1
|
Bamber JL, Oppenheimer M, Kopp RE, Aspinall WP, Cooke RM. Ice Sheet and Climate Processes Driving the Uncertainty in Projections of Future Sea Level Rise: Findings From a Structured Expert Judgement Approach. Earths Future 2022; 10:e2022EF002772. [PMID: 36590456 PMCID: PMC9787588 DOI: 10.1029/2022ef002772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 08/31/2022] [Accepted: 09/16/2022] [Indexed: 06/17/2023]
Abstract
The ice sheets covering Antarctica and Greenland present the greatest uncertainty in, and largest potential contribution to, future sea level rise. The uncertainty arises from a paucity of suitable observations covering the full range of ice sheet behaviors, incomplete understanding of the influences of diverse processes, and limitations in defining key boundary conditions for the numerical models. To investigate the impact of these uncertainties on ice sheet projections we undertook a structured expert judgement study. Here, we interrogate the findings of that study to identify the dominant drivers of uncertainty in projections and their relative importance as a function of ice sheet and time. We find that for the 21st century, Greenland surface melting, in particular the role of surface albedo effects, and West Antarctic ice dynamics, specifically the role of ice shelf buttressing, dominate the uncertainty. The importance of these effects holds under both a high-end 5°C global warming scenario and another that limits global warming to 2°C. During the 22nd century the dominant drivers of uncertainty shift. Under the 5°C scenario, East Antarctic ice dynamics dominate the uncertainty in projections, driven by the possible role of ice flow instabilities. These dynamic effects only become dominant, however, for a temperature scenario above the Paris Agreement 2°C target and beyond 2100. Our findings identify key processes and factors that need to be addressed in future modeling and observational studies in order to reduce uncertainties in ice sheet projections.
Collapse
Affiliation(s)
- J. L. Bamber
- School of Geographical SciencesUniversity of BristolBristolUK
- Department of Aerospace and GeodesyData Science in Earth ObservationTechnical University of MunichMunichGermany
| | - M. Oppenheimer
- Department of Geosciences and the School of Public and International AffairsPrinceton UniversityPrincetonNJUSA
| | - R. E. Kopp
- Department of Earth & Planetary SciencesInstitute of Earth, Ocean, and Atmospheric SciencesRutgers UniversityNew BrunswickNJUSA
| | - W. P. Aspinall
- School of Earth SciencesUniversity of BristolBristolUK
- Aspinall & AssociatesTisburyUK
| | - Roger M. Cooke
- Resources for the FutureWashingtonDCUSA
- Department of MathematicsDelft University of TechnologyDelftThe Netherlands
| |
Collapse
|
2
|
Vishwakarma BD, Royston S, Riva REM, Westaway RM, Bamber JL. Sea Level Budgets Should Account for Ocean Bottom Deformation. Geophys Res Lett 2020; 47:e2019GL086492. [PMID: 33288970 PMCID: PMC7687171 DOI: 10.1029/2019gl086492] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/13/2020] [Accepted: 01/14/2020] [Indexed: 06/12/2023]
Abstract
The conventional sea level budget (SLB) equates changes in sea surface height with the sum of ocean mass and steric change, where solid-Earth movements are included as corrections but limited to the impact of glacial isostatic adjustment. However, changes in ocean mass load also deform the ocean bottom elastically. Until the early 2000s, ocean mass change was relatively small, translating into negligible elastic ocean bottom deformation (OBD), hence neglected in the SLB equation. However, recently ocean mass has increased rapidly; hence, OBD is no longer negligible and likely of similar magnitude to the deep steric sea level contribution. Here, we use a mass-volume framework, which allows the ocean bottom to respond to mass load, to derive a SLB equation that includes OBD. We discuss the theoretical appearance of OBD in the SLB equation and its implications for the global SLB.
