Disappearance of an Alpine glacier over the 21st Century simulated from modeling its future surface mass balance

Abstract. General circulation models (GCMs) predict a rapid decrease in Arctic sea ice extent in the 21st century. The decline of September sea ice is expected to continue until the Arctic Ocean is seasonally ice free, leading to a much perturbed Arctic climate with large changes in surface energy flux. Svalbard, located on the present day sea ice edge, contains many low lying ice caps and glaciers which are extremely sensitive to changes in climate. Records of past accumulation indicate that the surface mass balance (SMB) of Svalbard is also sensitive to changes in the position of the sea ice edge. To investigate the impact of 21st Century sea ice decline on the climate and surface mass balance of Svalbard a high resolution (25 km) regional climate model (RCM) was forced with a repeating cycle of sea surface temperatures (SSTs) and sea ice conditions for the periods 1961–1990 and 2061–2090. By prescribing 20th Century SSTs and 21st Century sea ice for one simulation, the impact of sea ice decline is isolated. This study shows that the coupled impact of sea ice decline and SST increase results in a decrease in SMB, whereas the impact of sea ice decline alone causes an increase in SMB of similar magnitude.

Download Full-text

Estimation of the Greenland ice sheet surface mass balance for the 20th and 21st centuries

The Cryosphere ◽

10.5194/tc-2-117-2008 ◽

2008 ◽

Vol 2 (2) ◽

pp. 117-129 ◽

Cited By ~ 68

Author(s):

X. Fettweis ◽

E. Hanna ◽

H. Gallée ◽

P. Huybrechts ◽

M. Erpicum

Keyword(s):

Mass Balance ◽

Multiple Regression ◽

21St Century ◽

General Circulation ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

General Circulation Models ◽

Climate Simulation ◽

Surface Mass Balance ◽

Surface Mass

Abstract. Results from a regional climate simulation (1970–2006) over the Greenland ice sheet (GrIS) reveals that more than 97% of the interannual variability of the modelled Surface Mass Balance (SMB) can be explained by the GrIS summer temperature anomaly and the GrIS annual precipitation anomaly. This multiple regression is then used to empirically estimate the GrIS SMB since 1900 from climatological time series. The projected SMB changes in the 21st century are investigated with the set of simulations performed with atmosphere-ocean general circulation models (AOGCMs) of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4). These estimates show that the high surface mass loss rates of recent years are not unprecedented in the GrIS history of the last hundred years. The minimum SMB rate seems to have occurred earlier in the 1930s and corresponds to a zero SMB rate. The AOGCMs project that the SMB rate of the 1930s would be common at the end of 2100. The temperature would be higher than in the 1930s but the increase of accumulation in the 21st century would partly offset the acceleration of surface melt due to the temperature increase. However, these assumptions are based on an empirical multiple regression only validated for recent/current climatic conditions, and the accuracy and time homogeneity of the data sets and AOGCM results used in these estimations constitute a large uncertainty.

Download Full-text

The impact of a seasonally ice free Arctic Ocean on the temperature, precipitation and surface mass balance of Svalbard

The Cryosphere ◽

10.5194/tc-6-35-2012 ◽

2012 ◽

Vol 6 (1) ◽

pp. 35-50 ◽

Cited By ~ 21

Author(s):

J. J. Day ◽

J. L. Bamber ◽

P. J. Valdes ◽

J. Kohler

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Mass Balance ◽

21St Century ◽

Arctic Sea Ice ◽

Lower Atmosphere ◽

The Arctic ◽

Surface Mass Balance ◽

Surface Mass ◽

The Impact

Abstract. The observed decline in summer sea ice extent since the 1970s is predicted to continue until the Arctic Ocean is seasonally ice free during the 21st Century. This will lead to a much perturbed Arctic climate with large changes in ocean surface energy flux. Svalbard, located on the present day sea ice edge, contains many low lying ice caps and glaciers and is expected to experience rapid warming over the 21st Century. The total sea level rise if all the land ice on Svalbard were to melt completely is 0.02 m. The purpose of this study is to quantify the impact of climate change on Svalbard's surface mass balance (SMB) and to determine, in particular, what proportion of the projected changes in precipitation and SMB are a result of changes to the Arctic sea ice cover. To investigate this a regional climate model was forced with monthly mean climatologies of sea surface temperature (SST) and sea ice concentration for the periods 1961–1990 and 2061–2090 under two emission scenarios. In a novel forcing experiment, 20th Century SSTs and 21st Century sea ice were used to force one simulation to investigate the role of sea ice forcing. This experiment results in a 3.5 m water equivalent increase in Svalbard's SMB compared to the present day. This is because over 50 % of the projected increase in winter precipitation over Svalbard under the A1B emissions scenario is due to an increase in lower atmosphere moisture content associated with evaporation from the ice free ocean. These results indicate that increases in precipitation due to sea ice decline may act to moderate mass loss from Svalbard's glaciers due to future Arctic warming.

