Editing Holocene extinction (section)

==Historic extinction==
{{See also|Megafauna#Megafaunal_mass_extinctions|label 1=Megafaunal mass extinctions|Quaternary extinction}}

===Human activity===
====Activities contributing to extinctions====
[[File:Extinctions Africa Austrailia NAmerica Madagascar.gif|thumb|The percentage of [[megafauna]] on different land masses over time, with the arrival of humans indicated.]]
Extinction of animals, plants, and other organisms caused by human actions may go as far back as the late [[Pleistocene]], over 12,000 years ago.<ref name="SpecialIssue"/> There is a correlation between megafaunal extinction and the arrival of humans.<ref>{{cite journal|last1=Sandom|first1=Christopher |last2=Faurby|first2=Søren|last3= Sandel|first3=Brody|last4= Svenning|first4=Jens-Christian|date= 4 June 2014|title=Global late Quaternary megafauna extinctions linked to humans, not climate change|journal=[[Proceedings of the Royal Society B]]|volume=281|issue= 1787|page= 20133254|doi=10.1098/rspb.2013.3254 |pmid=24898370|pmc=4071532}}</ref><ref>{{cite journal |last1=Smith|first1=Felisa A.|last2=Elliott Smith|first2=Rosemary E. |last3=Lyons |first3=S. Kathleen |last4=Payne |first4=Jonathan L.|date=April 20, 2018|title=Body size downgrading of mammals over the late Quaternary |journal=Science|volume=360 |issue=6386|pages=310–313|doi=10.1126/science.aao5987|pmid=29674591|bibcode=2018Sci...360..310S|doi-access=free}}</ref><ref>{{cite journal|last1=Dembitzer|first1=Jacob|last2=Barkai|first2=Ran |last3=Ben-Dor|first3=Miki|last4=Meiri|first4=Shai|date=2022|title=Levantine overkill: 1.5 million years of hunting down the body size distribution|journal=[[Quaternary Science Reviews]]|volume=276|issue=|page=107316 |doi=10.1016/j.quascirev.2021.107316|bibcode=2022QSRv..27607316D|s2cid=245236379}}</ref> Megafauna that are still extant also suffered severe declines that were highly correlated with human expansion and activity.<ref>{{Cite journal |last1=Bergman |first1=Juraj |last2=Pedersen |first2=Rasmus Ø |last3=Lundgren |first3=Erick J. |last4=Lemoine |first4=Rhys T. |last5=Monsarrat |first5=Sophie |last6=Pearce |first6=Elena A. |last7=Schierup |first7=Mikkel H. |last8=Svenning |first8=Jens-Christian |date=24 November 2023 |title=Worldwide Late Pleistocene and Early Holocene population declines in extant megafauna are associated with Homo sapiens expansion rather than climate change |journal=[[Nature Communications]] |language=en |volume=14 |issue=1 |pages=7679 |doi=10.1038/s41467-023-43426-5 |pmid=37996436 |issn=2041-1723 |pmc=10667484 |bibcode=2023NatCo..14.7679B }}</ref> Over the past 125,000 years, the average body size of wildlife has fallen by 14% as actions by prehistoric humans eradicated [[megafauna]] on all continents with the exception of Africa.<ref>{{cite news|last=Carrington|first=Damian|date=May 23, 2019|title=Humans causing shrinking of nature as larger animals die off|work=The Guardian|url=https://www.theguardian.com/environment/2019/may/23/humans-causing-shrinking-of-nature-as-larger-animals-die-off|access-date=May 23, 2019|archive-date=February 24, 2021|archive-url=https://web.archive.org/web/20210224071938/https://www.theguardian.com/environment/2019/may/23/humans-causing-shrinking-of-nature-as-larger-animals-die-off|url-status=live}}</ref> Over the past 130,000 years, avian functional diversity has declined precipitously and disproportionately relative to phylogenetic diversity losses.<ref>{{Cite journal |last1=Matthews |first1=Thomas J. |last2=Triantis |first2=Kostas A. |last3=Wayman |first3=Joseph P. |last4=Martin |first4=Thomas E. |last5=Hume |first5=Julian P. |last6=Cardoso |first6=Pedro |last7=Faurby |first7=Søren |last8=Mendenhall |first8=Chase D. |last9=Dufour |first9=Paul |last10=Rigal |first10=François |last11=Cooke |first11=Rob |last12=Whittaker |first12=Robert J. |last13=Pigot |first13=Alex L. |last14=Thébaud |first14=Christophe |last15=Jørgensen |first15=Maria Wagner |date=4 October 2024 |title=The global loss of avian functional and phylogenetic diversity from anthropogenic extinctions |url=https://www.science.org/doi/10.1126/science.adk7898 |journal=[[Science (journal)|Science]] |language=en |volume=386 |issue=6717 |pages=55–60 |doi=10.1126/science.adk7898 |pmid=39361743 |bibcode=2024Sci...386...55M |issn=0036-8075 |access-date=11 October 2024}}</ref>

