Rapid worldwide growth of glacial lakes since 1990

Shugar, Dan H.; Burr, Aaron; Haritashya, U. K.; Kargel, Jeffrey S.; Watson, C. Scott; Kennedy, Maureen C.; Bevington, Alexandre; Betts, Richard; Harrison, Stephan; Strattman, Katherine

doi:10.1038/s41558-020-0855-4

Cited by 298 publications

(283 citation statements)

References 66 publications

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“…Ice marginal lakes form a dynamic component of terrestrial meltwater storage 9 . Proglacial lakes (including ice marginal lakes) currently hold up to 0.43 mm of sea level equivalent globally, which remains unaccounted for in present sea level change estimates 10 . Ice marginal lakes form at the fringes of glaciers and ice sheets where the outflow is dammed or restricted; for instance, by the ice itself or a moraine.…”

Section: Introductionmentioning

confidence: 99%

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Greenland-wide inventory of ice marginal lakes using a multi-method approach

How

Messerli

Mätzler

et al. 2021

Sci Rep

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Ice marginal lakes are a dynamic component of terrestrial meltwater storage at the margin of the Greenland Ice Sheet. Despite their significance to the sea level budget, local flood hazards and bigeochemical fluxes, there is a lack of Greenland-wide research into ice marginal lakes. Here, a detailed multi-sensor inventory of Greenland’s ice marginal lakes is presented based on three well-established detection methods to form a unified remote sensing approach. The inventory consists of 3347 ($$\pm 8$$ ± 8 %) ice marginal lakes ($$>0.05\,{{\text{ km }}^{2}}$$ > 0.05 km 2 ) detected for the year 2017. The greatest proportion of lakes lie around Greenland’s ice caps and mountain glaciers, and the southwest margin of the ice sheet. Through comparison to previous studies, a $$\sim 75$$ ∼ 75 % increase in lake frequency is evident over the west margin of the ice sheet since 1985. This suggests it is becoming increasingly important to include ice marginal lakes in future sea level projections, where these lakes will form a dynamic storage of meltwater that can influence outlet glacier dynamics. Comparison to existing global glacial lake inventories demonstrate that up to 56% of ice marginal lakes could be unaccounted for in global estimates of ice marginal lake change, likely due to the reliance on a single lake detection method.

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Section: Introductionmentioning

confidence: 99%

“…Recent studies have indicated that the number of ice marginal lakes in Greenland has increased over the past three decades, inundating larger areas of the terrestrial landscape 10 , 22 . In turn, the dynamics of GLOF events have also changed, for example GLOF frequency and GLOF water routing 19 , 23 , 24 .…”

Section: Introductionmentioning

confidence: 99%

Greenland-wide inventory of ice marginal lakes using a multi-method approach

How

Messerli

Mätzler

et al. 2021

Sci Rep

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“…However, since these lower values are more correct concerning the glaciers' contribution to sea-level rise, the issue points to the larger problem of distinguishing between glacier mass change, and the corresponding sea-level change, which are not exactly equal. However, Shugar et al (2020) also point out that glacial lake storage accounts for only about 1 % of glacier melt volume (excluding Greenland and Antarctica), which indicates that this inconsistency is of limited relevance. Gardner et al (2013) point to discrepancies between satellite-derived and in-situ estimates of glacier mass losses, alleging a negative bias in in-situ observations.…”

Section: Global Glacier Mass Lossmentioning

confidence: 98%

“…Only the disagreeing values from Cogley (2009) do not involve gravimetry measurements. Part of these disagreements might be explained by the storage of meltwater in glacial lakes (Shugar et al, 2020), which (because of the close proximity to the glaciers) cannot be separated from the ice mass in gravimetry data. GRACE will therefore observe lower mass change values than in-situ or geodetic observations.…”

