1
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Donda F, Rebesco M, Kovacevic V, Silvano A, Bensi M, De Santis L, Rosenthal Y, Torricella F, Baradello L, Gei D, Leventer A, Post A, Leitchenkov G, Noble T, Zgur F, Cova A, O'Brien P, Romeo R. Footprint of sustained poleward warm water flow within East Antarctic submarine canyons. Nat Commun 2024; 15:6028. [PMID: 39019883 PMCID: PMC11254908 DOI: 10.1038/s41467-024-50160-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 06/25/2024] [Indexed: 07/19/2024] Open
Abstract
The intrusion of relatively warm water onto the continental shelf is widely recognized as a threat to Antarctic ice shelves and glaciers grounded below sea level, as enhanced ocean heat increases their basal melt. While the circulation of warm water has been documented on the East Antarctic continental shelf, the modes of warm water transport from the deep ocean onto the shelf are still uncertain. This makes predicting the future responses of major East Antarctic marine-grounded glaciers, such as Totten and Ninnis glaciers, particularly challenging. Here, we outline the key role of submarine canyons to convey southward flowing currents that transport warm Circumpolar Deep Water toward the East Antarctic shelf break, thus facilitating warm water intrusion on the continental shelf. Sediment drifts on the eastern flank of the canyons provide evidence for sustained southward-directed flows. These morpho-sedimentary features thus highlight areas potentially prone to enhanced ocean heat transport toward the continental shelf, with repercussions for past, present, and future glacial melting and consequent sea level rise.
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Affiliation(s)
- Federica Donda
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy.
| | - Michele Rebesco
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy
| | - Vedrana Kovacevic
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy
| | - Alessandro Silvano
- School of Ocean and Earth Science, University of Southampton, University Road, Southampton, SO17 1BJ, UK
| | - Manuel Bensi
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy
| | - Laura De Santis
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy
| | - Yair Rosenthal
- Department of Marine and Coastal Sciences, Rutgers, State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Fiorenza Torricella
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy
| | - Luca Baradello
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy
| | - Davide Gei
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy
| | - Amy Leventer
- Geology Department, Colgate University, Hamilton, NY, 13346, USA
| | - Alix Post
- Geoscience Australia, GPO Box 378, Canberra, ACT, 2601, Australia
| | - German Leitchenkov
- The All-Russia Scientific Research Institute for Geology and Mineral Resources of the Ocean, St. Petersburg, Russia
- Institute of Earth Sciences, St. Petersburg State University, 199034, St. Petersburg, Russia
| | - Taryn Noble
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, 7001, Australia
| | - Fabrizio Zgur
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy
| | - Andrea Cova
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy
| | - Philip O'Brien
- Earth and Environmental Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Roberto Romeo
- National Institute of Oceanography and Applied Geophysics-OGS, Borgo Grotta Gigante 42/c, 34010, Sgonico, Trieste, Italy
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2
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North R, Barrows TT. High-resolution elevation models of Larsen B glaciers extracted from 1960s imagery. Sci Rep 2024; 14:14536. [PMID: 38977717 PMCID: PMC11231284 DOI: 10.1038/s41598-024-65081-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 06/17/2024] [Indexed: 07/10/2024] Open
Abstract
Accelerated warming since the 1950s has caused dramatic change to ice shelves and outlet glaciers on the Antarctic Peninsula. Long observational records of ice loss in Antarctica are rare but essential to accurately inform mass balance estimates of glaciers. Here, we use aerial images from 1968 to reveal glacier configurations in the Larsen B region. We use structure-from-motion photogrammetry to construct high-resolution (3.2 m at best) elevation models covering up to 91% of Jorum, Crane, Mapple, Melville and Flask Glaciers. The historical elevation models provide glacier geometries decades before the Larsen B Ice Shelf collapse in 2002, allowing the determination of pre-collapse and post-collapse elevation differences. Results confirm that these five tributary glaciers of the former Larsen B Ice Shelf were relatively stable between 1968 and 2001. However, the net surface elevation differences over grounded ice between 1968 and 2021 equate to 35.3 ± 1.2 Gt of ice loss related to dynamic changes after the ice shelf removal. Archived imagery is an underutilised resource in Antarctica and was crucial here to observe glacier geometry in high-resolution decades before significant changes to ice dynamics.
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Affiliation(s)
- Ryan North
- School of Earth, Atmospheric and Life Sciences, Environmental Futures Research Centre, University of Wollongong, Wollongong, NSW, 2522, Australia.
- Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, NSW, 2522, Australia.
| | - Timothy T Barrows
- Chronos Radiocarbon Facility, University of New South Wales, Sydney, 2052, Australia
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3
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Bozkurt D, Marín JC, Verdugo C, Barrett BS. Atmospheric blocking and temperatures in the Antarctic Peninsula. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 931:172852. [PMID: 38705290 DOI: 10.1016/j.scitotenv.2024.172852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 04/13/2024] [Accepted: 04/26/2024] [Indexed: 05/07/2024]
Abstract
The Antarctic Peninsula (AP) has displayed a propensity for persistent blocking ridges and anticyclonic conditions, particularly during recent summertime extreme weather events. This study investigates atmospheric blocking patterns over the AP through historical (1981-2010) and future (2071-2100, SSP5-8.5) periods using ERA5 reanalysis and six CMIP6 models, including multi-member realizations from two models totaling ten simulations. We focus particularly on 500 hPa geopotential height (Z500) and near-surface air temperature (T2m) anomalies. The historical analysis highlights significant differences between the CMIP6 models and ERA5 reanalysis, especially in the austral winter, with EC-Earth3 and INM-CM4 models matching closest with the ERA5. Future projections show that while the northern AP and the Drake Passage largely do not exhibit a clear trend towards increased blocking, there are exceptions. The EC-Earth3 model predicts more blocking-like conditions northwest of the AP in summer and a pronounced ridge over the Bellingshausen Sea in winter, indicating a potential increase in blocking events. The INM-CM4 model projects a minor increase in summer Z500 heights off the western and southern AP, without clear blocking patterns over the AP, and negligible winter changes. Localized intensification is noted in the northern parts of the blocking domain and southern AP during extreme blocking conditions. These variations are mirrored in T2m anomalies, suggesting warming in the northern and southern sections of AP but little change elsewhere. The results of this study underscore the need to more accurately capture complex blocking mechanisms and their impacts on regional climate patterns around the AP. We also suggest employing refined blocking definitions and incorporating a broader range of climate models to enhance our understanding of blocking patterns and their impacts in a changing climate.
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Affiliation(s)
- Deniz Bozkurt
- Departamento de Meteorología, Universidad de Valparaíso, Chile; Centro de Estudios Atmosféricos y Cambio Climático (CEACC), Universidad de Valparaíso, Chile; Center for Climate and Resilience Research (CR)2, Santiago, Chile; Center for Oceanographic Research COPAS COASTAL, Universidad de Concepción, Chile.
| | - Julio C Marín
- Departamento de Meteorología, Universidad de Valparaíso, Chile; Centro de Estudios Atmosféricos y Cambio Climático (CEACC), Universidad de Valparaíso, Chile
| | - Cristina Verdugo
- Centro de Estudios Atmosféricos y Cambio Climático (CEACC), Universidad de Valparaíso, Chile; Instituto de Física y Astronomía, Universidad de Valparaíso, Chile
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4
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Zhang Y, Moore JC, Zhao L, Werder MA, Gladstone R, Wolovick M. The role of hydraulic conductivity in the Pine Island Glacier's subglacial water distribution. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172144. [PMID: 38582110 DOI: 10.1016/j.scitotenv.2024.172144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/05/2024] [Accepted: 03/30/2024] [Indexed: 04/08/2024]
Abstract
Global climate warming leads to ever-increasing glacier mass loss. Pine Island Glacier in Antarctica is one of the largest contributors to global sea level rise (SLR). One of the biggest uncertainties in the assessment of glacier contribution to SLR at present are subglacial hydrology processes which are less well known than other ice dynamical processes. We use the Glacier Drainage System (GlaDS) model which couples both distributed and channelized components to simulate the basal hydrology of Pine Island Glacier with basal sliding and meltwater production taken from a full-Stokes Elmer/Ice model fitting observed surface velocities. We find ≈100 km long Rothlisberger channels up to 26 m in diameter extending up glacier from the grounding line along the main trunk of Pine Island Glacier delivering 51 m3 s-1 of fresh water to the grounding line. Channelization occurs at high water pressure because of high basal melt rates (maximum of 1 m a-1) caused by high rates of shear heating in regions with fast ice flow (>1000 m a-1). We simulate a shallow "swamp" of 0.8 m water depth where flow transitions from a distributed system into the channels. We performed a set of 38 sensitivity experiments varying sheet and channel conductivity over 4 orders of magnitude. We find a threshold behavior in distributed sheet conductivity above which basal water pressures are unaffected by changing channel conductivities. Our findings suggest a strong need to better understand controls on basal water conductivity through the distributed system. This issue is critical to improve model-based predictive capability for the Pine Island Glacier and, more generally, the Antarctic Ice Sheet.
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Affiliation(s)
- Yufang Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, 100875, China
| | - John C Moore
- Arctic Centre, University of Lapland, 96101 Rovaniemi, Finland.
| | - Liyun Zhao
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, 100875, China.
| | - Mauro A Werder
- Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland; Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | | | - Michael Wolovick
- Glaciology Section, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
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5
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Rignot E, Ciracì E, Scheuchl B, Tolpekin V, Wollersheim M, Dow C. Widespread seawater intrusions beneath the grounded ice of Thwaites Glacier, West Antarctica. Proc Natl Acad Sci U S A 2024; 121:e2404766121. [PMID: 38768351 PMCID: PMC11145208 DOI: 10.1073/pnas.2404766121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 04/18/2024] [Indexed: 05/22/2024] Open
Abstract
Warm water from the Southern Ocean has a dominant impact on the evolution of Antarctic glaciers and in turn on their contribution to sea level rise. Using a continuous time series of daily-repeat satellite synthetic-aperture radar interferometry data from the ICEYE constellation collected in March-June 2023, we document an ice grounding zone, or region of tidally controlled migration of the transition boundary between grounded ice and ice afloat in the ocean, at the main trunk of Thwaites Glacier, West Antarctica, a strong contributor to sea level rise with an ice volume equivalent to a 0.6-m global sea level rise. The ice grounding zone is 6 km wide in the central part of Thwaites with shallow bed slopes, and 2 km wide along its flanks with steep basal slopes. We additionally detect irregular seawater intrusions, 5 to 10 cm in thickness, extending another 6 km upstream, at high tide, in a bed depression located beyond a bedrock ridge that impedes the glacier retreat. Seawater intrusions align well with regions predicted by the GlaDS subglacial water model to host a high-pressure distributed subglacial hydrology system in between lower-pressure subglacial channels. Pressurized seawater intrusions will induce vigorous melt of grounded ice over kilometers, making the glacier more vulnerable to ocean warming, and increasing the projections of ice mass loss. Kilometer-wide, widespread seawater intrusion beneath grounded ice may be the missing link between the rapid, past, and present changes in ice sheet mass and the slower changes replicated by ice sheet models.
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Affiliation(s)
- Eric Rignot
- Department of Earth System Science, University of California, Irvine, CA92697
- Radar Science and Engineering Section, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA91109
- Department of Civil and Environmental Engineering, University of California, Irvine, CA92697
| | - Enrico Ciracì
- Department of Earth System Science, University of California, Irvine, CA92697
| | - Bernd Scheuchl
- Department of Earth System Science, University of California, Irvine, CA92697
| | | | | | - Christine Dow
- Department of Geography and Environmental Management, University of Waterloo, Waterloo, ONN2L 3G1, Canada
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6
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Dømgaard M, Schomacker A, Isaksson E, Millan R, Huiban F, Dehecq A, Fleischer A, Moholdt G, Andersen JK, Bjørk AA. Early aerial expedition photos reveal 85 years of glacier growth and stability in East Antarctica. Nat Commun 2024; 15:4466. [PMID: 38796492 PMCID: PMC11127979 DOI: 10.1038/s41467-024-48886-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 05/15/2024] [Indexed: 05/28/2024] Open
Abstract
During the last few decades, several sectors in Antarctica have transitioned from glacial mass balance equilibrium to mass loss. In order to determine if recent trends exceed the scale of natural variability, long-term observations are vital. Here we explore the earliest, large-scale, aerial image archive of Antarctica to provide a unique record of 21 outlet glaciers along the coastline of East Antarctica since the 1930s. In Lützow-Holm Bay, our results reveal constant ice surface elevations since the 1930s, and indications of a weakening of local land-fast sea-ice conditions. Along the coastline of Kemp and Mac Robertson, and Ingrid Christensen Coast, we observe a long-term moderate thickening of the glaciers since 1937 and 1960 with periodic thinning and decadal variability. In all regions, the long-term changes in ice thickness correspond with the trends in snowfall since 1940. Our results demonstrate that the stability and growth in ice elevations observed in terrestrial basins over the past few decades are part of a trend spanning at least a century, and highlight the importance of understanding long-term changes when interpreting current dynamics.