Collapse
Affiliation(s)
| | - S. Royston
- School of Geographical SciencesUniversity of BristolBristolUK
| | - R. E. M. Riva
- Faculty of Civil Engineering and GeosciencesDelft University of TechnologyDelftThe Netherlands
| | - R. M. Westaway
- School of Geographical SciencesUniversity of BristolBristolUK
| | - J. L. Bamber
- School of Geographical SciencesUniversity of BristolBristolUK
| |
Collapse
|
3
|
Dukhovskoy DS, Yashayaev I, Proshutinsky A, Bamber JL, Bashmachnikov IL, Chassignet EP, Lee CM, Tedstone AJ. Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic. J Geophys Res Oceans 2019; 124:3333-3360. [PMID: 31341755 PMCID: PMC6618073 DOI: 10.1029/2018jc014686] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 04/08/2019] [Accepted: 04/14/2019] [Indexed: 06/01/2023]
Abstract
The cumulative Greenland freshwater flux anomaly has exceeded 5,000 km3 since the 1990s. The volume of this surplus freshwater is expected to cause substantial freshening in the North Atlantic. Analysis of hydrographic observations in the subpolar seas reveals freshening signals in the 2010s. The sources of this freshening are yet to be determined. In this study, the relationship between the surplus Greenland freshwater flux and this freshening is tested by analyzing the propagation of the Greenland freshwater anomaly and its impact on salinity in the subpolar North Atlantic based on observational data and numerical experiments with and without the Greenland runoff. A passive tracer is continuously released during the simulations at freshwater sources along the coast of Greenland to track the Greenland freshwater anomaly. Tracer budget analysis shows that 44% of the volume of the Greenland freshwater anomaly is retained in the subpolar North Atlantic by the end of the simulation. This volume is sufficient to cause strong freshening in the subpolar seas if it stays in the upper 50-100 m. However, in the model the anomaly is mixed down to several hundred meters of the water column resulting in smaller magnitudes of freshening compared to the observations. Therefore, the simulations suggest that the accelerated Greenland melting would not be sufficient to cause the observed freshening in the subpolar seas and other sources of freshwater have contributed to the freshening. Impacts on salinity in the subpolar seas of the freshwater transport through Fram Strait and precipitation are discussed.
Collapse
Affiliation(s)
- D. S. Dukhovskoy
- Center for Ocean‐Atmospheric Prediction StudiesFlorida State UniversityTallahasseeFLUSA
| | - I. Yashayaev
- Bedford Institute of Oceanography, Fisheries and OceansDartmouthNova ScotiaCanada
| | | | - J. L. Bamber
- Bristol Glaciology Centre, School of Geographical SciencesUniversity of BristolBristolUK
| | - I. L. Bashmachnikov
- Department of Geographical SciencesSaint Petersburg State UniversitySt. PetersburgRussia
- Nansen International Environmental and Remote Sensing CentreSt. PetersburgRussia
| | - E. P. Chassignet
- Center for Ocean‐Atmospheric Prediction StudiesFlorida State UniversityTallahasseeFLUSA
| | - C. M. Lee
- Applied Physics LaboratoryUniversity of WashingtonSeattleWAUSA
| | - A. J. Tedstone
- Bristol Glaciology Centre, School of Geographical SciencesUniversity of BristolBristolUK
| |
Collapse
|
4
|
Bamber JL, Tedstone AJ, King MD, Howat IM, Enderlin EM, van den Broeke MR, Noel B. Land Ice Freshwater Budget of the Arctic and North Atlantic Oceans: 1. Data, Methods, and Results. J Geophys Res Oceans 2018; 123:1827-1837. [PMID: 29938150 PMCID: PMC5993240 DOI: 10.1002/2017jc013605] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 02/15/2018] [Indexed: 06/02/2023]
Abstract
The freshwater budget of the Arctic and sub-polar North Atlantic Oceans has been changing due, primarily, to increased river runoff, declining sea ice and enhanced melting of Arctic land ice. Since the mid-1990s this latter component has experienced a pronounced increase. We use a combination of satellite observations of glacier flow speed and regional climate modeling to reconstruct the land ice freshwater flux from the Greenland ice sheet and Arctic glaciers and ice caps for the period 1958-2016. The cumulative freshwater flux anomaly exceeded 6,300 ± 316 km3 by 2016. This is roughly twice the estimate of a previous analysis that did not include glaciers and ice caps outside of Greenland and which extended only to 2010. From 2010 onward, the total freshwater flux is about 1,300 km3/yr, equivalent to 0.04 Sv, which is roughly 40% of the estimated total runoff to the Arctic for the same time period. Not all of this flux will reach areas of deep convection or Arctic and Sub-Arctic seas. We note, however, that the largest freshwater flux anomalies, grouped by ocean basin, are located in Baffin Bay and Davis Strait. The land ice freshwater flux displays a strong seasonal cycle with summer time values typically around five times larger than the annual mean. This will be important for understanding the impact of these fluxes on fjord circulation, stratification, and the biogeochemistry of, and nutrient delivery to, coastal waters.
