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Greenland’s ice loss depends on propagation of mass loss from the marine glacier termini to the interior. An analysis of surface elevation change in 16 glacier catchments shows that the up-glacier extent of thinning is limited by glacier geometry.

A high-resolution update of Antarctic bed topography using mass conservation reveals broad stabilizing ridges for glaciers flowing across the Transantarctic Mountains, and stabilizing slopes beneath Moscow University, Totten and Lambert glacier system.

The Greenland ice sheet is a large contributor to sea-level rise primarily because of the increased speed of its glaciers in the southeast and northwest. This study looks at a previously stable ice stream in northeast Greenland, and finds that it is thinning due to regional warming. This region drains 16% of the ice sheet but has not figured in model projections of sea-level rise, indicating an under-estimation of Greenland contributions.

Greenland firn, the layer of compressed snow that today covers 90% of the ice sheet, currently retains half of the meltwater through refreezing. Here the authors use climate simulations to predict that refreezing in Greenland firn could peak at around 2130 and decline thereafter, rapidly increasing ice sheet mass loss and sea level rise.

Satellite observations over the Greenland Ice Sheet reveal a destructive mode of meltwater drainage whereby a subglacial flood induced by the rapid drainage of a subglacial lake burst through the surface, fracturing the ice sheet.

Observed estimates of ice losses in Antarctica combined with regional modelling of ice accumulation in the interior suggest that East Antarctica is close to a balanced mass budget, but large losses of ice occur in the narrow outlet channels of West Antarctic glaciers and at the northern tip of the Antarctic peninsula.

During the last interglacial period, the volume of the Greenland ice sheet was up to 60% smaller than today. Climate and ice-sheet modelling suggests that about 55% of this change was caused by higher ambient temperatures and the remaining 45% was a result of higher insolation and the associated climate feedbacks.

The authors combine measurements of ice loss from West Antarctica with climate modelling to show that periods of drought or extremely heavy precipitation can significantly increase or decrease rates of mass loss for periods lasting several years.

Surface melt is an important component of ice sheet dynamics, but for many remote regions the melt rates are mainly known from models. Here the authors present satellite observations of melt rates for Greenland and Antarctica, showing that East Antarctica has become a melting hotspot.

Surface melt water from the Greenland ice sheet can become trapped in firn, delaying its journey to the sea. Radar and ice-core observations provide direct evidence of a perennial aquifer in the firn layer in southern Greenland that represents a potentially significant contribution to the Greenland mass budget.

High-resolution 2-km Antarctic maps reveal higher snowfall and surface melt than low-resolution products, reconciling satellite-observed ice sheet mass change. Projected higher surface melt near grounding lines threatens future ice shelf stability.

Mass balance measurements from inland East Antarctica suggest a negative trend in surface mass balance from 2005 to 2020, probably associated with enhanced zonal winds.

The glaciers of the Antarctic Peninsula are experiencing faster melt because of increased temperatures; however, changes in precipitation may offset some of the future melt. This study looks at the relationship between glaciers and climate and finds a representative glacier is more sensitive to temperature change, rather than precipitation change. This indicates that precipitation increases are unlikely to counter the increased melt from warming.

In the Antarctic interior, assessments of surface mass balance may overestimate accumulation because high winds remove some of the annual snowfall. Geophysical observations reveal localized zones of persistent wind scour (where little or no snow accumulates) that are predicted to occur across approximately 5% of the Antarctic surface.

As the atmosphere warms it can hold more water so precipitation is expected to increase. This study uses palaeoclimate data and modelling results to investigate what this means for Antarctic mass balance and sea-level rise, as more snowfall will increase the water stored as ice on the continent.

Analysis of bedrock elastic deformation using high-resolution observations from 22 Greenland GNSS Network stations shows that the Greenland ice sheet buffers enough summer meltwater englacially to cause subsidence of about 5 mm during the melt season.

Melt ponding is an important process for the stability of ice shelves. Here the authors estimate the temperature thresholds at which melt ponding emerges over Antarctic ice shelves and find that cold and dry ice shelves are more vulnerable to melt ponding than expected.

Efficient statistical emulation of melting land ice under various climate scenarios to 2100 indicates a contribution from melting land ice to sea level increase of at least 13 centimetres sea level equivalent.

Glaciers on the west Antarctic Peninsula flowed on average 12% faster during the summer compared with winter due to a mix of oceanic and atmospheric influences, according to an analysis of remote sensing data from 2014 to 2021.

Greenland ice sheet melt is currently the largest single contributor to sea-level rise. This work combines observations and theory to show that Greenland ice sheet imbalance with recent climate (2000–2019) has already committed at least 3.3% ice volume loss, equivalent to 274 mm of global sea-level rise.

Accurate assessments of ice-sheet runoff are essential for sea-level projections. A new method using satellite altimeter observations can provide near real-time surface mass balance measurements across an entire ice sheet and reveal runoff variability not captured by global climate models.

Jakobshavn Isbrae, the largest source of ice mass loss from the Greenland Ice Sheet, has been re-advancing since 2016 after a decades-long retreat, reveals an analysis of airborne altimetry and satellite data. The advance coincides with regional ocean cooling.

Ice shelves modulate Antarctica’s contributions to sea-level rise. Regional-climate-model simulations and observations suggest historical ice melt intensification before collapse of Antarctic peninsula shelves, and project future melt evolution.

The different contributions of long-term and short-term variability to the evolution of ice sheets lead to substantial uncertainties in ice sheet models. This Review describes the response of ice sheets to oceanic, atmospheric and hydrological processes across a range of timescales.

Three techniques for estimating mass losses from the Greenland Ice Sheet produce comparable results for the period 1992–2018 that approach the trajectory of the highest rates of sea-level rise projected by the IPCC.

Ice-core-derived melt records reveal that atmospheric warming has recently intensified Greenland ice-sheet surface melt and runoff to levels that are exceptional over at least the last 350 years.

Aerial imagery from the 1980s is used to calculate ice mass loss around the entire Greenland Ice Sheet from 1900 to the present; during the twentieth century the Greenland Ice Sheet contributed at least 25.0 ± 9.4 millimetres of global-mean sea level rise.

This Review synthesizes knowledge on projections of the Antarctic and Greenland ice sheets at 1.5 °C and 2 °C of warming, discussing possible nonlinear responses, and outlining the need for more insight into future atmospheric and oceanic forcings.

Glacier retreat is the main process behind Greenland Ice Sheet dynamic mass loss over the past three decades, according to an analysis of discharge variability and calving front positions.