Editing Miocene (section)

==Climate==
[[File:65 Myr Climate Change.png|thumb|300px]]
Climates remained moderately warm, although the slow global cooling that eventually led to the [[Pleistocene]] [[glaciation]]s continued. Although a long-term cooling trend was well underway, there is evidence of a warm period during the Miocene when the global climate rivalled that of the [[Oligocene]].{{citation needed|date=March 2023}} The climate of the Miocene has been suggested as a good analogue for future warmer climates caused by [[anthropogenic global warming]],<ref name="ReconstructingTerrestrialPalaeoclimates" /> with this being especially true of the global climate during the [[Middle Miocene Climatic Optimum]] (MMCO),<ref name="TheFutureOfThePast" /><ref>{{cite journal |last1=Methner |first1=Katharina |last2=Campani |first2=Marion |last3=Fiebig |first3=Jens |last4=Löffler |first4=Niklas |last5=Kempf |first5=Oliver |last6=Mulch |first6=Andreas |date=14 May 2020 |title=Middle Miocene long-term continental temperature change in and out of pace with marine climate records |journal=[[Scientific Reports]] |volume=10 |issue=1 |page=7989 |doi=10.1038/s41598-020-64743-5 |pmid=32409728 |pmc=7224295 |bibcode=2020NatSR..10.7989M }}</ref><ref>{{Cite journal |last=You |first=Y. |date=17 February 2010 |title=Climate-model evaluation of the contribution of sea-surface temperature and carbon dioxide to the Middle Miocene Climate Optimum as a possible analogue of future climate change |url=http://www.tandfonline.com/doi/abs/10.1080/08120090903521671 |journal=[[Australian Journal of Earth Sciences]] |language=en |volume=57 |issue=2 |pages=207–219 |doi=10.1080/08120090903521671 |bibcode=2010AuJES..57..207Y |s2cid=129238665 |issn=0812-0099 |access-date=4 September 2023}}</ref> because the last time carbon dioxide levels were comparable to projected future atmospheric carbon dioxide levels resulting from anthropogenic [[climate change]] was during the MMCO.<ref name="DeepTimePerspectiveCO2">{{cite journal |last1=Retallack |first1=Gregory J. |last2=Conde |first2=Giselle D. |date=June 2020 |title=Deep time perspective on rising atmospheric CO2 |url=https://www.sciencedirect.com/science/article/abs/pii/S0921818120300680 |journal=[[Global and Planetary Change]] |volume=189 |page=103177 |doi=10.1016/j.gloplacha.2020.103177 |bibcode=2020GPC...18903177R |s2cid=216307251 |access-date=5 June 2023}}</ref> The Ross Sea margin of the East Antarctic Ice Sheet (EAIS) was highly dynamic during the Early Miocene.<ref>{{Cite journal |last1=Smellie |first1=J.L. |last2=Panter |first2=K.S. |last3=McIntosh |first3=W.C. |last4=Licht |first4=K.J. |date=July 2024 |title=Landscape evolution in the southern Transantarctic Mountains during the early Miocene (c. 20–17 Ma) and evidence for a highly dynamic East Antarctic Ice Sheet margin from the southernmost volcanoes in the world (87°S) |url=https://www.sciencedirect.com/science/article/pii/S0921818124001127 |journal=[[Global and Planetary Change]] |language=en |volume=238 |pages=104465 |doi=10.1016/j.gloplacha.2024.104465 |bibcode=2024GPC...23804465S |access-date=1 November 2024 |via=Elsevier Science Direct}}</ref>

The Miocene began with the Early Miocene Cool Event (Mi-1) around 23 million years ago, which marked the start of the Early Miocene Cool Interval (EMCI).<ref name="ChristopherScotese" /> This cool event occurred immediately after the Oligocene-Miocene Transition (OMT) during a major expansion of Antarctica's ice sheets,<ref>{{cite journal |last1=Greenop |first1=Rosanna |last2=Sodian |first2=Sindia M. |last3=Henehan |first3=Michael J. |last4=Wilson |first4=Paul A. |last5=Lear |first5=Caroline H. |last6=Foster |first6=Gavin L. |date=18 January 2019 |title=Orbital Forcing, Ice Volume, and CO2 Across the Oligocene-Miocene Transition |url=https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018PA003420 |journal=[[Paleoceanography and Paleoclimatology]] |volume=34 |issue=3 |pages=316–328 |doi=10.1029/2018PA003420 |bibcode=2019PaPa...34..316G |s2cid=133785754 |access-date=5 April 2023}}</ref> but was not associated with a significant drop in atmospheric carbon dioxide levels.