Download Full-text

Simulations of changes to Glaciar Zongo, Bolivia (16° S), over the 21st century using a 3-D full-Stokes model and CMIP5 climate projections

Annals of Glaciology ◽

10.3189/2015aog70a113 ◽

2015 ◽

Vol 56 (70) ◽

pp. 89-97 ◽

Cited By ~ 23

Author(s):

Marion Réveillet ◽

Antoine Rabatel ◽

Fabien Gillet-Chaulet ◽

Alvaro Soruco

Keyword(s):

Mass Balance ◽

21St Century ◽

Coupled Model ◽

Cmip5 Models ◽

Climate Projections ◽

Surface Mass Balance ◽

Equilibrium Line Altitude ◽

Surface Mass ◽

Temperature Changes ◽

Intercomparison Project

AbstractBolivian glaciers are an essential source of fresh water for the Altiplano, and any changes they may undergo in the near future due to ongoing climate change are of particular concern. Glaciar Zongo, Bolivia, located near the administrative capital La Paz, has been extensively monitored by the GLACIOCLIM observatory in the last two decades. Here we model the glacier dynamics using the 3-D full-Stokes model Elmer/Ice. The model was calibrated and validated over a recent period (1997–2010) using four independent datasets: available observations of surface velocities and surface mass balance were used for calibration, and changes in surface elevation and retreat of the glacier front were used for validation. Over the validation period, model outputs are in good agreement with observations (differences less than a small percentage). The future surface mass balance is assumed to depend on the equilibrium-line altitude (ELA) and temperature changes through the sensitivity of ELA to temperature. The model was then forced for the 21st century using temperature changes projected by nine Coupled Model Intercomparison Project phase 5 (CMIP5) models. Here we give results for three different representative concentration pathways (RCPs). The intermediate scenario RCP6.0 led to 69 ± 7% volume loss by 2100, while the two extreme scenarios, RCP2.6 and RCP8.5, led to 40 ± 7% and 89 ± 4% loss of volume, respectively.

Download Full-text

Sources of Uncertainty in Greenland Surface Mass Balance in the 21st century.

10.5194/egusphere-egu21-10213 ◽

2021 ◽

Author(s):

Katharina Meike Holube ◽

Tobias Zolles ◽

Andreas Born

Keyword(s):

Mass Balance ◽

Greenhouse Gas ◽

21St Century ◽

Climate Models ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Surface Mass Balance ◽

Surface Mass ◽

Sources Of Uncertainty ◽

Ensemble Of Simulations

The surface mass balance (SMB) of the Greenland Ice Sheet is subject to considerable uncertainties that complicate predictions of sea-level rise caused by climate change. We examine the SMB of the Greenland Ice Sheet and its uncertainty in the 21st century using a wide ensemble of simulations with the surface energy and mass balance model "BErgen Snow SImulator" (BESSI). We conduct simulations for four greenhouse gas emission scenarios using the output of 26 climate models from the sixth phase of the Coupled Model Intercomparison Project (CMIP6) to force BESSI. In addition, the uncertainty of the SMB simulation is estimated by using 16 different parameter sets in our SMB model. The median SMB across climate models, integrated over the ice sheet, decreases for every emission scenario and every parameter set. As expected, the decrease in SMB is stronger for higher greenhouse gas emissions. The uncertainty range in SMB is considerably greater in our ensemble than in other studies that used fewer climate models as forcing. An analysis of the different sources of uncertainty shows that the differences between climate models are the main reason for SMB uncertainty, exceeding even the uncertainty due to the choice of climate scenario. In comparison, the uncertainty caused by the snow model parameters is negligible. The differences between the climate models are most pronounced in the north of Greenland and in the area around the equilibrium line, whereas the ensemble of simulations agrees that the SMB decrease is greatest in the west of Greenland.&#160;

Download Full-text

The effect of overshooting 1.5 °C global warming on the mass loss of the Greenland ice sheet

Earth System Dynamics ◽

10.5194/esd-9-1169-2018 ◽

2018 ◽

Vol 9 (4) ◽

pp. 1169-1189 ◽

Cited By ~ 6

Author(s):

Martin Rückamp ◽

Ulrike Falk ◽

Katja Frieler ◽

Stefan Lange ◽

Angelika Humbert

Keyword(s):

Global Warming ◽

Mass Loss ◽

Mass Balance ◽

Sea Level Rise ◽

Sea Level ◽

21St Century ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Surface Mass Balance ◽

