Scand. Our results suggest that, except for the lowest emissions climate scenarios and for large glaciers with long response times, MB models with linear relationships for PDDs and precipitation are suitable for mountain glaciers with a marked topographical feedback. Soc. Then, we ran multiple simulations for this same period by altering the initial ice thickness by 30% and the glacier geometry update parametrizations by 10%, according to the estimated uncertainties of each of the two methods31. 14, 815829 (2010). 282, 104115 (2003). Internet Explorer). These conclusions drawn from these synthetic experiments could have large implications given the important sea-level contribution from ice cap-like ice bodies8. Positive degree-day factors for ablation on the Greenland ice sheet studied by energy-balance modelling. The 29 RCP-GCM-RCM combinations available, hereafter named climate members, are representative of future climate trajectories with different concentration levels of greenhouse gases (TableS1). Marzeion, B. et al. By the end of the century, we predict a glacier volume loss between 75 and 88%. Some of these models use a single DDF, while others have separate DDFs for snow and ice, producing a piecewise function composed of two linear sub-functions that can partially account for nonlinear MB dynamics depending on the snowpack. Spandre, P. et al. The Nature of Kinematic Waves in Glaciers and their Application to "Seeing the rapid and devastating collapse of this incredible and critical salmon in the Nisqually River is heartbreaking," said Troutt. S5b). Moreover these three aspects of glacier behavior are inextricably interwoven: a high sensitivity to climate change goes hand-in-hand with a large natural variability. Glaciers are experiencing important changes throughout the world as a consequence of anthropogenic climate change1. Simulations were then performed by averaging the outputs of each one of the 60 ensemble members. For intermediate and pessimistic climate scenarios, no significant differences were found (Fig. Seasonal Arctic sea ice forecasting with probabilistic deep learning, Global glacier mass changes and their contributions to sea-level rise from 1961 to 2016, Two decades of glacier mass loss along the Andes, Centennial response of Greenlands three largest outlet glaciers, Accelerated global glacier mass loss in the early twenty-first century, High Mountain Asian glacier response to climate revealed by multi-temporal satellite observations since the 1960s, Rapid glacier retreat and downwasting throughout the European Alps in the early 21st century, Ice velocity and thickness of the worlds glaciers, Constraining glacier elevation and mass changes in South America, https://meetingorganizer.copernicus.org/EGU2020/EGU2020-20908.html, https://doi.org/10.5194/egusphere-egu2020-20908, https://doi.org/10.18750/MASSBALANCE.2019.R2019, https://doi.org/10.1016/B978-0-12-821575-3.00009-8, https://doi.org/10.1038/s41561-021-00885-z, http://creativecommons.org/licenses/by/4.0/, Unabated wastage of the Muz Taw Glacier in the Sawir Mountains during 19592021. Reanalysis of 47 Years of Climate in the French Alps (19582005): Climatology and Trends for Snow Cover. Despite their limitations, temperature-index models, owing to their simplicity and parsimonious data requirements, have been widely used for large-scale glacier projections7,8. This dataset applies a statistical adjustment specific to French mountain regions based on the SAFRAN dataset, to EURO-CORDEX26 GCM-RCM-RCP members, covering a total of 29 different future climate scenarios for the 20052100 period. By Carol Rasmussen,NASA's Earth Science News Team. Winter tourism under climate change in the Pyrenees and the French Alps: relevance of snowmaking as a technical adaptation. To interactively describe to response of glaciers to climate change, a glacier parameterization scheme has been developed and implemented into the regional climate model REMO. 15 - Response of glaciers to climate change - Cambridge Core Additionally, the specific responses of the deep learning and Lasso MB models to air temperature and snowfall were extracted by performing a model sensitivity analysis. Overall, the evolving glaciers are expected to undergo rather stable climate conditions under RCP 4.5, but increasingly higher temperatures and rainfall under RCP 8.5 (Fig. Climate predictors consist of: the annual CPDD, winter snowfall, summer snowfall, monthly mean temperature and monthly snowfall. how climate change and glacier retreat are reshaping whole aquatic ecosystems, there is a need to develop an integrated understanding spanning multiple taxonomic groups and trophic levels in glacier-fed rivers (e.g., bacteria, protists, fungi, algae, diatoms, invertebrates, mammals, amphibians, and fish; Clitherow et al. Farinotti, D. et al. ICCV (2015) https://doi.org/10.1109/iccv.2015.123. Grenoble Alpes, CNRS, IRD, G-INP, Institut des Gosciences de lEnvironnement, Grenoble, France, INRAE, UR RiverLy, Lyon-Villeurbanne, France, Institute for Marine and Atmospheric research Utrecht, Utrecht University, Utrecht, Netherlands, Univ. Limnol. A knowledge of the areas once occupied by mountain glaciers reveals at least part of the past behavior of these glaciers. Since these flatter glaciers are more likely to go through extreme negative MB rates, nonlinear responses to future warming play a more important role, producing cumulative MB differences of up to 20% by the end of the century (Fig. Alternatively, the Lasso MB model displayed an RMSE of 0.85m.w.e. S1a). 