scholarly journals Semi-equilibrated global sea-level change projections for the next 10 000 years

2020 ◽  
Vol 11 (4) ◽  
pp. 953-976
Author(s):  
Jonas Van Breedam ◽  
Heiko Goelzer ◽  
Philippe Huybrechts
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Sea Level Change ◽  
Strong Increase ◽  
Antarctic Ice Sheet ◽  
Level Change ◽  
Global Sea Level ◽  
The Antarctic

Abstract. The emphasis for informing policy makers on future sea-level rise has been on projections by the end of the 21st century. However, due to the long lifetime of atmospheric CO2, the thermal inertia of the climate system and the slow equilibration of the ice sheets, global sea level will continue to rise on a multi-millennial timescale even when anthropogenic CO2 emissions cease completely during the coming decades to centuries. Here we present global sea-level change projections due to the melting of land ice combined with steric sea effects during the next 10 000 years calculated in a fully interactive way with the Earth system model of intermediate complexity LOVECLIMv1.3. The greenhouse forcing is based on the Extended Concentration Pathways defined until 2300 CE with no carbon dioxide emissions thereafter, equivalent to a cumulative CO2 release of between 460 and 5300 GtC. We performed one additional experiment for the highest-forcing scenario with the inclusion of a methane emission feedback where methane is slowly released due to a strong increase in surface and oceanic temperatures. After 10 000 years, the sea-level change rate drops below 0.05 m per century and a semi-equilibrated state is reached. The Greenland ice sheet is found to nearly disappear for all forcing scenarios. The Antarctic ice sheet contributes only about 1.6 m to sea level for the lowest forcing scenario with a limited retreat of the grounding line in West Antarctica. For the higher-forcing scenarios, the marine basins of the East Antarctic Ice Sheet also become ice free, resulting in a sea-level rise of up to 27 m. The global mean sea-level change after 10 000 years ranges from 9.2 to more than 37 m. For the highest-forcing scenario, the model uncertainty does not exclude the complete melting of the Antarctic ice sheet during the next 10 000 years.

scholarly journals Semi-equilibrated global sea-level change projections for the next 10 000 years

2020 ◽  
Author(s):  
Jonas Van Breedam ◽  
Heiko Goelzer ◽  
Philippe Huybrechts
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Carbon Dioxide Emissions ◽  
Ice Sheet ◽  
Thermal Inertia ◽  
Greenland Ice Sheet ◽  
Sea Level Change ◽  
Antarctic Ice Sheet ◽  
Level Change ◽  
Global Sea Level

Abstract. The emphasis for informing policy makers on future sea-level rise has been on projections by the end of the 21st century. However, due to the long lifetime of atmospheric CO2, the thermal inertia of the climate system and the slow equilibration of the ice sheets, global sea level will continue to rise on a multi-millennial timescale even when anthropogenic CO2 emissions cease completely during the coming decades to centuries. Here we present global sea-level change projections due to melting of land ice combined with steric sea effects during the next 10 000 years calculated in a fully interactive way with the Earth System Model of Intermediate Complexity LOVECLIMv1.3. The climate forcing is based on the Extended Concentration Pathways defined until 2300 AD with no carbon dioxide emissions thereafter and the inclusion of a methane-emission feedback for the highest forcing scenario, equivalent to a cumulative CO2 release of around 460 to 5800 GtC. After 10 000 years, the sea-level change rate drops below 0.05 m per century and a semi-equilibrated state is reached. The Greenland ice sheet is found to nearly disappear for all forcing scenarios. The Antarctic ice sheet contributes only about 1.6 m to sea level for the lowest forcing scenario with a limited retreat of the grounding line in West Antarctica. For the higher forcing scenarios, the marine basins of the East Antarctic ice sheet also become ice free, resulting in a sea-level rise of up to 27 m. The global mean sea-level change after 10 000 years ranges from 9.2 m to more than 37 m. The projections of multi-millennial semi-equilibrated sea-level rise for a given CO2 forcing are shown to be in good agreement with geological archives.

scholarly journals Combustion of available fossil fuel resources sufficient to eliminate the Antarctic Ice Sheet

2015 ◽  
Vol 1 (8) ◽  
pp. e1500589 ◽  
Author(s):  
Ricarda Winkelmann ◽  
Anders Levermann ◽  
Andy Ridgwell ◽  
Ken Caldeira
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Carbon Emissions ◽  
Fossil Fuel ◽  
Ice Sheet ◽  
Antarctic Ice Sheet ◽  
West Antarctic Ice Sheet ◽  
West Antarctic ◽  
Global Sea Level ◽  
The Antarctic

The Antarctic Ice Sheet stores water equivalent to 58 m in global sea-level rise. We show in simulations using the Parallel Ice Sheet Model that burning the currently attainable fossil fuel resources is sufficient to eliminate the ice sheet. With cumulative fossil fuel emissions of 10,000 gigatonnes of carbon (GtC), Antarctica is projected to become almost ice-free with an average contribution to sea-level rise exceeding 3 m per century during the first millennium. Consistent with recent observations and simulations, the West Antarctic Ice Sheet becomes unstable with 600 to 800 GtC of additional carbon emissions. Beyond this additional carbon release, the destabilization of ice basins in both West and East Antarctica results in a threshold increase in global sea level. Unabated carbon emissions thus threaten the Antarctic Ice Sheet in its entirety with associated sea-level rise that far exceeds that of all other possible sources.