Surface Mass

Abstract. Sea-level rise associated with changing climate is expected to pose a major challenge for societies. Based on the efforts of COP21 to limit global warming to 2.0 ∘C or even 1.5 ∘C by the end of the 21st century (Paris Agreement), we simulate the future contribution of the Greenland ice sheet (GrIS) to sea-level change under the low emission Representative Concentration Pathway (RCP) 2.6 scenario. The Ice Sheet System Model (ISSM) with higher-order approximation is used and initialized with a hybrid approach of spin-up and data assimilation. For three general circulation models (GCMs: HadGEM2-ES, IPSL-CM5A-LR, MIROC5) the projections are conducted up to 2300 with forcing fields for surface mass balance (SMB) and ice surface temperature (Ts) computed by the surface energy balance model of intermediate complexity (SEMIC). The projected sea-level rise ranges between 21–38 mm by 2100 and 36–85 mm by 2300. According to the three GCMs used, global warming will exceed 1.5 ∘C early in the 21st century. The RCP2.6 peak and decline scenario is therefore manually adjusted in another set of experiments to suppress the 1.5 ∘C overshooting effect. These scenarios show a sea-level contribution that is on average about 38 % and 31 % less by 2100 and 2300, respectively. For some experiments, the rate of mass loss in the 23rd century does not exclude a stable ice sheet in the future. This is due to a spatially integrated SMB that remains positive and reaches values similar to the present day in the latter half of the simulation period. Although the mean SMB is reduced in the warmer climate, a future steady-state ice sheet with lower surface elevation and hence volume might be possible. Our results indicate that uncertainties in the projections stem from the underlying GCM climate data used to calculate the surface mass balance. However, the RCP2.6 scenario will lead to significant changes in the GrIS, including elevation changes of up to 100 m. The sea-level contribution estimated in this study may serve as a lower bound for the RCP2.6 scenario, as the currently observed sea-level rise is not reached in any of the experiments; this is attributed to processes (e.g. ocean forcing) not yet represented by the model, but proven to play a major role in GrIS mass loss.

Download Full-text

Estimation of the Greenland ice sheet surface mass balance during 20th and 21st centuries

The Cryosphere Discussions ◽

10.5194/tcd-2-225-2008 ◽

2008 ◽

Vol 2 (2) ◽

pp. 225-254 ◽

Cited By ~ 1

Author(s):

X. Fettweis ◽

E. Hanna ◽

H. Gallée ◽

P. Huybrechts ◽

M. Erpicum

Keyword(s):

Mass Balance ◽

Multiple Regression ◽

21St Century ◽

General Circulation ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

General Circulation Models ◽

Climate Simulation ◽

Surface Mass Balance ◽

Surface Mass

Abstract. Results from a regional climate simulation (1970–2006) over the Greenland ice sheet (GrIS) reveals that more than 97% of the interannual variability of the modelled Surface Mass Balance (SMB) can be explained by the GrIS summer temperature anomaly and the GrIS annual precipitation anomaly. This multiple regression is then used to empirically estimate the GrIS SMB since 1900 from climatological time series. The projected SMB changes in the 21st century are investigated with the set of simulations performed with atmosphere-ocean general circulation models (AOGCMs) of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4). These estimates show that the high surface mass loss rates of recent years are not unprecedented in the GrIS history of the last hundred years. The minimum SMB rate seems to have occurred earlier in the 1930s. The AOGCMs project that the SMB rate of the 1930s would be common at the end of 2100. The temperature would be higher than in the 1930s but the increase of accumulation in the 21st century would partly offset the acceleration of surface melt due to the temperature increase. However, these assumptions are based on an empirical multiple regression only validated for recent/current climatic conditions, and the accuracy and time homogeneity of the data sets and AOGCM results used in these estimations constitute a large uncertainty.

Download Full-text

21st century projections of surface mass balance changes for major drainage systems of the Greenland ice sheet

Environmental Research Letters ◽

10.1088/1748-9326/7/4/045405 ◽

2012 ◽

Vol 7 (4) ◽

pp. 045405 ◽

Cited By ~ 30

Author(s):

M Tedesco ◽

X Fettweis

Keyword(s):

Mass Balance ◽

21St Century ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Surface Mass Balance ◽

Drainage Systems ◽

Surface Mass

Download Full-text

Future surface mass balance of the Elbrus Glacial Complex under climate change

10.5194/egusphere-egu21-6422 ◽

2021 ◽

Author(s):

Oleg Rybak ◽

Taisya Dymova ◽

Irina Korneva ◽

Stanislav Kutuzov ◽

Ivan Lavrentiev ◽

...