<ref>{{cite journal |last1=Roth-Nebelsick |first1=A. |last2=Utescher |first2=T. |last3=Mosbrugger |first3=V. |last4=Diester-Haass |first4=L. |last5=Walther |first5=T. |date=20 March 2004 |title=Changes in atmospheric CO2 concentrations and climate from the Late Eocene to Early Miocene: palaeobotanical reconstruction based on fossil floras from Saxony, Germany |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018203007545 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=205 |issue=1–2 |pages=43–67 |doi=10.1016/j.palaeo.2003.11.014 |bibcode=2004PPP...205...43R |access-date=20 July 2023}}</ref> Both continental and oceanic thermal gradients in mid-latitudes during the Early Miocene were very similar to those in the present.<ref name="GoedertEtAl2017">{{cite journal |last1=Goedert |first1=Jean |last2=Amiot |first2=Romain |last3=Arnaut-Godet |first3=Florent |last4=Cuny |first4=Gilles |last5=Fourel |first5=François |last6=Hernandez |first6=Jean-Alexis |last7=Pedreira-Segade |first7=Ulysse |last8=Lécuyer |first8=Christophe |date=1 September 2017 |title=Miocene (Burdigalian) seawater and air temperatures estimated from the geochemistry of fossil remains from the Aquitaine Basin, France |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018216307568 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=481 |pages=14–28 |doi=10.1016/j.palaeo.2017.04.024 |bibcode=2017PPP...481...14G |access-date=30 November 2022}}</ref> Global cooling caused the East Asian Summer Monsoon (EASM) to begin to take on its modern form during the Early Miocene.<ref>{{Cite journal |last1=Zhang |first1=Ran |last2=Zhang |first2=Zhongshi |last3=Jiang |first3=Dabang |date=23 October 2018 |title=Global Cooling Contributed to the Establishment of a Modern-Like East Asian Monsoon Climate by the Early Miocene |url=http://doi.wiley.com/10.1029/2018GL079930 |journal=[[Geophysical Research Letters]] |language=en |volume=45 |issue=21 |pages=11,941–11,948 |doi=10.1029/2018GL079930 |bibcode=2018GeoRL..4511941Z |s2cid=135353513 |access-date=4 September 2023}}</ref> From 22.1 to 19.7 Ma, the Xining Basin experienced relative warmth and humidity amidst a broader aridification trend.<ref>{{Cite journal |last1=Zhang |first1=Chunxia |last2=Xiao |first2=Guoqiao |last3=Guo |first3=Zhengtang |last4=Wu |first4=Haibin |last5=Hao |first5=Qingzhen |date=1 May 2015 |title=Evidence of late early Miocene aridification intensification in the Xining Basin caused by the northeastern Tibetan Plateau uplift |url=https://www.sciencedirect.com/science/article/pii/S0921818115000405 |journal=[[Global and Planetary Change]] |volume=128 |pages=31–46 |doi=10.1016/j.gloplacha.2015.02.002 |bibcode=2015GPC...128...31Z |issn=0921-8181 |access-date=12 January 2024 |via=Elsevier Science Direct}}</ref>

The EMCI ended 18 million years ago, giving way to the Middle Miocene Warm Interval (MMWI), the warmest part of which was the MMCO that began 16 million years ago.<ref name="ChristopherScotese">{{Cite journal |last1=Scotese |first1=Christopher R. |last2=Song |first2=Haijun |last3=Mills |first3=Benjamin J.W. |last4=van der Meer |first4=Douwe G. |date=April 2021 |title=Phanerozoic paleotemperatures: The earth's changing climate during the last 540 million years |journal=[[Earth-Science Reviews]] |volume=215 |page=103503 |bibcode=2021ESRv..21503503S |doi=10.1016/j.earscirev.2021.103503 |issn=0012-8252 |s2cid=233579194|url=https://eprints.whiterose.ac.uk/169823/1/Scotese_etal_phan_temp_AAM.pdf }} [https://eprints.whiterose.ac.uk/169823/ Alt URL]</ref> As the world transitioned into the MMCO, carbon dioxide concentrations varied between 300 and 500 ppm.<ref>{{cite journal |last1=Greenop |first1=Rosanna |last2=Foster |first2=Gavin L. |last3=Wilson |first3=Paul A. |last4=Lear |first4=Caroline H. |date=11 August 2014 |title=Middle Miocene climate instability associated with high-amplitude CO2 variability |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2014PA002653 |journal=[[Paleoceanography and Paleoclimatology]] |volume=29 |issue=9 |pages=845–853 |doi=10.1002/2014PA002653 |bibcode=2014PalOc..29..845G |s2cid=129813700 |access-date=5 April 2023}}</ref> Global annual mean surface temperature during the MMCO was about 18.4&nbsp;°C.