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Affiliation(s)
- Mads Dømgaard
- Department of Geoscience and Natural Resource Management, University of Copenhagen, 1350, Copenhagen K, Denmark.
| | - Anders Schomacker
- Department of Geosciences, UiT The Arctic University of Norway, Postboks 6050 Langnes, NO-9037, Tromsø, Norway
| | | | - Romain Millan
- Univ. Grenoble Alpes, IRD, CNRS, INRAE, Grenoble INP, IGE, 38000, Grenoble, France
| | - Flora Huiban
- Department of Geoscience and Natural Resource Management, University of Copenhagen, 1350, Copenhagen K, Denmark
| | - Amaury Dehecq
- Univ. Grenoble Alpes, IRD, CNRS, INRAE, Grenoble INP, IGE, 38000, Grenoble, France
| | - Amanda Fleischer
- Department of Geoscience and Natural Resource Management, University of Copenhagen, 1350, Copenhagen K, Denmark
| | | | - Jonas K Andersen
- Department of Geoscience and Natural Resource Management, University of Copenhagen, 1350, Copenhagen K, Denmark
| | - Anders A Bjørk
- Department of Geoscience and Natural Resource Management, University of Copenhagen, 1350, Copenhagen K, Denmark
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7
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Lowry DP, Han HK, Golledge NR, Gomez N, Johnson KM, McKay RM. Ocean cavity regime shift reversed West Antarctic grounding line retreat in the late Holocene. Nat Commun 2024; 15:3176. [PMID: 38653971 DOI: 10.1038/s41467-024-47369-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 03/25/2024] [Indexed: 04/25/2024] Open
Abstract
Recent geologic and modeled evidence suggests that the grounding line of the Siple Coast of the West Antarctic Ice Sheet (WAIS) retreated hundreds of kilometers beyond its present position in the middle to late Holocene and readvanced within the past 1.7 ka. This grounding line reversal has been attributed to both changing rates of isostatic rebound and regional climate change. Here, we test these two hypotheses using a proxy-informed ensemble of ice sheet model simulations with varying ocean thermal forcing, global glacioisostatic adjustment (GIA) model simulations, and coupled ice sheet-GIA simulations that consider the interactions between these processes. Our results indicate that a warm to cold ocean cavity regime shift is the most likely cause of this grounding line reversal, but that GIA influences the rate of ice sheet response to oceanic changes. This implies that the grounding line here is sensitive to future changes in sub-ice shelf ocean circulation.
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Affiliation(s)
- Daniel P Lowry
- Department of Surface Geosciences, GNS Science, Lower Hutt, New Zealand.
| | - Holly K Han
- Fluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Nicholas R Golledge
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - Natalya Gomez
- Department of Earth and Planetary Sciences, McGill University, Montréal, QC, Canada
| | - Katelyn M Johnson
- Department of Surface Geosciences, GNS Science, Lower Hutt, New Zealand
| | - Robert M McKay
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
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8
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Park T, Nakayama Y, Nam S. Amundsen Sea circulation controls bottom upwelling and Antarctic Pine Island and Thwaites ice shelf melting. Nat Commun 2024; 15:2946. [PMID: 38605000 PMCID: PMC11009355 DOI: 10.1038/s41467-024-47084-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 03/15/2024] [Indexed: 04/13/2024] Open
Abstract
The Pine Island and Thwaites Ice Shelves (PIIS/TIS) in the Amundsen Sea are melting rapidly and impacting global sea levels. The thermocline depth (TD) variability, the interface between cold Winter Water and warm modified Circumpolar Deep Water (mCDW), at the PIIS/TIS front strongly correlates with basal melt rates, but the drivers of its interannual variability remain uncertain. Here, using an ocean model, we propose that the strength of the eastern Amundsen Sea on-shelf circulation primarily controls TD variability and consequent PIIS/TIS melt rates. The TD variability occurs because the on-shelf circulation meanders following the submarine glacial trough, creating vertical velocity through bottom Ekman dynamics. We suggest that a strong or weak ocean circulation, possibly linked to remote winds in the Bellingshausen Sea, generates corresponding changes in bottom Ekman convergence, which modulates mCDW upwelling and TD variability. We show that interannual variability of off-shelf zonal winds has a minor effect on ocean heat intrusion into PIIS/TIS cavities, contrary to the widely accepted concept.
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Affiliation(s)
- Taewook Park
- Division of Ocean and Atmosphere Sciences, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.
| | - Yoshihiro Nakayama
- Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan.
| | - SungHyun Nam
- School of Earth and Environmental Sciences/Research Institute of Oceanography, Seoul National University, Gwanak-gu, Seoul, 08826, Republic of Korea
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9
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Clark RW, Wellner JS, Hillenbrand CD, Totten RL, Smith JA, Miller LE, Larter RD, Hogan KA, Graham AGC, Nitsche FO, Lehrmann AA, Lepp AP, Kirkham JD, Fitzgerald VT, Garcia-Barrera G, Ehrmann W, Wacker L. Synchronous retreat of Thwaites and Pine Island glaciers in response to external forcings in the presatellite era. Proc Natl Acad Sci U S A 2024; 121:e2211711120. [PMID: 38408214 PMCID: PMC10945778 DOI: 10.1073/pnas.2211711120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 04/27/2023] [Indexed: 02/28/2024] Open
Abstract
Today, relatively warm Circumpolar Deep Water is melting Thwaites Glacier at the base of its ice shelf and at the grounding zone, contributing to significant ice retreat. Accelerating ice loss has been observed since the 1970s; however, it is unclear when this phase of significant melting initiated. We analyzed the marine sedimentary record to reconstruct Thwaites Glacier's history from the early Holocene to present. Marine geophysical surveys were carried out along the floating ice-shelf margin to identify core locations from various geomorphic settings. We use sedimentological data and physical properties to define sedimentary facies at seven core sites. Glaciomarine sediment deposits reveal that the grounded ice in the Amundsen Sea Embayment had already retreated to within ~45 km of the modern grounding zone prior to ca. 9,400 y ago. Sediments deposited within the past 100+ y record abrupt changes in environmental conditions. On seafloor highs, these shifts document ice-shelf thinning initiating at least as early as the 1940s. Sediments recovered from deep basins reflect a transition from ice proximal to slightly more distal conditions, suggesting ongoing grounding-zone retreat since the 1950s. The timing of ice-shelf unpinning from the seafloor for Thwaites Glacier coincides with similar records from neighboring Pine Island Glacier. Our work provides robust new evidence that glacier retreat in the Amundsen Sea was initiated in the mid-twentieth century, likely associated with climate variability.
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Affiliation(s)
- Rachel W Clark
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77004
| | - Julia S Wellner
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77004
| | | | - Rebecca L Totten
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL 35401
| | - James A Smith
- British Antarctic Survey, Cambridge CB3 0ET, United Kingdom
| | - Lauren E Miller
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22903
| | | | - Kelly A Hogan
- British Antarctic Survey, Cambridge CB3 0ET, United Kingdom
| | - Alastair G C Graham
- College of Marine Science, University of South Florida, St. Petersburg, FL 33701
| | - Frank O Nitsche
- Lamont-Doherty Earth Observatory of Columbia University, New York, NY 10964
| | - Asmara A Lehrmann
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77004
| | - Allison P Lepp
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22903
| | - James D Kirkham
- British Antarctic Survey, Cambridge CB3 0ET, United Kingdom
- Scott Polar Research Institute, University of Cambridge, Cambridge CB2 1ER, United Kingdom
| | | | | | - Werner Ehrmann
- Institute for Geophysics & Geology, University of Leipzig, Leipzig 04103, Germany
| | - Lukas Wacker
- Ion Beam Physics, Eidgenössische Technische Hochschule Zürich, Zürich 8093, Switzerland
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10
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Liu H, Zheng W, Gao Y, Yang L, Yue F, Huang T, Xie Z. Increased Contribution of Circumpolar Deep Water Upwelling to Methylmercury in the Upper Ocean around Antarctica: Evidence from Mercury Isotopes in the Ornithogenic Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:2762-2773. [PMID: 38294849 DOI: 10.1021/acs.est.3c06923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Upwelling plays a pivotal role in supplying methylmercury (MeHg) to the upper oceans, contributing to the bioaccumulation of MeHg in the marine food web. However, the influence of the upwelling of Circumpolar Deep Water (CDW), the most voluminous water mass in the Southern Ocean, on the MeHg cycle in the surrounding oceans and marine biota of Antarctica remains unclear. Here, we study the mercury (Hg) isotopes in an ornithogenic sedimentary profile strongly influenced by penguin activity on Ross Island, Antarctica. Results indicate that penguin guano is the primary source of Hg in the sediments, and the mass-independent isotope fractionation of Hg (represented by Δ199Hg) can provide insights on the source of marine MeHg accumulated by penguin. The Δ199Hg in the sediments shows a significant decrease at ∼1550 CE, which is primarily attributed to the enhanced upwelling of CDW that brought more MeHg with lower Δ199Hg from the deeper seawater to the upper ocean. We estimate that the contribution of MeHg from the deeper seawater may reach more than 38% in order to explain the decline in Δ199Hg at ∼1550 CE. Moreover, we found that the intensified upwelling may have increased the MeHg exposure for marine organisms, highlighting the importance of CDW upwelling on the MeHg cycle in Antarctic coastal ecosystems.
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Affiliation(s)
- Hongwei Liu
- Department of Environmental Science and Engineering, Anhui Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wang Zheng
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
- School of Earth and Space Exploration, Arizona State University, Tempe, Arizona 85287, United States
| | - Yuesong Gao
- Department of Environmental Science and Engineering, Anhui Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Lianjiao Yang
- Department of Environmental Science and Engineering, Anhui Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fange Yue
- Department of Environmental Science and Engineering, Anhui Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Tao Huang
- School of Resources and Environmental Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Zhouqing Xie
- Department of Environmental Science and Engineering, Anhui Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei, Anhui 230026, China
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11
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Miles BWJ, Bingham RG. Progressive unanchoring of Antarctic ice shelves since 1973. Nature 2024; 626:785-791. [PMID: 38383628 PMCID: PMC10881387 DOI: 10.1038/s41586-024-07049-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 01/09/2024] [Indexed: 02/23/2024]
Abstract
Mass loss of the Antarctic Ice Sheet has been driven primarily by the thinning of the floating ice shelves that fringe the ice sheet1, reducing their buttressing potential and causing land ice to accelerate into the ocean2. Observations of ice-shelf thickness change by satellite altimetry stretch back only to 1992 (refs. 1,3-5) and previous information about thinning remains unquantified. However, extending the record of ice-shelf thickness change is possible by proxy, by measuring the change in area of the surface expression of pinning points-local bathymetric highs on which ice shelves are anchored6. Here we measure pinning-point change over three epochs spanning the periods 1973-1989, 1989-2000 and 2000-2022, and thus by proxy infer changes to ice-shelf thickness back to 1973-1989. We show that only small localized pockets of ice shelves were thinning between 1973 and 1989, located primarily in the Amundsen Sea Embayment and the Wilkes Land coastline. Ice-shelf thinning spreads rapidly into the 1990s and 2000s and is best characterized by the proportion of pinning points reducing in extent. Only 15% of pinning points reduced from 1973 to 1989, before increasing to 25% from 1989 to 2000 and 37% from 2000 to 2022. A continuation of this trend would further reduce the buttressing potential of ice shelves, enhancing ice discharge and accelerating the contribution of Antarctica to sea-level rise.
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12
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Uz M, Akyılmaz O, Shum CK, Atman KG, Olgun S, Güneş Ö. High-resolution temporal gravity field data products: Monthly mass grids and spherical harmonics from 1994 to 2021. Sci Data 2024; 11:71. [PMID: 38218975 PMCID: PMC10787793 DOI: 10.1038/s41597-023-02887-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 12/27/2023] [Indexed: 01/15/2024] Open
Abstract
Since April 2002, Gravity Recovery and Climate Experiment (GRACE) and GRACE-FO (FollowOn) satellite gravimetry missions have provided precious data for monitoring mass variations within the hydrosphere, cryosphere, and oceans with unprecedented accuracy and resolution. However, the long-term products of mass variations prior to GRACE-era may allow for a better understanding of spatio-temporal changes in climate-induced geophysical phenomena, e.g., terrestrial water cycle, ice sheet and glacier mass balance, sea level change and ocean bottom pressure (OBP). Here, climate-driven mass anomalies are simulated globally at 1.0° × 1.0° spatial and monthly temporal resolutions from January 1994 to January 2021 using an in-house developed hybrid Deep Learning architecture considering GRACE/-FO mascon and SLR-inferred gravimetry, ECMWF Reanalysis-5 data, and normalized time tag information as training datasets. Internally, we consider mathematical metrics such as RMSE, NSE and comparisons to previous studies, and externally, we compare our simulations to GRACE-independent datasets such as El-Nino and La-Nina indexes, Global Mean Sea Level, Earth Orientation Parameters-derived low-degree spherical harmonic coefficients, and in-situ OBP measurements for validation.
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Affiliation(s)
- Metehan Uz
- Dept. of Geomatics Eng., Istanbul Technical University, Istanbul, Turkey
| | - Orhan Akyılmaz
- Dept. of Geomatics Eng., Istanbul Technical University, Istanbul, Turkey.
| | - C K Shum
- Division of Geodetic Science, School of Earth Sciences, The Ohio State University, Columbus, Ohio, USA
| | - Kazım Gökhan Atman
- School of Mathematical Sciences, Queen Mary University of London, London, England
- Department of Physics, Ege University, Izmir, Turkey
| | - Sevda Olgun
- Dept. of Geomatics Eng., Kocaeli University, Kocaeli, Turkey
| | - Özge Güneş
- Dept. of Geomatics Eng., Yıldız Technical University, Istanbul, Turkey
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13
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Lenton TM, Abrams JF, Bartsch A, Bathiany S, Boulton CA, Buxton JE, Conversi A, Cunliffe AM, Hebden S, Lavergne T, Poulter B, Shepherd A, Smith T, Swingedouw D, Winkelmann R, Boers N. Remotely sensing potential climate change tipping points across scales. Nat Commun 2024; 15:343. [PMID: 38184618 PMCID: PMC10771461 DOI: 10.1038/s41467-023-44609-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/18/2023] [Indexed: 01/08/2024] Open
Abstract
Potential climate tipping points pose a growing risk for societies, and policy is calling for improved anticipation of them. Satellite remote sensing can play a unique role in identifying and anticipating tipping phenomena across scales. Where satellite records are too short for temporal early warning of tipping points, complementary spatial indicators can leverage the exceptional spatial-temporal coverage of remotely sensed data to detect changing resilience of vulnerable systems. Combining Earth observation with Earth system models can improve process-based understanding of tipping points, their interactions, and potential tipping cascades. Such fine-resolution sensing can support climate tipping point risk management across scales.
