming-Ko; Kung, Hsiang-Te (6 December 2012). Regional Hydrological Response to Climate Change. Springer Science & Business Media. p. 360.
- ^ "हिमालयी क्षेत्र में जीवन यापन पर रिसर्च करेंगे अमेरिका और भारत".
- ^ "In Little Tibet, a story of how displaced people rebuilt life in a distant land". 18 February 2020.
ISBN 0-528-83190-9pp. 164–65 ISBN 0-7230-1025-0p. 39- ^ "The Tibetan Empire in Central Asia (Christopher Beckwith)". Retrieved 19 February 2009.
- ^ Hopkirk 1983, p. 1
ISBN 978-0-306-46257-3. ISBN 978-1-4034-9898-4. ISBN 978-0-549-50627-0. ISBN 978-0-13-022484-2.- ^ "Natural World: Deserts". National Geographic. Archived from the original on 12 January 2006.
- ^ Leslie Hook (30 August 2013). "Tibet: life on the climate front line". Financial Times. Archived from the original on 10 December 2022. Retrieved 1 September 2013.
- – via Academia.edu.
S2CID 128916992. S2CID 14450823. ISBN 978-7-5085-0665-4.- ^ Petra Seibert and Lorne Stockman. "The Yamdrok Tso Hydropower Plant in Tibet: A Multi-facetted and Highly Controversial Project". Archived from the original on 5 August 2007. Retrieved 29 June 2007.
PMID 30854430.- . Retrieved 24 December 2022.
S2CID 135460949. Retrieved 6 November 2022.- . Retrieved 13 December 2022.
PMID 26371325. OCLC 855957425.- .
- .
hdl:10651/50748.- ^ "Wild China: The Tibetan Plateau". The Nature of Things. Canadian Broadcasting Corporation. Retrieved 21 March 2013.
- ^ David Miller. "Nomads of Tibet and Bhutan". asinart.com. Retrieved 10 February 2008.
- ^ In pictures: Tibetan nomads BBC News
PMID 30498126. ISBN 9780226732442.- ^ a b Oracle Thinkquest Education Foundation. monsoons: causes of monsoons. Archived 16 April 2009 at the Wayback Machine Retrieved on 22 May 2008.
- ^ "The Asian Monsoon". BBC Weather. Archived from the original on 1 November 2004.
- .
- ^ Kuhle, M (2004). "The High Glacial (Last Ice Age and LGM) ice cover in High and Central Asia". In Ehlers, J.; Gibbard, P.L. (eds.). Development in Quaternary Science 2c (Quaternary Glaciation – Extent and Chronology, Part III: South America, Asia, Africa, Australia, Antarctica). pp. 175–99.
S2CID 128089823. See chapter entitled: "Reconstruction of an approximately complete Quaternary Tibetan Inland Glaciation between the Mt. Everest and Cho Oyu Massifs and the Aksai Chin. – A new glaciogeomorphological southeast-northwest diagonal profile through Tibet and its consequences for the glacial isostasy and Ice Age cycle". S2CID 129234912. Tibet and High-Asia I. Results of the Sino-German Joint Expeditions (I).- ^ a b Kuhle, Matthias (2001). "The Tibetan Ice Sheet; its Impact on the Palaeomonsoon and Relation to the Earth's Orbital Variations". Polarforschung. 71 (1/2): 1–13.
PMID 34281625.- ^ "15,000-year-old viruses discovered in Tibetan glacier ice". ScienceDaily. 20 July 2021. Retrieved 14 August 2023.
- ^ "Global warming benefits to Tibet: Chinese official". Agence France-Presse. 18 August 2009.
S2CID 250091380.- ^
S2CID 252849121. S2CID 245917456.Sources
ISBN 978-0-87477-257-9.- Brantingham, P. J. & Xing, G. (2006). "Peopling of the northern Tibetan Plateau". World Archaeology. 38 (3): 387–414.
S2CID 13534630.External links
Wikimedia Commons has media related to Tibetan Plateau.Look up Tibetan Plateau in Wiktionary, the free dictionary.
- ON THINNER ICE 如履薄冰 (by GRIP, Asia Society and MediaStorm)
- The Third Pole: Understanding Asia's Water Crisis
- The End of Earth's Summer
- Long Rivers and Distant Sources
- "Roof of the Earth" Offers Clues About How Our Planet Was Shaped Archived 31 October 2012 at the Wayback Machine
- Plateau Perspectives (international NGO)
- Leaf morphology and the timing of the rise of the Tibetan Plateau
- "Weather in the eastern Chang Tang". Archived from the original on 19 March 2006. Retrieved 9 May 2006.
{{cite web}}
: CS1 maint: bot: original URL status unknown (link)- Protected areas of the Tibetan Plateau region
- "North Tibetan Plateau-Kunlun Mountains alpine desert". Terrestrial Ecoregions. World Wildlife Fund.
- Photos of Tibetan nomads
- "Roof of the Earth" Offers Clues About How Our Planet Was Shaped
- Contemporary lifestyle and language learning center from Tibet lhasa, the official language of Tibetan. podcast.
- Tibetan History-The true history of any region cannot be fully understood without knowing the basic characteristics of a region and of its inhabitants