Collapse
Affiliation(s)
- J. L. Bamber
- School of Geographical SciencesUniversity of BristolBristolUK
| | - A. J. Tedstone
- School of Geographical SciencesUniversity of BristolBristolUK
| | - M. D. King
- Byrd Polar Research CenterOhio State UniversityColumbusOHUSA
| | - I. M. Howat
- Byrd Polar Research CenterOhio State UniversityColumbusOHUSA
| | - E. M. Enderlin
- School of Earth and Climate SciencesUniversity of MaineOronoMEUSA
| | - M. R. van den Broeke
- Institute for Marine and Atmospheric ResearchUtrecht UniversityUtrechtNetherlands
| | - B. Noel
- Institute for Marine and Atmospheric ResearchUtrecht UniversityUtrechtNetherlands
| |
Collapse
|
5
|
Morlighem M, Williams CN, Rignot E, An L, Arndt JE, Bamber JL, Catania G, Chauché N, Dowdeswell JA, Dorschel B, Fenty I, Hogan K, Howat I, Hubbard A, Jakobsson M, Jordan TM, Kjeldsen KK, Millan R, Mayer L, Mouginot J, Noël BPY, O'Cofaigh C, Palmer S, Rysgaard S, Seroussi H, Siegert MJ, Slabon P, Straneo F, van den Broeke MR, Weinrebe W, Wood M, Zinglersen KB. BedMachine v3: Complete Bed Topography and Ocean Bathymetry Mapping of Greenland From Multibeam Echo Sounding Combined With Mass Conservation. Geophys Res Lett 2017; 44:11051-11061. [PMID: 29263561 PMCID: PMC5726375 DOI: 10.1002/2017gl074954] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 05/11/2023]
Abstract
Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland's marine-terminating glaciers. Here we present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation approach. A new 150 m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface, yielding major improvements over previous data sets, particularly in the marine-terminating sectors of northwest and southeast Greenland. Our map reveals that the total sea level potential of the Greenland ice sheet is 7.42 ± 0.05 m, which is 7 cm greater than previous estimates. Furthermore, it explains recent calving front response of numerous outlet glaciers and reveals new pathways by which AW can access glaciers with marine-based basins, thereby highlighting sectors of Greenland that are most vulnerable to future oceanic forcing.
Collapse
Affiliation(s)
- M. Morlighem
- Department of Earth System ScienceUniversity of CaliforniaIrvineCAUSA
| | - C. N. Williams
- Bristol Glaciology Centre, School of Geographical SciencesUniversity of BristolBristolUK
- Now at British Geological SurveyNottinghamUK
| | - E. Rignot
- Department of Earth System ScienceUniversity of CaliforniaIrvineCAUSA
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - L. An
- Department of Earth System ScienceUniversity of CaliforniaIrvineCAUSA
| | - J. E. Arndt
- Alfred‐Wegener‐Institute, Helmholtz Centre for Polar and Marine ResearchBremerhavenGermany
| | - J. L. Bamber
- Bristol Glaciology Centre, School of Geographical SciencesUniversity of BristolBristolUK
| | - G. Catania
- Institute of GeophysicsUniversity of Texas at AustinAustinTXUSA
| | - N. Chauché
- Department of Geography and Earth ScienceAberystwyth UniversityAberystwythUK
| | - J. A. Dowdeswell
- Scott Polar Research InstituteUniversity of CambridgeCambridgeUK
| | - B. Dorschel
- Alfred‐Wegener‐Institute, Helmholtz Centre for Polar and Marine ResearchBremerhavenGermany
| | - I. Fenty
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - K. Hogan
- British Antarctic SurveyNatural Environment Research CouncilCambridgeUK
| | - I. Howat
- Byrd Polar and Climate Research CenterOhio State UniversityColumbusOHUSA
| | - A. Hubbard
- Department of Geography and Earth ScienceAberystwyth UniversityAberystwythUK
- Centre for Arctic Gas Hydrate, Environment and Climate, Department of GeosciencesUiT The Arctic University of NorwayTromsøNorway
| | - M. Jakobsson
- Department of Geology and GeochemistryStockholm UniversityStockholmSweden
| | - T. M. Jordan
- Bristol Glaciology Centre, School of Geographical SciencesUniversity of BristolBristolUK
| | - K. K. Kjeldsen
- Centre for GeoGenetics, Natural History Museum of DenmarkUniversity of CopenhagenCopenhagenDenmark
- Department of Earth SciencesUniversity of OttawaOttawaOntarioCanada
- Department of Geodesy, DTU Space, National Space InstituteTechnical University of DenmarkKongens LyngbyDenmark
| | - R. Millan
- Department of Earth System ScienceUniversity of CaliforniaIrvineCAUSA
| | - L. Mayer
- Center for Coastal and Ocean MappingUniversity of New HampshireDurhamNHUSA
| | - J. Mouginot
- Department of Earth System ScienceUniversity of CaliforniaIrvineCAUSA
| | - B. P. Y. Noël
- Institute for Marine and Atmospheric Research UtrechtUtrecht UniversityUtrechtNetherlands
| | - C. O'Cofaigh
- Department of GeographyDurham UniversityDurhamUK
| | - S. Palmer
- College of Life and Environmental SciencesUniversity of ExeterExeterUK
| | - S. Rysgaard
- Centre for Earth Observation Science, Department of Environment and GeographyUniversity of ManitobaWinnipegManitobaCanada
- Greenland Institute of Natural ResourcesNuukGreenland
