The Antarctic Peninsula is warming rapidly, with more frequent extreme temperature and precipitation events, reduced sea ice, glacier retreat, ice shelf collapse, and ecological shifts. Here, we review its behaviour under present-day climate, and low (SSP 1–2.6), medium-high (SSP 3–7.0) and very high (SSP 5–8.5) future emissions scenarios, corresponding to global temperature increases of 1.8 °C, 3.6 °C and 4.4 °C by 2100. Higher emissions will bring more days above 0 °C, increased liquid precipitation, ocean warming, and more intense extreme weather events such as ocean heat waves and atmospheric rivers. Surface melt on ice shelves will increase, depleting firn air content and promoting meltwater ponding. Under the highest emission scenario, collapse of the Larsen C and Wilkins ice shelves is likely by 2100 CE, and loss of sea ice and ice shelves around the Peninsula will exacerbate the current trends of land-ice mass loss. Collapse of George VI Ice Shelf by 2300 under SSP 5–8.5 would substantially increase sea level contributions. Under this very high emissions scenario, sea level contributions from the Peninsula could reach 7.5 ± 14.1 mm by 2100 CE and 116.3 ± 66.9 mm by 2300 CE. Conversely, under the lower emissions scenarios, the Antarctic Peninsula’s sea ice remains similar to present, and land ice is predicted to undergo only minor grounding line recession and thinning. Changes in sea surface temperatures and the change from snow to rain will impact marine and terrestrial biota, altering species richness and enhancing colonisation by non-native species. Ranges of key species such as krill and salps are likely to contract to the south, impacting their marine vertebrate predators. These changing conditions will also influence Antarctic Peninsula research, fisheries, tourism, infrastructure and logistics. The future of the Peninsula depends on the choices made today. Limiting temperatures to below 2 °C, and as close as possible to 1.5 °C (by following the SSP 1–1.9 or 1–2.6 scenarios), combined with effective governance, will result in increased resilience and relatively modest changes. Any higher emissions scenarios will damage pristine systems, cause sustained, irreversible ice loss on human timescales, and spread to Antarctic regions beyond the Peninsula.

The Intergovernmental Panel on Climate Change (IPCC) AR6 report (2021) provides a range of projections on greenhouse gas emissions and global warming, and the consequential impact on global sea level through thermal expansion of sea water and by glacier and ice-sheet mass loss. This paper assesses the likelihood of lower IPCC sea-level rise scenarios (SSP1-1.9 and SSP1-2.6) in light of current ice-sheet observations and model limitations, alongside today's emissions trends and current shortfall of climate commitments. We conclude that 'low-end' projections may underestimate the true pace and magnitude of future sea-level rise and, if we continue on today's mid-higher emissions pathway (SSP3-7.0), sea-level outcomes of more than 1 m by 2100 should be planned for. The worst can still be avoided through rapid deep emissions reductions, but it is essential that the IPCC continues to reflect these true risks for decision-makers, with rises of more than 2 m this century and several metres thereafter a real possibility. This article is part of the Theo Murphy meeting issue 'Next generation ice-sheet bed measurements'.

The rapid mass loss of the Antarctic Ice Sheet (AIS), with severe consequences such as sea-level rise, underlies the importance of understanding ice-sheet behavior into the future. Previous studies have identified subglacial volcanoes in Antarctica using various observational and geophysical methods, and have shown that subglacial volcanism can modify subglacial conditions and influence ice-sheet dynamics. However, the distribution, structure, and morphology of Antarctic subglacial volcanoes have not yet been systematically documented across the continent, despite this being a potentially valuable boundary condition for ice-sheet modelling, because volcanic morphology—including edifice relief, shape, and slope—can regulate basal meltwater production and routing, thereby shaping subglacial hydrology and modulating basal traction and ice-flow dynamics, with implications for AIS stability. This study presents a continent-wide reference inventory of Antarctic subglacial volcanic candidates, in which we compile and quantify their key morphological characteristics to explore how volcanic relief and edifice shape may influence basal melt, subglacial hydrology, and, in turn, the dynamics of the AIS and its global sea-level implications. The inventory includes 207 subglacial volcanic edifices that have been interpreted as volcanic in previous studies and for which we can constrain geographic locations. From this compilation, we analyze their distribution, morphological characteristics, and classification in order to provide key geometric and topographic constraints for future studies of their potential interactions with the AIS. This effort enables a novel understanding of Antarctic subglacial volcanism and also provides a needed reference for subglacial volcanoes to support further critical research concerning the evolution of Antarctica's great ice sheets.

