MB rates only begin to approach equilibrium towards the end of the century under RCP 2.6, for which glaciers could potentially stabilize with the climate in the first decades of the 22nd century depending on their response time (Fig. Glaciers are large-scale, highly sensitive climate instruments which, ideally, should be picked up and weighed once a year. Earths Future https://doi.org/10.1029/2019EF001470 (2020). The machine learning models used in this study are useful to highlight and quantify how nonlinearities in MB affect climate-glacier interactions, but are limited in terms of process understanding. J.B. was supported by a NWO VIDI grant 016.Vidi.171.063. The Nature of Kinematic Waves in Glaciers and their Application to The maximum downvalley position of the glacier is marked by either a Fr Hydrobiol. The vast majority of glaciers in the French Alps are very small glaciers (<0.01km2), that are mainly remnants from the Little Ice Age, with a strong imbalance with the current climate15. The scheme simulates the mass balance as well as changes of the areal . We acknowledge the more than 50 years of glaciological monitoring performed by the GLACIOCLIM French National Observatory (https://glacioclim.osug.fr), which provided essential observations for our modelling study. volume13, Articlenumber:409 (2022) ISSN 2041-1723 (online). Then in 1884, Allen Mason photographed the glacier for the first time . The dataset of initial glacier ice thickness, available for the year 2003, determines the starting point of our simulations. A physically-based method for mapping glacial debris-cover thickness from ASTER satellite imagery: development and testing at Miage Glacier, Italian Alps Discovery - the University of Dundee Research Portal Here, we compare our results with those from a recent study that focused on the European Alps10. 5). Additionally, glacier surface area was found to be a minor predictor in our MB models31. This synthetic setup allowed us to reproduce the climatic conditions to be undergone by most ice caps, with their mean surface altitude hardly evolving through time. The first main difference is related to the climate data used to force the models. Therefore, we were capable of isolating the different behaviours of the nonlinear deep learning model and a linear machine learning model based on the Lasso30. The performance of this parametrization was validated in a previous study, indicating a correct agreement with observations31. By monitoring the change in size of glaciers around the world, scientists can learn about global climate change. Tom R. Andersson, J. Scott Hosking, Emily Shuckburgh, Shfaqat A. Khan, Anders A. Bjrk, Toni Schenk, Romain Hugonnet, Robert McNabb, Andreas Kb, Atanu Bhattacharya, Tobias Bolch, Tandong Yao, Christian Sommer, Philipp Malz, Matthias H. Braun, Romain Millan, Jrmie Mouginot, Mathieu Morlighem, Matthias H. Braun, Philipp Malz, Thorsten C. Seehaus, Nature Communications DDFs are known to vary much less with increasing temperatures for intermediate values of albedo (i.e. Rackauckas, C. et al. The lower fraction of variance explained by linear models is present under all climate scenarios. Without these cold water resources during the hottest months of the year, many aquatic and terrestrial ecosystems will be impacted due to changes in runoff, water temperature or habitat humidity6,21,22. 22, 21462160 (2009). By the end of the century, we predict a glacier volume loss between 75 and 88%. Kinematic waves on glaciers move as several times the speed of the ice as a whole, and are subtle in topographic expression. Article Sci. The two models with linear MB responses to PDDs and accumulation simulate more positive MB rates under RCP 2.6, highlighting their over-sensitivity to negative air temperature anomalies and positive snowfall anomalies (Fig. Roe, G. H. Orographic precipitation. Map-based methods for estimating glacier equilibrium-line altitudes Finally, there are differences as well in the glacier dynamics of both models, with ALPGM using a glacier-specific parameterized approach and GloGEMflow explicitly reproducing the ice flow dynamics. The authors declare no competing interests. Future high-mountain hydrology: a new parameterization of glacier retreat. Fundam. Under warmer conditions (RCP 8.5), the differences between the linear and nonlinear MB model become smaller, as the topographical feedback from glacier retreat compensates for an important fraction of the losses induced by the late century warmer climate (Fig. "The Patagonia Icefields are dominated by so-called 'calving' glaciers," Rignot said. Temperature-index models are known to be over-sensitive to temperature changes, mainly due to important differences in the processes contributing to future warming. 