title: Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation.
abstract: The covariation of carbon dioxide (CO(2)) concentration and temperature in Antarctic ice-core records suggests a close link between CO(2) and climate during the Pleistocene ice ages. The role and relative importance of CO(2) in producing these climate changes remains unclear, however, in part because the ice-core deuterium record reflects local rather than global temperature. Here we construct a record of global surface temperature from 80 proxy records and show that temperature is correlated with and generally lags CO(2) during the last (that is, the most recent) deglaciation. Differences between the respective temperature changes of the Northern Hemisphere and Southern Hemisphere parallel variations in the strength of the Atlantic meridional overturning circulation recorded in marine sediments. These observations, together with transient global climate model simulations, support the conclusion that an antiphased hemispheric temperature response to ocean circulation changes superimposed on globally in-phase warming driven by increasing CO(2) concentrations is an explanation for much of the temperature change at the end of the most recent ice age.
authors.affiliation: Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, USA. shakun@fas.harvard.edu
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Shakun
authors.forename: Peter U
authors.initials: PU
authors.lastname: Clark
authors.forename: Feng
authors.initials: F
authors.lastname: He
authors.forename: Shaun A
authors.initials: SA
authors.lastname: Marcott
authors.forename: Alan C
authors.initials: AC
authors.lastname: Mix
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Liu
authors.forename: Bette
authors.initials: B
authors.lastname: Otto-Bliesner
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmittner
authors.forename: Edouard
authors.initials: E
authors.lastname: Bard
mesh_terms: D000864:Antarctic Regions; D001272:Atmosphere / Q000737:chemistry; D002245:Carbon Dioxide / Q000032:analysis*; D005580:Fossils; D005843:Geography; D019015:Geologic Sediments / Q000737:chemistry; D057232:Global Warming / Q000706:statistics & numerical data*; D006116:Greenland; D049690:History, Ancient; D046448:Ice Cover; D008962:Models, Theoretical; D009010:Monte Carlo Method; D011058:Pollen; D012623:Seawater / Q000032:analysis; D013696:Temperature; D035501:Uncertainty
chemical_list: D002245:Carbon Dioxide