Subglacial topography and basal conditions form critical controls on ice-sheet dynamics and ice-flow pathways. These controls modulate basal shear stress, affect grounding-line stability and allow the potential for marine ice-sheet instability. Deep troughs and reverse slopes facilitate rapid retreat driven by ocean warming, while topographic ridges and bumps can anchor ice margins. However, substantial data gaps in ice-sheet bed measurements limit the accuracy of sea-level rise projections from numerical ice-sheet models that require such information as inputs. Interpolation techniques often smooth over key features, creating digital elevation models (DEMs) that do not replicate 'real' glacierized systems. This causes uncertainty in simulations of ice-sheet evolution. Advances in physics-informed methods, which use surface velocity and mass conservation to infer bed elevation, have improved reconstructions of bed topography. Nonetheless, important details that characterize glacierized surfaces remain to be resolved in the DEMs and bed topography grids that models rely on. Future priorities to improve these data products involve dense, targeted surveys in key areas such as grounding zones. Machine learning (ML) offers promising tools for optimizing interpolation, prioritizing survey targets and planning future surveys. As ice-sheet model projections extend to 2300 CE and beyond, survey strategies must anticipate migrating grounding lines. Automation and repeat observations, including swath radar and unmanned aerial vehicle (UAV)-based campaigns, will be vital for maintaining up-to-date, high-resolution bed datasets. Ultimately, significant advancements in subglacial mapping are possible within the next 10-20 years, which could greatly improve model accuracy and better inform sea-level rise mitigation and adaptation strategies. This article is part of the Theo Murphy meeting issue 'Next generation ice-sheet bed measurements'.

Recent sub-ice topography investigations have imaged-with greatly improved detail-a set of low-elevation V-shaped basins hidden beneath a very large sector of the East Antarctic Ice Sheet. Here we jointly interpret sub-ice topography and geophysical data and show that these basins form a semi-continental-sized, fan-shaped physiographic unit that radiates from a focal point near the South Pole. We name this the East Antarctic Fan-Shaped Basin Province. We propose that the fan-like landscape is the product of distributed intraplate rotational extension before the breakup of Gondwana, with three continental-scale consequences. Laterally, to the west, it caused compression and the consequent uplift of the Gamburtsev Mountains. To the east, the northernmost Transantarctic Mountains segment was rotated clockwise by similar to 20 degrees, overriding the West Antarctic Rift System's hot lithosphere and causing segmentation of the mountain chain into three blocks and their differential uplift due to thermal buoyancy. To the north, the transcurrent edge of the fan formed the lithospheric weakness that controlled the breakup of Gondwana by driving the propagation of Antarctica-Australia separation and shaping the resulting semi-circular passive continental margins. These processes have influenced the present-day East Antarctica sub-ice landscape and the evolution of the overlying ice sheet, including the development of glacial troughs and outlet glaciers.

A major subglacial lake, Lake Snow Eagle (LSE), was identified in East Antarctica by airborne geophysical surveys. LSE, contained within a subglacial canyon, likely hosts a valuable sediment record of the geological and glaciological changes of interior East Antarctica. Understanding past lake activity is crucial for interpreting this record. Here, we present the englacial radiostratigraphy in the LSE area mapped by airborne ice-penetrating radar, which reveals a localized high-amplitude variation in ice unit thickness that is estimated to be similar to 12 ka old. Using an ice-flow model that simulates englacial stratigraphy, we investigate the origin of this feature and its relationship to changes in ice dynamical boundary conditions. Our results reveal that local snowfall redistribution initiated around the early Holocene is likely the primary cause, resulting from a short-wavelength (similar to 10 km) high-amplitude (similar to 20 m) ice surface slope variation caused by basal lubrication over a large subglacial lake. This finding indicates an increase in LSE water volume during the Holocene, illustrating the sensitivity in volume of a major topographically constrained subglacial lake across a single glacial cycle. This study demonstrates how englacial stratigraphy can provide valuable insight into subglacial hydrological changes before modern satellite observations, both for LSE and potentially at other locations.

