Assessing Global Ocean Circulation Sensitivity to Changes in Antarctic Ice Discharge
The principal goal of this research is to assess how projected increases in meltwater discharge and iceberg calving from the Antarctic Ice Sheet will impact climate in the next 250 years. In short, the sensitivity of the global ocean circulation and climate, and in particular the Atlantic Meridional...
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ftosti:oai:osti.gov:1560641 2024-01-14T10:00:57+01:00 Assessing Global Ocean Circulation Sensitivity to Changes in Antarctic Ice Discharge Condron, Alan 2023-12-11 application/pdf http://www.osti.gov/servlets/purl/1560641 https://www.osti.gov/biblio/1560641 https://doi.org/10.2172/1560641 unknown http://www.osti.gov/servlets/purl/1560641 https://www.osti.gov/biblio/1560641 https://doi.org/10.2172/1560641 doi:10.2172/1560641 58 GEOSCIENCES 2023 ftosti https://doi.org/10.2172/1560641 2023-12-16T23:50:57Z The principal goal of this research is to assess how projected increases in meltwater discharge and iceberg calving from the Antarctic Ice Sheet will impact climate in the next 250 years. In short, the sensitivity of the global ocean circulation and climate, and in particular the Atlantic Meridional Overturning Circulation (AMOC), to large increases in iceberg calving and meltwater discharges to the Southern Ocean are poorly understood. The requirement to investigate this topic is heightened by growing evidence that the West Antarctic Ice Sheet (WAIS) is vulnerable to rapid retreat and collapse through marine-ice-sheet-instability (MISI) on multidecadal-to-centennial timescales. Future model simulations of the AIS show the potential for rapid ice sheet retreat in the next 50 – 300 years, with such a collapse associated with the discharge of enormous volumes of ice and meltwater to the Southern Ocean. This project uses a combination of an ice sheet/shelf model and a fully coupled (ocean-atmosphere-seaice) model (CESM 1.2) to explore the sensitive of global climate to future changes in runoff from the Antarctic continent under future greenhouse gas emissions scenarios IPCC RCP4.5 and 8.5. Overall, accounting for Antarctic meltwater reduces the projected global mean anthropogenic greenhouse warming by up to 2 deg C. during peak WAIS collapse and by ~1 deg. for most of the simulation. In addition, the increased meltwater contribution raises sub-surface ocean temperatures at the Antarctic ice sheet margin by more than 1ºC, such that the ice shelf basal melt rates increase beyond those currently projected. In contrast, the model predicts a strong cooling of both the surface air and ocean temperatures over the Southern Ocean that results in a massive expansion and thickening of the perennial sea-ice. The slow-down in anthropogenic warming also results in the onset of ice-free conditions in the Arctic being delayed in the model by several decades, and the projected slowdown in the AMOC to reduce. Other/Unknown Material Antarc* Antarctic Arctic Ice Sheet Ice Shelf Iceberg* Iceberg* Sea ice Southern Ocean SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Arctic Antarctic Southern Ocean The Antarctic West Antarctic Ice Sheet Misi ENVELOPE(26.683,26.683,66.617,66.617) |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
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ftosti |
language |
unknown |
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58 GEOSCIENCES |
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58 GEOSCIENCES Condron, Alan Assessing Global Ocean Circulation Sensitivity to Changes in Antarctic Ice Discharge |
topic_facet |
58 GEOSCIENCES |
description |
The principal goal of this research is to assess how projected increases in meltwater discharge and iceberg calving from the Antarctic Ice Sheet will impact climate in the next 250 years. In short, the sensitivity of the global ocean circulation and climate, and in particular the Atlantic Meridional Overturning Circulation (AMOC), to large increases in iceberg calving and meltwater discharges to the Southern Ocean are poorly understood. The requirement to investigate this topic is heightened by growing evidence that the West Antarctic Ice Sheet (WAIS) is vulnerable to rapid retreat and collapse through marine-ice-sheet-instability (MISI) on multidecadal-to-centennial timescales. Future model simulations of the AIS show the potential for rapid ice sheet retreat in the next 50 – 300 years, with such a collapse associated with the discharge of enormous volumes of ice and meltwater to the Southern Ocean. This project uses a combination of an ice sheet/shelf model and a fully coupled (ocean-atmosphere-seaice) model (CESM 1.2) to explore the sensitive of global climate to future changes in runoff from the Antarctic continent under future greenhouse gas emissions scenarios IPCC RCP4.5 and 8.5. Overall, accounting for Antarctic meltwater reduces the projected global mean anthropogenic greenhouse warming by up to 2 deg C. during peak WAIS collapse and by ~1 deg. for most of the simulation. In addition, the increased meltwater contribution raises sub-surface ocean temperatures at the Antarctic ice sheet margin by more than 1ºC, such that the ice shelf basal melt rates increase beyond those currently projected. In contrast, the model predicts a strong cooling of both the surface air and ocean temperatures over the Southern Ocean that results in a massive expansion and thickening of the perennial sea-ice. The slow-down in anthropogenic warming also results in the onset of ice-free conditions in the Arctic being delayed in the model by several decades, and the projected slowdown in the AMOC to reduce. |
author |
Condron, Alan |
author_facet |
Condron, Alan |
author_sort |
Condron, Alan |
title |
Assessing Global Ocean Circulation Sensitivity to Changes in Antarctic Ice Discharge |
title_short |
Assessing Global Ocean Circulation Sensitivity to Changes in Antarctic Ice Discharge |
title_full |
Assessing Global Ocean Circulation Sensitivity to Changes in Antarctic Ice Discharge |
title_fullStr |
Assessing Global Ocean Circulation Sensitivity to Changes in Antarctic Ice Discharge |
title_full_unstemmed |
Assessing Global Ocean Circulation Sensitivity to Changes in Antarctic Ice Discharge |
title_sort |
assessing global ocean circulation sensitivity to changes in antarctic ice discharge |
publishDate |
2023 |
url |
http://www.osti.gov/servlets/purl/1560641 https://www.osti.gov/biblio/1560641 https://doi.org/10.2172/1560641 |
long_lat |
ENVELOPE(26.683,26.683,66.617,66.617) |
geographic |
Arctic Antarctic Southern Ocean The Antarctic West Antarctic Ice Sheet Misi |
geographic_facet |
Arctic Antarctic Southern Ocean The Antarctic West Antarctic Ice Sheet Misi |
genre |
Antarc* Antarctic Arctic Ice Sheet Ice Shelf Iceberg* Iceberg* Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Arctic Ice Sheet Ice Shelf Iceberg* Iceberg* Sea ice Southern Ocean |
op_relation |
http://www.osti.gov/servlets/purl/1560641 https://www.osti.gov/biblio/1560641 https://doi.org/10.2172/1560641 doi:10.2172/1560641 |
op_doi |
https://doi.org/10.2172/1560641 |
_version_ |
1788066813473456128 |