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Affiliation(s)
| | - Jesse F Abrams
- Global Systems Institute, University of Exeter, Exeter, UK
| | - Annett Bartsch
- b.geos GmbH, Industriestrasse 1A, 2100, Korneuburg, Austria
- Austrian Polar Research Institute, Vienna, Austria
| | - Sebastian Bathiany
- Earth System Modelling, School of Engineering & Design, Technical University of Munich, Munich, Germany
- Potsdam Institute for Climate Impact Research, Potsdam, Germany
| | | | | | - Alessandra Conversi
- National Research Council of Italy, ISMAR-Lerici, Forte Santa Teresa, Loc. Pozzuolo, 19032, Lerici (SP), Italy
| | | | - Sophie Hebden
- Future Earth Secretariat, Stockholm, Sweden
- European Space Agency, ECSAT, Harwell, Oxfordshire, UK
| | | | | | - Andrew Shepherd
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle, UK
| | - Taylor Smith
- Institute of Geosciences, University of Potsdam, Potsdam, Germany
| | - Didier Swingedouw
- University of Bordeaux, CNRS, Bordeaux INP, EPOC, UMR 5805, 33600, Pessac, France
| | | | - Niklas Boers
- Global Systems Institute, University of Exeter, Exeter, UK
- Earth System Modelling, School of Engineering & Design, Technical University of Munich, Munich, Germany
- Potsdam Institute for Climate Impact Research, Potsdam, Germany
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14
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Wang Y, Wu Q, Zhang X, Zhai Z. Record-breaking Antarctic snowfall in 2022 delays global sea level rise. Sci Bull (Beijing) 2023; 68:3154-3157. [PMID: 37734981 DOI: 10.1016/j.scib.2023.08.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 08/18/2023] [Accepted: 08/19/2023] [Indexed: 09/23/2023]
Affiliation(s)
- Yetang Wang
- College of Geography and Environment, Shandong Normal University, Jinan 250014, China.
| | - Qingli Wu
- College of Geography and Environment, Shandong Normal University, Jinan 250014, China
| | - Xueying Zhang
- College of Geography and Environment, Shandong Normal University, Jinan 250014, China
| | - Zhaosheng Zhai
- College of Geography and Environment, Shandong Normal University, Jinan 250014, China
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15
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Lau SCY, Wilson NG, Golledge NR, Naish TR, Watts PC, Silva CNS, Cooke IR, Allcock AL, Mark FC, Linse K, Strugnell JM. Genomic evidence for West Antarctic Ice Sheet collapse during the Last Interglacial. Science 2023; 382:1384-1389. [PMID: 38127761 DOI: 10.1126/science.ade0664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/30/2023] [Indexed: 12/23/2023]
Abstract
The marine-based West Antarctic Ice Sheet (WAIS) is considered vulnerable to irreversible collapse under future climate trajectories, and its tipping point may lie within the mitigated warming scenarios of 1.5° to 2°C of the United Nations Paris Agreement. Knowledge of ice loss during similarly warm past climates could resolve this uncertainty, including the Last Interglacial when global sea levels were 5 to 10 meters higher than today and global average temperatures were 0.5° to 1.5°C warmer than preindustrial levels. Using a panel of genome-wide, single-nucleotide polymorphisms of a circum-Antarctic octopus, we show persistent, historic signals of gene flow only possible with complete WAIS collapse. Our results provide the first empirical evidence that the tipping point of WAIS loss could be reached even under stringent climate mitigation scenarios.
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Affiliation(s)
- Sally C Y Lau
- Centre for Sustainable Tropical Fisheries and Aquaculture and College of Science and Engineering, James Cook University, Townsville, Qld, Australia
- Securing Antarctica's Environmental Future, James Cook University, Townsville, Qld, Australia
| | - Nerida G Wilson
- Collections & Research, Western Australian Museum, Welshpool, WA, Australia
- School of Biological Sciences, University of Western Australia, Perth, WA, Australia
- Securing Antarctica's Environmental Future, Western Australian Museum, Welshpool, WA, Australia
| | - Nicholas R Golledge
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - Tim R Naish
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - Phillip C Watts
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Catarina N S Silva
- Centre for Sustainable Tropical Fisheries and Aquaculture and College of Science and Engineering, James Cook University, Townsville, Qld, Australia
- Centre for Functional Ecology - Science for People & the Planet (CFE), Associate Laboratory TERRA, Department of Life Sciences, University of Coimbra, Portugal
| | - Ira R Cooke
- Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Townsville, Qld, Australia
| | - A Louise Allcock
- School of Natural Sciences and Ryan Institute, University of Galway, Galway, Ireland
| | - Felix C Mark
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | | | - Jan M Strugnell
- Centre for Sustainable Tropical Fisheries and Aquaculture and College of Science and Engineering, James Cook University, Townsville, Qld, Australia
- Securing Antarctica's Environmental Future, James Cook University, Townsville, Qld, Australia
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16
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Rosa KKDA, Perondi C, Lorenz JL, Auger JD, Cazaroto P, Petsch C, Siqueira RG, Simões JC, Vieira R. Glacier fluctuations and a proglacial evolution in King George Bay (King George Island), Antarctica, since 1980 decade. AN ACAD BRAS CIENC 2023; 95:e20230624. [PMID: 38126381 DOI: 10.1590/0001-3765202320230624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 11/18/2023] [Indexed: 12/23/2023] Open
Abstract
This study aims to investigate the glacier shrinkage and recent proglacial environment in King George Bay, Antarctica, since 1988 in response to climate change. Remote sensing data (SPOT, Sentinel, Landsat and Planet Scope images) were applied to glacial landforms and ice-marginal fluctuations mapping. Annual mean near-surface air temperature reanalysis solutions from ERA-Interim were analyzed. Moraines and glaciofluvial landforms were identified. The Ana Northern Glacier has the highest retreat value (3.64 km) (and area loss of 31%) in response to higher depth in frontal ice-margin and reveal ocean-glacier linkages. The Ana South Glacier changed from a tidewater glacier to land-terminating after 1995, and had an outline minimum elevation variation of 89 meters, a shrinkage of 0.63 km, and a new proglacial subaerial sector. The Ana South Glacier foreland had recessional moraines (probably formed between 1995 and 2022), lagoons, and lakes. There are many flutings in low-relief environments. The 1980-1989, 1990-1999, 2000-2009, 2010-2019 anomaly plots concerning to the 1980-2019 average for atmospheric temperature, are shown to be a driver of the local glacial trends.
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Affiliation(s)
- Kátia K DA Rosa
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Cleiva Perondi
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Júlia L Lorenz
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Jeffrey D Auger
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Pamela Cazaroto
- Universidade de São Paulo, Departamento de Geografia, Av. Professor Lineu Prestes, 338, 05508-000 São Paulo, SP, Brazil
| | - Carina Petsch
- Universidade Federal de Santa Maria, Departamento de Geociências, Av. Roraima, 1000, 97105-900 Santa Maria, RS, Brazil
| | - Rafael G Siqueira
- Universidade Federal de Viçosa, Departamento de Solos, Av. PH Rolfs, s/n, 36570-900 Viçosa, MG, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Rosemary Vieira
- Universidade Federal Fluminense, Departamento de Geografia, Av. Gal. Milton Tavares de Souza, s/n, Campus da Praia Vermelha, Boa Viagem, 24210-346 Niterói, RJ, Brazil
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17
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Noël B, van Wessem JM, Wouters B, Trusel L, Lhermitte S, van den Broeke MR. Higher Antarctic ice sheet accumulation and surface melt rates revealed at 2 km resolution. Nat Commun 2023; 14:7949. [PMID: 38040701 PMCID: PMC10692123 DOI: 10.1038/s41467-023-43584-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 11/14/2023] [Indexed: 12/03/2023] Open
Abstract
Antarctic ice sheet (AIS) mass loss is predominantly driven by increased solid ice discharge, but its variability is governed by surface processes. Snowfall fluctuations control the surface mass balance (SMB) of the grounded AIS, while meltwater ponding can trigger ice shelf collapse potentially accelerating discharge. Surface processes are essential to quantify AIS mass change, but remain poorly represented in climate models typically running at 25-100 km resolution. Here we present SMB and surface melt products statistically downscaled to 2 km resolution for the contemporary climate (1979-2021) and low, moderate and high-end warming scenarios until 2100. We show that statistical downscaling modestly enhances contemporary SMB (3%), which is sufficient to reconcile modelled and satellite mass change. Furthermore, melt strongly increases (46%), notably near the grounding line, in better agreement with in-situ and satellite records. The melt increase persists by 2100 in all warming scenarios, revealing higher surface melt rates than previously estimated.
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Affiliation(s)
- Brice Noël
- Laboratoire de Climatologie et Topoclimatologie, University of Liège, Liège, Belgium.
- Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, Netherlands.
| | - J Melchior van Wessem
- Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, Netherlands
| | - Bert Wouters
- Department of Geoscience and Remote Sensing, Delft University of Technology, Delft, Netherlands
| | - Luke Trusel
- Department of Geography, Pennsylvania State University, University Park, PA, USA
| | - Stef Lhermitte
- Department of Geoscience and Remote Sensing, Delft University of Technology, Delft, Netherlands
- Department of Earth and Environmental Sciences, KU Leuven, Leuven, Belgium
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18
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Washam P, Lawrence JD, Stevens CL, Hulbe CL, Horgan HJ, Robinson NJ, Stewart CL, Spears A, Quartini E, Hurwitz B, Meister MR, Mullen AD, Dichek DJ, Bryson F, Schmidt BE. Direct observations of melting, freezing, and ocean circulation in an ice shelf basal crevasse. SCIENCE ADVANCES 2023; 9:eadi7638. [PMID: 37889975 PMCID: PMC10610921 DOI: 10.1126/sciadv.adi7638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023]
Abstract
Ocean conditions near the grounding zones of Antarctica's ice shelves play a key role in controlling the outflow and mass balance of the ice sheet. However, ocean observations in these regions are largely absent. Here, we present a detailed spatial survey collected with an underwater vehicle in a basal crevasse located in the ocean cavity at the Ross Ice Shelf grounding zone. The observations depict fine-scale variability in ocean forcing that drives asymmetric melting along the lower crevasse sidewalls and freezing in the upper reaches of the crevasse. Freshwater release from melting at depth and salt rejection from freezing above drives an overturning circulation. This vertical circulation pattern overlays a dominant throughflow jet, which funnels water parallel to the coastline, orthogonal to the direction of tidal currents. Importantly, these data reveal that basal crevasses influence ocean circulation and mixing at ice shelf grounding zones to an extent previously unknown.
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Affiliation(s)
- Peter Washam
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - Craig L. Stevens
- Ocean Dynamics Group, National Institute for Water and Atmospheric Research, Greta Point, Wellington, New Zealand
- Department of Physics, University of Auckland, Auckland, New Zealand
| | | | - Huw J. Horgan
- Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland
- Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL), Birmensdorf, Switzerland
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - Natalie J. Robinson
- Ocean Dynamics Group, National Institute for Water and Atmospheric Research, Greta Point, Wellington, New Zealand
| | - Craig L. Stewart
- Ocean Dynamics Group, National Institute for Water and Atmospheric Research, Greta Point, Wellington, New Zealand
| | - Anthony Spears
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Enrica Quartini
- Department of Astronomy, Cornell University, Ithaca, NY, USA
| | - Benjamin Hurwitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Matthew R. Meister
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | | | | | - Frances Bryson
- Department of Astronomy, Cornell University, Ithaca, NY, USA
| | - Britney E. Schmidt
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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19
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Pelle T, Greenbaum JS, Dow CF, Jenkins A, Morlighem M. Subglacial discharge accelerates future retreat of Denman and Scott Glaciers, East Antarctica. SCIENCE ADVANCES 2023; 9:eadi9014. [PMID: 37889971 PMCID: PMC10610922 DOI: 10.1126/sciadv.adi9014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023]
Abstract
Ice shelf basal melting is the primary mechanism driving mass loss from the Antarctic Ice Sheet, yet it is unknown how the localized melt enhancement from subglacial discharge will affect future Antarctic glacial retreat. We develop a parameterization of ice shelf basal melt that accounts for both ocean and subglacial discharge forcing and apply it in future projections of Denman and Scott Glaciers, East Antarctica, through 2300. In forward simulations, subglacial discharge accelerates the onset of retreat of these systems into the deepest continental trench on Earth by 25 years. During this retreat, Denman Glacier alone contributes 0.33 millimeters per year to global sea level rise, comparable to half of the contemporary sea level contribution of the entire Antarctic Ice Sheet. Our results stress the importance of resolving complex interactions between the ice, ocean, and subglacial environments in future Antarctic Ice Sheet projections.
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Affiliation(s)
- Tyler Pelle
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA
| | - Jamin S Greenbaum
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA
| | - Christine F Dow
- Department of Geography and Environmental Management, University of Waterloo, Waterloo, ON, Canada
| | - Adrian Jenkins
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
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20
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Davison BJ, Hogg AE, Gourmelen N, Jakob L, Wuite J, Nagler T, Greene CA, Andreasen J, Engdahl ME. Annual mass budget of Antarctic ice shelves from 1997 to 2021. SCIENCE ADVANCES 2023; 9:eadi0186. [PMID: 37824617 DOI: 10.1126/sciadv.adi0186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 09/07/2023] [Indexed: 10/14/2023]
Abstract
Antarctic ice shelves moderate the contribution of the Antarctic Ice Sheet to global sea level rise; however, ice shelf health remains poorly constrained. Here, we present the annual mass budget of all Antarctic ice shelves from 1997 to 2021. Out of 162 ice shelves, 71 lost mass, 29 gained mass, and 62 did not change mass significantly. Of the shelves that lost mass, 68 had statistically significant negative mass trends, 48 lost more than 30% of their initial mass, and basal melting was the dominant contributor to that mass loss at a majority (68%). At many ice shelves, mass losses due to basal melting or iceberg calving were significantly positively correlated with grounding line discharge anomalies; however, the strength and form of this relationship varied substantially between ice shelves. Our results illustrate the utility of partitioning high-resolution ice shelf mass balance observations into its components to quantify the contributors to ice shelf mass change and the response of grounded ice.