[[Civilization|Human civilization]] was founded on and grew from agriculture.<ref name="Ruddiman-2009" /> The more land used for farming, the greater the population a civilization could sustain,<ref name="Ruddiman-2003"/><ref name="Ruddiman-2009">{{Cite journal|last=Ruddiman|first=W.F.|date=2009|title=Effect of per-capita land use changes on Holocene forest clearance and CO<sub>2</sub> emissions|journal=Quaternary Science Reviews |volume=28|issue=27–28|pages=3011–3015|doi=10.1016/j.quascirev.2009.05.022|bibcode=2009QSRv...28.3011R}}</ref> and subsequent popularization of farming led to widespread habitat conversion.<ref name="PimmJenkins"/>

[[Habitat destruction#Human causes|Habitat destruction by humans]], thus replacing the original local ecosystems, is a major driver of extinction.<ref>{{cite journal|last1=Vitousek|first1=P. M.|last2=Mooney |first2=H. A. |last3=Lubchenco|first3=J.|last4=Melillo|first4=J. M.|year=1997|title=Human Domination of Earth's Ecosystems|journal=Science|volume=277|issue=5325|pages=494–499|doi=10.1126/science.277.5325.494 |citeseerx=10.1.1.318.6529|s2cid=8610995 }}</ref> The sustained conversion of biodiversity rich forests and wetlands into poorer fields and pastures (of lesser carrying capacity for wild species), over the last 10,000 years, has considerably reduced the Earth's carrying capacity for wild birds and mammals, among other organisms, in both population size and species count.<ref name=Biodiversity-Global-Change-chapter2>{{cite book |last=Teyssèdre|first=A.|year=2004|title= Towards a sixth mass extinction crisis?|chapter=Biodiversity and Global Change|location=Paris|publisher=ADPF|isbn=978-2-914-935289}}</ref><ref>{{cite journal |last1=Gaston|first1=K.J.|last2=Blackburn|first2=T.N.G.|last3=Klein Goldewijk|first3=K. |year=2003 |title=Habitat conversion and global avian biodiversity loss|journal=Proceedings of the Royal Society B |volume=270|issue=1521|pages=1293–1300|doi=10.1098/rspb.2002.2303|pmid=12816643|pmc=1691371}}</ref><ref>{{cite journal|last1=Teyssèdre|first1=A.|last2=Couvet|first2=D.|year=2007|title=Expected impact of agriculture expansion on the global avifauna|journal=C. R. Biologies|volume=30|issue=3|pages=247–254|doi=10.1016/j.crvi.2007.01.003|pmid=17434119|url=https://comptes-rendus.academie-sciences.fr/biologies/articles/10.1016/j.crvi.2007.01.003/|access-date=2023-10-05|archive-date=2023-10-30|archive-url=https://web.archive.org/web/20231030161043/https://comptes-rendus.academie-sciences.fr/biologies/articles/10.1016/j.crvi.2007.01.003/|url-status=live}}</ref>

Other, related human causes of the extinction event include [[deforestation]], hunting, pollution,<ref>{{cite web|date=2008-11-06|website=[[Reuters]]|url=https://www.reuters.com/article/us-extinct-idUSTRE4A501920081106|title=Measuring extinction, species by species|access-date=2010-05-20 |archive-url=https://web.archive.org/web/20130502002359/http://www.reuters.com/article/2008/11/06/us-extinct-idUSTRE4A501920081106 |archive-date=2013-05-02|url-status=live}}</ref> the introduction in various regions of [[Invasive species|non-native species]], and the [[globalization and disease|widespread]] [[transmission (medicine)|transmission]] of [[infectious disease]]s spread through livestock and crops.<ref name=lawton95/>

