Editing Monsoon (section)

===Asian monsoon===
Strengthening of the Asian monsoon has been linked to the uplift of the [[Tibetan Plateau]] after the collision of the [[Indian subcontinent]] and Asia around 50&nbsp;million years ago.<ref>{{cite journal |last1=Zhisheng |first1=An |last2=Kutzbach |first2=John E. |last3=Prell |first3=Warren L. |last4=Porter |first4=Stephen C. |title=Evolution of Asian monsoons and phased uplift of the Himalaya–Tibetan plateau since Late Miocene times |journal=Nature |date=2001 |volume=411 |issue=6833 |pages=62–66 |doi=10.1038/35075035 |pmid=11333976 |bibcode=2001Natur.411...62Z |doi-access= |s2cid=4398615 }}</ref> Because of studies of records from the [[Arabian Sea]] and that of the wind-blown dust in the [[Loess Plateau]] of China, many geologists believe the monsoon first became strong around 8&nbsp;million years ago. More recently, studies of plant fossils in China and new long-duration [[sediment]] records from the [[South China Sea]] led to a timing of the monsoon beginning 15–20&nbsp;million years ago and linked to early Tibetan uplift.<ref>P. D. Clift, M. K. Clark, and L. H. Royden. [http://www.cosis.net/abstracts/EAE03/04300/EAE03-J-04300.pdf An Erosional Record of the Tibetan Plateau Uplift and Monsoon Strengthening in the Asian Marginal Seas.] {{webarchive|url=https://web.archive.org/web/20080527203658/http://www.cosis.net/abstracts/EAE03/04300/EAE03-J-04300.pdf |date=2008-05-27 }} Retrieved on 2008-05-11.</ref> Testing of this hypothesis awaits deep ocean sampling by the [[Integrated Ocean Drilling Program]].<ref>[[Integrated Ocean Drilling Program]]. [http://www.iodp.org/index.php?option=com_docman&task=doc_download&gid=2 Earth, Oceans, and Life.] {{webarchive|url=https://web.archive.org/web/20071026011448/http://www.iodp.org/index.php?option=com_docman&task=doc_download&gid=2 |date=2007-10-26 }} Retrieved on 2008-05-11.</ref> The monsoon has varied significantly in strength since this time, largely linked to global [[climate change]], especially the cycle of the [[Pleistocene]] ice ages.<ref>{{cite journal |last1=Gupta |first1=A. K. |last2=Thomas |first2=E. |title=Initiation of Northern Hemisphere glaciation and strengthening of the northeast Indian monsoon: Ocean Drilling Program Site 758, eastern equatorial Indian Ocean |journal=[[Geology (journal)|Geology]] |date=2003 |volume=31 |issue=1 |pages=47–50 |doi=10.1130/0091-7613(2003)031<0047:IONHGA>2.0.CO;2|bibcode=2003Geo....31...47G |url=http://repository.ias.ac.in/21931/1/311.pdf }}</ref> A study of Asian monsoonal climate cycles from 123,200 to 121,210 years BP, during the [[Eemian]] interglacial, suggests that they had an average duration of around 64 years, with the minimum duration being around 50 years and the maximum approximately 80 years, similar to today.<ref name="WangEtAl2020">{{cite journal |last1=Wang |first1=Zhenjun |last2=Chen |first2=Shitao |last3=Wang |first3=Yongjin |last4=Cheng |first4=Hai |last5=Liang |first5=Yijia |last6=Yang |first6=Shaohua |last7=Zhang |first7=Zhenqiu |last8=Zhou |first8=Xueqin |last9=Wang |first9=Meng |date=1 March 2020 |title=Sixty-year quasi-period of the Asian monsoon around the Last Interglacial derived from an annually resolved stalagmite δ18O record |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018219308491 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=541 |page=109545 |doi=10.1016/j.palaeo.2019.109545 |bibcode=2020PPP...54109545W |s2cid=214283369 |access-date=5 November 2022}}</ref>

A study of marine plankton suggested that the South Asian Monsoon (SAM) strengthened around 5&nbsp;million years ago. Then, during ice periods, the sea level fell and the [[Geology of Indonesia#Indonesian seaway|Indonesian Seaway]] closed. When this happened, cold waters in the Pacific were impeded from flowing into the Indian Ocean. It is believed that the resulting increase in sea surface temperatures in the Indian Ocean increased the intensity of monsoons.<ref>{{cite journal |first1=M. S.|last1= Srinivasan |first2=D. K.