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Affiliation(s)
| | - Anna E Hogg
- School of Earth and Environment, University of Leeds, Leeds, UK
| | - Noel Gourmelen
- School of Geosciences, University of Edinburgh, Edinburgh, UK
- Earthwave, Codebase, Office L2, 3 Lady Lawson St, Edinburgh, UK
| | - Livia Jakob
- Earthwave, Codebase, Office L2, 3 Lady Lawson St, Edinburgh, UK
| | - Jan Wuite
- ENVEO IT GmbH, Innsbruck 6020, Austria
| | | | - Chad A Greene
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Julia Andreasen
- Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN, USA
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21
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Hirano D, Tamura T, Kusahara K, Fujii M, Yamazaki K, Nakayama Y, Ono K, Itaki T, Aoyama Y, Simizu D, Mizobata K, Ohshima KI, Nogi Y, Rintoul SR, van Wijk E, Greenbaum JS, Blankenship DD, Saito K, Aoki S. On-shelf circulation of warm water toward the Totten Ice Shelf in East Antarctica. Nat Commun 2023; 14:4955. [PMID: 37591840 PMCID: PMC10435550 DOI: 10.1038/s41467-023-39764-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 06/26/2023] [Indexed: 08/19/2023] Open
Abstract
The Totten Glacier in East Antarctica, with an ice volume equivalent to >3.5 m of global sea-level rise, is grounded below sea level and, therefore, vulnerable to ocean forcing. Here, we use bathymetric and oceanographic observations from previously unsampled parts of the Totten continental shelf to reveal on-shelf warm water pathways defined by deep topographic features. Access of warm water to the Totten Ice Shelf (TIS) cavity is facilitated by a deep shelf break, a broad and deep depression on the shelf, a cyclonic circulation that carries warm water to the inner shelf, and deep troughs that provide direct access to the TIS cavity. The temperature of the warmest water reaching the TIS cavity varies by ~0.8 °C on an interannual timescale. Numerical simulations constrained by the updated bathymetry demonstrate that the deep troughs play a critical role in regulating ocean heat transport to the TIS cavity and the subsequent basal melt of the ice shelf.
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Grants
- JP20H04961 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP20K12132 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP22H05003 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP17H06316 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP17H06317 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP17H06322 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP17H04710 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP21H04931 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP22H05003 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP17H06323 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP19K12301 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP22H05003 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP22H01337 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP21K13989 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP21H03587 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP20H04970 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP22H05003 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP17H06316 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP17H06317 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP17H01157 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP20H05707 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP17H06322 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP17H01615 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP21H04918 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- OPP-2114454 National Science Foundation (NSF)
- OPP-1543452 National Science Foundation (NSF)
- OPP-1543452 National Science Foundation (NSF)
- the Joint Research Program of the Institute of Low Temperature Science, Hokkaido University
- National Institute of Polar Research (NIPR) through Project Research KP-303; the Center for the Promotion of Integrated Sciences of SOKENDAI
- MEXT-Program for the advanced studies of climate change projection (SENTAN) Grant Number JPMXD0722681344
- National Institute of Polar Research (NIPR) through Project Research KP-306; "Challenging Exploratory Research Projects for the Future" grant from Research Organization of Information and Systems
- Inoue Science Research Award from Inoue Science Foundation
- the Australian Government as part of the Antarctic Science Collaboration Initiative program; the Centre for Southern Hemisphere Oceans Research
- NASA’s Cryosphere Program under grant 80NSSC22K0387; the G. Unger Vetlesen Foundation
- the Science Program of Japanese Antarctic Research Expedition (JARE) as Prioritized Research Project
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Affiliation(s)
- Daisuke Hirano
- National Institute of Polar Research, Tachikawa, Japan.
- The Graduate University for Advanced Studies, SOKENDAI, Tachikawa, Japan.
| | - Takeshi Tamura
- National Institute of Polar Research, Tachikawa, Japan
- The Graduate University for Advanced Studies, SOKENDAI, Tachikawa, Japan
| | - Kazuya Kusahara
- Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
| | - Masakazu Fujii
- National Institute of Polar Research, Tachikawa, Japan
- The Graduate University for Advanced Studies, SOKENDAI, Tachikawa, Japan
| | - Kaihe Yamazaki
- National Institute of Polar Research, Tachikawa, Japan
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
- The Australian Centre for Excellence in Antarctic Science, University of Tasmania, Hobart, TAS, Australia
| | - Yoshihiro Nakayama
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
| | - Kazuya Ono
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Takuya Itaki
- National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Yuichi Aoyama
- National Institute of Polar Research, Tachikawa, Japan
- The Graduate University for Advanced Studies, SOKENDAI, Tachikawa, Japan
| | | | - Kohei Mizobata
- Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Kay I Ohshima
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
| | - Yoshifumi Nogi
- National Institute of Polar Research, Tachikawa, Japan
- The Graduate University for Advanced Studies, SOKENDAI, Tachikawa, Japan
| | - Stephen R Rintoul
- CSIRO Environment, Hobart, TAS, Australia
- Centre for Southern Hemisphere Oceans Research, Hobart, TAS, Australia
- Australian Antarctic Program Partnership, University of Tasmania, Hobart, TAS, Australia
| | - Esmee van Wijk
- CSIRO Environment, Hobart, TAS, Australia
- Australian Antarctic Program Partnership, University of Tasmania, Hobart, TAS, Australia
| | - Jamin S Greenbaum
- Scripps Institution of Oceanography, University of California, San Diego, CA, USA
| | | | - Koji Saito
- Japan Coast Guard, Hydrographic and Oceanographic Department, Tokyo, Japan
| | - Shigeru Aoki
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
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22
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Li R, Cheng Y, Chang T, Gwyther DE, Forbes M, An L, Xia M, Yuan X, Qiao G, Tong X, Ye W. Satellite record reveals 1960s acceleration of Totten Ice Shelf in East Antarctica. Nat Commun 2023; 14:4061. [PMID: 37429894 DOI: 10.1038/s41467-023-39588-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 06/21/2023] [Indexed: 07/12/2023] Open
Abstract
Wilkes Land and Totten Glacier (TG) in East Antarctica (EA) have been losing ice mass significantly since 1989. There is a lack of knowledge of long-term mass balance in the region which hinders the estimation of its contribution to global sea level rise. Here we show that this acceleration trend in TG has occurred since the 1960s. We reconstruct ice flow velocity fields of 1963-1989 in TG from the first-generation satellite images of ARGON and Landsat-1&4, and build a five decade-long record of ice dynamics. We find a persistent long-term ice discharge rate of 68 ± 1 Gt/y and an acceleration of 0.17 ± 0.02 Gt/y2 from 1963 to 2018, making TG the greatest contributor to global sea level rise in EA. We attribute the long-term acceleration near grounding line from 1963 to 2018 to basal melting likely induced by warm modified Circumpolar Deep Water. The speed up in shelf front during 1973-1989 was caused by a large calving front retreat. As the current trend continues, intensified monitoring in the TG region is recommended in the next decades.
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Affiliation(s)
- Rongxing Li
- Center for Spatial Information Science and Sustainable Development Applications, Tongji University, 1239 Siping Road, Shanghai, China
- College of Surveying and Geo-Informatics, Tongji University, 1239 Siping Road, Shanghai, China
| | - Yuan Cheng
- Institute for the Conservation of Cultural Heritage, School of Cultural Heritage and Information Management, Shanghai University, Shanghai, China.
| | - Tian Chang
- Center for Spatial Information Science and Sustainable Development Applications, Tongji University, 1239 Siping Road, Shanghai, China
- College of Surveying and Geo-Informatics, Tongji University, 1239 Siping Road, Shanghai, China
| | - David E Gwyther
- School of Earth and Environmental Sciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Martin Forbes
- National School of Surveying, University of Otago, Dunedin, New Zealand
| | - Lu An
- Center for Spatial Information Science and Sustainable Development Applications, Tongji University, 1239 Siping Road, Shanghai, China.
- College of Surveying and Geo-Informatics, Tongji University, 1239 Siping Road, Shanghai, China.
| | - Menglian Xia
- Center for Spatial Information Science and Sustainable Development Applications, Tongji University, 1239 Siping Road, Shanghai, China
- College of Surveying and Geo-Informatics, Tongji University, 1239 Siping Road, Shanghai, China
| | - Xiaohan Yuan
- Center for Spatial Information Science and Sustainable Development Applications, Tongji University, 1239 Siping Road, Shanghai, China
- College of Surveying and Geo-Informatics, Tongji University, 1239 Siping Road, Shanghai, China
| | - Gang Qiao
- Center for Spatial Information Science and Sustainable Development Applications, Tongji University, 1239 Siping Road, Shanghai, China
- College of Surveying and Geo-Informatics, Tongji University, 1239 Siping Road, Shanghai, China
| | - Xiaohua Tong
- Center for Spatial Information Science and Sustainable Development Applications, Tongji University, 1239 Siping Road, Shanghai, China
- College of Surveying and Geo-Informatics, Tongji University, 1239 Siping Road, Shanghai, China
| | - Wenkai Ye
- Center for Spatial Information Science and Sustainable Development Applications, Tongji University, 1239 Siping Road, Shanghai, China
- College of Surveying and Geo-Informatics, Tongji University, 1239 Siping Road, Shanghai, China
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23
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Akhoudas CH, Sallée JB, Reverdin G, Haumann FA, Pauthenet E, Chapman CC, Margirier F, Lo Monaco C, Metzl N, Meilland J, Stranne C. Isotopic evidence for an intensified hydrological cycle in the Indian sector of the Southern Ocean. Nat Commun 2023; 14:2763. [PMID: 37179409 PMCID: PMC10183002 DOI: 10.1038/s41467-023-38425-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 05/02/2023] [Indexed: 05/15/2023] Open
Abstract
The hydrological cycle is expected to intensify in a warming climate. However, observational evidence of such changes in the Southern Ocean is difficult to obtain due to sparse measurements and a complex superposition of changes in precipitation, sea ice, and glacial meltwater. Here we disentangle these signals using a dataset of salinity and seawater oxygen isotope observations collected in the Indian sector of the Southern Ocean. Our results show that the atmospheric water cycle has intensified in this region between 1993 and 2021, increasing the salinity in subtropical surface waters by 0.06 ± 0.07 g kg-1 per decade, and decreasing the salinity in subpolar surface waters by -0.02 ± 0.01 g kg-1 per decade. The oxygen isotope data allow to discriminate the different freshwater processes showing that in the subpolar region, the freshening is largely driven by the increase in net precipitation (by a factor two) while the decrease in sea ice melt is largely balanced by the contribution of glacial meltwater at these latitudes. These changes extend the growing evidence for an acceleration of the hydrological cycle and a melting cryosphere that can be expected from global warming.
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Affiliation(s)
- Camille Hayatte Akhoudas
- Department of Geological Sciences, Stockholm University, Stockholm, Sweden.
- Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden.
| | | | | | - F Alexander Haumann
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- Ludwig-Maximilians-University Munich, Munich, Germany
- Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, NJ, USA
| | - Etienne Pauthenet
- LOPS, CNRS/IFREMER/IRD/UBO, Institut Universitaire Européen de la Mer, Plouzané, France
| | | | - Félix Margirier
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - Nicolas Metzl
- CNRS/IRD/MNHN, LOCEAN, Sorbonne Université, Paris, France
| | | | - Christian Stranne
- Department of Geological Sciences, Stockholm University, Stockholm, Sweden
- Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
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24
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Iizuka M, Seki O, Wilson DJ, Suganuma Y, Horikawa K, van de Flierdt T, Ikehara M, Itaki T, Irino T, Yamamoto M, Hirabayashi M, Matsuzaki H, Sugisaki S. Multiple episodes of ice loss from the Wilkes Subglacial Basin during the Last Interglacial. Nat Commun 2023; 14:2129. [PMID: 37072396 PMCID: PMC10113383 DOI: 10.1038/s41467-023-37325-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 03/10/2023] [Indexed: 04/20/2023] Open
Abstract
The Last Interglacial (LIG: 130,000-115,000 years ago) was a period of warmer global mean temperatures and higher and more variable sea levels than the Holocene (11,700-0 years ago). Therefore, a better understanding of Antarctic ice-sheet dynamics during this interval would provide valuable insights for projecting sea-level change in future warming scenarios. Here we present a high-resolution record constraining ice-sheet changes in the Wilkes Subglacial Basin (WSB) of East Antarctica during the LIG, based on analysis of sediment provenance and an ice melt proxy in a marine sediment core retrieved from the Wilkes Land margin. Our sedimentary records, together with existing ice-core records, reveal dynamic fluctuations of the ice sheet in the WSB, with thinning, melting, and potentially retreat leading to ice loss during both early and late stages of the LIG. We suggest that such changes along the East Antarctic Ice Sheet margin may have contributed to fluctuating global sea levels during the LIG.
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Affiliation(s)
- Mutsumi Iizuka
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan.
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.
- Geological Survey of Japan, The National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
| | - Osamu Seki
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan.
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.
| | - David J Wilson
- London Geochemistry and Isotope Centre (LOGIC), Institute of Earth and Planetary Sciences, University College London and Birkbeck, University of London, London, UK
| | - Yusuke Suganuma
- National Institute of Polar Research, Tachikawa, Japan
- Department of Polar Science, School of Multidisciplinary Sciences, The Graduate University for Advanced Studies (SOKENDAI), Tachikawa, Japan
| | - Keiji Horikawa
- Faculty of Science, Academic Assembly, University of Toyama, Gofuku, Japan
| | - Tina van de Flierdt
- Department of Earth Science and Engineering, Imperial College London, London, UK
| | - Minoru Ikehara
- Marine Core Research Institute (MaCRI), Kochi University, Nankoku, Japan
| | - Takuya Itaki
- Geological Survey of Japan, The National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Tomohisa Irino
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
- Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan
| | - Masanobu Yamamoto
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
- Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan
| | | | - Hiroyuki Matsuzaki
- Micro Analysis Laboratory, Tandem accelerator (MALT), The University of Tokyo, Bunkyo, Japan
| | - Saiko Sugisaki
- Geological Survey of Japan, The National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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25
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Cai W, Gao L, Luo Y, Li X, Zheng X, Zhang X, Cheng X, Jia F, Purich A, Santoso A, Du Y, Holland DM, Shi JR, Xiang B, Xie SP. Southern ocean warming and its climatic impacts. Sci Bull (Beijing) 2023; 68:946-960. [PMID: 37085399 DOI: 10.1016/j.scib.2023.03.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 03/12/2023] [Accepted: 03/13/2023] [Indexed: 04/05/2023]
Abstract
The Southern Ocean has warmed substantially, and up to early 21st century, Antarctic stratospheric ozone depletion and increasing atmospheric CO2 have conspired to intensify Southern Ocean warming. Despite a projected ozone recovery, fluxes to the Southern Ocean of radiative heat and freshwater from enhanced precipitation and melting sea ice, ice shelves, and ice sheets are expected to increase, as is a Southern Ocean westerly poleward intensification. The warming has far-reaching climatic implications for melt of Antarctic ice shelf and ice sheet, sea level rise, and remote circulations such as the intertropical convergence zone and tropical ocean-atmosphere circulations, which affect extreme weathers, agriculture, and ecosystems. The surface warm and freshwater anomalies are advected northward by the mean circulation and deposited into the ocean interior with a zonal-mean maximum at ∼45°S. The increased momentum and buoyancy fluxes enhance the Southern Ocean circulation and water mass transformation, further increasing the heat uptake. Complex processes that operate but poorly understood include interactive ice shelves and ice sheets, oceanic eddies, tropical-polar interactions, and impact of the Southern Ocean response on the climate change forcing itself; in particular, limited observations and low resolution of climate models hinder rapid progress. Thus, projection of Southern Ocean warming will likely remain uncertain, but recent community effort has laid a solid foundation for substantial progress.
