NSFGEO-NERC: Collaborative Research: How important are sea-level feedbacks in stabilizing marine-based ice streams?
Lead Research Organisation:
University of Stirling
Department Name: Biological and Environmental Sciences
Abstract
The purpose of the proposed research is to investigate the importance of sea-level feedbacks (SLF) in stabilizing marine-based ice sheets during their retreat. The proposed investigation will combine new late Pleistocene/Holocene relative sea-level constraints to be collected from raised shorelines, existing
offshore marine cores, and isolation basins from across northwestern Scotland to refine the glacial isostatic adjustment (GIA) models for the British Isles. The proposal will also investigate SLF feedbacks at a more local level and at the scale of a Late Pleistocene ice stream that once flowed through the Minch of northwestern Scotland. Specifically, we will test three hypotheses: 1.) SLF did not provide a stabilizing influence for the Minch Ice Stream during its retreat following the Last Glacial Maximum, 2.) along indented ice-sheet margins, SLF are governed not by the local ice front but by the regional GIA signal, and 3.) the influence of SLF in stabilizing marine ice streams is a function of the rheology of the Earth beneath it.
One of the largest uncertainties related to future projections of sea-level rise is the influence of ice sheets. Model projections differ by as much as 2 m over the next 100 years depending on how existing ice sheets behave with respect to ongoing sea-level rise and warming. Our understanding of the feedbacks between ice sheet behavior and sea-level changes at the scale of extant ice streams of concern (e.g. Thwaites Glacier in Antarctica, Jakobshavn Isbrae in Greenland) is limited to numerical models that have rarely been tested against real-world examples at decadal to century time-scales. The retreat of ice streams following the Last Glacial Maximum provides an excellent test ground for the factors controlling the behavior of ice streams during their retreat. The data generated as part of this project will not only examine ice-sheet behavior but also contribute to GIA models used to predict future sea-level changes and past studies of climate, paleogeography, and archeology. It will also provide some of the first absolute ages on raised shorelines across northwestern Scotland.
offshore marine cores, and isolation basins from across northwestern Scotland to refine the glacial isostatic adjustment (GIA) models for the British Isles. The proposal will also investigate SLF feedbacks at a more local level and at the scale of a Late Pleistocene ice stream that once flowed through the Minch of northwestern Scotland. Specifically, we will test three hypotheses: 1.) SLF did not provide a stabilizing influence for the Minch Ice Stream during its retreat following the Last Glacial Maximum, 2.) along indented ice-sheet margins, SLF are governed not by the local ice front but by the regional GIA signal, and 3.) the influence of SLF in stabilizing marine ice streams is a function of the rheology of the Earth beneath it.
One of the largest uncertainties related to future projections of sea-level rise is the influence of ice sheets. Model projections differ by as much as 2 m over the next 100 years depending on how existing ice sheets behave with respect to ongoing sea-level rise and warming. Our understanding of the feedbacks between ice sheet behavior and sea-level changes at the scale of extant ice streams of concern (e.g. Thwaites Glacier in Antarctica, Jakobshavn Isbrae in Greenland) is limited to numerical models that have rarely been tested against real-world examples at decadal to century time-scales. The retreat of ice streams following the Last Glacial Maximum provides an excellent test ground for the factors controlling the behavior of ice streams during their retreat. The data generated as part of this project will not only examine ice-sheet behavior but also contribute to GIA models used to predict future sea-level changes and past studies of climate, paleogeography, and archeology. It will also provide some of the first absolute ages on raised shorelines across northwestern Scotland.
Organisations
People |
ORCID iD |
| Tom Bradwell (Principal Investigator) |
| Description | Online invited talk/presentation: March 2023 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Public/other audiences |
| Results and Impact | I gave an invited talk (online) for the NW Highlands Geoheritage Festival talk series on March 2nd 2023 (at 19:30). 100 members of the public attended / tuned in remotely. Attendance was capped at 100 owing to Zoom license restrictions. The talk lasted 45 mins and was followed by 15-20 mins of questions from members of the public. The talk was recorded and has been posted online. The talk was aimed at the public but made specific mention to new work we have done / will be doing as part of the NSF-NERC funded research project. The Geopark staff reported an increase in interest and enquiries from the public in the days after the talk. I have made plans for future related activity including giving a further talk in person (in the summer); conducting fieldwork in different areas following feedback; and engaging with local community officers and Geopark staff about the NERC funded project. |
| Year(s) Of Engagement Activity | 2023 |
| URL | https://www.nwhgeopark.com/geoheritage-festival-talks/ |
| Description | Short talk and Scientific Field Excursion (Ullapool, Wester Ross) |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | 30-50 people attended a talk (Ullapool High School) followed by a 2-3 day scientific excursion, including key sites involved in the NSF-NERC Research project. Myself and 4 other Project PIs were involved in this event (May 2023). |
| Year(s) Of Engagement Activity | 2023 |