The DeepMIP contribution to PMIP4: methodologies for selection, compilation and analysis of latest Paleocene and early Eocene climate proxy data, incorporating version 0.1 of the DeepMIP database

Abstract

Abstract. The early Eocene (56 to 48 million years ago) is inferred to have been the most recent time that Earth's atmospheric CO2 concentrations exceeded 1000 ppm. Global mean temperatures were also substantially warmer than present day. As such, study of early Eocene climate provides insight into how a super-warm Earth system behaves and offers an opportunity to evaluate climate models under conditions of high greenhouse gas forcing. The Deep Time Model Intercomparison Project (DeepMIP) is a systematic model-model and model-data intercomparison of three early Paleogne time slices: latest Paleocene, Paleocene-Eocene thermal maximum and early Eocene climatic optimum. A previous article outlined the model experimental design for climate model simulations. In this article, we outline the methodologies to be used for the compilation and analysis of climate proxy data, primarily proxies for temperature and CO2. This paper establishes the protocols for a concerted and coordinated effort to compile the climate proxy records across a wide geographic range. The resulting climate atlas will be used to constrain and evaluate climate models for the three selected time intervals, and provide insights into the mechanisms that control these warm climate states. We provide version 0.1 of this database, in anticipation that this will be expanded in subsequent publications.

Terrestrial environmental change across the onset of the PETM and the associated impact on biomarker proxies: A cautionary tale

“…Branched GDGT-derived MAAT estimates from the lower laminated lignite pre-PETM Figure 4a; Table 1), in agreement with existing proxy-based CO2 estimates for the PETM (Hollis et al, 2019). They also agree with climate model simulations which have modified specific model parameters (e.g.…”

“…The marine realm also indicates increasing temperatures in northern Europe during the PETM, with evidence for 3 to 4°C of surface ocean warming in both the Bay of Biscay (Bornemann et al, 2014) and the North Sea (Schoon et al, 2015). Decreasing terrestrial temperatures also differ from the global response during the PETM (Hollis et al, 2019;Jones et al, 2013;McInerney and Wing, 2011). Collectively, this implies that the biomarker-based paleotemperature proxies in the upper laminated lignite and blocky lignite are impacted by non-thermal influences or ecological signals; below we explore what these controls may be.…”

A geochemical and biostratigraphic approach to investigating regional changes in sandstone composition through time; an example from Paleocene–Eocene strata, Taranaki Basin, New Zealand

“…The Taranaki basement map is modified from Tulloch & Mortimer (2017) and palaeogeography maps modified from Strogen (2011). The Palaeogene palaeoclimate estimate is based on TEX 86 H records for New Zealand (red dashed line being the 3-point moving average), which is a proxy for sea surface temperature, from Hollis et al (2019).…”

Bayesian calibration of the Mg/Ca paleothermometer in planktic foraminifera

“…For ⌦, we test two assumptions: 1) that the foraminifera are essentially pristine, unaltered by seafloor dissolution (⌦ = 5), and 2) that the foraminifera have experienced dissolution on par with what we would expect at the site locations today. For this latter assumption, we draw ⌦ from GLODAPv2 using the paleolatitude and paleolongitude (calculated from Baatsen et al (2016), as suggested in C. Hollis et al (2019)) and the inferred Eocene water depth as described in the original publication. We use an uninformative prior standard deviation of 10 C. (Wara et al, 2005).…”

“…J. Hollis et al, 2009C. J. Hollis et al, , 2012Bijl et al, 2013;Inglis et al, 2015;Cramwinckel et al, 2018) calibrated with BAYSPAR (Tierney & Tingley, 2014;C. Hollis et al, 2019) (Fig.…”