<ref>{{Cite journal |last1=You |first1=Y. |last2=Huber |first2=M. |last3=Müller |first3=R. D. |last4=Poulsen |first4=C. J. |last5=Ribbe |first5=J. |date=19 February 2009 |title=Simulation of the Middle Miocene Climate Optimum |url=http://doi.wiley.com/10.1029/2008GL036571 |journal=[[Geophysical Research Letters]] |language=en |volume=36 |issue=4 |pages=1–5 |doi=10.1029/2008GL036571 |bibcode=2009GeoRL..36.4702Y |s2cid=17326204 |issn=0094-8276 |access-date=4 September 2023}}</ref> MMCO warmth was driven by the activity of the [[Columbia River Basalt Group|Columbia River Basalts]]<ref>{{cite journal |last1=Armstrong McKay |first1=David I. |last2=Tyrrell |first2=Toby |last3=Wilson |first3=Paul A. |last4=Foster |first4=Gavin L. |date=1 October 2014 |title=Estimating the impact of the cryptic degassing of Large Igneous Provinces: A mid-Miocene case-study |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X14004257 |journal=[[Earth and Planetary Science Letters]] |volume=403 |pages=254–262 |doi=10.1016/j.epsl.2014.06.040 |bibcode=2014E&PSL.403..254A |access-date=29 April 2023}}</ref><ref>{{Cite journal |last1=Holbourn |first1=Ann |last2=Kuhnt |first2=Wolfgang |last3=Kochhann |first3=Karlos G.D. |last4=Andersen |first4=Nils |last5=Sebastian Meier |first5=K.J. |date=1 February 2015 |title=Global perturbation of the carbon cycle at the onset of the Miocene Climatic Optimum |url=http://pubs.geoscienceworld.org/geology/article/43/2/123/131763/Global-perturbation-of-the-carbon-cycle-at-the |journal=[[Geology (journal)|Geology]] |language=en |volume=43 |issue=2 |pages=123–126 |doi=10.1130/G36317.1 |bibcode=2015Geo....43..123H |issn=1943-2682 |access-date=4 September 2023}}</ref><ref>{{Cite journal |last1=Goto |first1=Kosuke T. |last2=Tejada |first2=Maria Luisa G. |last3=Tajika |first3=Eiichi |last4=Suzuki |first4=Katsuhiko |date=26 January 2023 |title=Enhanced magmatism played a dominant role in triggering the Miocene Climatic Optimum |url=https://www.nature.com/articles/s43247-023-00684-x |journal=[[Communications Earth & Environment]] |language=en |volume=4 |issue=1 |page=21 |doi=10.1038/s43247-023-00684-x |bibcode=2023ComEE...4...21G |issn=2662-4435 |access-date=26 November 2023}}</ref> and enhanced by decreased [[albedo]] from the reduction of deserts and expansion of forests.<ref>{{cite journal |last1=Henrot |first1=A.-J. |last2=François |first2=L. |last3=Favre |first3=E. |last4=Butzin |first4=M. |last5=Ouberdous |first5=M. |last6=Munhoven |first6=G. |date=21 October 2010 |title=Effects of CO2, continental distribution, topography and vegetation changes on the climate at the Middle Miocene: a model study |url=https://cp.copernicus.org/articles/6/675/2010/ |journal=[[Climate of the Past]] |volume=6 |issue=5 |pages=675–694 |doi=10.5194/cp-6-675-2010 |bibcode=2010CliPa...6..675H |access-date=21 April 2023 |doi-access=free }}</ref> [[Climate model]]ling suggests additional, currently unknown, factors also worked to create the warm conditions of the MMCO.<ref>{{Cite journal |last1=Goldner |first1=A. |last2=Herold |first2=N. |last3=Huber |first3=M. |date=13 March 2014 |title=The challenge of simulating the warmth of the mid-Miocene climatic optimum in CESM1 |url=https://cp.copernicus.org/articles/10/523/2014/ |journal=[[Climate of the Past]] |language=en |volume=10 |issue=2 |pages=523–536 |doi=10.5194/cp-10-523-2014 |bibcode=2014CliPa..10..523G |issn=1814-9332 |access-date=4 September 2023 |doi-access=free }}</ref> The MMCO saw the expansion of the tropical climatic zone to much larger than its current size.<ref>{{Cite journal |last=Kroh |first=Andreas |date=14 September 2007 |title=Climate changes in the Early to Middle Miocene of the Central Paratethys and the origin of its echinoderm fauna |url=https://www.sciencedirect.com/science/article/pii/S0031018207002003 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |series=Miocene Climate in Europe - patterns and evolution. First synthesis of NECLIME |volume=253 |issue=1 |pages=169–207 |doi=10.1016/j.palaeo.2007.03.039 |bibcode=2007PPP...253..169K |issn=0031-0182 |access-date=12 October 2023}}</ref> The July ITCZ, the zone of maximal monsoonal rainfall, moved to the north, increasing precipitation over southern China whilst simultaneously decreasing it over Indochina during the EASM.