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Affiliation(s)
- Wenju Cai
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Physical Oceanography, Ocean University of China, Qingdao 266100, China; Laboratory for Ocean and Climate Dynamics, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Southern Hemisphere Oceans Research, Commonwealth Scientific and Industrial Research Organisation (CSIRO) Oceans and Atmosphere, Hobart 7004, Australia.
| | - Libao Gao
- First Institute of Oceanography and Key Laboratory of Marine Science and Numerical Modeling, Ministry of Natural Resources, Qingdao 266061, China; Laboratory for Regional Oceanography and Numerical Modeling, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Yiyong Luo
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Physical Oceanography, Ocean University of China, Qingdao 266100, China; Laboratory for Ocean and Climate Dynamics, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Xichen Li
- Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Xiaotong Zheng
- Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Physical Oceanography, Ocean University of China, Qingdao 266100, China; Laboratory for Ocean and Climate Dynamics, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Xuebin Zhang
- Center for Southern Hemisphere Oceans Research, Commonwealth Scientific and Industrial Research Organisation (CSIRO) Oceans and Atmosphere, Hobart 7004, Australia
| | - Xuhua Cheng
- College of Oceanography, Hohai University, Nanjing 210098, China
| | - Fan Jia
- Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Ariaan Purich
- Climate Change Research Centre, University of New South Wales, Sydney 2052, Australia; Australian Research Council Centre of Excellence for Climate Extremes, University of New South Wales, Sydney 2052, Australia
| | - Agus Santoso
- Center for Southern Hemisphere Oceans Research, Commonwealth Scientific and Industrial Research Organisation (CSIRO) Oceans and Atmosphere, Hobart 7004, Australia; Australian Research Council Centre of Excellence for Climate Extremes, University of New South Wales, Sydney 2052, Australia
| | - Yan Du
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
| | - David M Holland
- Courant Institute of Mathematical Sciences, New York University, New York NY 10012, USA
| | - Jia-Rui Shi
- Woods Hole Oceanographic Institution, Woods Hole MA 02543, USA
| | - Baoqiang Xiang
- NOAA/Geophysical Fluid Dynamics Laboratory, Princeton NJ 08540, USA; University Corporation for Atmospheric Research, Boulder CO 80307, USA
| | - Shang-Ping Xie
- Scripps Institution of Oceanography, University of California San Diego, La Jolla CA 92093, USA
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26
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Jordan JR, Miles BWJ, Gudmundsson GH, Jamieson SSR, Jenkins A, Stokes CR. Increased warm water intrusions could cause mass loss in East Antarctica during the next 200 years. Nat Commun 2023; 14:1825. [PMID: 37005432 PMCID: PMC10067810 DOI: 10.1038/s41467-023-37553-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 03/22/2023] [Indexed: 04/04/2023] Open
Abstract
The East Antarctic Ice Sheet (EAIS) is currently surrounded by relatively cool water, but climatic shifts have the potential to increase basal melting via intrusions of warm modified Circumpolar Deep Water (mCDW) onto the continental shelf. Here we use an ice sheet model to show that under the current ocean regime, with only limited intrusions of mCDW, the EAIS will likely gain mass over the next 200 years due to the increased precipitation from a warming atmosphere outweighing increased ice discharge due to ice-shelf melting. However, if the ocean regime were to become dominated by greater mCDW intrusions, the EAIS would have a negative mass balance, contributing up to 48 mm of SLE over this time period. Our modelling finds George V Land to be particularly at risk to increased ocean induced melting. With warmer oceans, we also find that a mid range RCP4.5 emissions scenario is likely to result in a more negative mass balance than a high RCP8.5 emissions scenario, as the relative difference between increased precipitation due to a warming atmosphere and increased ice discharge due to a warming ocean is more negative in the mid range RCP4.5 emission scenario.
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Affiliation(s)
- James R Jordan
- Department of Geography and Environmental Sciences, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, UK.
- Laboratoire de Glaciologie, Université libre de Bruxelles (ULB), Brussels, Belgium.
| | - B W J Miles
- Department of Geography, Durham University, Durham, DH1 3LE, UK
- School of Geosciences, University of Edinburgh, Edinburgh, UK
| | - G H Gudmundsson
- Department of Geography and Environmental Sciences, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, UK
| | - S S R Jamieson
- Department of Geography, Durham University, Durham, DH1 3LE, UK
| | - A Jenkins
- Department of Geography and Environmental Sciences, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, UK
| | - C R Stokes
- Department of Geography, Durham University, Durham, DH1 3LE, UK
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27
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Davison BJ, Hogg AE, Rigby R, Veldhuijsen S, van Wessem JM, van den Broeke MR, Holland PR, Selley HL, Dutrieux P. Sea level rise from West Antarctic mass loss significantly modified by large snowfall anomalies. Nat Commun 2023; 14:1479. [PMID: 36932070 PMCID: PMC10023770 DOI: 10.1038/s41467-023-36990-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 02/27/2023] [Indexed: 03/18/2023] Open
Abstract
Mass loss from the West Antarctic Ice Sheet is dominated by glaciers draining into the Amundsen Sea Embayment (ASE), yet the impact of anomalous precipitation on the mass balance of the ASE is poorly known. Here we present a 25-year (1996-2021) record of ASE input-output mass balance and evaluate how two periods of anomalous precipitation affected its sea level contribution. Since 1996, the ASE has lost 3331 ± 424 Gt ice, contributing 9.2 ± 1.2 mm to global sea level. Overall, surface mass balance anomalies contributed little (7.7%) to total mass loss; however, two anomalous precipitation events had larger, albeit short-lived, impacts on rates of mass change. During 2009-2013, persistently low snowfall led to an additional 51 ± 4 Gt yr-1 mass loss in those years (contributing positively to the total loss of 195 ± 4 Gt yr-1). Contrastingly, extreme precipitation in the winters of 2019 and 2020 decreased mass loss by 60 ± 16 Gt yr-1 during those years (contributing negatively to the total loss of 107 ± 15 Gt yr-1). These results emphasise the important impact of extreme snowfall variability on the short-term sea level contribution from West Antarctica.
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Affiliation(s)
| | - Anna E Hogg
- School of Earth and Environment, University of Leeds, Leeds, UK
| | - Richard Rigby
- School of Earth and Environment, University of Leeds, Leeds, UK
| | - Sanne Veldhuijsen
- Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Jan Melchior van Wessem
- Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Michiel R van den Broeke
- Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, the Netherlands
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28
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Lawrence JD, Washam PM, Stevens C, Hulbe C, Horgan HJ, Dunbar G, Calkin T, Stewart C, Robinson N, Mullen AD, Meister MR, Hurwitz BC, Quartini E, Dichek DJG, Spears A, Schmidt BE. Crevasse refreezing and signatures of retreat observed at Kamb Ice Stream grounding zone. NATURE GEOSCIENCE 2023; 16:238-243. [PMID: 36920161 PMCID: PMC10005960 DOI: 10.1038/s41561-023-01129-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
Ice streams flowing into Ross Ice Shelf are presently responsible for around 10% of the mass flux from West Antarctica, with the noteworthy exception of Kamb Ice Stream, which stagnated in the late 1800s. The subsequent reduction in ice supply led to grounding-line retreat at the coastal margin where Kamb transitions into the floating Ross Ice Shelf. Grounding-line migration is linked to broader changes in ice-sheet mass balance and sea level, but our understanding of related ice, ocean and seafloor interactions is limited by the difficulty in accessing these remote regions. Here we report in situ observations from an underwater vehicle deployed at Kamb that show how fine-scale variability in ice and ocean structure combine to influence a diversity of ice-ocean interactions. We found a stratified water column within a tenth of a degree of freezing at the ice base and mapped basal crevasses with supercooled water and active marine ice formation. At the seafloor, we interpret parallel ridges as crevasse impressions left as the ice lifted off during grounding-line retreat. These observations from a recently ungrounded sub-shelf environment illuminate both the geomorphological signatures of past grounding-line retreat and the fine-scale sensitivity of ongoing ice-ocean interactions to ice topography.
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Affiliation(s)
- J. D. Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Honeybee Robotics, Exploration Systems, Altadena, CA USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - P. M. Washam
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - C. Stevens
- Ocean Dynamics Group, National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
- Department of Physics, University of Auckland, Auckland, New Zealand
| | - C. Hulbe
- School of Surveying, University of Otago, Dunedin, New Zealand
| | - H. J. Horgan
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - G. Dunbar
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - T. Calkin
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - C. Stewart
- Ocean Dynamics Group, National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
| | - N. Robinson
- Ocean Dynamics Group, National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
| | - A. D. Mullen
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - M. R. Meister
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - B. C. Hurwitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
| | - E. Quartini
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - D. J. G. Dichek
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - A. Spears
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
| | - B. E. Schmidt
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
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29
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Park JY, Schloesser F, Timmermann A, Choudhury D, Lee JY, Nellikkattil AB. Future sea-level projections with a coupled atmosphere-ocean-ice-sheet model. Nat Commun 2023; 14:636. [PMID: 36788205 PMCID: PMC9929224 DOI: 10.1038/s41467-023-36051-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 01/12/2023] [Indexed: 02/16/2023] Open
Abstract
Climate-forced, offline ice-sheet model simulations have been used extensively in assessing how much ice-sheets can contribute to future global sea-level rise. Typically, these model projections do not account for the two-way interactions between ice-sheets and climate. To quantify the impact of ice-ocean-atmosphere feedbacks, here we conduct greenhouse warming simulations with a coupled global climate-ice-sheet model of intermediate complexity. Following the Shared Socioeconomic Pathway (SSP) 1-1.9, 2-4.5, 5-8.5 emission scenarios, the model simulations ice-sheet contributions to global sea-level rise by 2150 of 0.2 ± 0.01, 0.5 ± 0.01 and 1.4 ± 0.1 m, respectively. Antarctic ocean-ice-sheet-ice-shelf interactions enhance future subsurface basal melting, while freshwater-induced atmospheric cooling reduces surface melting and iceberg calving. The combined effect is likely to decelerate global sea-level rise contributions from Antarctica relative to the uncoupled climate-forced ice-sheet model configuration. Our results demonstrate that estimates of future sea-level rise fundamentally depend on the complex interactions between ice-sheets, icebergs, ocean and the atmosphere.
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Affiliation(s)
- Jun-Young Park
- Center for Climate Physics, Institute for Basic Science, Busan, Republic of Korea. .,Department of Climate System, Pusan National University, Busan, Republic of Korea.
| | - Fabian Schloesser
- International Pacific Research Center, University of Hawaii, Honolulu, Hawaii, USA.
| | - Axel Timmermann
- grid.410720.00000 0004 1784 4496Center for Climate Physics, Institute for Basic Science, Busan, Republic of Korea ,grid.262229.f0000 0001 0719 8572Pusan National University, Busan, Republic of Korea
| | - Dipayan Choudhury
- grid.410720.00000 0004 1784 4496Center for Climate Physics, Institute for Basic Science, Busan, Republic of Korea ,grid.1005.40000 0004 4902 0432Climate Change Research Centre, University of New South Wales, Sydney, NSW Australia
| | - June-Yi Lee
- grid.410720.00000 0004 1784 4496Center for Climate Physics, Institute for Basic Science, Busan, Republic of Korea ,grid.262229.f0000 0001 0719 8572Department of Climate System, Pusan National University, Busan, Republic of Korea ,grid.262229.f0000 0001 0719 8572Research Center for Climate Sciences, Pusan National University, Busan, Republic of Korea
| | - Arjun Babu Nellikkattil
- grid.410720.00000 0004 1784 4496Center for Climate Physics, Institute for Basic Science, Busan, Republic of Korea ,grid.262229.f0000 0001 0719 8572Department of Climate System, Pusan National University, Busan, Republic of Korea
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Davis PED, Nicholls KW, Holland DM, Schmidt BE, Washam P, Riverman KL, Arthern RJ, Vaňková I, Eayrs C, Smith JA, Anker PGD, Mullen AD, Dichek D, Lawrence JD, Meister MM, Clyne E, Basinski-Ferris A, Rignot E, Queste BY, Boehme L, Heywood KJ, Anandakrishnan S, Makinson K. Suppressed basal melting in the eastern Thwaites Glacier grounding zone. Nature 2023; 614:479-485. [PMID: 36792735 PMCID: PMC9931584 DOI: 10.1038/s41586-022-05586-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 11/22/2022] [Indexed: 02/17/2023]
Abstract
Thwaites Glacier is one of the fastest-changing ice-ocean systems in Antarctica1-3. Much of the ice sheet within the catchment of Thwaites Glacier is grounded below sea level on bedrock that deepens inland4, making it susceptible to rapid and irreversible ice loss that could raise the global sea level by more than half a metre2,3,5. The rate and extent of ice loss, and whether it proceeds irreversibly, are set by the ocean conditions and basal melting within the grounding-zone region where Thwaites Glacier first goes afloat3,6, both of which are largely unknown. Here we show-using observations from a hot-water-drilled access hole-that the grounding zone of Thwaites Eastern Ice Shelf (TEIS) is characterized by a warm and highly stable water column with temperatures substantially higher than the in situ freezing point. Despite these warm conditions, low current speeds and strong density stratification in the ice-ocean boundary layer actively restrict the vertical mixing of heat towards the ice base7,8, resulting in strongly suppressed basal melting. Our results demonstrate that the canonical model of ice-shelf basal melting used to generate sea-level projections cannot reproduce observed melt rates beneath this critically important glacier, and that rapid and possibly unstable grounding-line retreat may be associated with relatively modest basal melt rates.
