Preprints
https://doi.org/10.5194/egusphere-2023-2738
https://doi.org/10.5194/egusphere-2023-2738
04 Dec 2023
 | 04 Dec 2023

Climate variability, heat distribution and polar amplification in the unipolar ‘doubthouse’ of the Oligocene

Dominique K. L. L. Jenny, Tammo Reichgelt, Charlotte L. O'Brien, Xiaoqing Liu, Peter K. Bijl, Matthew Huber, and Appy Sluijs

Abstract. The Oligocene (33.9–23.03 Ma) was characterised by generally warm climates, with flattened meridional temperature gradients while Antarctica retained a significant cryosphere. This makes the Oligocene an imperfect analogue to long-term future climate states with unipolar icehouse conditions. Although local and regional climate and environmental reconstructions of Oligocene conditions are available, the community lacks synthesis of regional reconstructions. In order to provide a comprehensive overview of marine and terrestrial climate and environmental conditions in the Oligocene, as well as a reconstruction of trends through time, we here review marine and terrestrial proxy records and numerical climate model simulations of the Oligocene. Results display weaker temperature gradients during the Oligocene compared to modern times, with generally warm poles and colder-than-modern temperatures around the equator. Sea surface temperatures (SSTs) show similar trends to the land temperatures, with warm temperatures around the mid and high latitudes (~60–90°) of especially the Southern Hemisphere. Vegetation-based precipitation reconstructions of the Oligocene suggest drier conditions compared to modern times, in particular around the equator. When compared to proxy-based data, climate modelling approaches overestimate Oligocene precipitation in most areas, in particular the tropics. Temperature around the mid to high latitudes is generally underestimated in models compared to proxy data and tend to overestimate the warming in the tropics. In line with previous conclusions models underestimate polar amplification and the equator-to-pole heat distribution that prevailed during the Oligocene. Despite prevalent glaciation on Antarctica, the Oligocene “icehouse” experienced warm global average temperatures while still maintaining a unipolar icehouse state.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Dominique K. L. L. Jenny, Tammo Reichgelt, Charlotte L. O'Brien, Xiaoqing Liu, Peter K. Bijl, Matthew Huber, and Appy Sluijs

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2738', Anonymous Referee #1, 15 Jan 2024
    • AC1: 'Reply on RC1', Dominique Jenny, 16 Feb 2024
  • RC2: 'Comment on egusphere-2023-2738', Anonymous Referee #2, 17 Jan 2024
    • AC2: 'Reply on RC2', Dominique Jenny, 16 Feb 2024
  • EC1: 'Comment on egusphere-2023-2738', Gerilyn (Lynn) Soreghan, 20 Jan 2024

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2738', Anonymous Referee #1, 15 Jan 2024
    • AC1: 'Reply on RC1', Dominique Jenny, 16 Feb 2024
  • RC2: 'Comment on egusphere-2023-2738', Anonymous Referee #2, 17 Jan 2024
    • AC2: 'Reply on RC2', Dominique Jenny, 16 Feb 2024
  • EC1: 'Comment on egusphere-2023-2738', Gerilyn (Lynn) Soreghan, 20 Jan 2024
Dominique K. L. L. Jenny, Tammo Reichgelt, Charlotte L. O'Brien, Xiaoqing Liu, Peter K. Bijl, Matthew Huber, and Appy Sluijs
Dominique K. L. L. Jenny, Tammo Reichgelt, Charlotte L. O'Brien, Xiaoqing Liu, Peter K. Bijl, Matthew Huber, and Appy Sluijs

Viewed

Total article views: 655 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
440 177 38 655 24 21
  • HTML: 440
  • PDF: 177
  • XML: 38
  • Total: 655
  • BibTeX: 24
  • EndNote: 21
Views and downloads (calculated since 04 Dec 2023)
Cumulative views and downloads (calculated since 04 Dec 2023)

Viewed (geographical distribution)

Total article views: 654 (including HTML, PDF, and XML) Thereof 654 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 15 Jul 2024
Download
Short summary
This study reviews the current state of knowledge regarding the Oligocene “icehouse” climate. We extend an existing marine climate proxy data compilation and present a new compilation and analysis of terrestrial plant assemblages to assess long-term climate trends and variability. Our data-climate model comparison reinforces the notion that models underestimate polar amplification of Oligocene climates and identify potential future research directions.