|last2= Sinha |url=https://www.ias.ac.in/article/fulltext/jess/109/03/0315-0328 |title=Ocean circulation in the tropical Indo-Pacific during early Pliocene (5.6–4.2 Ma): Paleobiogeographic and isotopic evidence |journal=Proceedings of the Indian Academy of Sciences - Earth and Planetary Sciences |issn=0253-4126 |year=2000 |volume=109 |pages=315–328 |issue=3|doi= 10.1007/BF03549815 |bibcode= 2000JESS..109..315S |s2cid= 127257455 |doi-access=free }}</ref> In 2018, a study of the SAM's variability over the past million years found that precipitation resulting from the monsoon was significantly reduced during [[glacial period]]s compared to [[interglacial]] periods like the present day.<ref name="GebregiorgisEtAl2018">{{cite journal |last1=Gebregiorgis |first1=D. |last2=Hathorne |first2=E. C. |last3=Giosan |first3=L. |last4=Clemens |first4=S. |last5=Nürnberg |first5=D. |last6=Frank |first6=M. |date=8 November 2018 |title=Southern Hemisphere forcing of South Asian monsoon precipitation over the past ~1 million years |journal=[[Nature Communications]] |volume=9 |issue=1 |page=4702 |doi=10.1038/s41467-018-07076-2 |pmid=30410007 |pmc=6224551 |bibcode=2018NatCo...9.4702G }}</ref> The Indian Summer Monsoon (ISM) underwent several intensifications during the warming following the Last Glacial Maximum, specifically during the time intervals corresponding to 16,100–14,600 BP, 13,600–13,000 BP, and 12,400–10,400 BP as indicated by vegetation changes in the Tibetan Plateau displaying increases in humidity brought by an intensifying ISM.<ref name="QingfengMa2019">{{cite journal |last1=Ma |first1=Qingfeng |last2=Zhu |first2=Liping |last3=Lü |first3=Xinmiao |last4=Wang |first4=Junbo |last5=Ju |first5=Jianting |last6=Kasper |first6=Thomas |last7=Daut |first7=Gerhard |last8=Haberzettl |first8=Torsten |date=March 2019 |title=Late glacial and Holocene vegetation and climate variations at Lake Tangra Yumco, central Tibetan Plateau |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818117305246 |journal=[[Global and Planetary Change]] |volume=174 |pages=16–25 |doi=10.1016/j.gloplacha.2019.01.004 |bibcode=2019GPC...174...16M |s2cid=134300820 |access-date=8 December 2022}}</ref> Though the ISM was relatively weak for much of the Late Holocene, significant glacial accumulation in the Himalayas still occurred due to cold temperatures brought by westerlies from the west.<ref>{{cite journal |last1=Peng |first1=Xu |last2=Chen |first2=Yixin |last3=Li |first3=Yingkui |last4=Liu |first4=Beibei |last5=Liu |first5=Qing |last6=Yang |first6=Weilin |last7=Cui |first7=Zhijiu |last8=Liu |first8=Gengnian |date=April 2020 |title=Late Holocene glacier fluctuations in the Bhutanese Himalaya |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818120300278 |journal=[[Global and Planetary Change]] |volume=187 |page=103137 |doi=10.1016/j.gloplacha.2020.103137 |bibcode=2020GPC...18703137P |s2cid=213557014 |access-date=9 January 2023}}</ref>

During the [[Middle Miocene]], the July ITCZ, the zone of rainfall maximum, migrated northwards, increasing precipitation over southern China during the East Asian Summer Monsoon (EASM) while making Indochina drier.<ref name="LiuEtAl2019">{{cite journal |last1=Liu |first1=Chang |last2=Clift |first2=Peter D. |last3=Giosan |first3=Liviu |last4=Miao |first4=Yunfa |last5=Warny |first5=Sophie |last6=Wan |first6=Shiming |date=1 July 2019 |title=Paleoclimatic evolution of the SW and NE South China Sea and its relationship with spectral reflectance data over various age scales |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018218307302 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=525 |pages=25–43 |doi=10.1016/j.palaeo.2019.02.019 |bibcode=2019PPP...525...25L |s2cid=135413974 |access-date=14 November 2022}}</ref> During the Late Miocene Global Cooling (LMCG), from 7.9 to 5.8 million years ago, the East Asian Winter Monsoon (EAWM) became stronger as the subarctic front shifted southwards.<ref>{{cite journal |last1=Matsuzaki |first1=Kenji M. |last2=Ikeda |first2=Masayuki |last3=Tada |first3=Ryuji |date=20 July 2022 |title=Weakened pacific overturning circulation, winter monsoon dominance and tectonism re-organized Japan Sea paleoceanography during the Late Miocene global cooling |journal=[[Scientific Reports]] |volume=12 |issue=1 |page=11396 |doi=10.1038/s41598-022-15441-x |pmid=35859095 |pmc=9300741 |bibcode=2022NatSR..1211396M }}</ref> An abrupt intensification of the EAWM occurred 5.5 million years ago.