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Affiliation(s)
| | | | - David M Holland
- Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
- Center for Global Sea Level Change, New York University Abu Dhabi, Abu Dhabi, UAE
| | | | - Peter Washam
- Department of Astronomy, Cornell University, Ithaca, NY, USA
| | - Kiya L Riverman
- Department of Environmental Studies, University of Portland, Portland, OR, USA
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | | | | | - Clare Eayrs
- Center for Global Sea Level Change, New York University Abu Dhabi, Abu Dhabi, UAE
| | | | | | - Andrew D Mullen
- Department of Astronomy, Cornell University, Ithaca, NY, USA
| | - Daniel Dichek
- Department of Astronomy, Cornell University, Ithaca, NY, USA
| | | | | | - Elisabeth Clyne
- Department of Geosciences, Pennsylvania State University, State College, PA, USA
- Environmental Studies, Lewis & Clark College, Portland, OR, USA
| | | | - Eric Rignot
- Department of Earth System Science, University of California, Irvine, Irvine, CA, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Bastien Y Queste
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Lars Boehme
- Scottish Oceans Institute, University of St Andrews, St. Andrews, UK
| | - Karen J Heywood
- Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, UK
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Schmidt BE, Washam P, Davis PED, Nicholls KW, Holland DM, Lawrence JD, Riverman KL, Smith JA, Spears A, Dichek DJG, Mullen AD, Clyne E, Yeager B, Anker P, Meister MR, Hurwitz BC, Quartini ES, Bryson FE, Basinski-Ferris A, Thomas C, Wake J, Vaughan DG, Anandakrishnan S, Rignot E, Paden J, Makinson K. Heterogeneous melting near the Thwaites Glacier grounding line. Nature 2023; 614:471-478. [PMID: 36792738 PMCID: PMC9931587 DOI: 10.1038/s41586-022-05691-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 12/22/2022] [Indexed: 02/17/2023]
Abstract
Thwaites Glacier represents 15% of the ice discharge from the West Antarctic Ice Sheet and influences a wider catchment1-3. Because it is grounded below sea level4,5, Thwaites Glacier is thought to be susceptible to runaway retreat triggered at the grounding line (GL) at which the glacier reaches the ocean6,7. Recent ice-flow acceleration2,8 and retreat of the ice front8-10 and GL11,12 indicate that ice loss will continue. The relative impacts of mechanisms underlying recent retreat are however uncertain. Here we show sustained GL retreat from at least 2011 to 2020 and resolve mechanisms of ice-shelf melt at the submetre scale. Our conclusions are based on observations of the Thwaites Eastern Ice Shelf (TEIS) from an underwater vehicle, extending from the GL to 3 km oceanward and from the ice-ocean interface to the sea floor. These observations show a rough ice base above a sea floor sloping upward towards the GL and an ocean cavity in which the warmest water exceeds 2 °C above freezing. Data closest to the ice base show that enhanced melting occurs along sloped surfaces that initiate near the GL and evolve into steep-sided terraces. This pronounced melting along steep ice faces, including in crevasses, produces stratification that suppresses melt along flat interfaces. These data imply that slope-dependent melting sculpts the ice base and acts as an important response to ocean warming.
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Affiliation(s)
- B E Schmidt
- Department of Astronomy, Cornell University, Ithaca, NY, USA.
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA.
| | - P Washam
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | | | | | - D M Holland
- Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
- Center for Global Sea Level Change, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - J D Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - K L Riverman
- Department of Environmental Studies, University of Portland, Portland, OR, USA
| | - J A Smith
- British Antarctic Survey, Cambridge, UK
| | - A Spears
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - D J G Dichek
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - A D Mullen
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - E Clyne
- Department of Geosciences, Pennsylvania State University, State College, PA, USA
- Environmental Studies, Lewis & Clark College, Portland, OR, USA
| | - B Yeager
- Center for Global Sea Level Change, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - P Anker
- British Antarctic Survey, Cambridge, UK
| | - M R Meister
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - B C Hurwitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - E S Quartini
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
| | - F E Bryson
- Department of Astronomy, Cornell University, Ithaca, NY, USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - A Basinski-Ferris
- Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
| | - C Thomas
- British Antarctic Survey, Cambridge, UK
| | - J Wake
- British Antarctic Survey, Cambridge, UK
| | | | - S Anandakrishnan
- Department of Geosciences, Pennsylvania State University, State College, PA, USA
| | - E Rignot
- Department of Earth System Science, University of California, Irvine, Irvine, CA, USA
| | - J Paden
- Center for Remote Sensing and Integrated Systems, University of Kansas, Lawrence, KS, USA
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Christie FDW, Steig EJ, Gourmelen N, Tett SFB, Bingham RG. Inter-decadal climate variability induces differential ice response along Pacific-facing West Antarctica. Nat Commun 2023; 14:93. [PMID: 36646677 PMCID: PMC9842681 DOI: 10.1038/s41467-022-35471-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 12/05/2022] [Indexed: 01/18/2023] Open
Abstract
West Antarctica has experienced dramatic ice losses contributing to global sea-level rise in recent decades, particularly from Pine Island and Thwaites glaciers. Although these ice losses manifest an ongoing Marine Ice Sheet Instability, projections of their future rate are confounded by limited observations along West Antarctica's coastal perimeter with respect to how the pace of retreat can be modulated by variations in climate forcing. Here, we derive a comprehensive, 12-year record of glacier retreat around West Antarctica's Pacific-facing margin and compare this dataset to contemporaneous estimates of ice flow, mass loss, the state of the Southern Ocean and the atmosphere. Between 2003 and 2015, rates of glacier retreat and acceleration were extensive along the Bellingshausen Sea coastline, but slowed along the Amundsen Sea. We attribute this to an interdecadal suppression of westerly winds in the Amundsen Sea, which reduced warm water inflow to the Amundsen Sea Embayment. Our results provide direct observations that the pace, magnitude and extent of ice destabilization around West Antarctica vary by location, with the Amundsen Sea response most sensitive to interdecadal atmosphere-ocean variability. Thus, model projections accounting for regionally resolved ice-ocean-atmosphere interactions will be important for predicting accurately the short-term evolution of the Antarctic Ice Sheet.
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Affiliation(s)
- Frazer D. W. Christie
- grid.5335.00000000121885934Scott Polar Research Institute, University of Cambridge, Cambridge, CB2 1ER UK ,grid.4305.20000 0004 1936 7988School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP UK
| | - Eric J. Steig
- grid.34477.330000000122986657Department of Earth & Space Sciences, University of Washington, Seattle, WA 98195-1310 USA
| | - Noel Gourmelen
- grid.4305.20000 0004 1936 7988School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP UK
| | - Simon F. B. Tett
- grid.4305.20000 0004 1936 7988School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP UK
| | - Robert G. Bingham
- grid.4305.20000 0004 1936 7988School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP UK
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Ocean variability beneath Thwaites Eastern Ice Shelf driven by the Pine Island Bay Gyre strength. Nat Commun 2022; 13:7840. [PMID: 36543787 PMCID: PMC9772408 DOI: 10.1038/s41467-022-35499-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
West Antarctic ice-shelf thinning is primarily caused by ocean-driven basal melting. Here we assess ocean variability below Thwaites Eastern Ice Shelf (TEIS) and reveal the importance of local ocean circulation and sea-ice. Measurements obtained from two sub-ice-shelf moorings, spanning January 2020 to March 2021, show warming of the ice-shelf cavity and an increase in meltwater fraction of the upper sub-ice layer. Combined with ocean modelling results, our observations suggest that meltwater from Pine Island Ice Shelf feeds into the TEIS cavity, adding to horizontal heat transport there. We propose that a weakening of the Pine Island Bay gyre caused by prolonged sea-ice cover from April 2020 to March 2021 allowed meltwater-enriched waters to enter the TEIS cavity, which increased the temperature of the upper layer. Our study highlights the sensitivity of ocean circulation beneath ice shelves to local atmosphere-sea-ice-ocean forcing in neighbouring open oceans.
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Soil Geochemical Properties Influencing the Diversity of Bacteria and Archaea in Soils of the Kitezh Lake Area, Antarctica. BIOLOGY 2022; 11:biology11121855. [PMID: 36552364 PMCID: PMC9775965 DOI: 10.3390/biology11121855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 12/06/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
It is believed that polar regions are influenced by global warming more significantly, and because polar regions are less affected by human activities, they have certain reference values for future predictions. This study aimed to investigate the effects of climate warming on soil microbial communities in lake areas, taking Kitezh Lake, Antarctica as the research area. Below-peak soil, intertidal soil, and sediment were taken at the sampling sites, and we hypothesized that the diversity and composition of the bacterial and archaeal communities were different among the three sampling sites. Through 16S rDNA sequencing and analysis, bacteria and archaea with high abundance were obtained. Based on canonical correspondence analysis and redundancy analysis, pH and phosphate had a great influence on the bacterial community whereas pH and nitrite had a great influence on the archaeal community. Weighted gene coexpression network analysis was used to find the hub bacteria and archaea related to geochemical factors. The results showed that in addition to pH, phosphate, and nitrite, moisture content, ammonium, nitrate, and total carbon content also play important roles in microbial diversity and structure at different sites by changing the abundance of some key microbiota.
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Marini S, Bonofiglio F, Corgnati LP, Bordone A, Schiaparelli S, Peirano A. Long-term High Resolution Image Dataset of Antarctic Coastal Benthic Fauna. Sci Data 2022; 9:750. [PMID: 36463241 PMCID: PMC9719491 DOI: 10.1038/s41597-022-01865-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 11/23/2022] [Indexed: 12/07/2022] Open
Abstract
Antarctica is a remote place, the continent is covered by ice and its surrounding coastal areas are frozen for the majority of the year. Due to its peculiarity the observation of the underwater organisms is particularly difficult, complicated by logistic factors. We present a long-term dataset consisting of 755 images acquired by using a non-invasive, autonomous imaging device and encompassing both the Antarctic daylight and dark periods, including the corresponding transition phases. All images have the same field of view showing the benthic fauna and part of the water column above, including fishes present in the monitored period. All the images are manually annotated after a visual inspection performed by expert biologists. The extended monitoring period and the annotated images make the dataset a valuable benchmark suitable for studying the dynamics of the long-term Antarctic underwater fauna as well as for developing and testing algorithms for automated image analysis focused on the recognition and classification of the Antarctic organisms and the automated analysis of their long-term dynamics.
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Affiliation(s)
- Simone Marini
- National Research Council of Italy (CNR), Institute of Marine Sciences, La Spezia, 19132, Italy.
- Stazione Zoologica Anton Dohrn, Naples, 80121, Italy.
| | - Federico Bonofiglio
- National Research Council of Italy (CNR), Institute of Marine Sciences, La Spezia, 19132, Italy
| | - Lorenzo Paolo Corgnati
- National Research Council of Italy (CNR), Institute of Marine Sciences, La Spezia, 19132, Italy
| | - Andrea Bordone
- ENEA-Marine Environment Research Centre, La Spezia, 19132, Italy
| | | | - Andrea Peirano
- ENEA-Marine Environment Research Centre, La Spezia, 19132, Italy
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36
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van de Wal RSW, Nicholls RJ, Behar D, McInnes K, Stammer D, Lowe JA, Church JA, DeConto R, Fettweis X, Goelzer H, Haasnoot M, Haigh ID, Hinkel J, Horton BP, James TS, Jenkins A, LeCozannet G, Levermann A, Lipscomb WH, Marzeion B, Pattyn F, Payne AJ, Pfeffer WT, Price SF, Seroussi H, Sun S, Veatch W, White K. A High-End Estimate of Sea Level Rise for Practitioners. EARTH'S FUTURE 2022; 10:e2022EF002751. [PMID: 36590252 PMCID: PMC9787942 DOI: 10.1029/2022ef002751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 09/23/2022] [Accepted: 10/03/2022] [Indexed: 06/17/2023]
Abstract
Sea level rise (SLR) is a long-lasting consequence of climate change because global anthropogenic warming takes centuries to millennia to equilibrate for the deep ocean and ice sheets. SLR projections based on climate models support policy analysis, risk assessment and adaptation planning today, despite their large uncertainties. The central range of the SLR distribution is estimated by process-based models. However, risk-averse practitioners often require information about plausible future conditions that lie in the tails of the SLR distribution, which are poorly defined by existing models. Here, a community effort combining scientists and practitioners builds on a framework of discussing physical evidence to quantify high-end global SLR for practitioners. The approach is complementary to the IPCC AR6 report and provides further physically plausible high-end scenarios. High-end estimates for the different SLR components are developed for two climate scenarios at two timescales. For global warming of +2°C in 2100 (RCP2.6/SSP1-2.6) relative to pre-industrial values our high-end global SLR estimates are up to 0.9 m in 2100 and 2.5 m in 2300. Similarly, for a (RCP8.5/SSP5-8.5), we estimate up to 1.6 m in 2100 and up to 10.4 m in 2300. The large and growing differences between the scenarios beyond 2100 emphasize the long-term benefits of mitigation. However, even a modest 2°C warming may cause multi-meter SLR on centennial time scales with profound consequences for coastal areas. Earlier high-end assessments focused on instability mechanisms in Antarctica, while here we emphasize the importance of the timing of ice shelf collapse around Antarctica. This is highly uncertain due to low understanding of the driving processes. Hence both process understanding and emission scenario control high-end SLR.
