title: On the identification of a Pliocene time slice for data-model comparison.
abstract: The characteristics of the mid-Pliocene warm period (mPWP: 3.264-3.025 Ma BP) have been examined using geological proxies and climate models. While there is agreement between models and data, details of regional climate differ. Uncertainties in prescribed forcings and in proxy data limit the utility of the interval to understand the dynamics of a warmer than present climate or evaluate models. This uncertainty comes, in part, from the reconstruction of a time slab rather than a time slice, where forcings required by climate models can be more adequately constrained. Here, we describe the rationale and approach for identifying a time slice(s) for Pliocene environmental reconstruction. A time slice centred on 3.205 Ma BP (3.204-3.207 Ma BP) has been identified as a priority for investigation. It is a warm interval characterized by a negative benthic oxygen isotope excursion (0.21-0.23‰) centred on marine isotope stage KM5c (KM5.3). It occurred during a period of orbital forcing that was very similar to present day. Climate model simulations indicate that proxy temperature estimates are unlikely to be significantly affected by orbital forcing for at least a precession cycle centred on the time slice, with the North Atlantic potentially being an important exception.
authors.affiliation: School of Earth and Environment, University of Leeds, , Woodhouse Lane, Leeds LS2 9JT, UK.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Haywood
authors.forename: Aisling M
authors.initials: AM
authors.lastname: Dolan
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Pickering
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Dowsett
authors.forename: Erin L
authors.initials: EL
authors.lastname: McClymont
authors.forename: Caroline L
authors.initials: CL
authors.lastname: Prescott
authors.forename: Ulrich
authors.initials: U
authors.lastname: Salzmann
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hill
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Hunter
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Lunt
authors.forename: James O
authors.initials: JO
authors.lastname: Pope
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Valdes
keywords: Earth system sensitivity; Pliocene; climate models; climate sensitivity
references.citation: Science. 2010 Jun 18;328(5985):1550-3
references.pmid: 20558716
references.citation: Nature. 2008 Aug 28;454(7208):1102-5
references.pmid: 18756254
references.citation: Nature. 2009 Apr 30;458(7242):1158-62
references.pmid: 19407799
references.citation: Science. 2009 Jul 17;325(5938):306-10
references.pmid: 19608915
references.citation: Philos Trans A Math Phys Eng Sci. 2009 Jan 13;367(1886):189-204
references.pmid: 18854302
references.citation: Philos Trans A Math Phys Eng Sci. 2013 Sep 16;371(2001):20130094
references.pmid: 24043868
references.citation: Ann N Y Acad Sci. 2010 Sep;1206:56-79
references.pmid: 20860683
references.citation: Philos Trans A Math Phys Eng Sci. 2009 Jan 13;367(1886):157-68
references.pmid: 18854304
references.citation: Science. 2010 Jun 18;328(5985):1530-4
references.pmid: 20558711
references.citation: Nature. 2006 Jun 1;441(7093):601-5
references.pmid: 16738653
references.citation: Science. 2006 Mar 24;311(5768):1751-3
references.pmid: 16556838
references.citation: Nature. 2009 Mar 19;458(7236):329-32
references.pmid: 19295608
references.citation: Philos Trans A Math Phys Eng Sci. 2011 Mar 13;369(1938):933-56
references.pmid: 21282155
references.citation: Philos Trans A Math Phys Eng Sci. 2013 Sep 16;371(2001):20120524
references.pmid: 24043866
references.citation: Nature. 2009 Mar 19;458(7236):322-8
references.pmid: 19295607
references.citation: Science. 2005 Jul 29;309(5735):758-61
references.pmid: 15976271