<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> Western Australia was at this time characterised by exceptional aridity.<ref name="GroeneveldEtAl2017">{{cite journal |last1=Groeneveld |first1=Jeroen |last2=Henderiks |first2=Jorijntje |last3=Renema |first3=Willem |last4=McHugh |first4=Cecilia M. |last5=De Vleeschouwer |first5=David |last6=Christensen |first6=Beth A. |last7=Fulthorpe |first7=Craig S. |last8=Reuning |first8=Lars |last9=Gallager |first9=Stephen J. |last10=Bogus |first10=Kara |last11=Auer |first11=Gerald |last12=Ishiwa |first12=Takeshige |last13=Expedition 356 Scientists |date=10 May 2017 |title=Australian shelf sediments reveal shifts in Miocene Southern Hemisphere westerlies |journal=[[Science Advances]] |volume=3 |issue=5 |pages=e1602567 |doi=10.1126/sciadv.1602567 |pmid=28508066 |pmc=5425240 |bibcode=2017SciA....3E2567G }}</ref> In Antarctica, average summer temperatures on land reached 10&nbsp;°C.<ref>{{Cite journal |last1=Warny |first1=Sophie |last2=Askin |first2=Rosemary A. |last3=Hannah |first3=Michael J. |last4=Mohr |first4=Barbara A.R. |last5=Raine |first5=J. Ian |last6=Harwood |first6=David M. |last7=Florindo |first7=Fabio |last8=the SMS Science Team |date=1 October 2009 |title=Palynomorphs from a sediment core reveal a sudden remarkably warm Antarctica during the middle Miocene |url=https://pubs.geoscienceworld.org/gsa/geology/article/37/10/955/103994/Palynomorphs-from-a-sediment-core-reveal-a-sudden |journal=[[Geology (journal)|Geology]] |language=en |volume=37 |issue=10 |pages=955–958 |doi=10.1130/G30139A.1 |bibcode=2009Geo....37..955W |issn=1943-2682 |access-date=4 September 2023}}</ref> In the oceans, the [[lysocline]] shoaled by approximately half of a kilometre during warm phases that corresponded to [[orbital eccentricity]] maxima.<ref>{{Cite journal |last1=Kochhann |first1=Karlos G. D. |last2=Holbourn |first2=Ann |last3=Kuhnt |first3=Wolfgang |last4=Channell |first4=James E. T. |last5=Lyle |first5=Mitch |last6=Shackford |first6=Julia K. |last7=Wilkens |first7=Roy H. |last8=Andersen |first8=Nils |date=22 August 2016 |title=Eccentricity pacing of eastern equatorial Pacific carbonate dissolution cycles during the Miocene Climatic Optimum: ECCENTRICITY-PACED DISSOLUTION CYCLES |url=http://doi.wiley.com/10.1002/2016PA002988 |journal=[[Paleoceanography and Paleoclimatology]] |language=en |volume=31 |issue=9 |pages=1176–1192 |doi=10.1002/2016PA002988 |access-date=4 September 2023}}</ref> The MMCO ended around 14 million years ago,<ref name="ChristopherScotese" /> when global temperatures fell in the [[Middle Miocene disruption|Middle Miocene Climate Transition]] (MMCT).<ref>{{Cite journal |last1=Shevenell |first1=Amelia E. |author-link=Amelia E. Shevenell |last2= Kennett |first2=James P. |last3=Lea |first3=David W. |date=17 September 2004 |title=Middle Miocene Southern Ocean Cooling and Antarctic Cryosphere Expansion |journal=[[Science (journal)|Science]] |url=https://www.science.org/doi/10.1126/science.1100061 |language=en |volume=305 |issue=5691 |pages=1766–1770 |doi=10.1126/science.1100061 |issn=0036-8075 |pmid=15375266 |bibcode=2004Sci...305.1766S |s2cid=27369039 |access-date=5 April 2023}}</ref> Abrupt increases in [[opal]] deposition indicate this cooling was driven by enhanced drawdown of carbon dioxide via silicate weathering.<ref>{{Cite journal |last1=Holbourn |first1=A. |last2=Kuhnt |first2=W. |last3=Lyle |first3=M. |last4=Schneider |first4=L. |last5=Romero |first5=O. |last6=Andersen |first6=N. |date=1 January 2014 |title=Middle Miocene climate cooling linked to intensification of eastern equatorial Pacific upwelling |url=https://pubs.geoscienceworld.org/geology/article/42/1/19-22/131310 |journal=[[Geology (journal)|Geology]] |language=en |volume=42 |issue=1 |pages=19–22 |doi=10.1130/G34890.1 |bibcode=2014Geo....42...19H |issn=0091-7613 |access-date=4 September 2023}}</ref> The MMCT caused a [[sea surface temperature]] (SST) drop of approximately 6&nbsp;°C in the North Atlantic.