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Affiliation(s)
- R. S. W. van de Wal
- Institute for Marine and Atmospheric Research UtrechtUtrecht UniversityTA UtrechtThe Netherlands
- Department of Physical GeographyUtrecht UniversityTA UtrechtThe Netherlands
| | - R. J. Nicholls
- Tyndall Centre for Climate Change ResearchUniversity of East AngliaNorwichUK
| | - D. Behar
- San Francisco Public Utilities CommissionSan FranciscoCAUSA
| | - K. McInnes
- Climate Change Research CentreUNSW AustraliaSydneyNSWAustralia
| | - D. Stammer
- Centrum für Erdsystemforschung und NachhaltigkeitUniversität HamburgHamburgGermany
| | - J. A. Lowe
- Met Office Hadley CentreExeterUK
- Priestley CentreUniversity of LeedsLeedsUK
| | - J. A. Church
- Climate Change Research CentreUNSW AustraliaSydneyNSWAustralia
- Australian Centre for Excellence in Antarctic Science (ACEAS)University of TasmaniaHobartTASAustralia
| | - R. DeConto
- Department of GeosciencesUniversity of Massachusetts‐AmherstAmherstMAUSA
| | - X. Fettweis
- Department of GeographySPHERES Research UnitUniversity of LiègeLiègeBelgium
| | - H. Goelzer
- NORCE Norwegian Research CentreBjerknes Centre for Climate ResearchBergenNorway
| | | | - I. D. Haigh
- School of Ocean and Earth ScienceUniversity of SouthamptonNational Oceanography CentreSouthamptonUK
| | - J. Hinkel
- Adaptation and Social LearningGlobal Climate ForumBerlinGermany
| | - B. P. Horton
- Earth Observatory of SingaporeNanyang Technological UniversitySingaporeSingapore
- Asian School of the EnvironmentNanyang Technological UniversitySingaporeSingapore
| | - T. S. James
- Natural Resources CanadaGeological Survey of CanadaSidneyBCCanada
| | - A. Jenkins
- Department of Geography and Environmental SciencesNorthumbria UniversityNewcastle upon TyneUK
| | - G. LeCozannet
- Coastal Risks and Climate Change UnitRisks and Prevention DivisionBRGMOrléansFrance
| | - A. Levermann
- Potsdam Institute for Climate Impact ResearchPotsdamGermany
- LDEOColumbia UniversityNew YorkNYUSA
- Physics InstituteUniversity of PotsdamPotsdamGermany
| | - W. H. Lipscomb
- Climate and Global Dynamics LaboratoryNational Center for Atmospheric ResearchBoulderCOUSA
| | - B. Marzeion
- Institute of Geography and MARUM ‐ Center for Marine Environmental SciencesUniversity of BremenBremenGermany
| | - F. Pattyn
- Laboratoire de GlaciologieUniversité libre de BruxellesBrusselsBelgium
| | - A. J. Payne
- School of Geographical SciencesUniversity of BristolBristolUK
| | - W. T. Pfeffer
- INSTAAR and Department of Civil, Environmental, Architectural EngineeringUniversity of ColoradoBoulderCOUSA
| | - S. F. Price
- Theoretical DivisionLos Alamos National LaboratoryLos AlamosNMUSA
| | - H. Seroussi
- Thayer School of EngineeringDartmouth CollegeHanoverNHUSA
| | - S. Sun
- Coastal Risks and Climate Change UnitRisks and Prevention DivisionBRGMOrléansFrance
| | - W. Veatch
- US Army Corps of Engineers, HeadquartersWashingtonDCUSA
| | - K. White
- US Department of DefenseOffice of the Deputy Assistant Secretary of Defense (Environment and Energy Resilience)DCWashingtonUSA
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Oelerich R, Heywood KJ, Damerell GM, Thompson AF. Wind-Induced Variability of Warm Water on the Southern Bellingshausen Sea Continental Shelf. JOURNAL OF GEOPHYSICAL RESEARCH. OCEANS 2022; 127:e2022JC018636. [PMID: 36589532 PMCID: PMC9787697 DOI: 10.1029/2022jc018636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 10/08/2022] [Accepted: 10/19/2022] [Indexed: 06/17/2023]
Abstract
The Bellingshausen Sea hosts heat transport onto the continental shelf, potentially enhancing ice shelf basal melt. Here, we use the GLORYS12V1 1993-2018 reanalysis to identify physical processes that set seasonal and interannual variability of water mass properties in the Eltanin and Latady Bays on the southern Bellingshausen Sea continental shelf. Annual means of potential temperature from 300 m to the seabed reveal interannual variability and allow separation into warm and cold regimes. The Amundsen Sea Low (ASL) is more intense and extends further east during the warm regime than the cold regime. In the warm regime, a wind-induced reduction of sea ice concentration near the coast increases surface heat loss, convection, and formation of cold dense water in winter, associated with a decrease in heat content of the southern Bellingshausen Sea over time and a net northward heat transport. In contrast, in the cold regime, increased sea ice concentration reduces surface heat loss and thus formation of cold, dense water. Combined with an increase in heat content over time and a net southward heat transport, this results in a warming of the southern Bellingshausen Sea. This suggests that variability in the deep water temperature in the southern Bellingshausen Sea is primarily due to local surface heat fluxes above the shelf. The variability of surface heat fluxes is related to the variability of the ASL and its influence on sea ice extent and local formation of cold, dense water in winter.
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Affiliation(s)
- Ria Oelerich
- Centre for Ocean and Atmospheric SciencesSchool of Environmental SciencesUniversity of East AngliaNorwichUK
| | - Karen J. Heywood
- Centre for Ocean and Atmospheric SciencesSchool of Environmental SciencesUniversity of East AngliaNorwichUK
| | - Gillian M. Damerell
- Centre for Ocean and Atmospheric SciencesSchool of Environmental SciencesUniversity of East AngliaNorwichUK
| | - Andrew F. Thompson
- Environmental Science and EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
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38
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Medley B, Lenaerts JTM, Dattler M, Keenan E, Wever N. Predicting Antarctic Net Snow Accumulation at the Kilometer Scale and Its Impact on Observed Height Changes. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2022GL099330. [PMID: 36589269 PMCID: PMC9787652 DOI: 10.1029/2022gl099330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 09/26/2022] [Accepted: 09/26/2022] [Indexed: 06/17/2023]
Abstract
Sub-grid-scale processes occurring at or near the surface of an ice sheet have a potentially large impact on local and integrated net accumulation of snow via redistribution and sublimation. Given observational complexity, they are either ignored or parameterized over large-length scales. Here, we train random forest (RF) models to predict variability in net accumulation over the Antarctic Ice Sheet using atmospheric variables and topographic characteristics as predictors at 1 km resolution. Observations of net snow accumulation from both in situ and airborne radar data provide the input observable targets needed to train the RF models. We find that local net accumulation deviates by as much as 172% of the atmospheric model mean. The correlation in space between the predicted net accumulation variability and satellite-derived surface-height change indicates that surface processes operate differently through time, driven largely by the seasonal anomalies in snow accumulation.
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Affiliation(s)
- B. Medley
- Cryospheric Sciences LaboratoryNASA Goddard Space Flight CenterGreenbeltMDUSA
| | - J. T. M. Lenaerts
- Department of Atmospheric and Oceanic SciencesUniversity of Colorado BoulderBoulderCOUSA
| | - M. Dattler
- Cryospheric Sciences LaboratoryNASA Goddard Space Flight CenterGreenbeltMDUSA
- Department of Atmospheric and Oceanic ScienceUniversity of Maryland College ParkCollege ParkMDUSA
| | - E. Keenan
- Department of Atmospheric and Oceanic SciencesUniversity of Colorado BoulderBoulderCOUSA
| | - N. Wever
- Department of Atmospheric and Oceanic SciencesUniversity of Colorado BoulderBoulderCOUSA
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39
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Bart PJ, Kratochvil M. A paleo-perspective on West Antarctic Ice Sheet retreat. Sci Rep 2022; 12:17693. [PMID: 36271134 PMCID: PMC9586952 DOI: 10.1038/s41598-022-22450-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/14/2022] [Indexed: 01/18/2023] Open
Abstract
Geological records of ice sheet collapse can provide perspective on the ongoing retreat of grounded and floating ice. An abrupt retreat of the West Antarctic Ice Sheet (WAIS) that occurred during the early deglaciation is well recorded on the eastern Ross Sea continental shelf. There, an ice shelf breakup at 12.3 ± 0.6 cal. (calibrated) kyr BP caused accelerated ice-mass loss from the Bindschadler Ice Stream (BIS). The accelerated mass loss led to a significant negative mass balance that re-organized WAIS flow across the central and eastern Ross Sea. By ~ 11.5 ± 0.3 cal kyr BP, dynamic thinning of grounded ice triggered a retreat that opened a ~ 200-km grounding-line embayment on the Whales Deep Basin (WDB) middle continental shelf. Here, we reconstruct the pattern, duration and rate of retreat from a backstepping succession of small-scale grounding-zone ridges that formed on the embayment's eastern flank. We used two end-member paleo-sediment fluxes, i.e., accumulation rates, to convert the cumulative sediment volumes of the ridge field to elapsed time for measured distances of grounding-line retreat. The end-members fluxes correspond to deposition rates for buttressed and unbuttressed ice stream flow. Both scenarios require sustained rapid retreat that exceeded several centuries. Grounding-line retreat is estimated to have averaged between ~ 100 ± 32 and ~ 700 ± 79 ma-1. The evidence favors the latter scenario because iceberg furrows that cross cut the ridges in deep water require weakly buttressed flow as the embayment opened. In comparison with the modern grounding-zone dynamics, this paleo-perspective provides confidence in model projections that a large-scale sustained contraction of grounded ice is underway in several Pacific-Ocean sectors of the WAIS.
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Affiliation(s)
- Philip J. Bart
- grid.64337.350000 0001 0662 7451Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803 USA
| | - Matthew Kratochvil
- grid.64337.350000 0001 0662 7451Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803 USA
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40
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Potential for perceived failure of stratospheric aerosol injection deployment. Proc Natl Acad Sci U S A 2022; 119:e2210036119. [PMID: 36166478 PMCID: PMC9546631 DOI: 10.1073/pnas.2210036119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
As anthropogenic activities warm the Earth, the fundamental solution of reducing greenhouse gas emissions remains elusive. Given this mitigation gap, global warming may lead to intolerable climate changes as adaptive capacity is exceeded. Thus, there is emerging interest in solar radiation modification, which is the process of deliberately increasing Earth's albedo to cool the planet. Stratospheric aerosol injection (SAI)-the theoretical deployment of particles in the stratosphere to enhance reflection of incoming solar radiation-is one strategy to slow, pause, or reverse global warming. If SAI is ever pursued, it will likely be for a specific aim, such as affording time to implement mitigation strategies, lessening extremes, or reducing the odds of reaching a biogeophysical tipping point. Using an ensemble climate model experiment that simulates the deployment of SAI in the context of an intermediate greenhouse gas trajectory, we quantified the probability that internal climate variability masks the effectiveness of SAI deployment on regional temperatures. We found that while global temperature was stabilized, substantial land areas continued to experience warming. For example, in the SAI scenario we explored, up to 55% of the global population experienced rising temperatures over the decade following SAI deployment and large areas exhibited high probability of extremely hot years. These conditions could cause SAI to be perceived as a failure. Countries with the largest economies experienced some of the largest probabilities of this perceived failure. The potential for perceived failure could therefore have major implications for policy decisions in the years immediately following SAI deployment.
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41
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Economic impacts of melting of the Antarctic Ice Sheet. Nat Commun 2022; 13:5819. [PMID: 36192387 PMCID: PMC9529876 DOI: 10.1038/s41467-022-33406-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 09/16/2022] [Indexed: 11/23/2022] Open
Abstract
Melting of the Antarctic Ice Sheet (AIS) could contribute metres to global sea level rise (SLR) in the long run. We couple models of AIS melting due to rising temperatures, SLR, and economic impacts of SLR on coastlines worldwide. We report SLR projections close to the latest literature. Coastal impacts of AIS melting are very heterogeneous: they are large as a share of GDP in one to two dozen countries, primarily Small Island Developing States. Costs can be reduced dramatically by economically efficient, proactive coastal planning: relative to a no adaptation scenario, optimal adaptation reduces total costs by roughly an order of magnitude. AIS melting increases the social cost of carbon by an expected 7% on low to medium emissions scenarios and with moderate discounting. There is a tail risk of very large increases in the social cost of carbon, particularly on a high emissions scenario. Melting of the Antarctic Ice Sheet is projected to impose severe costs on Small Island Developing States, and increase the worldwide social cost of carbon emissions, but costs could be reduced dramatically by efficient, proactive coastal planning.
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42
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Maclennan ML, Lenaerts JTM, Shields C, Wille JD. Contribution of Atmospheric Rivers to Antarctic Precipitation. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2022GL100585. [PMID: 36246739 PMCID: PMC9539845 DOI: 10.1029/2022gl100585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 08/24/2022] [Indexed: 06/16/2023]
Abstract
Atmospheric rivers (ARs) are efficient mechanisms for transporting atmospheric moisture from low latitudes to the Antarctic Ice Sheet (AIS). While AR events occur infrequently, they can lead to extreme precipitation and surface melt events on the AIS. Here we estimate the contribution of ARs to total Antarctic precipitation, by combining precipitation from atmospheric reanalyses and a polar-specific AR detection algorithm. We show that ARs contribute substantially to Antarctic precipitation, especially in East Antarctica at elevations below 3,000 m. ARs contribute substantially to year-to-year variability in Antarctic precipitation. Our results highlight that ARs are an important component for understanding present and future Antarctic mass balance trends and variability.
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Affiliation(s)
- Michelle L. Maclennan
- Department of Atmospheric and Oceanic SciencesUniversity of Colorado BoulderBoulderCOUSA
| | - Jan T. M. Lenaerts
- Department of Atmospheric and Oceanic SciencesUniversity of Colorado BoulderBoulderCOUSA
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43
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Dawson EJ, Schroeder DM, Chu W, Mantelli E, Seroussi H. Ice mass loss sensitivity to the Antarctic ice sheet basal thermal state. Nat Commun 2022; 13:4957. [PMID: 36104329 PMCID: PMC9474861 DOI: 10.1038/s41467-022-32632-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 08/05/2022] [Indexed: 11/30/2022] Open
Abstract
Sea-level rise projections rely on accurate predictions of ice mass loss from Antarctica. Climate change promotes greater mass loss by destabilizing ice shelves and accelerating the discharge of upstream grounded ice. Mass loss is further exacerbated by mechanisms such as the Marine Ice Sheet Instability and the Marine Ice Cliff Instability. However, the effect of basal thermal state changes of grounded ice remains largely unexplored. Here, we use numerical ice sheet modeling to investigate how warmer basal temperatures could affect the Antarctic ice sheet mass balance. We find increased mass loss in response to idealized basal thawing experiments run over 100 years. Most notably, frozen-bed patches could be tenuously sustaining the current ice configuration in parts of George V, Adélie, Enderby, and Kemp Land regions of East Antarctica. With less than 5 degrees of basal warming, these frozen patches may begin to thaw, producing new loci of mass loss. This study uses ice sheet modeling experiments to show that thawing portions of the Antarctic ice sheet bed can increase century-scale mass loss, particularly in the Wilkes and Enderby Land regions of East Antarctica.