Continued greenhouse gases emissions are warming our planet, with catastrophic consequences for its habitability and the natural world. Rapid and deep decarbonization to "net zero" carbon dioxide emissions will be needed to halt global warming, and must be achieved by 2050 to stay within the 2015 Paris Agreement thresholds. However, the public debate is increasingly exposed to claims that technological geoengineering "fixes" could reduce projected climate impacts, including in polar regions where current and projected changes have severe and irreversible consequences locally and globally. As a community of polar and cryosphere scientists, we have evaluated five highly publicized geoengineering proposals that are either focused on the polar regions or would have major impacts on these systems: stratospheric aerosol injection, sea curtains/sea walls to prevent warm waters reaching glaciers and ice shelves, sea ice management through modifying albedo and thickening sea ice, slowing ice sheet flow through basal water removal and ocean fertilization. Based on our rigorous analysis of technological availability, logistical feasibility, cost, predictable adverse consequences, environmental damage, scalability (in time and space), governance, and ethics, we conclude that none of these geoengineering ideas pass an objective and comprehensive test regarding its use in the coming decades. Instead, many of the proposed ideas are environmentally dangerous. Furthermore, funds spent in researching these ideas further is divesting from much needed research on mitigation and adaptation to climate change and bestow unwarranted public credibility to these geoengineering schemes. We stress that given their feasibility challenges and risks of negative consequences, these ideas should not distract from the foremost priority to reduce greenhouse gas emissions and achieve successful adaptation.

Recent sub-ice topography compilations of East Antarctica have imaged a wide sector, spanning from 100° E to 160° E in longitude and from the Oates, George V and Adelie coastlines to 85° S in latitude, which contains numerous low-lying basins of variable size and uncertain origin. The sector shows a Basin and Range style tectonics comprising two major basins of continental proportions, the Wilkes Basin and the Aurora Basin complex, and many smaller basins such as the Adventure, Concordia, Aurora and Vostok trenches. The main longitudinal axes of the basins consistently point towards the South Pole and many exhibit intriguing distinct triangular shapes, sitting within an approximately 2000 x 2000 km fan-shaped physiographic region limited by a semi-circular coast line. We name this region as the East Antarctic Fan shaped Basin Province (EAFBP). To the West, this sector is limited by the intraplate Gamburtsev Mountains (GM) and to the East by the Transantarctic Mountains (TAM) constituting the uplifted shoulder of the Cenozoic West Antarctic Rift System (WARS). Origins and inter-relationships between these four fundamental Antarctic tectonic units (WARS, TAM, EAFBP, GM) are still poorly understood and strongly debated. Very little is known about the mechanism generating the basins in the EAFBP, their formation time, whether they are all coeval and if and how they relate to Australia basins before Antarctica-Australia rifting. Present genetic hypotheses for some of the basins span from continental rifting to a purely flexural origin or a combination of the two. Also, post-tectonic erosional and depositional processes may have had a significant impact on the present-day topographic configuration. Here we interpret the EAFBP as the result of a single genetic mechanism: a wide fan-shaped intra-continental extension around a near pivot point at about 135° E, 85° S that likely occurred at the Mesozoic-Cenozoic transition. We discuss evidence from the sub-ice topography and potential field airborne and satellite data. We have applied image segmentation techniques to the rebounded sub-ice topography to semi-automatically trace the first order shape of the sub-ice basins, that we assume to be fault controlled. Then we have fitted the edges of the basins by maximum circles and estimated the best Euler pole identified by their intersection. Potential field anomalies have been taken into account in order to enlighten major discontinuities not revealed by the sub-ice topography. The reconnaissance of this large sector of East Antarctica as the result of rotational extension may have major implications on global and regional tectonics plate reconstructions, plate deformation assumptions and new tectonic evolutionary models of WARS, TAM, and GM.