4e). 4e). We further assessed the effect of MB nonlinearities by comparing our simulated glacier changes with those obtained from other glacier evolution studies from the literature, which rely on temperature-index models for MB modelling. Nonlinear sensitivity of glacier mass balance to future climate change Across the globe, glaciers are decreasing in volume and number in response to climate change. Differences in projected glacier changes become more pronounced from the second half of the century, when about half of the initial 2015 ice volume has already been lost independent of the considered scenario. The lower fraction of variance explained by linear models is present under all climate scenarios. A well-established parametrization based on empirical functions50 was used in order to redistribute the annually simulated glacier-wide mass changes over each glacier. A He uniform initialization45 was used for the network parameters. Meteorol. Simulating these processes at a large geographical scale is challenging, with models requiring several parametrizations and simplifications to operate. Robinson, C. T., Thompson, C. & Freestone, M. Ecosystem development of streams lengthened by rapid glacial recession. Lett. Rev. You are using a browser version with limited support for CSS. This rapid glacier retreat is already having an environmental impact on natural hazards20, mountain ecosystems21, and biodiversity6. a1) over the French Alps. Since these two glaciers are expected to be some of the few large glaciers that will survive the 21st century climate, an accurate representation of their initial ice thickness has an important effect on the estimates of remaining ice. Average ice velocities on the Nisqually Glacier were previously measured at approximately 200 mm/day (8 in) (Hodge 1974). 3c). longwave radiation budget, turbulent fluxes), in comparison with a future warmer climate. B Methodol. Deep artificial neural networks (ANNs) are nonlinear models that offer an alternative approach to these classic methods. Lett. Both the Lasso and the temperature-index MB model rely on linear relationships between PDDs, solid precipitation and MB. Large glaciers and glaciers flowing slowly down shallow slopes respond more sluggishly to short-term climate changes, as might be expected. The estimated ice thickness for Mer de Glace (28.87km2 in 2015) was increased by 25% in order to correct the bias with respect to field observations31. Explore awards | National Oceanic and Atmospheric Administration Activity 13.3 Nisqually Glacier Response to Climate Change Course/Section Date: Name: Nisqually Glacier is a mountain glacier located on the south side of Mt. Many studies have investigated the effects of climate change on glacier runoff using observations or modelling, with a recent focus on High Mountain Asia 14,16,17 and the Andes 18,19,20.The degree . Zemp, M. et al. Sci. On the one hand, MB nonlinearities for mountain glaciers appear to be only relevant for climate scenarios with a reduction in greenhouse gases emissions (Fig. The original ice thickness estimates of the methods used by both models are different10,32, and for ALPGM we performed some additional modifications to the two largest glaciers in the French Alps (see Glacier geometry evolution for details). DDFs are known to vary much less with increasing temperatures for intermediate values of albedo (i.e. Rackauckas, C. et al. In order to do so, we applied a deterministic sampling process as a sensitivity analysis to both the deep learning and the Lasso MB models. 60, 11401154 (2014). Hock, R. Temperature index melt modelling in mountain areas. Overall, this results in linear MB models overestimating both extreme positive (Fig. 6 (2018). Vertical axes are different for the two analyses. Gabbi, J., Carenzo, M., Pellicciotti, F., Bauder, A. This parametrization reproduces in an empirical manner the changes in glacier geometry due to the combined effects of ice dynamics and MB. 51, 313323 (2005). NASA finds Asian glaciers slowed by ice loss - Climate Change: Vital Since the climate and glacier systems are known to be nonlinear13, we investigate the benefits of using a model treating, among others, PDDs in a nonlinear way in order to simulate annual glacier-wide MB at a regional scale. and JavaScript. creates a Nisqually Glacier