<ref>{{Cite journal |last1=Super |first1=James R. |last2=Thomas |first2=Ellen |last3=Pagani |first3=Mark |last4=Huber |first4=Matthew |last5=O'Brien |first5=Charlotte |last6=Hull |first6=Pincelli M. |date=26 April 2018 |title=North Atlantic temperature and pCO2 coupling in the early-middle Miocene |url=https://pubs.geoscienceworld.org/gsa/geology/article/46/6/519/530691/North-Atlantic-temperature-and-pCO2-coupling-in |journal=[[Geology (journal)|Geology]] |language=en |volume=46 |issue=6 |pages=519–522 |doi=10.1130/G40228.1 |bibcode=2018Geo....46..519S |issn=0091-7613 |access-date=4 September 2023}}</ref> The drop in benthic foraminiferal δ<sup>18</sup>O values was most noticeable in the waters around Antarctica, suggesting cooling was most intense there.<ref>{{Cite journal |last1=Woodruff |first1=Fay |last2=Savin |first2=Samuel |date=December 1991 |title=Mid-Miocene isotope stratigraphy in the deep sea: High-resolution correlations, paleoclimatic cycles, and sediment preservation |url=http://doi.wiley.com/10.1029/91PA02561 |journal=[[Paleoceanography and Paleoclimatology]] |language=en |volume=6 |issue=6 |pages=755–806 |doi=10.1029/91PA02561 |bibcode=1991PalOc...6..755W |access-date=4 September 2023}}</ref> Around this time the Mi3b glacial event (a massive expansion of Antarctic glaciers) occurred.<ref>{{cite journal |last1=Mathew |first1=Manoj |last2=Makhankova |first2=Adelya |last3=Menier |first3=David |last4=Sautter |first4=Benjamin |last5=Betzler |first5=Christian |last6=Pierson |first6=Bernard |date=28 April 2020 |title=The emergence of Miocene reefs in South China Sea and its resilient adaptability under varying eustatic, climatic and oceanographic conditions |url=https://www.researchgate.net/publication/340974067 |journal=[[Scientific Reports]] |volume=10 |issue=1 |page=7141 |doi=10.1038/s41598-020-64119-9 |pmid=32346046 |pmc=7189246 |bibcode=2020NatSR..10.7141M |access-date=23 April 2023}}</ref> The East Antarctic Ice Sheet (EAIS) markedly stabilised following the MMCT.<ref>{{Cite journal |last1=Flower |first1=Benjamin P. |last2=Kennett |first2=James P. |date=April 1994 |title=The middle Miocene climatic transition: East Antarctic ice sheet development, deep ocean circulation and global carbon cycling |url=https://linkinghub.elsevier.com/retrieve/pii/0031018294902518 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=108 |issue=3–4 |pages=537–555 |doi=10.1016/0031-0182(94)90251-8 |bibcode=1994PPP...108..537F |access-date=4 September 2023}}</ref> The intensification of glaciation caused a decoherence of sediment deposition from the 405 kyr eccentricity cycle.<ref>{{Cite journal |last1=Tian |first1=Jun |last2=Zhao |first2=Quanhong |last3=Wang |first3=Pinxian |last4=Li |first4=Qianyu |last5=Cheng |first5=Xinrong |date=September 2008 |title=Astronomically modulated Neogene sediment records from the South China Sea: NEOGENE BENTHIC ISOTOPES |url=http://doi.wiley.com/10.1029/2007PA001552 |journal=[[Paleoceanography and Paleoclimatology]] |language=en |volume=23 |issue=3 |pages=1–20 |doi=10.1029/2007PA001552 |access-date=19 September 2023}}</ref> 
[[File:Rattlesnake Formation Mural.jpg|thumb|left|300px|Restoration of the volcanic eruption in Harney Basin, of the western US, represented by the [[Rattlesnake Formation]]]] 
The MMWI ended about 11 Ma, when the Late Miocene Cool Interval (LMCI) started.<ref name="ChristopherScotese" /> A major but transient warming occurred around 10.8-10.7 Ma.<ref>{{Cite journal |last1=Holbourn |first1=Ann |last2=Kuhnt |first2=Wolfgang |last3=Clemens |first3=Steven |last4=Prell |first4=Warren |last5=Andersen |first5=Nils |date=11 November 2013 |title=Middle to late Miocene stepwise climate cooling: Evidence from a high-resolution deep water isotope curve spanning 8 million years: MIOCENE BENTHIC ISOTOPES |url=http://doi.wiley.com/10.1002/2013PA002538 |journal=[[Paleoceanography and Paleoclimatology]] |language=en |volume=28 |issue=4 |pages=688–699 |doi=10.1002/2013PA002538 |s2cid=128368245 |access-date=4 September 2023}}</ref> During the Late Miocene, the Earth's climate began to display a high degree of similarity to that of the present day{{according to whom|date=January 2024}}{{citation needed|date=January 2024}}. The 173 kyr [[Milankovitch cycles|obliquity modulation cycle]] governed by Earth's interactions with Saturn became detectable in the Late Miocene.