The sub-ice topography of East Antarctica provides a crucial record of the long-term geological, geomorphological, and glaciological evolution of the continent. In particular, the morphology of the East Antarctic Ice Sheet (EAIS) bed is a valuable and hitherto underexploited archive of past ice-sheet behaviour. Analysis of the subglacial landscape can therefore help improve our understanding of the response of the ice sheet to episodes of warming in the geological past that serve as analogues for current and projected future climate change. Here, we conduct a systematic search of the extensive repositories of airborne ice-penetrating radar data acquired in the past two decades to map the distribution of low-relief subglacial bed surfaces close to the East Antarctic ice margin between Princess Elizabeth Land and George V Land (70°E to 160°E). Individual surfaces are characterised by consistent elevations over distances of 10s to 100s of kilometres and relatively low-amplitude, high-frequency roughness (i.e., valleys and inselbergs). We map 31 separate low-relief bed surfaces, which range from 500 to 50,000 km2 in area and comprise ~40% of the perimeter of this sector of the East Antarctic margin. The surfaces are typically overlain by cold-based, slow-moving ice and bounded by deep subglacial troughs that host fast-flowing ice streams and outlet glaciers. Underneath the modern-day EAIS, these low-relief bed surfaces are situated at a broad range of elevations. However, when the elevations are isostatically adjusted for the removal of the EAIS, the distribution narrows substantially and, alongside cluster analysis of the morphology of the surfaces, indicates that they constitute a single, statistically consistent population around the entirety of this sector of the EAIS margin. Under ice-free conditions, the coastal surfaces would be situated above sea level and gently dipping in a seaward direction, and we suggest that they are remnants of a widespread fluvial planation surface formed following Gondwana break-up and preserved with only minor geomorphological modification since EAIS inception. The presence of these ancient surfaces has important implications for the past, present, and future behaviour of this sector of the EAIS.

Dielectric anisotropy in ice alters the propagation of polarized radio waves, so polarimetric radar sounding can be used to survey anisotropic properties of ice masses. Ice anisotropy is either intrinsic, associated with ice-crystal orientation fabric (COF), or extrinsic, associated with material heterogeneity, such as bubbles, fractures, and directional roughness at the glacier bed. Anisotropy develops through a history of snow deposition and ice flow, and the consequent mechanical properties of anisotropy then feed back to influence ice flow. Constraints on anisotropy are therefore important for understanding ice dynamics, ice-sheet history, and future projections of ice flow and associated sea-level change. Radar techniques, applied using ground-based, airborne, or spaceborne instruments, can be deployed more quickly and over a larger area than either direct sampling, via ice-core drilling, or analogous seismic techniques. Here, we review the physical nature of dielectric anisotropy in glacier ice, the general theory for radio-wave propagation through anisotropic media, polarimetric radar instruments and survey strategies, and the extent of applications in glacier settings. We close by discussing future directions, such as polarimetric interpretations outside COF, planetary and astrophysical applications, innovative survey geometries, and polarimetric profiling. We argue that the recent proliferation in polarimetric subsurface sounding radar marks a critical inflection, since there are now several approaches for data collection and processing. This review aims to guide the expanding polarimetric user base to appropriate techniques so they can address new and existing challenges in glaciology, such as constraining ice viscosity, a critical control on ice flow and future sea-level change.

Antarctic bed topography influences how the overlying ice sheet responds to climate change and provides a record of long-term glacial history. However, knowledge of the processes that governed the development of the landscape before glacial inception and how this modulated subsequent ice-sheet evolution remains limited. Here we use radio-echo sounding to reveal extensive flat surfaces beneath the ice margin between Princess Elizabeth Land and George V Land, East Antarctica. When their elevations are isostatically adjusted for unloading of the present-day ice load, these surfaces cluster at 200–450 metres above sea level and dip gently in an offshore direction. We show that the surfaces are fragments of a once-contiguous coastal plain formed by fluvial erosion, which dates from between the separation of East Antarctica from Australia ( 100–80 Ma) and the onset of Southern Hemisphere ice-sheet glaciation ( 34 Ma). The preservation of these landforms indicates a lack of intense, selective erosion of the surfaces throughout Antarctica’s glacial history. Fast-flowing ice has instead been directed through inherited tectonic structures and fluvial valleys, leading to the incision of overdeepened subglacial troughs between the flat surfaces and thus modulating the responsiveness of the ice sheet to climate change. Extensive flat surfaces observed beneath the East Antarctic Ice Sheet margin were formed by fluvial erosion and have modulated the ice-sheet response to climate change, according to an analysis of radio-echo sounding data.

