TY  - JOUR
A1  - Huggel, Christian
A1  - Clague, John J.
A1  - Korup, Oliver
T1  - Is climate change responsible for changing landslide activity in high mountains?
JF  - Earth surface processes and landforms : the journal of the British Geomorphological Research Group
N2  - Climate change, manifested by an increase in mean, minimum, and maximum temperatures and by more intense rainstorms, is becoming more evident in many regions. An important consequence of these changes may be an increase in landslides in high mountains. More research, however, is necessary to detect changes in landslide magnitude and frequency related to contemporary climate, particularly in alpine regions hosting glaciers, permafrost, and snow. These regions not only are sensitive to changes in both temperature and precipitation, but are also areas in which landslides are ubiquitous even under a stable climate. We analyze a series of catastrophic slope failures that occurred in the mountains of Europe, the Americas, and the Caucasus since the end of the 1990s. We distinguish between rock and ice avalanches, debris flows from de-glaciated areas, and landslides that involve dynamic interactions with glacial and river processes. Analysis of these events indicates several important controls on slope stability in high mountains, including: the non-linear response of firn and ice to warming; three-dimensional warming of subsurface bedrock and its relation to site geology; de-glaciation accompanied by exposure of new sediment; and combined short-term effects of precipitation and temperature. Based on several case studies, we propose that the following mechanisms can significantly alter landslide magnitude and frequency, and thus hazard, under warming conditions: (1) positive feedbacks acting on mass movement processes that after an initial climatic stimulus may evolve independently of climate change; (2) threshold behavior and tipping points in geomorphic systems; (3) storage of sediment and ice involving important lag-time effects.
KW  - climate change
KW  - landslides
KW  - glaciers
KW  - permafrost
Y1  - 2012
U6  - https://doi.org/10.1002/esp.2223
SN  - 0197-9337
VL  - 37
IS  - 1
SP  - 77
EP  - 91
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Veh, Georg
A1  - Lützow, Natalie
A1  - Kharlamova, Varvara
A1  - Petrakov, Dmitry
A1  - Hugonnet, Romain
A1  - Korup, Oliver
T1  - Trends, breaks, and biases in the frequency of reported glacier lake outburst floods
JF  - Earth's future
N2  - Thousands of glacier lakes have been forming behind natural dams in high mountains following glacier retreat since the early 20th century. Some of these lakes abruptly released pulses of water and sediment with disastrous downstream consequences. Yet it remains unclear whether the reported rise of these glacier lake outburst floods (GLOFs) has been fueled by a warming atmosphere and enhanced meltwater production, or simply a growing research effort. Here we estimate trends and biases in GLOF reporting based on the largest global catalog of 1,997 dated glacier-related floods in six major mountain ranges from 1901 to 2017. We find that the positive trend in the number of reported GLOFs has decayed distinctly after a break in the 1970s, coinciding with independently detected trend changes in annual air temperatures and in the annual number of field-based glacier surveys (a proxy of scientific reporting). We observe that GLOF reports and glacier surveys decelerated, while temperature rise accelerated in the past five decades. Enhanced warming alone can thus hardly explain the annual number of reported GLOFs, suggesting that temperature-driven glacier lake formation, growth, and failure are weakly coupled, or that outbursts have been overlooked. Indeed, our analysis emphasizes a distinct geographic and temporal bias in GLOF reporting, and we project that between two to four out of five GLOFs on average might have gone unnoticed in the early to mid-20th century. We recommend that such biases should be considered, or better corrected for, when attributing the frequency of reported GLOFs to atmospheric warming.
KW  - glaciers
KW  - climate change
KW  - hazard
KW  - mountains
KW  - cryosphere
KW  - frequency
Y1  - 2022
U6  - https://doi.org/10.1029/2021EF002426
SN  - 2328-4277
VL  - 10
IS  - 3
PB  - American Geophysical Union
CY  - Washington
ER  -