Subglacial discharge accelerates future retreat of Denman and Scott Glaciers, East Antarctica.

Ice shelf basal melting is the primary mechanism driving mass loss from the Antarctic Ice Sheet, yet it is unknown how the localized melt enhancement from subglacial discharge will affect future Antarctic glacial retreat. We develop a parameterization of ice shelf basal melt that accounts for both ocean and subglacial discharge forcing and apply it in future projections of Denman and Scott Glaciers, East Antarctica, through 2300. In forward simulations, subglacial discharge accelerates the onset of retreat of these systems into the deepest continental trench on Earth by 25 years.

An ancient river landscape preserved beneath the East Antarctic Ice Sheet.

The East Antarctic Ice Sheet (EAIS) has its origins ca. 34 million years ago. Since then, the impact of climate change and past fluctuations in the EAIS margin has been reflected in periods of extensive vs.

On-shelf circulation of warm water toward the Totten Ice Shelf in East Antarctica.

The Totten Glacier in East Antarctica, with an ice volume equivalent to >3.5 m of global sea-level rise, is grounded below sea level and, therefore, vulnerable to ocean forcing. Here, we use bathymetric and oceanographic observations from previously unsampled parts of the Totten continental shelf to reveal on-shelf warm water pathways defined by deep topographic features.

The International Bathymetric Chart of the Southern Ocean Version 2.

The Southern Ocean surrounding Antarctica is a region that is key to a range of climatic and oceanographic processes with worldwide effects, and is characterised by high biological productivity and biodiversity. Since 2013, the International Bathymetric Chart of the Southern Ocean (IBCSO) has represented the most comprehensive compilation of bathymetry for the Southern Ocean south of 60°S. Recently, the IBCSO Project has combined its efforts with the Nippon Foundation - GEBCO Seabed 2030 Project supporting the goal of mapping the world's oceans by 2030.

Integral correlation for uneven and differently sampled data, and its application to the Law Dome Antarctic climate record.

We present a new simple and efficient method for correlation of unevenly and differently sampled data. This new method overcomes problems with other methods for correlation with non-uniform sampling and is an easy modification to existing correlation based codes. To demonstrate the usefulness of this new method to real-world examples, we apply the method with good success to two glaciological examples to map the ages from a well-dated ice core to a nearby core, and by tracing isochronous layers within the ice sheet measured from ice-penetrating radar between the two ice core sites.

Intrinsic processes drive variability in basal melting of the Totten Glacier Ice Shelf.

Over the period 2003-2008, the Totten Ice Shelf (TIS) was shown to be rapidly thinning, likely due to basal melting. However, a recent study using a longer time series found high interannual variability present in TIS surface elevation without any apparent trend. Here we show that low-frequency intrinsic ocean variability potentially accounts for a large fraction of the variability in the basal melting of TIS.

Basal channels drive active surface hydrology and transverse ice shelf fracture.

Ice shelves control sea-level rise through frictional resistance, which slows the seaward flow of grounded glacial ice. Evidence from around Antarctica indicates that ice shelves are thinning and weakening, primarily driven by warm ocean water entering into the shelf cavities. We have identified a mechanism for ice shelf destabilization where basal channels underneath the shelves cause ice thinning that drives fracture perpendicular to flow.

Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian Arctic.

Subglacial lakes are unique environments that, despite the extreme dark and cold conditions, have been shown to host microbial life. Many subglacial lakes have been discovered beneath the ice sheets of Antarctica and Greenland, but no spatially isolated water body has been documented as hypersaline. We use radio-echo sounding measurements to identify two subglacial lakes situated in bedrock troughs near the ice divide of Devon Ice Cap, Canadian Arctic.

Ocean heat drives rapid basal melt of the Totten Ice Shelf.

Mass loss from the West Antarctic ice shelves and glaciers has been linked to basal melt by ocean heat flux. The Totten Ice Shelf in East Antarctica, which buttresses a marine-based ice sheet with a volume equivalent to at least 3.5 m of global sea-level rise, also experiences rapid basal melt, but the role of ocean forcing was not known because of a lack of observations near the ice shelf.

A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes.

The first Cenozoic ice sheets initiated in Antarctica from the Gamburtsev Subglacial Mountains and other highlands as a result of rapid global cooling ∼34 million years ago. In the subsequent 20 million years, at a time of declining atmospheric carbon dioxide concentrations and an evolving Antarctic circumpolar current, sedimentary sequence interpretation and numerical modelling suggest that cyclical periods of ice-sheet expansion to the continental margin, followed by retreat to the subglacial highlands, occurred up to thirty times. These fluctuations were paced by orbital changes and were a major influence on global sea levels.