4). The mountain has three major peaks: Liberty Cap, Point Success, and Columbia Crest (the latter is the summit, located on the rim of the caldera). This has the strongest impact under RCP 2.6, where positive MB rates are more frequent (Fig. Glacier-wide MB is simulated annually for individual glaciers using deep learning (i.e. Consortium, R. G. I. Randolph Glacier Inventory 6.0 (2017) https://doi.org/10.7265/N5-RGI-60. Huss, M. & Hock, R. A new model for global glacier change and sea-level rise. 12, 168173 (2019). Res. In this study, we demonstrated the advantages of using deep learning to model glacier MB at regional scales, both in terms of variance and bias. When using the linear MB model (Lasso), glaciers are close to reaching an equilibrium with the climate in the last decades of the century, which is not the case for the nonlinear MB model (deep learning). When it was built in the early 1900s, the road into Mount Rainier National Park from the west passed near the foot of the Nisqually Glacier, one of the mountain's longest . Massifs without glaciers by 2100 are marked with a cross, b Glacier ice volume distribution per massif, with its remaining fraction by 2100 (with respect to 2015), c Annual glacier-wide MB per massif, d Annual snowfall per massif, e Annual cumulative positive degree-days (CPDD) per massif. Lett. Google Scholar. Analysis of a 24-Year photographic record of Nisqually glacier, Mount J. Hydrol. In the United States, glaciers can be found in the Rocky Mountains, the Sierra Nevada, the Cascades, and throughout Alaska. Since in ALPGM the climate forcing of glaciers is extracted at the mean glacier altitude, we do not expect these altitude differences to drive important MB differences between models. This method has the advantage of including glacier-specific dynamics in the model, encompassing a wide range of different glacier behaviours. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. However, the impact of different climate configurations, such as a more continental and drier climate or a more oceanic and humid climate, would certainly have an impact on the results, albeit a much less important one than the lack of topographical feedback explored here. Nature Communications thanks Mohd Anul Haq, Lauren Vargo, and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. (Zenodo, 2020). Future projections of glacier-wide MB evolution were performed using climate projections from ADAMONT25. . 48, 24872512 (2009). Earth Syst. Huss, M. et al. Together with recent findings by another study41 highlighting the increased uncertainties in ice thickness distribution estimates of ice caps compared to mountain glaciers, our results raise further awareness on the important uncertainties in glacier projections for ice caps. 3c). 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. A comprehensive bibliography of scientific publications relating to the glacier is included. In fact, in many cases the surface lowering into warmer air causes this impact on the MB to be negative, further enhancing extreme negative mass balance rates. Deep artificial neural networks (ANNs) are nonlinear models that offer an alternative approach to these classic methods. J. Appl. Use the Previous and Next buttons to navigate the slides or the slide controller buttons at the end to navigate through each slide. The new research suggests that the world's glaciers are disappearing more quickly than scientists previously estimated, and they . This creates an interesting dilemma, with more complex temperature-index MB models generally outperforming simpler models for more climatically homogeneous past periods but introducing important biases for future projections under climate change. 58, 267288 (1996). Recent efforts have been made to improve the representation of ice flow dynamics in these models, replacing empirical parametrizations with simplified physical models9,10. Uncertainties of existing projections of future glacier evolution are particularly large for the second half of the 21st century due to a large uncertainty on future climatic conditions. 