Lake 90°E in Antarctica encompasses an area of 2000 km2, ranking it the second largest subglacial lake identified in the country by area, following Vostok Subglacial Lake. In this study, the overlying ice thickness and lake elevation of Lake 90°E were determined using airborne radio-echo sounding across two survey lines, conducted by the International Collaborative Exploration of the Cryosphere by Airborne Profiling in Princess Elizabeth Land (ICECAP/PEL) campaign during the 32nd Chinese National Antarctic Research Expedition (CHINARE 32, 2015–2016), and the depth of lake water was inversed by coupling with synchronous airborne gravity data. The analysis revealed a 15-m elevation increase in the ice sheet surface from the southeast to the northwest, correlating with a gradient in ice thickness that progresses from thin in the southeast to thick in the northwest. The maximum water depth of Lake 90°E is estimated as 320 m along the central line, bifurcated by a topographic ridge into two zones of varying depths, with exceptionally shallow water at its periphery. Thermodynamic modeling using data from two points along the survey lines indicated that melt rates at the ice–water interface have consistently been low over the last 400,000 years, varying between 0.56–0.95 mm/yr and 2.70–3.41 mm/yr, balanced by either basal freezing to the south or downstream water loss, thereby maintaining a thermodynamically stable state. Satellite imagery and altimetry data analyses identified no significant changes in the outline or elevation of the ice surface over the past 20 years. This study presents novel insights into the physiography and thermodynamic state of Lake 90°E, establishing a foundation for future drilling initiatives.

Earth’s climate is warming because we burn fossil fuels for electricity, transport, heating, and food production, and this releases greenhouse gases. The polar regions (the Arctic and Antarctic) are warming faster than anywhere else, and ice melting there will affect the whole planet. To stop the melting, we must reduce fossil fuel use. However, some people believe reducing fossil fuel use is too difficult or expensive and suggest developing technologies to control the climate. These ideas are called geoengineering. But geoengineering is risky, expensive, slow to develop, and may not work. It also requires global cooperation and could harm fragile polar ecosystems. The best solution is to cut greenhouse gas emissions. We already have the technology to do so, it is proven to work, and it will benefit everyone, including the polar regions, if we act now. Cutting emissions is the safest and most effective way to protect our planet.

Basal melting of Antarctic ice shelves is primarily driven by heat delivery from warm Circumpolar Deep Water. Here we classify near-shelf water masses in an eddy-resolving numerical model of the Southern Ocean to develop a unified view of warm water intrusion onto the Antarctic continental shelf. We identify four regimes on seasonal timescales. In regime 1 (East Antarctica), heat intrusions are driven by easterly winds via Ekman dynamics. In regime 2 (West Antarctica), intrusion is primarily determined by the strength of a shelf-break undercurrent. In regime 3, the warm water cycle on the shelf is in antiphase with dense shelf water production (Adélie Coast). Finally, in regime 4 (Weddell and Ross seas), shelf-ward warm water inflow occurs along the western edge of canyons during periods of dense shelf water outflow. Our results advocate for a reformulation of the traditional annual-mean regime classification of the Antarctic continental shelf.

Understanding basal processes across ice-sheet grounding lines is crucial in accurately modeling ice-sheet dynamics and estimating global sea-level rise. The grounding line, which demarcates the specific boundary between a grounded ice sheet and a floating ice shelf, is notoriously challenging to locate precisely. Existing methods for determining grounding line location rely on indirect methods, such as tide-induced vertical ice-shelf motion (the point of flexure determining the grounding line) and ice-surface slope change (the sharp change in gradient toward being flat indicating the grounding line). In this study, we use ice-penetrating radar (IPR) data to extract grounding line information from the LambertAmery glacier system. By incorporating ice bed topography and the reflection amplitude differences between ice-water and ice-bedrock interfaces, we establish an automated method to extract grounding line positions from radar survey lines. From 53 radar survey lines, we identified 85 grounding points. The comparison with the positions from an existing satellite InSAR-based grounding line product shows an average difference of 0.69 +/- 0.70 km. Tidally-induced migration of grounding lines at different points of the tidal cycle, and advance/retreat of the grounding line with the evolution of the ice shelf, are the main reasons for the discrepancy between the radar-derived results and the existing grounding line products. In general, the results demonstrate the feasibility of IPR in confirming grounding line positions, and show great potential in constraining indirect satellite remote sensing or modeling evaluations at both regional and continental scales. Our work facilitates an ongoing effort of the Scientific Committee on Antarctic Research (SCAR)'s RINGS program to develop gapless coverage of bed topography in the coastal regions around Antarctica.

