Editing Climate variability and change (section)

=== Paleo-eocene thermal maximum ===
[[File:65 Myr Climate Change.png|thumb|upright=1.35|right|Climate changes over the past 65 million years, using proxy data including [[Oxygen-18]] ratios from [[foraminifera]].]]
The [[Paleocene–Eocene Thermal Maximum]] (PETM) was a time period with more than 5–8&nbsp;°C global average temperature rise across the event.<ref name="McInherney-2011">{{cite journal|author=McInherney, F.A..|author2=Wing, S.|year=2011|title=A perturbation of carbon cycle, climate, and biosphere with implications for the future|url=http://www.whoi.edu/fileserver.do?id=136084&pt=2&p=148709|journal=Annual Review of Earth and Planetary Sciences|volume=39|issue=1 |pages=489–516|bibcode=2011AREPS..39..489M|doi=10.1146/annurev-earth-040610-133431|access-date=26 October 2019|archive-date=14 September 2016|archive-url=https://web.archive.org/web/20160914003526/http://www.whoi.edu/fileserver.do?id=136084&pt=2&p=148709|url-status=live|url-access=subscription}}</ref> This climate event occurred at the time boundary of the [[Paleocene]] and [[Eocene]] geological [[Epoch (geology)|epochs]].<ref name="Evans-2008">{{cite journal|author=Westerhold, T..|author2=Röhl, U.|author3=Raffi, I.|author4=Fornaciari, E.|author5=Monechi, S.|author6=Reale, V.|author7=Bowles, J.|author8=Evans, H. F.|year=2008|title=Astronomical calibration of the Paleocene time|url=https://www.geo.arizona.edu/~reiners/fortransfer6/WesterholdEtAl_PPP2008.pdf |archive-url=https://web.archive.org/web/20170809094938/http://www.geo.arizona.edu/~reiners/fortransfer6/WesterholdEtAl_PPP2008.pdf |archive-date=2017-08-09 |url-status=live|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume=257|issue=4|pages=377–403|bibcode=2008PPP...257..377W|doi=10.1016/j.palaeo.2007.09.016}}</ref> During the event large amounts of [[methane]] was released, a potent greenhouse gas.{{Sfn|Burroughs|2007|p=|pp=190–91}} The PETM represents a "case study" for modern climate change as in the greenhouse gases were released in a geologically relatively short amount of time.<ref name="McInherney-2011"/> During the PETM, a mass extinction of organisms in the deep ocean took place.<ref>{{Cite journal|last1=Ivany|first1=Linda C.|last2=Pietsch|first2=Carlie|last3=Handley|first3=John C.|last4=Lockwood|first4=Rowan|last5=Allmon|first5=Warren D.|last6=Sessa|first6=Jocelyn A.|date=1 September 2018|title=Little lasting impact of the Paleocene-Eocene Thermal Maximum on shallow marine molluscan faunas|journal=Science Advances|language=en|volume=4|issue=9|pages=eaat5528|doi=10.1126/sciadv.aat5528|issn=2375-2548|pmid=30191179|pmc=6124918|bibcode=2018SciA....4.5528I}}</ref>