==== Agriculture and climate change ====
[[File:Operação Hymenaea, Julho-2016 (29399454651).jpg|thumb|[[Deforestation of the Amazon rainforest|Deforestation]] in the [[Maranhão]] state, Brazil, in July 2016]]
Recent investigations into the practice of landscape burning during the [[Neolithic Revolution]] have a major implication for the current debate about the timing of the Anthropocene and the role that humans may have played in the production of greenhouse gases prior to the [[Industrial Revolution]].<ref name="Ruddiman-2009" /> Studies of early hunter-gatherers raise questions about the current use of population size or density as a [[Proxy (climate)|proxy]] for the amount of land clearance and anthropogenic burning that took place in pre-industrial times.<ref name="Lynch-2011">{{Cite web|url=https://climate.nasa.gov/news/649/|title=Secrets from the past point to rapid climate change in the future|last=Lynch|first=Patrick|date=15 December 2011|publisher=NASA's Earth Science News Team|access-date=2 April 2016|archive-date=29 June 2016|archive-url=https://web.archive.org/web/20160629173812/https://climate.nasa.gov/news/649/|url-status=live}}</ref><ref name="Ruddiman-2013">{{Cite journal|last=Ruddiman|first=W.F.|date=2013|title=The Anthropocene|journal=Annual Review of Earth and Planetary Sciences|volume=41|pages=45–68|doi=10.1146/annurev-earth-050212-123944|bibcode=2013AREPS..41...45R}}</ref> Scientists have questioned the correlation between population size and early territorial alterations.<ref name="Ruddiman-2013" /> Ruddiman and Ellis' research paper in 2009 makes the case that early farmers involved in systems of agriculture used more land per capita than growers later in the Holocene, who intensified their labor to produce more food per unit of area (thus, per laborer); arguing that agricultural involvement in rice production implemented thousands of years ago by relatively small populations created significant environmental impacts through large-scale means of deforestation.<ref name="Ruddiman-2009" />

While a number of human-derived factors are recognized as contributing to rising atmospheric concentrations of CH<sub>4</sub> (methane) and CO<sub>2</sub> (carbon dioxide), deforestation and territorial clearance practices associated with agricultural development may have contributed most to these concentrations globally in earlier millennia.<ref name="Cruzten-2002" /><ref name="Ruddiman-2009" /><ref name="Tollefson-2011" /> Scientists that are employing a variance of [[Archaeology|archaeological]] and paleoecological data argue that the processes contributing to substantial human modification of the environment spanned many thousands of years on a global scale and thus, not originating as late as the [[Industrial Revolution]]. Palaeoclimatologist [[William Ruddiman]] has argued that in the early Holocene 11,000 years ago, atmospheric carbon dioxide and methane levels fluctuated in a pattern which was different from the Pleistocene epoch before it.<ref name="Ruddiman-2003"/><ref name="Lynch-2011" /><ref name="Tollefson-2011">{{Cite journal|last=Tollefson|first=Jeff|date=2011-03-25|title=The 8,000-year-old climate puzzle|url=http://www.nature.com/news/2011/110325/full/news.2011.184.html|journal=Nature News|doi=10.1038/news.2011.184|doi-access=free|access-date=2016-04-08|archive-date=2021-03-08|archive-url=https://web.archive.org/web/20210308145040/https://www.nature.com/news/2011/110325/full/news.2011.184.html|url-status=live}}</ref> He argued that the patterns of the significant decline of CO<sub>2</sub> levels during the last ice age of the Pleistocene inversely correlate to the Holocene where there have been dramatic increases of CO<sub>2</sub> around 8000 years ago and CH<sub>4</sub> levels 3000 years after that.<ref name="Tollefson-2011" /> The correlation between the decrease of CO<sub>2</sub> in the Pleistocene and the increase of it during the [[Holocene]] implies that the causation of this spark of greenhouse gases into the atmosphere was the growth of [[Agriculture|human agriculture]] during the Holocene.<ref name="Ruddiman-2003"/><ref name="Tollefson-2011" />

===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>