<ref name="HanFangBergerYin2011">{{cite journal |last1=Han |first1=Wenxia |last2=Fang |first2=Xiaomin |last3=Berger |first3=André |last4=Yin |first4=Qiuzhen |date=22 December 2011 |title=An astronomically tuned 8.1 Ma eolian record from the Chinese Loess Plateau and its implication on the evolution of Asian monsoon |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2011JD016237 |journal=[[Journal of Geophysical Research]] |volume=116 |issue=D24 |pages=1–13 |doi=10.1029/2011JD016237 |bibcode=2011JGRD..11624114H |access-date=20 March 2023}}</ref> The EAWM was still significantly weaker relative to today between 4.3 and 3.8 million years ago but abruptly became more intense around 3.8 million years ago<ref>{{cite journal |last1=Igarashi |first1=Yaeko |last2=Irino |first2=Tomohisa |last3=Sawada |first3=Ken |last4=Song |first4=Lu |last5=Furota |first5=Satoshi |date=April 2018 |title=Fluctuations in the East Asian monsoon recorded by pollen assemblages in sediments from the Japan Sea off the southwestern coast of Hokkaido, Japan, from 4.3 Ma to the present |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818117303752 |journal=[[Global and Planetary Change]] |volume=163 |pages=1–9 |doi=10.1016/j.gloplacha.2018.02.001 |bibcode=2018GPC...163....1I |access-date=14 November 2022}}</ref> as crustal stretching widened the Tsushima Strait and enabled greater inflow of the warm Tsushima Current into the Sea of Japan.<ref>{{cite journal |last1=Gallagher |first1=Stephen J. |last2=Kitamura |first2=Akihisa |last3=Iryu |first3=Yasufumi |last4=Itaki |first4=Takuya |last5=Koizumi |first5=Itaru |last6=Hoiles |first6=Peter W. |date=27 June 2015 |title=The Pliocene to recent history of the Kuroshio and Tsushima Currents: a multi-proxy approach |journal=Progress in Earth and Planetary Science |volume=2 |page=17 |doi=10.1186/s40645-015-0045-6 |bibcode=2015PEPS....2...17G |s2cid=129045722 |hdl=11343/57355 |hdl-access=free |doi-access=free }}</ref> Circa 3.0 million years ago, the EAWM became more stable, having previously been more variable and inconsistent, in addition to being enhanced further amidst a period of global cooling and sea level fall.<ref name="KimEtAl2019PPP">{{cite journal |last1=Kim |first1=Yongmi |last2=Yi |first2=Sangheon |last3=Kim |first3=Gil-Young |last4=Lee |first4=Eunmi |last5=Kong |first5=Sujin |date=15 April 2019 |title=Palynological study of paleoclimate and paleoceanographic changes in the Eastern South Korea Plateau, East Sea, during the Plio-Pleistocene climate transition |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018218307077 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=520 |pages=18–29 |doi=10.1016/j.palaeo.2019.01.021 |bibcode=2019PPP...520...18K |s2cid=134641370 |access-date=3 December 2022}}</ref> The EASM was weaker during cold intervals of glacial periods such as the [[Last Glacial Maximum]] (LGM) and stronger during interglacials and warm intervals of glacial periods.<ref>{{cite journal |last1=Vats |first1=Nishant |last2=Mishra |first2=Sibasish |last3=Singh |first3=Raj K. |last4=Gupta |first4=Anil K. |last5=Pandey |first5=D. K. |date=June 2020 |title=Paleoceanographic changes in the East China Sea during the last ~400 kyr reconstructed using planktic foraminifera |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818120300643 |journal=[[Global and Planetary Change]] |volume=189 |page=103173 |doi=10.1016/j.gloplacha.2020.103173 |bibcode=2020GPC...18903173V |s2cid=216428856 |access-date=13 September 2022}}</ref> Another EAWM intensification event occurred 2.6 million years ago, followed by yet another one around 1.0 million years ago.<ref name="HanFangBergerYin2011" /> During [[Dansgaard–Oeschger event]]s, the EASM grew in strength, but it has been suggested to have decreased in strength during [[Heinrich event]]s.<ref name="AhnEtAl2012">{{cite journal |last1=Ahn |first1=Jinho |last2=Brooks |first2=Edward J. |last3=Schmittner |first3=Andreas |last4=Kreutz |first4=Karl |date=28 September 2012 |title=Abrupt change in atmospheric CO2 during the last ice age |journal=[[Geophysical Research Letters]] |volume=39 |issue=18 |pages=1–5 |doi=10.1029/2012GL053018 |bibcode=2012GeoRL..3918711A |s2cid=15020102 |doi-access=free }}</ref> The EASM expanded its influence deeper into the interior of Asia as sea levels rose following the LGM;<ref>{{cite journal |last1=Li |first1=Qin |last2=Wu |first2=Haibin |last3=Yu |first3=Yanyan |last4=Sun |first4=Aizhi |last5=Marković |first5=Slobodan B. |last6=Guo |first6=Zhengtang |date=October 2014 |title=Reconstructed moisture evolution of the deserts in northern China since the Last Glacial Maximum and its implications for the East Asian Summer Monsoon |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818114001428 |journal=[[Global and Planetary Change]] |volume=121 |pages=101–112 |doi=10.1016/j.gloplacha.2014.07.009 |bibcode=2014GPC...121..101L |access-date=13 November 2022}}</ref> it also underwent a period of intensification during the Middle Holocene, around 6,000 years ago, due to orbital forcing made more intense by the fact that the Sahara at the time was much more vegetated and emitted less dust.