The unexpected September 2019 calving event from the Amery Ice Shelf, the largest since 1963 and which occurred almost a decade earlier than expected, was triggered by atmospheric extremes. Explosive twin polar cyclones provided a deterministic role in this event by creating oceanward sea surface slope triggering the calving. The observed record-anomalous atmospheric conditions were promoted by blocking ridges and Antarctic-wide anomalous poleward transport of heat and moisture.

Convergent sea ice motion produces a thick ice cover through ridging. We studied sea ice deformation derived from high-resolution satellite imagery and related it to the corresponding thickness change. We found that deformation explains the observed dynamic thickness change. We show that deformation can be used to model realistic ice thickness distributions. Our results revealed new relationships between thickness redistribution and deformation that could improve sea ice models.

We describe the relationships between snow depth, vegetation canopy, and local-scale processes during the snow accumulation period using terrestrial laser scanning (TLS). In addition to topography and wind, our findings suggest the importance of fine-scale tree structure, species type, and distributions on snow depth. Snow depth increases from the canopy edge toward the open areas, but wind and topographic controls may affect this trend. TLS data are complementary to wide-area lidar surveys.

This paper investigates changes in the dates of ice freeze-up and breakup for 678 Northern Hemisphere lakes and rivers from 1931–2005. From 3510 time series, the results show that breakup dates have gradually occurred earlier through time, whilst freeze-up trends have tended to be significantly more variable. These data combined show that the number of annual open-water days has increased through time for most sites, with the magnitude of change at its largest in more recent years.

Ice sheet and ice shelf models rely on data from experiments to accurately represent the way ice moves. Performing experiments at the temperatures and stresses that are generally present in nature takes a long time, and so there are few of these datasets. Here, we test the method of speeding up an experiment by running it initially at a higher temperature, before dropping to a lower target temperature to generate the relevant data. We show that this method can reduce experiment time by 55 %.

The modelling of Smith-Johnson et al. (The Cryosphere, 14, 841–854, 2020) suggests that a very large heat flux of more than 10 times the usual geothermal heat flux is required to have initiated or to control the huge Northeast Greenland Ice Stream. Our comparison with known hotspots, such as Iceland and Yellowstone, shows that such an exceptional heat flux would be unique in the world and is incompatible with known geological processes that can raise the heat flux.

We have explicitly resolved optical properties of coated BC in snow for explaining complex enhancement of snow albedo reduction due to coating effect in real environments. The parameterizations are developed for climate models to improve the understanding of BC in snow on global climate. We demonstrated that the contribution of BC coating effect to snow light absorption has exceeded dust over north China and will significantly contribute to the retreat of Arctic sea ice and Tibetan glaciers.

We study the surface energy balance from a cold-arid permafrost environment in the Indian Himalayan region. The GEOtop model was used for the modelling of surface energy balance. Our results show that the variability in the turbulent heat fluxes is similar to that reported from the seasonally frozen ground and permafrost regions of the Tibetan Plateau. Further, the low relative humidity could be playing a critical role in the surface energy balance and the permafrost processes.

The surface mass balance scheme dEBM (diurnal Energy Balance Model) provides a novel, computationally inexpensive interface between the atmosphere and land ice for Earth system modeling. The dEBM is particularly suitable for Earth system modeling on multi-millennial timescales as it accounts for changes in the Earth's orbit and atmospheric greenhouse gas concentration.

We apply first-principle hydrology models designed for global river routing to route flows hourly through 10 000 individual supraglacial channels in Greenland. Our results uniquely show the role of process controls (network density, hillslope flow, channel friction) on routed meltwater. We also confirm earlier suggestions that large channels do not dewater overnight despite the shutdown of runoff and surface mass balance runoff being mistimed and overproducing runoff, as validated in situ.

Observations from 1890 to 2020 of ice phenology for 101 Norwegian lakes were used to detect variation in ice phenology. The average date of ice break-up occurred later in spring with increasing elevation, latitude and longitude. The average date of freeze-up and the length of the ice-free period decreased with elevation and longitude. Lakes were completely frozen later recently in autumn. There is a significant trend for earlier break-up, later freeze-up and completely frozen lakes after 1991.

We present a record of circum-Antarctic glacier and ice shelf front change over the last two decades in combination with potential environmental variables forcing frontal retreat. Along the Antarctic coastline, glacier and ice shelf front retreat dominated between 1997–2008 and advance between 2009–2018. Decreasing sea ice days, intense snowmelt, weakening easterly winds, and relative changes in sea surface temperature were identified as enabling factors for glacier and ice shelf front retreat.

Extreme precipitation events in summer 2019 led to catastrophic loss of cave and surface ice in SE Europe at levels unprecedented during the last century. The projected continuous warming and increase in precipitation extremes could pose an additional threat to glaciers in southern Europe, resulting in a potentially ice-free SE Europe by the middle of the next decade (2035 CE).

We study the creep and fracture behavior of 3 m × 6 m floating edge-cracked rectangular plates of warm columnar freshwater S2 ice under creep/cyclic-recovery loading and monotonic loading to fracture. Under the testing conditions, the ice response was elastic–viscoplastic; no significant viscoelasticity or major recovery was detected. There was no clear effect of the creep/cyclic loading on the fracture properties: failure load and crack opening displacements at crack growth initiation.

It has been suggested that the observed sudden breakup of Arctic and Antarctic floating ice covers may be due to fatigue failure associated with cyclic loading from ocean swells that can penetrate deeply into an ice pack. To investigate this possibility, we measured the flexural strength of saline ice after cyclic loading. Contrary to expectations, we find that the flexural strength of saline ice increases upon cycling, similar to the behavior of laboratory-grown ice and natural lake ice.

We re-estimate pan-Arctic sea ice thickness (SIT) values by combining data from the Envisat and CryoSat-2 missions with data from a new, reanalysis-driven snow model. Because a decreasing amount of ice is being hidden below the waterline by the weight of overlying snow, we argue that SIT may be declining faster than previously calculated in some regions. Because the snow product varies from year to year, our new SIT calculations also display much more year-to-year variability.

Climate warming puts infrastructure built on permafrost at risk of failure. There is a growing need for appropriate model-based risk assessments. Here we present a modelling study and show an exemplary case of how a gravel road in a cold permafrost environment in Alaska might suffer from degrading permafrost under a scenario of intense climate warming. We use this case study to discuss the broader-scale applicability of our model for simulating future Arctic infrastructure failure.

Acoustic backscattering data from Peace River frazil events are interpreted to develop a quantitative model of interactions between ice particles in the water column and riverbed ice layers. Two generic behaviours, evident in observed time variability, are linked to differences in the relative stability of in situ anchor ice layers which develop at the beginning of each frazil interval and are determined by cooling rates. Changes in these layers are shown to control water column frazil content.

This study presents rock surface temperatures (RSTs) of steep high-Arctic rock walls on Svalbard from 2016 to 2020. The field data show that coastal cliffs are characterized by warmer RSTs than inland locations during winter seasons. By running model simulations, we analyze factors leading to that effect, calculate the surface energy balance and simulate different future scenarios. Both field data and model results can contribute to a further understanding of RST in high-Arctic rock walls.