The Sea Level Change from the Antarctic Ice Sheet Based on GRACE

2009 ◽  
Vol 52 (5) ◽  
pp. 936-942 ◽  
Author(s):  
Dong-Chen E ◽  
Yuan-De YANG ◽  
Ding-Bo CHAO
Keyword(s):  
Sea Level ◽  
Ice Sheet ◽  
Sea Level Change ◽  
Antarctic Ice Sheet ◽  
Level Change ◽  
The Antarctic

The influence of the solid Earth on the contribution of marine sections of the Antarctic ice sheet to future sea level change

2021 ◽  
Author(s):  
Maryam Yousefi ◽  
Jeannette Wang ◽  
Linda Pan ◽  
Natalya Gomez ◽  
Konstantin Latychev ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Solid Earth ◽  
Sea Level ◽  
Ice Sheet ◽  
Sea Level Change ◽  
Earth Structure ◽  
Level Change ◽  
Grounding Line ◽  
Level Model ◽  
The Antarctic

<p>The future retreat of marine-based sectors of the Antarctic Ice Sheet (AIS) and its consequent global mean sea level (GMSL) rise is driven by various climatic and non-climatic feedbacks between ice, ocean, atmosphere, and solid Earth. The primary mode of ice loss in marine sectors of the AIS is dynamic flow of ice across the grounding line into the ocean. The flux of ice across the grounding line is strongly sensitive to the thickness of ice there, which is in turn proportional to the water depth (sea level) such that sea level rise enhances ice loss and grounding line retreat while sea level fall acts to slow or stop migration of the grounding line. In response to the unloading from removal of ice mass, the underlying bedrock deforms isostatically leading to lower local sea surface which promotes stabilization of the grounding line. In addition to its effect on AIS evolution, solid Earth deformation also alters the shape and size of the ocean basin areas that are exposed as marine areas of ice retreat and influences the amount of meltwater that leaves Antarctica and contributes to global sea-level rise. The solid Earth deformational response to surface loading changes, in terms of both magnitude and timescales, depends on Earth rheology. Seismic tomography models indicate that the interior structure of the Earth is highly variable over the Antarctica with anomalously low shallow mantle viscosities across the western section of the AIS. An improved projection of the contribution from AIS to sea level change requires a consideration of this complexity in Earth structure. Here we adopt a state-of-the-art seismic velocity model to build a high-resolution 3D viscoelastic structure model beneath Antarctica. We incorporate this structure into a high spatiotemporal resolution sea-level model to simulate the influence of solid Earth deformation on contributions of the AIS evolution to future sea-level change. Our sea-level model is coupled with the dynamics of PSU ice sheet model and our calculations are based on a range of future climate forcings. We show that the influence of applying a spatially variable Earth structure is significant, particularly in the regions of West Antarctica where upper mantle viscosities are lower and the elastic lithosphere is thinned.</p>

scholarly journals The GRISLI-LSCE contribution to ISMIP6, Part 2: projections of the Antarctic ice sheet evolution by the end of the 21<sup>st</sup> century

2020 ◽  
Author(s):  
Aurélien Quiquet ◽  
Christophe Dumas
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Greenhouse Gas Emission ◽  
Ice Sheet ◽  
Companion Paper ◽  
Antarctic Ice Sheet ◽  
Grounding Line ◽  
Common Framework ◽  
Global Sea Level ◽  
The Antarctic

Abstract. Of primary societal importance, the ice sheet contribution to global sea level rise over the 21st century remains largely uncertain. In particular, the contribution of the Antarctic ice sheet by 2100 ranges from a few millimetres to more than one metre in the recent literature. The Ice Sheet Model Intercomparison Project for CMIP6 aimed at reducing the uncertainties on the fate of the ice sheets in the future by gathering various ice sheet models in a common framework. While in a companion paper we present the GRISLI-LSCE contribution to ISMIP6-Greenland, we present here the GRISLI-LSCE contribution to ISMIP6-Antarctica. We show that our model is strongly sensitive to the climate forcing used, with a contribution of the Antarctic ice sheet to global sea level rise by 2100 that ranges from −50 mm to +150 mm of sea level equivalent. Future oceanic warming leads to a decrease in thickness of the ice shelves and implies grounding line retreats while increased precipitation partially mitigates the ice sheet contribution to global sea level rise. Most of ice sheet changes over the next century are dampened under low greenhouse gas emission scenarios. Uncertainties related to sub-shelf basal melt induce large differences in simulated grounding line retreats, confirming the importance of this process and its representation in ice sheet models for the projections of the Antarctic ice sheet.

