Preprints
https://doi.org/10.5194/tc-2022-213
https://doi.org/10.5194/tc-2022-213
09 Nov 2022
 | 09 Nov 2022
Status: a revised version of this preprint was accepted for the journal TC and is expected to appear here in due course.

Cosmogenic-nuclide data from Antarctic nunataks can constrain past ice sheet sensitivity to marine ice margin instabilities

Anna Ruth Weston Halberstadt, Greg Balco, Hannah Buchband, and Perry Spector

Abstract. We apply geologic evidence from ice-free areas in Antarctica to evaluate model simulations of ice sheet response to warm climates. This is important because such simulations are used to predict ice sheet behaviour in future warm climates, but geologic evidence of smaller-than-present past ice sheets is buried under the present ice sheet and therefore generally unavailable for model benchmarking. We leverage an alternative accessible geologic dataset for this purpose: cosmogenic-nuclide concentrations in bedrock surfaces of interior nunataks. These data produce a frequency distribution of ice thickness over multimillion-year periods, which is also simulated by ice sheet modeling. End-member transient models parameterized with strong and weak marine ice sheet instability processes, which predict large and small sea-level impacts during warm periods, also predict contrasting and distinct frequency distributions of ice thickness. We identify regions of Antarctica where predicted frequency distributions are diagnostic of marine ice sheet instability parameterizations. We then show that a single comprehensive data set from one bedrock site in West Antarctica is sufficiently detailed to show that the data are consistent only with a weak marine ice sheet instability end-member, but other less extensive data sets are insufficient and/or ambiguous. Finally, we highlight locations where collecting additional data could constrain the amplitude of past and therefore future response to warm climates.

Anna Ruth Weston Halberstadt et al.

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2022-213', Anonymous Referee #1, 21 Dec 2022
    • AC1: 'Reply on RC1', Anna Ruth Halberstadt, 25 Jan 2023
  • RC2: 'Comment on tc-2022-213', Jorge Bernales, 01 Jan 2023
    • AC2: 'Reply on RC2', Anna Ruth Halberstadt, 21 Feb 2023

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2022-213', Anonymous Referee #1, 21 Dec 2022
    • AC1: 'Reply on RC1', Anna Ruth Halberstadt, 25 Jan 2023
  • RC2: 'Comment on tc-2022-213', Jorge Bernales, 01 Jan 2023
    • AC2: 'Reply on RC2', Anna Ruth Halberstadt, 21 Feb 2023

Anna Ruth Weston Halberstadt et al.

Data sets

5 million year transient Antarctic ice sheet model run with "sensitized" marine ice margin instabilities Balco, G., Buchband, H., & Halberstadt, A. R. https://doi.org/10.15784/601602

5 million year transient Antarctic ice sheet model run with "desensitized" marine ice margin instabilities Balco, G., Buchband, H., & Halberstadt, A. R. https://doi.org/10.15784/601601

Anna Ruth Weston Halberstadt et al.

Viewed

Total article views: 377 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
256 106 15 377 4 5
  • HTML: 256
  • PDF: 106
  • XML: 15
  • Total: 377
  • BibTeX: 4
  • EndNote: 5
Views and downloads (calculated since 09 Nov 2022)
Cumulative views and downloads (calculated since 09 Nov 2022)

Viewed (geographical distribution)

Total article views: 372 (including HTML, PDF, and XML) Thereof 372 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 26 Mar 2023
Download
Short summary
This paper explores the use of multi-million-year exposure ages from Antarctic bedrock outcrops to benchmark ice sheet model predictions and thereby infer ice sheet sensitivity to warm climates. We describe a new approach for model/data comparison, highlight an example where observational data are used to distinguish end member models, and provide guidance for targeted sampling around Antarctica that can improve understanding of ice sheet response to climate warming in the past and future.