<ref name="GreenSaharaAsianMonsoon">{{cite journal |last1=Piao |first1=Jinling |last2=Chen |first2=Wen |last3=Wang |first3=Lin |last4=Pausata |first4=Francesco S.R. |last5=Zhang |first5=Qiong |date=January 2020 |title=Northward extension of the East Asian summer monsoon during the mid-Holocene |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818119305314 |journal=[[Global and Planetary Change]] |volume=184 |page=103046 |doi=10.1016/j.gloplacha.2019.103046 |bibcode=2020GPC...18403046P |s2cid=210319430 |access-date=7 November 2022}}</ref> This Middle Holocene interval of maximum EASM was associated with an expansion of temperate deciduous forest steppe and temperate mixed forest steppe in northern China.<ref name="WangEtAl2019PPP">{{cite journal |last1=Wang |first1=Wei |last2=Liu |first2=Lina |last3=Li |first3=Yanyan |last4=Niu |first4=Zhimei |last5=He |first5=Jiang |last6=Ma |first6=Yuzhen |last7=Mensing |first7=Scott A. |date=15 August 2019 |title=Pollen reconstruction and vegetation dynamics of the middle Holocene maximum summer monsoon in northern China |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018218309180 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=528 |pages=204–217 |doi=10.1016/j.palaeo.2019.05.023 |bibcode=2019PPP...528..204W |s2cid=182641708 |access-date=6 December 2022}}</ref> By around 5,000 to 4,500 BP, the East Asian monsoon's strength began to wane, weakening from that point until the present day.<ref>{{cite journal |last1=Chen |first1=Xu |last2=McGowan |first2=Suzanne |last3=Xiao |first3=Xiayun |last4=Stevenson |first4=Mark A. |last5=Yang |first5=Xiangdong |last6=Li |first6=Yanling |last7=Zhang |first7=Enlou |date=1 August 2018 |title=Direct and indirect effects of Holocene climate variations on catchment and lake processes of a treeline lake, SW China |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018218301421 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=502 |pages=119–129 |doi=10.1016/j.palaeo.2018.04.027 |bibcode=2018PPP...502..119C |s2cid=135099188 |access-date=6 December 2022}}</ref> A particularly notable weakening took place ~3,000 BP.<ref>{{cite journal |last1=Cheng |first1=Bei |last2=Liu |first2=Jianbao |last3=Chen |first3=Shengqian |last4=Zhang |first4=Zhiping |last5=Shen |first5=Zhongwei |last6=Yan |first6=Xinwei |last7=Li |first7=Fanyi |last8=Chen |first8=Guangjie |last9=Zhang |first9=Xiaosen |last10=Wang |first10=Xin |last11=Chen |first11=Jianhui |date=5 February 2020 |title=Impact of Abrupt Late Holocene Monsoon Climate Change on the Status of an Alpine Lake in North China |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JD031877 |journal=[[Journal of Geophysical Research]] |volume=125 |issue=4 |doi=10.1029/2019JD031877 |bibcode=2020JGRD..12531877C |s2cid=214431404 |access-date=13 April 2023}}</ref> The location of the EASM shifted multiple times over the course of the Holocene: first, it moved southward between 12,000 and 8,000 BP, followed by an expansion to the north between approximately 8,000 and 4,000 BP, and most recently retreated southward once more between 4,000 and 0 BP.<ref name="ChengEtAl2020GPC">{{cite journal |last1=Cheng |first1=Ying |last2=Liu |first2=Hongyan |last3=Dong |first3=Zhibao |last4=Duan |first4=Keqin |last5=Wang |first5=Hongya |last6=Han |first6=Yue |date=April 2020 |title=East Asian summer monsoon and topography co-determine the Holocene migration of forest-steppe ecotone in northern China |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818120300254 |journal=[[Global and Planetary Change]] |volume=187 |page=103135 |doi=10.1016/j.gloplacha.2020.103135 |bibcode=2020GPC...18703135C |s2cid=213786940 |access-date=1 December 2022}}</ref>