scholarly journals Elevation Change of the Antarctic Ice Sheet: 1985 to 2020

2021 ◽  
Author(s):  
Johan Nilsson ◽  
Alex Gardner ◽  
Fernando Paolo
Keyword(s):  
Sea Level ◽  
Ice Sheet ◽  
Sea Level Change ◽  
Similar Amount ◽  
Elevation Change ◽  
Antarctic Ice Sheet ◽  
Sea Levels ◽  
Level Change ◽  
Novel Approach ◽  
The Antarctic

Abstract. The largest uncertainty in future projections of sea level change comes from the uncertain response of the Antarctic Ice Sheet to the warming oceans and atmosphere. The ice sheet gains roughly 2000 km3 of ice from precipitation each year and losses a similar amount through solid ice discharge into the surrounding oceans. Numerous studies have shown that the ice sheet is currently out of long-term equilibrium, losing mass at an accelerated rate and increasing sea levels rise. Projections of sea-level change rely on accurate estimates of the contribution of land ice to the contemporary sea level budget. The longest observational record available to study the mass balance of the Earth’s ice sheets comes from satellite altimeters. This record, however, consists of multiple satellite missions with different life-spans, inconsistent measurement types (radar and laser) and of varying quality. To fully utilize these data, measurements from different missions must be cross-calibrated and integrated into a consistent record of change. Here, we present a novel approach for generating such a record. We describe in detail the advanced geophysical corrections applied and the processes needed to derive elevation change estimates. We processed the full archive record of satellite altimetry data, providing a seamless record of elevation change for the Antarctic Ice Sheet that spans the period 1985 to 2020. The data are produced and distributed as part of the NASA MEaSUREs ITS_LIVE project (Nilsson et al., 2021).

scholarly journals Mass gains of the Antarctic ice sheet exceed losses

2015 ◽  
Vol 61 (230) ◽  
pp. 1019-1036 ◽  
Author(s):  
H. Jay Zwally ◽  
Jun Li ◽  
John W. Robbins ◽  
Jack L. Saba ◽  
Donghui Yi ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Snow Accumulation ◽  
Antarctic Ice Sheet ◽  
Drainage Systems ◽  
Ice Cloud ◽  
West Antarctic ◽  
Global Sea Level ◽  
The Antarctic

AbstractMass changes of the Antarctic ice sheet impact sea-level rise as climate changes, but recent rates have been uncertain. Ice, Cloud and land Elevation Satellite (ICESat) data (2003–08) show mass gains from snow accumulation exceeded discharge losses by 82 ± 25 Gt a−1, reducing global sea-level rise by 0.23 mm a−1. European Remote-sensing Satellite (ERS) data (1992–2001) give a similar gain of 112 61 Gt a−1. Gains of 136 Gt a−1 in East Antarctica (EA) and 72 Gt a−1 in four drainage systems (WA2) in West Antarctic (WA) exceed losses of 97 Gt a−1 from three coastal drainage systems (WA1) and 29 Gt a−1 from the Antarctic Peninsula (AP). EA dynamic thickening of 147 Gt a−1 is a continuing response to increased accumulation (>50%) since the early Holocene. Recent accumulation loss of 11 Gt a−1 in EA indicates thickening is not from contemporaneous snowfall increases. Similarly, the WA2 gain is mainly (60 Gt a−1) dynamic thickening. In WA1 and the AP, increased losses of 66 ± 16 Gt a−1 from increased dynamic thinning from accelerating glaciers are 50% offset by greater WA snowfall. The decadal increase in dynamic thinning in WA1 and the AP is approximately one-third of the long-term dynamic thickening in EA and WA2, which should buffer additional dynamic thinning for decades.

scholarly journals A new projection of sea level change in response to collapse of marine sectors of the Antarctic Ice Sheet

2010 ◽  
Vol 180 (2) ◽  
pp. 623-634 ◽  
Author(s):  
Natalya Gomez ◽  
Jerry X. Mitrovica ◽  
Mark E. Tamisiea ◽  
Peter U. Clark
Keyword(s):  
Sea Level ◽  
Ice Sheet ◽  
Sea Level Change ◽  
Antarctic Ice Sheet ◽  
Level Change ◽  
The Antarctic
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