<ref name="ZhangEtAl2022">{{cite journal |last1=Zhang |first1=Rui |last2=Li |first2=Xiaojuan |last3=Xu |first3=Yong |last4=Li |first4=Jianxian |last5=Sun |first5=Lu |last6=Yue |first6=Leping |last7=Pan |first7=Feng |last8=Xian |first8=Feng |last9=Wei |first9=Xiaohao |last10=Cao |first10=Yuge |date=10 January 2022 |title=The 173-kyr Obliquity Cycle Pacing the Asian Monsoon in the Eastern Chinese Loess Plateau From Late Miocene to Pliocene |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL097008 |journal=[[Geophysical Research Letters]] |volume=49 |issue=2 |doi=10.1029/2021GL097008 |bibcode=2022GeoRL..4997008Z |s2cid=245868256 |access-date=20 March 2023}}</ref> By 12 Ma, [[Oregon]] was a savanna akin to that of the western margins of the [[Sierra Nevada]] of northern [[California]].<ref>{{Cite journal |last=Retallack |first=Gregory J. |date=4 November 2004 |title=Late Miocene climate and life on land in Oregon within a context of Neogene global change |url=https://www.sciencedirect.com/science/article/pii/S0031018204003943 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=214 |issue=1 |pages=97–123 |doi=10.1016/j.palaeo.2004.07.024 |issn=0031-0182 |access-date=12 January 2024 |via=Elsevier Science Direct}}</ref> Central Australia became progressively drier,<ref>{{cite journal |last1=Mao |first1=Xuegang |last2=Retallack |first2=Gregory |date=15 January 2019 |title=Late Miocene drying of central Australia |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018218306898 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=514 |pages=292–304 |doi=10.1016/j.palaeo.2018.10.008 |bibcode=2019PPP...514..292M |s2cid=135124769 |access-date=14 July 2023}}</ref> although southwestern Australia experienced significant wettening from around 12 to 8 Ma.<ref name="GroeneveldEtAl2017" /> The South Asian Winter Monsoon (SAWM) underwent strengthening ~9.2–8.5 Ma.<ref>{{cite journal |last1=Lee |first1=Jongmin |last2=Kim |first2=Sunghan |last3=Lee |first3=Jae Il |last4=Cho |first4=Hyen Goo |last5=Phillips |first5=Stephen C. |last6=Khim |first6=Bo-Kyeun |date=15 December 2020 |title=Monsoon-influenced variation of clay mineral compositions and detrital Nd-Sr isotopes in the western Andaman Sea (IODP Site U1447) since the late Miocene |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018219303773 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=538 |page=109339 |doi=10.1016/j.palaeo.2019.109339 |bibcode=2020PPP...53809339L |s2cid=202179283 |access-date=7 July 2023}}</ref> From 7.9 to 5.8 Ma, the East Asian Winter Monsoon (EAWM) became stronger synchronously with a southward shift of the subarctic front.<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> [[Greenland]] may have begun to have large glaciers as early as 8 to 7 Ma,<ref>{{cite journal |last1=Larsen |first1=H. C. |last2=Saunders |first2=A. D. |last3=Clift |first3=P. D. |last4=Beget |first4=J. |last5=Wei |first5=W. |last6=Spezzaferri |first6=S. |title=Seven Million Years of Glaciation in Greenland |journal=[[Science (journal)|Science]] |date=13 May 1994 |volume=264 |issue=5161 |pages=952–955 |doi=10.1126/science.264.5161.952|pmid=17830083 |bibcode=1994Sci...264..952L |s2cid=10031704 |url=https://digitalcommons.unl.edu/geosciencefacpub/55 }}</ref><ref>{{cite journal |last1=John |first1=Kristen E. K. St. |last2=Krissek |first2=Lawrence A. |title=The late Miocene to Pleistocene ice-rafting history of southeast Greenland |journal=[[Boreas (journal)|Boreas]] |date=28 June 2008 |volume=31 |issue=1 |pages=28–35 |doi=10.1111/j.1502-3885.2002.tb01053.x|s2cid=128606939 |doi-access=free }}</ref> although the climate for the most part remained warm enough to support forests there well into the Pliocene.<ref>{{cite journal |last1=Funder |first1=Svend |last2=Abrahamsen |first2=Niels |last3=Bennike |first3=Ole |last4=Feyling-Hanssen |first4=Rolf W. |title=Forested Arctic: Evidence from North Greenland |journal=[[Geology (journal)|Geology]] |date=1 August 1985 |volume=13 |issue=8 |pages=542–546 |doi=10.1130/0091-7613(1985)13<542:FAEFNG>2.0.CO;2|bibcode=1985Geo....13..542F }}</ref> Zhejiang, China was noticeably more humid than today.