Editing Holocene extinction (section)

===Climate change===
[[File:Aridity ice age vs early holocene vs modern.jpg|thumb|right|''Top:'' [[Arid]] ice age climate{{Clear}}''Middle:'' [[Atlantic period]], warm and wet{{Clear}}''Bottom:'' Potential vegetation in climate now if not for human effects like agriculture.<ref name=ORNL_paleoclimate>{{Cite web|title=Global land environments since the last interglacial
|last=Adams | first=Jonathan M. | year=1997
|url=https://www.esd.ornl.gov/projects/qen/nerc.html|access-date=2023-01-06
|archive-url=https://web.archive.org/web/20080116122058/http://www.esd.ornl.gov/projects/qen/nerc.html|archive-date=2008-01-16
|publisher=Oak Ridge National Laboratory, TN, USA}}</ref>]]
One of the main theories explaining early Holocene extinctions is [[climate change (general concept)|historic climate change]]. The climate change theory has suggested that a change in climate near the end of the late Pleistocene stressed the megafauna to the point of extinction.<ref name="Zalasiewicz">{{cite journal|last=Zalasiewicz|first=Jan|author2=Williams, Mark|author3=Smith, Alan|author4=Barry, Tiffany L. |author5=Coe, Angela L.|author6=Bown, Paul R.|author7=Brenchley, Patrick|author8=Cantrill, David |author9=Gale, Andrew|author10=Gibbard, Philip|author11=Gregory, F. John|author12=Hounslow, Mark W. |author13=Kerr, Andrew C.|author14=Pearson, Paul|author15=Knox, Robert|author16=Powell, John |author17=Waters, Colin|author18=Marshall, John|author19=Oates, Michael|author20=Rawson, Peter |author21=Stone, Philip|title=Are we now living in the Anthropocene|journal=GSA Today|year=2008 |volume=18|issue=2|pages=4|doi=10.1130/GSAT01802A.1|bibcode=2008GSAT...18b...4Z |doi-access=free}}</ref><ref>{{cite book|last1=Graham |first1=R. W.|last2=Mead|first2=J. I.|year=1987|chapter=Environmental fluctuations and evolution of mammalian faunas during the last deglaciation in North America|editor1-last=Ruddiman|editor1-first=W. F. |editor2-last=Wright|editor2-first=J. H. E.|title=North America and Adjacent Oceans During the Last Deglaciation |volume=K-3|series=The Geology of North America|publisher=[[Geological Society of America]] |isbn=978-0-8137-5203-7}}</ref> Some scientists favor abrupt climate change as the catalyst for the extinction of the megafauna at the end of the Pleistocene, most who believe increased hunting from early modern humans also played a part, with others even suggesting that the two interacted.<ref name="Kolbert-2014" /><ref>{{cite book|last=Martin |first=P. S. |year=1967 |chapter=Prehistoric overkill |title=Pleistocene extinctions: The search for a cause|editor1-first=P. S. |editor1-last=Martin|editor2-first=H. E.|editor2-last=Wright|location=New Haven|publisher=Yale University Press|isbn=978-0-300-00755-8}}</ref><ref>{{cite journal|author=Lyons, S.K.|author2=Smith, F.A.|author3=Brown, J.H.|title=Of mice, mastodons and men: human-mediated extinctions on four continents|journal=Evolutionary Ecology Research |volume=6|pages=339–358|url=http://biology.unm.edu/fasmith/Web_Page_PDFs/Lyons_et_al_2004_EER.pdf |year=2004|access-date=18 October 2012|url-status=dead|archive-date=6 March 2012|archive-url=https://web.archive.org/web/20120306013121/http://biology.unm.edu/fasmith/Web_Page_PDFs/Lyons_et_al_2004_EER.pdf}}</ref> In the Americas, a controversial explanation for the shift in climate is presented under the [[Younger Dryas impact hypothesis]], which states that the impact of comets cooled global temperatures.<ref name="PNAS07A">{{cite journal |vauthors=Firestone RB, West A, Kennett JP, etal |title=Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling|journal=Proc. Natl. Acad. Sci. U.S.A.|volume=104|issue=41 |pages=16016–16021|date=October 2007|pmid=17901202 |pmc=1994902|doi=10.1073/pnas.0706977104 |bibcode=2007PNAS..10416016F|doi-access=free}}</ref><ref name=Bunch>{{cite journal |vauthors=Bunch TE, Hermes RE, Moore AM, Kennettd DJ, Weaver JC, Wittke JH, DeCarli PS, Bischoff JL, Hillman GC, Howard GA, Kimbel DR, Kletetschka G, Lipo CP, Sakai S, Revay Z, West A, Firestone RB, Kennett JP |title=Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=109 |issue=28|pages=E1903–12|date=June 2012|pmid=22711809|pmc=3396500 |doi=10.1073/pnas.1204453109 |bibcode=2012PNAS..109E1903B|doi-access=free}}</ref> Despite its popularity among nonscientists, this hypothesis has never been accepted by relevant experts, who dismiss it as a fringe theory.<ref>{{cite journal |last1=Boslough |first1=Mark |date=March 2023 |title=Apocalypse! |url=https://www.skeptic.com/reading_room/graham-hancocks-ancient-apocalypse-hypothesis-put-to-test/ |journal=Skeptic Magazine |volume=28 |issue=1 |pages=51–59 |access-date=2023-06-19 |archive-date=2023-11-27 |archive-url=https://web.archive.org/web/20231127180234/https://www.skeptic.com/reading_room/graham-hancocks-ancient-apocalypse-hypothesis-put-to-test/ |url-status=live }}</ref>