Ice sheet models should be able to accurately simulate palaeo ice sheets to have confidence in their projections of future polar ice sheet mass loss and resulting global sea level rise. This requires accurate reconstructions of the extent and flow patterns of palaeo ice sheets using real-world data. Such reconstructions can be achieved by tracing the detrital components of offshore sedimentary records back to their source areas on land. For Antarctica, however, sediment provenance data and ice sheet model results have not been directly linked, despite the complementary information each can provide on the other. Here, we present a computational framework (Tracing Antarctic Sediment Provenance, TASP) that predicts marine geochemical sediment provenance data using the output of numerical ice sheet modelling. The ice sheet model is used to estimate the spatial pattern of erosion potential and to trace ice flow pathways. Beyond the ice sheet margin, approximations of modern detrital particle transport mechanisms using ocean reanalysis data produce a good agreement between our predictions for the modern ice sheet–ocean system and seabed surface sediments. These results show that the algorithm could be used to predict the provenance signature of past ice sheet configurations. TASP currently predicts neodymium isotope compositions using the PSUICE3D ice sheet model, but thanks to its design it could be adapted to predict other provenance indicators or use the outputs of other ice sheet models.

We present Bedmap3, the latest suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60 °S. Bedmap3 incorporates and adds to all post-1950s datasets previously used for Bedmap2, including 84 new aero-geophysical surveys by 15 data providers, an additional 52 million data points and 1.9 million line-kilometres of measurement. These efforts have filled notable gaps including in major mountain ranges and the deep interior of East Antarctica, along West Antarctic coastlines and on the Antarctic Peninsula. Our new Bedmap3/RINGS grounding line similarly consolidates multiple recent mappings into a single, spatially coherent feature. Combined with updated maps of surface topography, ice shelf thickness, rock outcrops and bathymetry, Bedmap3 reveals in much greater detail the subglacial landscape and distribution of Antarctica’s ice, providing new opportunities to interpret continental-scale landscape evolution and to model the past and future evolution of the Antarctic ice sheets.

Abstract. Radio-echo sounding (RES) has revealed an internal architecture within Antarctica’s ice sheets that records their depositional, deformational and melting histories. Crucially, spatially-widespread RES-imaged internal-reflecting horizons, tied to ice-core age-depth profiles, can be treated as isochrones that record the age-depth structure across the Antarctic ice sheets. These enable the reconstruction of past climate and ice-dynamical processes on large scales, which are complementary to but more spatially-extensive than commonly used proxy records across Antarctica. We review progress towards building a pan-Antarctic age-depth model from these data by first introducing the relevant RES datasets that have been acquired across Antarctica over the last six decades (focussing specifically on those that detected internal-reflecting horizons), and outlining the processing steps typically undertaken to visualise, trace and date (by intersection with ice cores, or modelling) the RES-imaged isochrones. We summarise the scientific applications to which Antarctica’s internal architecture has been applied to date and present a pathway to expanding Antarctic radiostratigraphy across the continent to provide a benchmark for a wider range of investigations: (1) Identification of optimal sites for retrieving new ice-core palaeoclimate records targeting different periods; (2) Reconstruction of surface mass balance on millennial or historical timescales; (3) Estimates of basal melting and geothermal heat flux from radiostratigraphy and comprehensively mapping basal-ice units, to complement inferences from other geophysical and geological methods; (4) Advancing knowledge of volcanic activity and fallout across Antarctica; (5) The refinement of numerical models that leverage radiostratigraphy to tune time-varying accumulation, basal melting and ice flow, firstly to reconstruct past behaviour, and then to reduce uncertainties in projecting future ice-sheet behaviour.

Ridge B is one of the least studied areas in Antarctica but has been considered to be a potential location for the oldest ice on Earth. Among important parameters for calculating where very old ice may exist, geothermal heat flux (GHF) is critical but poorly understood. Here, GHF is determined by quantifying the transitions between dry and wet basal conditions using a radioglaciological method applied to airborne radio-echo sounding data. GHF is then constrained by a thermodynamic model matched to the transitions. The results show that GHF in Ridge B varies locally and ranges from 48.5 to 65.1 mW m-2, with an average value of 58.0 mW m-2, which is consistent with the current known GHF constrained by subglacial lakes and derived from Vostok ice core temperature measurements. Our work highlights the value of considering local GHF when locating the oldest ice in this potential region or other regions.