Keyword(s):

Mass Balance ◽

21St Century ◽

Climate Modeling ◽

Regional Climate ◽

Regional Climate Modeling ◽

Meteorological Station ◽

Surface Mass Balance ◽

Southern Slope ◽

Surface Mass ◽

Glacial Complex

The evolution of the Elbrus glacier complex, consisting of two dozen of glaciers, in the last two decades of the 20th century and at the beginning of the 21st century generally corresponded to the trend of a decrease in the glaciated area of &#8203;&#8203;the whole Caucasus. Over the period 1960-2014, the area of &#8203;&#8203;Elbrus glaciation decreased by approximately 15%, and over two decades 1997-2017 - by almost 11%. As of 2017, the area of &#8203;&#8203;Elbrus glaciation was estimated to ca. 112 sq. km, its volume exceeded 5 cub. km. Elbrus glaciation contributes significantly to the formation of the hydrological regime in the region, and, therefore, may be considered as a major challenge ti the regional socio-economic development. The latter circumstance requires an accurate assessment of the glacial runoff, and, consequently, the calculation of the surface mass balance of the glacial complex. We use an energy balance model to calculate the current and future surface mass balance. The series of observations at the Terskol meteorological station, located fifteen kilometers from the southern spurs of Elbrus, and the Mestia meteorological station, located somewhat further, on the territory of Georgia on the southern slope of the Main Caucasian ridge, as well as data from automatic weather stations on Elbrus slopes and on Djankuat glacier a few tens of kilometers from Elbrus, were applied for model forcing to reproduce present surface mass balance. The modeling results were validated by comparison with the measured surfave mass balance components on Garabashi glacier, one of the glaciers on the southern slope of Elbrus. Climate projections until the end of the 21st century for the Elbrus region were composed on the basis of multi-model results of regional climate modeling within the CORDEX project for various scenarios.We demonstrate that simultaneous surface air temperature and insolation growth accompanied by decrease in precipitation, predicted by multi-model regional climate modeling and downscaled to the Central Caucasus area, will cause essential lifting of the equilibrium line altitude and shrinking of accumulation area. As a result, we must expect an accelerated degradation of Elbrus glaciation in forthcoming decades. &#160;&#160;The reported study was funded by RFBR and RS, project number 21-55-100003

Download Full-text

Projections of 21st century sea-level contribution from the retreat of Humboldt Glacier, North Greenland

10.5194/egusphere-egu21-13956 ◽

2021 ◽

Author(s):

Trevor Hillebrand ◽

Matthew Hoffman ◽

Mauro Perego ◽

Stephen Price ◽

Abby Roat ◽

...

Keyword(s):

Mass Balance ◽

Sea Level Rise ◽

Sea Level ◽

21St Century ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Surface Velocity ◽

Surface Mass Balance ◽

Surface Mass ◽

Basal Friction

Humboldt Glacier drains ~5% of the Greenland Ice Sheet and has retreated and accelerated since the late 1990s. The northern section of the terminus has retreated towards an overdeepening in the glacier bed that extends tens of kilometers towards the ice sheet interior, raising the possibility of a rapid increase in ice discharge and retreat in the near future. Here we investigate the potential 21st century sea-level contribution from Humboldt Glacier with the MPAS-Albany Land Ice (MALI) ice sheet model. First, we optimize the basal friction field using observations of surface velocity and ice surface elevation to obtain an initial condition for the year 2007. Next, we tune parameters for calving, basal friction, and submarine melt to match the observed retreat rates and surface velocity changes. We then simulate glacier evolution to 2100 under a range of climate forcings from the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6), using ocean temperatures from the MIROC5 Earth System Model, with surface mass balance and subglacial discharge from MAR3.9/MIROC5. Our simulations predict ~3.5 mm of sea-level rise from the retreat of Humboldt Glacier by 2100 for RCP8.5, and ~1 mm for RCP2.6. The results are insensitive to the choice of calving parameters for grounded ice, but a low stress threshold for calving from floating ice is necessary to initiate retreat. We find that a highly plastic basal friction law is required to reproduce the observed acceleration, but the choice of basal friction law does not have a large effect on the magnitude of sea-level contribution by 2100 because much of the ice is at present close to floatation in the areas that retreat most significantly. Instead, the majority of ice mass loss comes from increasingly negative surface mass balance. Preliminary results from experiments with a subglacial hydrology model suggest that the simple treatment of subglacial discharge used in our 21st century projections (as used in the ISMIP6-Greenland protocol) underestimates spatial variability of melting at the glacier front but gives a reasonable approximation of total melt. When compared to the recent ISMIP6 estimates of 60&#8211;140 mm sea-level rise from the entire Greenland Ice Sheet by 2100, our estimate of 3.5 mm from Humboldt Glacier indicates a significant but far from dominant contribution from this single large outlet.

Download Full-text