response similar to those seen from its historical waves, suggesting that there are other factors contributing to kinematic wave formation, and 4) the Nisqually . At this point, it is important to clarify the different ways of treating PDDs in the Lasso and the temperature-index MB models analysed in this study in order to justify analogies. Nature 575, 341344 (2019). For these 32 glaciers, a total of 1048 annual glacier-wide MB values are available, covering the 19672015 period with gaps. The source code of the glacier model can be freely accessed in the following repository: https://github.com/JordiBolibar/ALPGM. Other articles where Nisqually Glacier is discussed: Mount Rainier: from the broad summit, including Nisqually Glacier, whose retreat and advance over the last 150 years has helped scientists determine patterns in the Earth's climate. Glaciers are large-scale, highly sensitive climate instruments which, ideally, should be picked up and weighed once a year. Sci. This reanalysis is specifically designed to represent meteorological conditions over complex mountain terrain, being divided by mountain massif, aspect and elevation bands of 300m. Winter climate data are computed between October 1 and March 31, and summer data between April 1 and September 30. During the last decade, various global glacier evolution models have been used to provide estimates on the future sea-level contribution from glaciers7,8. The effect of glaciers shrinking to smaller extents is not captured by these synthetic experiments, but this effect is less important for flat glaciers that are dominated by thinning (Fig. Nat. 49, 26652683 (2017). In summary, the linear approximations used by the Lasso manage to correctly fit the main cluster of average values but perform poorly for extreme values31. This adjustment represents a major improvement over most climate data used to force regional and global glacier models. 4e and 5). Glaciers are important for agriculture, hydropower, recreation, tourism, and biological communities. Relatively minor climate changes during the Little Ice Age (A.D. 1200-1850) impart significant glacial responses. The nonlinearities present in the simulated annual glacier-wide MB values were assessed by running two different glacier simulations with two different MB models. All these glacier models, independently from their approach, need to resolve the two main processes that determine glacier evolution: (1) glacier mass balance, as the difference between the mass gained via accumulation (e.g. Since both MB models also include monthly temperature data as predictors, this CPDD anomaly was distributed evenly between the ablation season (April 1September 30), following the expected increase in mostly summer temperatures instead of winter temperatures in the future (Fig. The first main difference is related to the climate data used to force the models. Glob. As for the MB modelling approach, a detailed explanation on this method can be found in a previous dedicated paper on the methods31. Loss of glaciers contributes to sea-level rise, creates environmental hazards and can alter aquatic habitats. McKinley, Alaska, change in response to the local climate. Climate variations change a glacier's mass balance by affecting ablation and accumulation amounts. Regarding air temperature forcings, the linear Lasso MB model was found to be slightly under-sensitive to extreme positive cumulative PDD (CPDD) and over-sensitive to extreme negative CPDDs. This is particularly important for the ablation season and for ice DDFs, which need to accommodate the progressively decreasing role that shortwave radiation will play in the future glacier surface energy budget under warmer conditions. S7). Hock, R. et al. This annual geometry adjustment accounts for the effects of glacier retreat on the climate signal received by glaciers. 3, 16751685 (2019). Glacier Length Variations and Climate Change: Comparative Glacier J. Glaciol. Geophys. Geosci. This is well in agreement with the known uncertainties of glacier evolution models, with glacier ice thickness being the second largest uncertainty after the future GCM-RCM-RCP climate members used to force the model29. Smiatek, G., Kunstmann, H. & Senatore, A. EURO-CORDEX regional climate model analysis for the Greater Alpine Region: performance and expected future change: climate change in the gar area. Multiple copies of this dataset were created, and for each individual copy a single predictor (i.e. Common climatic signal from glaciers in the European Alps over the last 50 years: Common Climatic Signal in the Alps. The record, which was started in 1931, shows the glacier's dramatic responses to about half a century of small but significant climatic variations. In order to investigate the effects of MB nonlinearities on flatter glaciers, we conducted a synthetic experiment using the French Alps dataset.
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