<ref>{{Cite journal |last1=Wang |first1=Xue-Lian |last2=Wang |first2=Zi-Xi |last3=Li |first3=Rui-Yun |last4=Deng |first4=Peng |last5=Ma |first5=Li |last6=Sun |first6=Bai-Nian |date=January 2016 |title=Vein density of angiosperms as a paleoclimate proxy: a case study using fossil leaves of Zelkova and Machilus |url=https://linkinghub.elsevier.com/retrieve/pii/S1871174X15000785 |journal=[[Palaeoworld]] |language=en |volume=25 |issue=1 |pages=60–66 |doi=10.1016/j.palwor.2015.11.002 |access-date=20 July 2024 |via=Elsevier Science Direct}}</ref> In the [[Great Rift Valley]] of [[Kenya]], there was a gradual and progressive trend of increasing aridification, though it was not unidirectional, and wet humid episodes continued to occur.<ref>{{cite journal |last1=Jacobs |first1=Bonnie Fine |date=8 April 2016 |title=Estimation of low-latitude paleoclimates using fossil angiosperm leaves: examples from the Miocene Tugen Hills, Kenya |url=https://www.cambridge.org/core/journals/paleobiology/article/abs/estimation-of-lowlatitude-paleoclimates-using-fossil-angiosperm-leaves-examples-from-the-miocene-tugen-hills-kenya/93FE0A15844E2E21153DCCE41906B7BB |journal=[[Paleobiology (journal)|Paleobiology]] |volume=28 |issue=3 |pages=399–421 |doi=10.1666/0094-8373(2002)028<0399:EOLLPU>2.0.CO;2 <!-- several wrong dois for this one --> |bibcode=2002Pbio...28..399J |access-date=16 June 2023 |jstor=3595489 |s2cid=198156844 }}</ref> Between 7 and 5.3 Ma, temperatures dropped sharply again in the Late Miocene Cooling (LMC),<ref name="ChristopherScotese" /> most likely as a result of a decline in atmospheric carbon dioxide<ref name="BrownEtAl2022">{{cite journal |last1=Brown |first1=Rachel M. |last2=Chalk |first2=Thomas B. |last3=Crocker |first3=Anya J. |last4=Wilson |first4=Paul A. |last5=Foster |first5=Gavin L. |date=25 July 2022 |title=Late Miocene cooling coupled to carbon dioxide with Pleistocene-like climate sensitivity |url=https://www.nature.com/articles/s41561-022-00982-7 |journal=[[Nature Geoscience]] |volume=15 |issue=8 |pages=664–670 |doi=10.1038/s41561-022-00982-7 |bibcode=2022NatGe..15..664B |hdl=10037/29226 |s2cid=251043167 |access-date=8 December 2022|hdl-access=free }}</ref><ref>{{cite journal |last1=Tanner |first1=Thomas |last2=Hernández-Almeida |first2=Iván |last3=Drury |first3=Anna Joy |last4=Guitián |first4=José |last5=Stoll |first5=Heather |date=10 December 2020 |title=Decreasing Atmospheric CO2 During the Late Miocene Cooling |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020PA003925 |journal=[[Paleoceanography and Paleoclimatology]] |volume=35 |issue=12 |doi=10.1029/2020PA003925 |bibcode=2020PaPa...35.3925T |s2cid=230534117 |access-date=17 March 2023}}</ref><ref>{{cite journal |last1=Wen |first1=Yixiong |last2=Zhang |first2=Laiming |last3=Holbourn |first3=Ann E. |last4=Zhu |first4=Chenguang |last5=Huntington |first5=Katharine W. |last6=Jin |first6=Tianjie |last7=Li |first7=Yalin |last8=Wang |first8=Chengshan |date=23 January 2013 |title=CO2-forced Late Miocene cooling and ecosystem reorganizations in East Asia |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=120 |issue=5 |pages=e2214655120 |doi=10.1073/pnas.2214655120 |pmid=36689658 |pmc=9945954 |doi-access=free }}</ref> and a drop in the amplitude of Earth's obliquity,<ref name="QinEtAl2022">{{cite journal |last1=Qin |first1=Jie |last2=Zhang |first2=Rui |last3=Kravchinsky |first3=Vadim A. |last4=Valet |first4=Jean-Pierre |last5=Sagnotti |first5=Leonardo |last6=Li |first6=Jianxing |last7=Xu |first7=Yong |last8=Anwar |first8=Taslima |last9=Yue |first9=Leping |date=2 April 2022 |title=1.2 Myr Band of Earth-Mars Obliquity Modulation on the Evolution of Cold Late Miocene to Warm Early Pliocene Climate |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022JB024131 |journal= Journal of Geophysical Research: Solid Earth|volume=127 |issue=4 |doi=10.1029/2022JB024131 |bibcode=2022JGRB..12724131Q |s2cid=247933545 |access-date=24 November 2022}}</ref> and the [[Antarctic ice sheet]] was approaching its present-day size and thickness. Ocean temperatures plummeted to near-modern values during the LMC;<ref>{{cite journal |last1=Herbert |first1=Timothy D. |last2=Lawrence |first2=Kira T. |last3=Tzanova |first3=Alexandrina |last4=Peterson |first4=Laura Cleaveland |last5=Caballero-Gill |first5=Rocio |last6=Kelly |first6=Christopher S. |date=26 September 2016 |title=Late Miocene global cooling and the rise of modern ecosystems |url=https://www.nature.com/articles/ngeo2813?error=cookies_not_supported&code=e9cbd054-4333-471e-b97c-72ec80d9099d |journal=[[Nature Geoscience]] |volume=9 |issue=11 |pages=843–847 |doi=10.1038/ngeo2813 |bibcode=2016NatGe...9..843H |access-date=17 March 2023}}</ref> extratropical [[sea surface temperature]]s dropped substantially by approximately 7–9&nbsp;°C.