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44
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Crotti I, Quiquet A, Landais A, Stenni B, Wilson DJ, Severi M, Mulvaney R, Wilhelms F, Barbante C, Frezzotti M. Wilkes subglacial basin ice sheet response to Southern Ocean warming during late Pleistocene interglacials. Nat Commun 2022; 13:5328. [PMID: 36088458 PMCID: PMC9464198 DOI: 10.1038/s41467-022-32847-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 08/18/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractThe response of the East Antarctic Ice Sheet to past intervals of oceanic and atmospheric warming is still not well constrained but is critical for understanding both past and future sea-level change. Furthermore, the ice sheet in the Wilkes Subglacial Basin appears to have undergone thinning and ice discharge events during recent decades. Here we combine glaciological evidence on ice sheet elevation from the TALDICE ice core with offshore sedimentological records and ice sheet modelling experiments to reconstruct the ice dynamics in the Wilkes Subglacial Basin over the past 350,000 years. Our results indicate that the Wilkes Subglacial Basin experienced an extensive retreat 330,000 years ago and a more limited retreat 125,000 years ago. These changes coincide with warmer Southern Ocean temperatures and elevated global mean sea level during those interglacial periods, confirming the sensitivity of the Wilkes Subglacial Basin ice sheet to ocean warming and its potential role in sea-level change.
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45
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Garnett J, Halsall C, Winton H, Joerss H, Mulvaney R, Ebinghaus R, Frey M, Jones A, Leeson A, Wynn P. Increasing Accumulation of Perfluorocarboxylate Contaminants Revealed in an Antarctic Firn Core (1958-2017). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11246-11255. [PMID: 35881889 PMCID: PMC9386903 DOI: 10.1021/acs.est.2c02592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/12/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Perfluoroalkyl acids (PFAAs) are synthetic chemicals with a variety of industrial and consumer applications that are now widely distributed in the global environment. Here, we report the measurement of six perfluorocarboxylates (PFCA, C4-C9) in a firn (granular compressed snow) core collected from a non-coastal, high-altitude site in Dronning Maud Land in Eastern Antarctica. Snow accumulation of the extracted core dated from 1958 to 2017, a period coinciding with the advent, use, and geographical shift in the global industrial production of poly/perfluoroalkylated substances, including PFAA. We observed increasing PFCA accumulation in snow over this time period, with chemical fluxes peaking in 2009-2013 for perfluorooctanoate (PFOA, C8) and nonanoate (PFNA, C9) with little evidence of a decline in these chemicals despite supposed recent global curtailments in their production. In contrast, the levels of perfluorobutanoate (PFBA, C4) increased markedly since 2000, with the highest fluxes in the uppermost snow layers. These findings are consistent with those previously made in the Arctic and can be attributed to chlorofluorocarbon replacements (e.g., hydrofluoroethers) as an inadvertent consequence of global regulation.
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Affiliation(s)
- Jack Garnett
- Lancaster
Environment Centre, Lancaster University, Lancaster LA1 4YQ, U.K.
| | - Crispin Halsall
- Lancaster
Environment Centre, Lancaster University, Lancaster LA1 4YQ, U.K.
| | - Holly Winton
- British
Antarctic Survey, Cambridge, High Cross, Madingley Road, Cambridge CB3 0ET, U.K.
- Antarctic
Research Centre, Victoria University of
Wellington, Wellington 6012, New Zealand
| | - Hanna Joerss
- Helmholtz-Zentrum
Hereon, Max-Planck-Straße 1, 21502 Geesthacht, Germany
| | - Robert Mulvaney
- British
Antarctic Survey, Cambridge, High Cross, Madingley Road, Cambridge CB3 0ET, U.K.
| | - Ralf Ebinghaus
- Helmholtz-Zentrum
Hereon, Max-Planck-Straße 1, 21502 Geesthacht, Germany
| | - Markus Frey
- British
Antarctic Survey, Cambridge, High Cross, Madingley Road, Cambridge CB3 0ET, U.K.
| | - Anna Jones
- British
Antarctic Survey, Cambridge, High Cross, Madingley Road, Cambridge CB3 0ET, U.K.
| | - Amber Leeson
- Lancaster
Environment Centre, Lancaster University, Lancaster LA1 4YQ, U.K.
| | - Peter Wynn
- Lancaster
Environment Centre, Lancaster University, Lancaster LA1 4YQ, U.K.
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46
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Stokes CR, Abram NJ, Bentley MJ, Edwards TL, England MH, Foppert A, Jamieson SSR, Jones RS, King MA, Lenaerts JTM, Medley B, Miles BWJ, Paxman GJG, Ritz C, van de Flierdt T, Whitehouse PL. Response of the East Antarctic Ice Sheet to past and future climate change. Nature 2022; 608:275-286. [PMID: 35948707 DOI: 10.1038/s41586-022-04946-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/07/2022] [Indexed: 11/09/2022]
Abstract
The East Antarctic Ice Sheet contains the vast majority of Earth's glacier ice (about 52 metres sea-level equivalent), but is often viewed as less vulnerable to global warming than the West Antarctic or Greenland ice sheets. However, some regions of the East Antarctic Ice Sheet have lost mass over recent decades, prompting the need to re-evaluate its sensitivity to climate change. Here we review the response of the East Antarctic Ice Sheet to past warm periods, synthesize current observations of change and evaluate future projections. Some marine-based catchments that underwent notable mass loss during past warm periods are losing mass at present but most projections indicate increased accumulation across the East Antarctic Ice Sheet over the twenty-first century, keeping the ice sheet broadly in balance. Beyond 2100, high-emissions scenarios generate increased ice discharge and potentially several metres of sea-level rise within just a few centuries, but substantial mass loss could be averted if the Paris Agreement to limit warming below 2 degrees Celsius is satisfied.
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Affiliation(s)
| | - Nerilie J Abram
- Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory, Australia.,Australian Centre for Excellence in Antarctic Science, Australian National University, Canberra, Australian Capital Territory, Australia
| | | | | | - Matthew H England
- Climate Change Research Centre, University of New South Wales, Sydney, New South Wales, Australia.,Australian Centre for Excellence in Antarctic Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Annie Foppert
- Australian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | | | - Richard S Jones
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Victoria, Australia.,Securing Antarctica's Environmental Future, Monash University, Clayton, Victoria, Australia
| | - Matt A King
- School of Geography, Planning, and Spatial Sciences, University of Tasmania, Hobart, Tasmania, Australia.,Australian Centre for Excellence in Antarctic Science, University of Tasmania, Hobart, Tasmania, Australia
| | - Jan T M Lenaerts
- Department of Atmospheric and Oceanic Sciences, University of Colorado Boulder, Boulder, CO, USA
| | - Brooke Medley
- Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | | | - Guy J G Paxman
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | - Catherine Ritz
- Institut des Géosciences de l'Environnement, Université Grenoble Alpes, Grenoble, France
| | - Tina van de Flierdt
- Department of Earth Science and Engineering, Imperial College London, London, UK
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47
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Long-Term Monitoring and Change Analysis of Pine Island Ice Shelf Based on Multi-Source Satellite Observations during 1973–2020. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2022. [DOI: 10.3390/jmse10070976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Pine Island Glacier (PIG) is one of the largest contributors to sea level rise in Antarctica. Continuous thinning and frequent calving imply significant destabilization of Pine Island Glacier Ice Shelf (PIGIS). To understand the mechanism of its accelerated disintegration and its future development, we conducted a long-term monitoring and comprehensive analysis of PIGIS, including ice flow velocity, ice shelf fronts, ocean water temperature, rifts, and surface strain rates, based on multi-source satellite observations during 1973–2020. The results reveal that: (1) ice flow velocities of PIGIS increased from 2.3 km/yr in 1973 to 4.5 km/yr in 2020, with two rapid acceleration periods of 1995–2009 and 2017–2020, and its change was highly correlated to the ocean water temperature variation. (2) At least 13 calving events occurred during 1973–2020, with four unprecedented successive retreats in 2015, 2017, 2018, and 2020. (3) The acceleration of ice shelf rifting and calving may correlate to the destruction of shear margins, while this damage was likely a response to the warming of bottom seawater. The weakening southern shear margin may continue to recede, indicating that the instability of PIGIS will continue.
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48
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Clem KR, Bozkurt D, Kennett D, King JC, Turner J. Central tropical Pacific convection drives extreme high temperatures and surface melt on the Larsen C Ice Shelf, Antarctic Peninsula. Nat Commun 2022; 13:3906. [PMID: 35831281 PMCID: PMC9279480 DOI: 10.1038/s41467-022-31119-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 06/06/2022] [Indexed: 11/09/2022] Open
Abstract
Northern sections of the Larsen Ice Shelf, eastern Antarctic Peninsula (AP) have experienced dramatic break-up and collapse since the early 1990s due to strong summertime surface melt, linked to strengthened circumpolar westerly winds. Here we show that extreme summertime surface melt and record-high temperature events over the eastern AP and Larsen C Ice Shelf are triggered by deep convection in the central tropical Pacific (CPAC), which produces an elongated cyclonic anomaly across the South Pacific coupled with a strong high pressure anomaly over Drake Passage. Together these atmospheric circulation anomalies transport very warm and moist air to the southwest AP, often in the form of "atmospheric rivers", producing strong foehn warming and surface melt on the eastern AP and Larsen C Ice Shelf. Therefore, variability in CPAC convection, in addition to the circumpolar westerlies, is a key driver of AP surface mass balance and the occurrence of extreme high temperatures.
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Affiliation(s)
- Kyle R Clem
- School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand.
| | - Deniz Bozkurt
- Department of Meteorology, University of Valparaíso, Valparaíso, Chile.,Center for Climate and Resilience Research (CR)2, Santiago, Chile.,Center for Oceanographic Research COPAS COASTAL, Universidad de Concepción, Concepción, Chile
| | - Daemon Kennett
- School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - John C King
- British Antarctic Survey, Natural Environment Research Council, Cambridge, UK
| | - John Turner
- British Antarctic Survey, Natural Environment Research Council, Cambridge, UK
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49
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Miles BWJ, Stokes CR, Jamieson SSR, Jordan JR, Gudmundsson GH, Jenkins A. High spatial and temporal variability in Antarctic ice discharge linked to ice shelf buttressing and bed geometry. Sci Rep 2022; 12:10968. [PMID: 35768612 PMCID: PMC9243100 DOI: 10.1038/s41598-022-13517-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/25/2022] [Indexed: 11/09/2022] Open
Abstract
Antarctica's contribution to global mean sea level rise has been driven by an increase in ice discharge into the oceans. The rate of change and the mechanisms that drive variability in ice discharge are therefore important to consider in the context of projected future warming. Here, we report observations of both decadal trends and inter-annual variability in ice discharge across the Antarctic Ice Sheet at a variety of spatial scales that range from large drainage basins to individual outlet glacier catchments. Overall, we find a 37 ± 11 Gt year-1 increase in discharge between 1999 and 2010, but a much smaller increase of 4 ± 8 Gt year-1 between 2010 and 2018. Furthermore, comparisons reveal that neighbouring outlet glaciers can behave synchronously, but others show opposing trends, despite their close proximity. We link this spatial and temporal variability to changes in ice shelf buttressing and the modulating effect of local glacier geometry.
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Affiliation(s)
- Bertie W J Miles
- School of Geosciences, Edinburgh University, Edinburgh, EH8 9XP, UK. .,Department of Geography, Durham University, Durham, DH1 3LE, UK.
| | - Chris R Stokes
- Department of Geography, Durham University, Durham, DH1 3LE, UK
| | | | - Jim R Jordan
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK.,Laboratoire de Glaciologie, Université Libre de Bruxelles, Brussels, Belgium
| | - G Hilmar Gudmundsson
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
| | - Adrian Jenkins
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
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50
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Fan S, Gao Y, Lai B, Elzinga EJ, Yu S. Aerosol iron speciation and seasonal variation of iron oxidation state over the western Antarctic Peninsula. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 824:153890. [PMID: 35182624 DOI: 10.1016/j.scitotenv.2022.153890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/07/2022] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
The iron (Fe) speciation and oxidation state have been considered critical factors affecting Fe solubility in the atmosphere and bioavailability in the surface ocean. In this study, elemental composition and Fe speciation in aerosol samples collected at the Palmer Station in the West Antarctic Peninsula were determined using synchrotron-based X-ray fluorescence (XRF) and X-ray Absorption Near-Edge Structure (XANES) spectroscopy. The elemental composition of coarse-mode (>1 μm) Fe-containing particles suggests that the region's crustal emission is the primary source of aerosol Fe. The Fe minerals in these aerosol particles were predominantly hematite and biotite, but minor fractions of pyrite and ilmenite were observed as well. The Fe oxidation state showed an evident seasonal variation. The Fe(II) content accounted for 71% of the total Fe in the austral summer, while this fraction dropped to 60% in the austral winter. Multivariate linear models involving meteorological parameters suggested that the wind speed, relative humidity, and solar irradiance were the factors that significantly controlled the percentage of Fe(II) in the austral summer. On the contrary, no relationship was found between these factors and the Fe(II) percentage in the austral winter, suggesting that atmospheric photoreduction and regional dust emission were limited. Moreover, the snow depth was significantly (p < 0.05) correlated with the aerosol Fe concentration, confirming the limiting effect of snow/ice cover on the regional dust emission. Given that the Antarctic Peninsula has experienced rapid warming during recent decades, the ice-free areas in the Antarctic Peninsula may act as potential dust sources.
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Affiliation(s)
- Songyun Fan
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ 07102, USA
| | - Yuan Gao
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ 07102, USA.
| | - Barry Lai
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Evert J Elzinga
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ 07102, USA
| | - Shun Yu
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ 07102, USA
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