The role of atmospheric CO2 in controlling sea surface temperature change during the Pliocene
Journal
Climate of the Past
Journal Volume
20
Journal Issue
5
Start Page
1177
End Page
1194
ISSN
1814-9332
Date Issued
2024-05-17
Author(s)
Burton, Lauren E.
Haywood, Alan M.
Tindall, Julia C.
Dolan, Aisling M.
Hill, Daniel J.
McClymont, Erin L.
Ford, Heather L.
DOI
10.5194/cp-20-1177-2024
Abstract
We present the role of CO2 forcing in controlling Late Pliocene sea surface temperature (SST) change using six models from Phase 2 of the Pliocene Model Intercomparison Project (PlioMIP2) and palaeoclimate proxy data from the PlioVAR working group. At a global scale, SST change in the Late Pliocene relative to the pre-industrial is predominantly driven by CO2 forcing in the low and mid-latitudes and non-CO2 forcing in the high latitudes. We find that CO2 is the dominant driver of SST change at the vast majority of proxy data sites assessed (17 out of 19), but the relative dominance of this forcing varies between all proxy sites, with CO2 forcing accounting for between 27% and 82% of the total change seen. The dearth of proxy data sites in the high latitudes means that only two sites assessed here are predominantly forced by non-CO2 forcing (such as changes to ice sheets and orography), both of which are in the North Atlantic Ocean. We extend the analysis to show the seasonal patterns of SST change and its drivers at a global scale and at a site-specific level for three chosen proxy data sites. We also present a new estimate of Late Pliocene climate sensitivity using site-specific proxy data values. This is the first assessment of site-specific drivers of SST change in the Late Pliocene and highlights the strengths of using palaeoclimate proxy data alongside model outputs to further develop our understanding of the Late Pliocene. We use the best available proxy and model data, but the sample sizes remain limited, and the confidence in our results would be improved with greater data availability.
Subjects
climate forcing
climate modeling
environmental assessment
midlatitude environment
paleoclimate
Pliocene
proxy climate record
sea surface temperature
Publisher
Copernicus GmbH
Type
journal article