Section: Global Glacier Mass Lossmentioning

confidence: 99%

20th century global glacier mass change: an ensemble-based model reconstruction

Malles¹,

Marzeion²

2020

Preprint

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Abstract. Negative glacier mass balances in most of Earth's glacierized regions contribute roughly one quarter to currently observed rates of sea-level rise, and have likely contributed an even larger fraction during the 20th century. The distant past and future of glaciers' mass balances, and hence their contribution to sea-level rise, can only be calculated using numerical models. Since independent of complexity, models always rely on some form of parameterizations and a choice of boundary conditions, a need for optimization arises. In this work, a model for computing monthly mass balances of glaciers on the global scale was forced with nine different data sets of near-surface air temperature and precipitation anomalies, as well as with their mean and median, leading to a total of eleven different forcing data sets. Five global parameters of the model’s mass balance equations were varied systematically, within physically plausible ranges, for each forcing data set. We then identified optimal parameter combinations by cross-validating the model results against in-situ mass balance observations, using three criteria: model bias, temporal correlation, and the ratio between the observed and modeled temporal standard deviation of specific mass balances. The goal is to better constrain the glaciers' 20th century sea-level budget contribution and its uncertainty. We find that the disagreement between the different ensemble members is often larger than the uncertainties obtained via cross-validation, particularly in times and places where few or no validation data are available, such as the first half of the 20th century. We show that the reason for this is that the availability of mass balance observations often coincides with less uncertainty in the forcing data, such that the cross-validation procedure does not capture the true out-of-sample uncertainty of the glacier model. Therefore, ensemble spread is introduced as an additional estimate of reconstruction uncertainty, increasing the total uncertainty compared to the model uncertainty obtained in the cross validation. Our ensemble mean estimate indicates a sea-level contribution by global glaciers (excluding Antarctic periphery) for 1901–2018 of 76.2 ± 5.9 mm sea-level equivalent (SLE), or 0.65 ± 0.05 mm SLE yr−1.

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“…Second, the current distribution and fluctuation of pro-glacial lakes as well as and supraglacial pond extents is also of interest for assessing glacier-related hazards. Recent studies have reported an increase in pro-and supraglacial lake area and number in the Himalaya and worldwide as a response to climatic changes (Shugar et al, 2020a;Nie et al, 2017;Shukla et al, 2018). Some of the supraglacial ponds have been shown to coalesce and form larger supraglacial lakes, or to evolve into fully-formed pro-glacial ice or moraine-dammed lakes.…”

Section: Introductionmentioning

confidence: 99%

Surface composition of debris-covered glaciers across the Himalaya using spectral unmixing and multi-sensor imagery

Racoviteanu¹,

Nicholson²,

Glasser³

2021

Preprint

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Abstract. The Hindu-Kush Himalaya mountain range is characterized by highly glacierized, complex, dynamic topography. The ablation area of these glaciers is often covered a highly heterogeneous debris cover mantle comprising ponds, steep and shallow slopes of various aspects, variable debris thickness and exposed ice cliffs. These surface elements are associated with differing ice ablation rates, and understanding the composition of the glacier surface is essential for a proper understanding of glacier hydrology and glacier-related hazards. Here we use high-resolution Pleiades (2 m) and RapidEye imagery (5 m) combined with Landsat Operational Land Imager (OLI) imagery (30 m) to estimate the composition of debris-covered glacier tongues across the Himalaya around the year 2015. We use linear spectral unmixing to map various types of debris, clean ice, supraglacial ponds and vegetation on debris-covered glaciers across the mountain range. We develop the spectral unmixing methods in the Khumbu region of eastern Nepal, and then apply them over the entire Himalaya (a glacier area of 2,254 km2). This allowed us to convert 30 m fractional maps into finer classification maps and to estimate the composition of debris-covered glaciers at various spatial scales. Debris-covered glaciers across the mountain range comprised 2.1 % supraglacial ponds, 12.8 % dark debris, 60.9 % light debris and 4.5 % supra glacial vegetation, with negligible amounts of clean ice and clouds and unclassified areas. Supraglacial ponds were more prevalent in the monsoon-influenced central-eastern Himalaya (up to 4 % of the debris cover area) compared to the monsoon-dry transition zone (only 0.3 %). The automated fractional supraglacial pond maps developed here serve to complement and improve the accuracy of existing regional lake datasets. They also provide a basis for exploring the turbidity of lakes and ponds as indicators of glacier change processes, and to monitor the evolution of ponds in the context of glacial hazards.

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Rapid worldwide growth of glacial lakes since 1990

Cited by 298 publications

References 66 publications

Greenland-wide inventory of ice marginal lakes using a multi-method approach

Greenland-wide inventory of ice marginal lakes using a multi-method approach

20th century global glacier mass change: an ensemble-based model reconstruction

Surface composition of debris-covered glaciers across the Himalaya using spectral unmixing and multi-sensor imagery

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