<ref>{{cite journal |last1=Mejía |first1=Luz María |last2=Méndez-Vicente |first2=Ana |last3=Abrevaya |first3=Lorena |last4=Lawrence |first4=Kira T. |last5=Ladlow |first5=Caroline |last6=Bolton |first6=Clara |last7=Cacho |first7=Isabel |last8=Stoll |first8=Heather |date=1 December 2017 |title=A diatom record of CO2 decline since the late Miocene |journal=[[Earth and Planetary Science Letters]] |volume=479 |pages=18–33 |doi=10.1016/j.epsl.2017.08.034 |bibcode=2017E&PSL.479...18M |doi-access=free }}</ref> 41 kyr obliquity cycles became the dominant orbital climatic control 7.7 Ma and this dominance strengthened 6.4 Ma.<ref>{{Cite journal |last1=Drury |first1=Anna Joy |last2=Westerhold |first2=Thomas |last3=Frederichs |first3=Thomas |last4=Tian |first4=Jun |last5=Wilkens |first5=Roy |last6=Channell |first6=James E.T. |last7=Evans |first7=Helen |last8=John |first8=Cédric M. |last9=Lyle |first9=Mitch |last10=Röhl |first10=Ursula |date=1 October 2017 |title=Late Miocene climate and time scale reconciliation: Accurate orbital calibration from a deep-sea perspective |url=https://linkinghub.elsevier.com/retrieve/pii/S0012821X17304223 |journal=[[Earth and Planetary Science Letters]] |language=en |volume=475 |pages=254–266 |doi=10.1016/j.epsl.2017.07.038 |bibcode=2017E&PSL.475..254D |access-date=20 July 2024 |via=Elsevier Science Direct}}</ref> Benthic δ<sup>18</sup>O values show significant glaciation occurred from 6.26 to 5.50 Ma, during which glacial-interglacial cycles were governed by the 41 kyr obliquity cycle.<ref>{{Cite journal |last1=Hodell |first1=David A. |last2=Curtis |first2=Jason H. |last3=Sierro |first3=Francisco J. |last4=Raymo |first4=Maureen E. |date=April 2004 |title=Correlation of Late Miocene to Early Pliocene sequences between the Mediterranean and North Atlantic |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/1999PA000487 |journal=[[Paleoceanography and Paleoclimatology]] |language=en |volume=16 |issue=2 |pages=164–178 |doi=10.1029/1999PA000487 |issn=0883-8305 |access-date=19 September 2023}}</ref> A major reorganisation of the [[carbon cycle]] occurred approximately 6 Ma, causing continental carbon reservoirs to no longer expand during cold spells, as they had done during cold periods in the Oligocene and most of the Miocene.<ref>{{cite journal |last1=De Vleeschouwer |first1=David |last2=Drury |first2=Anna Joy |last3=Vahlenkamp |first3=Maximilian |last4=Rochholz |first4=Fiona |last5=Liebrand |first5=Diederik |last6=Pälike |first6=Heiko |date=6 October 2020 |title=High-latitude biomes and rock weathering mediate climate–carbon cycle feedbacks on eccentricity timescales |journal=[[Nature Communications]] |volume=11 |issue=1 |page=5013 |doi=10.1038/s41467-020-18733-w |pmid=33024102 |pmc=7538577 |bibcode=2020NatCo..11.5013D }}</ref> At the end of the Miocene, global temperatures rose again as the [[amplitude]] of Earth's obliquity increased,<ref name="QinEtAl2022" /> which caused increased aridity in Central Asia.<ref>{{Cite journal |last1=Ao |first1=Hong |last2=Rohling |first2=Eelco J. |last3=Zhang |first3=Ran |last4=Roberts |first4=Andrew P. |last5=Holbourn |first5=Ann E. |last6=Ladant |first6=Jean-Baptiste |last7=Dupont-Nivet |first7=Guillaume |last8=Kuhnt |first8=Wolfgang |last9=Zhang |first9=Peng |last10=Wu |first10=Feng |last11=Dekkers |first11=Mark J. |last12=Liu |first12=Qingsong |last13=Liu |first13=Zhonghui |last14=Xu |first14=Yong |last15=Poulsen |first15=Christopher J. |date=26 November 2021 |title=Global warming-induced Asian hydrological climate transition across the Miocene–Pliocene boundary |journal=[[Nature Communications]] |language=en |volume=12 |issue=1 |page=6935 |doi=10.1038/s41467-021-27054-5 |issn=2041-1723 |pmc=8626456 |pmid=34836960 |bibcode=2021NatCo..12.6935A }}</ref> Around 5.5 Ma, the EAWM underwent a period of rapid intensification.<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>