- Arctic Research CentreAarhus UniversityAarhusDenmark
| | - H. Seroussi
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - M. J. Siegert
- Grantham Institute and Department of Earth Science and EngineeringImperial College LondonLondonUK
| | - P. Slabon
- Alfred‐Wegener‐Institute, Helmholtz Centre for Polar and Marine ResearchBremerhavenGermany
| | - F. Straneo
- Department of Physical OceanographyWoods Hole Oceanographic InstitutionWoods HoleMAUSA
| | - M. R. van den Broeke
- Institute for Marine and Atmospheric Research UtrechtUtrecht UniversityUtrechtNetherlands
| | - W. Weinrebe
- Alfred‐Wegener‐Institute, Helmholtz Centre for Polar and Marine ResearchBremerhavenGermany
| | - M. Wood
- Department of Earth System ScienceUniversity of CaliforniaIrvineCAUSA
| | | |
Collapse
|
6
|
Bamber JL, Aspinall WP, Cooke RM. A commentary on "how to interpret expert judgment assessments of twenty-first century sea-level rise" by Hylke de Vries and Roderik SW van de Wal. Clim Change 2016; 137:321-328. [PMID: 32355371 PMCID: PMC7175728 DOI: 10.1007/s10584-016-1672-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 04/01/2016] [Indexed: 05/24/2023]
Abstract
We clarify key aspects of the evaluation, by de Vries and van de Wal (2015), of our expert elicitation paper on the contributions of ice sheet melting to sea level rise due to future global temperature rise scenarios (Bamber and Aspinall 2013), and extend the conversation with further analysis of their proposed approach for combining expert uncertainty judgments.
Collapse
Affiliation(s)
- JL Bamber
- School of Geographical Sciences and Cabot Institute, University of Bristol, Bristol, BS8 1SS UK
| | - WP Aspinall
- School of Earth Sciences and Cabot Institute, University of Bristol, Bristol, BS8 1RJ UK
| | - RM Cooke
- Department of Mathematics, TU Delft, The Netherlands (ret) and Resources for the Future, Washington, DC USA
| |
Collapse
|
7
|
Wouters B, Martin-Espanol A, Helm V, Flament T, van Wessem JM, Ligtenberg SRM, van den Broeke MR, Bamber JL. Dynamic thinning of glaciers on the Southern Antarctic Peninsula. Science 2015; 348:899-903. [DOI: 10.1126/science.aaa5727] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
8
|
Wright AP, Young DA, Roberts JL, Schroeder DM, Bamber JL, Dowdeswell JA, Young NW, Le Brocq AM, Warner RC, Payne AJ, Blankenship DD, van Ommen TD, Siegert MJ. Evidence of a hydrological connection between the ice divide and ice sheet margin in the Aurora Subglacial Basin, East Antarctica. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jf002066] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
9
|
Rippin DM, Bamber JL, Siegert MJ, Vaughan DG, Corr HFJ. Basal topography and ice flow in the Bailey/Slessor region of East Antarctica. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2003jf000039] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- D. M. Rippin
- Bristol Glaciology Centre, School of Geographical Sciences; University of Bristol; Bristol UK
| | - J. L. Bamber
- Bristol Glaciology Centre, School of Geographical Sciences; University of Bristol; Bristol UK
| | - M. J. Siegert
- Bristol Glaciology Centre, School of Geographical Sciences; University of Bristol; Bristol UK
| | | | | |
Collapse
|
10
|
Davis CH, McConnell JR, Bolzan J, Bamber JL, Thomas RH, Mosley-Thompson E. Elevation change of the southern Greenland ice sheet from 1978 to 1988: Interpretation. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001jd900167] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
11
|
Bamber JL, Layberry RL, Gogineni SP. A new ice thickness and bed data set for the Greenland ice sheet: 1. Measurement, data reduction, and errors. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001jd900054] [Citation(s) in RCA: 340] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
12
|
Layberry RL, Bamber JL. A new ice thickness and bed data set for the Greenland ice sheet: 2. Relationship between dynamics and basal topography. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001jd900053] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
13
|
Abstract
It has been suggested that as much as 90% of the discharge from the Antarctic Ice Sheet is drained through a small number of fast-moving ice streams and outlet glaciers fed by relatively stable and inactive catchment areas. Here, evidence obtained from balance velocity estimates suggests that each major drainage basin is fed by complex systems of tributaries that penetrate up to 1000 kilometers from the grounding line into the interior of the ice sheet. This finding has important consequences for the modeled or estimated dynamic response time of past and present ice sheets to climate forcing.
Collapse
Affiliation(s)
- JL Bamber
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UK. British Antarctic Survey High Cross, Madingley Road, Cambridge, CB3 OET, UK. Jet Propulsion Laboratory, California
| | | | | |
Collapse
|