3c), which is directly linked to summer air temperatures and has a strong influence on surface albedo. Relatively minor climate changes during the Little Ice Age (A.D. 1200-1850) impart significant glacial responses. Toward mountains without permanent snow and ice: mountains without permanent snow and ice. Remote Sens. Thank you for visiting nature.com. a1 and a r2 of 0.69, explaining 69% of the total MB variance. Rabatel, A., Sanchez, O., Vincent, C. & Six, D. Estimation of glacier thickness from surface mass balance and ice flow velocities: a case study on Argentire Glacier, France. Analyses were made of the annual photographs . These results revealed that the main uncertainties on glacier simulations arise from the initial ice thickness used to initialize the model. Nisqually Glacier - glaciers.pdx.edu Hock, R. et al. Nisqually Glacier | glacier, Washington, United States Relative performance of empirical and physical models in assessing the seasonal and annual glacier surface mass balance of Saint-Sorlin Glacier (French Alps). Hugonnet, R. et al. As such, these values reflect both the climatic forcing and the changing glacier geometry. This creates a total of 34 input predictors for each year (7 topographical, 3 seasonal climate, and 24 monthly climate predictors). Nature Geosciences, https://doi.org/10.1038/s41561-021-00885-z (2022). Average cumulative MB projections of French Alpine glaciers with a nonlinear deep learning vs. a linear Lasso model for 29 climate scenarios; a with topographical feedback (allowing for glacier retreat) and e without topographical feedback (synthetic experiment with constant mean glacier altitude). a1), but when conditions deviate from this mean training data centroid, the Lasso can only linearly approximate the extremes based on the linear trend set on the main cluster of average values (Fig. 36, L23501 (2009). Pellicciotti, F. et al. The maximum advance of Nisqually Glacier in the last thousand years was located, and retreat from this point is believed to have started about 1840. However, to further investigate these findings, experiments designed more towards ice caps, and including crucial mechanisms such as ice-ocean interactions and thermodynamics, should be used for this purpose. 5). The ice thickness data for two of the largest glaciers in the French Alps were modified in order to improve data quality. Glacier topography is a crucial driver of future glacier projections and is expected to play an important role in determining the magnitude that nonlinearities will have on the mass balance. Studies have warned about the use of temperature-index models for snow and ice projections under climate change for decades34,35,36. The temperature-index model includes up to three different DDFs, for ice, firn and snow, resulting in three parameters. J. Hosp. Huss, M., Jouvet, G., Farinotti, D. & Bauder, A. 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. Our analysis suggests that due to this positive impact on the MB signal, only relevant differences are observed between nonlinear and linear MB models for the lowest emission climate scenarios (Fig. Glacier landscapes are expected to see important changes throughout the French Alps, with the average glacier altitude becoming 300m (RCP 4.5) and 400m (RCP 8.5) higher than nowadays (Fig. MATH With this setup, we reproduced the ice cap-like behaviour with a lack of topographical adjustment to higher elevations. These are among the cascading effects linked to glacier loss which impact ecosystems and . Our results show that the mean elevation is far more variable than the kinematic ELA ( Fig. The high spatial resolution enables a detailed representation of mountain weather patterns, which are often undermined by coarser resolution climate datasets. (b) Climate predictors are based on climatic anomalies computed at the glaciers mean altitude with respect to the 19672015 reference period mean values. Dyn. 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. Between 1857 and 1979, Nisqually Glacier receded a total of 1,945 meters and advanced a total of 294 meters. In order to simulate annual glacier-wide MB values, (a) topographical and (b) climate data for those glaciers and years were compiled for each of the 1048 glacier-year values. 5). 4), as the linear model tends to over-estimate positive MB rates both from air temperature and snowfall (Fig. Positive degree-day factors for ablation on the Greenland ice sheet studied by energy-balance modelling. Through synthetic experiments, we showed that the associated uncertainties are likely to be even more pronounced for ice caps, which host the largest reserves of ice outside the two main ice sheets32. Multiple copies of this dataset were created, and for each individual copy a single predictor (i.e. 4a). Nevertheless, we previously demonstrated that glacier surface area is not an important predictor of MB changes in our models29, and ice caps evolve mostly through thinning and not shrinking (Fig. Maussion, F. et al. Long-term historical interactions between French society and glaciers have developed a dependency of society on them for water resources, agriculture, tourism18particularly the ski business19and hydropower generation. Vincent, C. et al. By submitting a comment you agree to abide by our Terms and Community Guidelines. a Projected mean glacier altitude evolution between 2015 and 2100. Explore awards | National Oceanic and Atmospheric Administration
Intel 2022 Workweek Calendar, Articles N