Editing Climate variability and change (section)

==== Orbital variations ====
[[File:MilankovitchCyclesOrbitandCores.png|thumb|left|upright=1.35|Milankovitch cycles from 800,000 years ago in the past to 800,000 years in the future.]]
Slight variations in Earth's motion lead to changes in the seasonal distribution of sunlight reaching the Earth's surface and how it is distributed across the globe. There is very little change to the area-averaged annually averaged sunshine; but there can be strong changes in the geographical and seasonal distribution. The three types of [[Kinematics|kinematic]] change are variations in Earth's [[Orbital eccentricity|eccentricity]], changes in [[axial tilt|the tilt angle of Earth's axis of rotation]], and [[precession]] of Earth's axis. Combined, these produce [[Milankovitch cycles]] which affect climate and are notable for their correlation to [[glacial period|glacial]] and [[interglacial period]]s,<ref name="UniMontana">{{cite web |url=http://www.homepage.montana.edu/~geol445/hyperglac/time1/milankov.htm|archive-url=https://web.archive.org/web/20110716144130/http://www.homepage.montana.edu/~geol445/hyperglac/time1/milankov.htm|archive-date=16 July 2011|title= Milankovitch Cycles and Glaciation|access-date=2 April 2009 |publisher= University of Montana}}</ref> their correlation with the advance and retreat of the [[Sahara]],<ref name="UniMontana"/> and for their [[cyclostratigraphy|appearance]] in the [[geologic record|stratigraphic record]].<ref>{{cite journal |doi=10.1111/j.1365-3121.1989.tb00403.x|title=A Milankovitch scale for Cenomanian time|year=1989|author=Gale, Andrew S. |journal=Terra Nova |volume=1|pages=420–25|issue=5|bibcode=1989TeNov...1..420G}}</ref><ref>{{cite web|title=Same forces as today caused climate changes 1.4 billion years ago|url=http://www.sdu.dk/en/Om_SDU/Fakulteterne/Naturvidenskab/Nyheder/2015_03_10_climate_cycles|website=sdu.dk|publisher=University of Denmark.|url-status=dead|archive-url=https://web.archive.org/web/20150312163250/http://www.sdu.dk/en/Om_SDU/Fakulteterne/Naturvidenskab/Nyheder/2015_03_10_climate_cycles|archive-date=12 March 2015}}</ref>

During the glacial cycles, there was a high correlation between {{CO2}} concentrations and temperatures. Early studies indicated that {{CO2}} concentrations lagged temperatures, but it has become clear that this is not always the case.<ref name="van Nes-2015">{{Cite journal|last1=van Nes|first1=Egbert H.|last2=Scheffer|first2=Marten|last3=Brovkin|first3=Victor|last4=Lenton|first4=Timothy M.|last5=Ye|first5=Hao|last6=Deyle|first6=Ethan|last7=Sugihara|first7=George|date=2015|title=Causal feedbacks in climate change|journal=Nature Climate Change|language=en|volume=5|issue=5|pages=445–48|doi=10.1038/nclimate2568|bibcode=2015NatCC...5..445V|issn=1758-6798}}</ref> When ocean temperatures increase, the [[solubility]] of {{CO2}} decreases so that it is released from the ocean. The exchange of {{CO2}} between the air and the ocean can also be impacted by further aspects of climatic change.<ref>[http://archive.ipcc.ch/publications_and_data/ar4/wg1/en/ch6s6-4.html Box 6.2: What Caused the Low Atmospheric Carbon Dioxide Concentrations During Glacial Times?] {{Webarchive|url=https://web.archive.org/web/20230108231413/https://archive.ipcc.ch/publications_and_data/ar4/wg1/en/ch6s6-4.html |date=8 January 2023 }} in {{Harvnb|IPCC AR4 WG1|2007}} .</ref> These and other self-reinforcing processes allow small changes in Earth's motion to have a large effect on climate.<ref name="van Nes-2015" />