Vintage film reveals Antarctic glacier melting

Newly-digitised vintage film has doubled how far back scientists can peer into the history of underground ice in Antarctica, and revealed that an ice shelf on Thwaites Glacier in West Antarctica is being thawed by a warming ocean more quickly than previously thought. This finding contributes to predictions for sea-level rise that would impact coastal communities around the world.

Researchers digitised about 250,000 flight miles of Antarctic radar data originally captured on 35mm optical film between 1971 and 1979 as part of a collaboration between Stanford and the Scott Polar Research Institute (SPRI) at the University of Cambridge. The data has been released to an online public archive through Stanford Libraries, enabling other scientists to compare it with modern radar data in order to understand long-term changes in ice thickness, features within glaciers and baseline conditions over 40 years.

Professor Julian Dowdeswell, Director of the Scott Polar Research Institute, a co-author of the paper, commented: "These early records of ice thickness provide an important baseline against which we can measure the rate of change of the Antarctic Ice Sheet over the past 40 or so years. The high-resolution digitization of these records crucially makes them available for a series of important investigations on aspects of Antarctic environmental change."

Reconstructing the past extent of Northern Hemisphere ice sheets

Dr Christine Batchelor and Professor Philip Gibbard of the Scott Polar Research Institute, together with researchers from the University of Cambridge's Department of Zoology, Durham University, University of Sussex, and Charles University in Prague, have published a paper in Nature Communications about the configuration of Northern Hemisphere ice sheets through the Quaternary.

In this study, the authors compile a synthesis of empirical data and numerical modelling results related to Northern Hemisphere ice sheets to produce new hypotheses regarding their extent at 17 time-slices that span the last 3.6 million years. These reconstructions, which are available as a series of maps and shapefiles of ice-sheet extent, illustrate significant variations in ice-marginal positions between glacial cycles.

Origins of water beneath Mars' south polar ice cap

Dr Neil Arnold, in collaboration with Dr Matt Balme and Dr Frances Butcher (a former undergraduate in the Department of Geography here in Cambridge) of the Open University, and Dr Susan Conway of the University of Nantes, France, have published a paper in the Journal of Geophysical Research: Planets investigating the location of the recently-detected water layer beneath part of Mars' south polar ice cap.

Mars' present‐day ice deposits are generally assumed to be frozen throughout given its very cold climate, but new evidence from orbital radar data suggests a possible present‐day ~20km‐wide area of liquid water beneath Mars' south polar ice cap. Subglacial lakes are common on Earth, and their locations have been successfully predicted from ice surface topography and ice thickness using theories for subglacial water flow. This paper uses surface topography and ice thickness data for Mars' south polar ice cap to calculate the theoretical locations of possible subglacial lakes beneath the ice cap, and compares these with the location of the observed possible present‐day area of liquid water. The observed patch of possible liquid water does not coincide with the predicted lake locations however, which the paper interprets as implying that the liquid water is most likely to be an isolated patch of liquid, possibly caused by locally raised geothermal heating, rather than the liquid forming a "true", topographically constrained, subglacial lake.

SPRI Emeritus Professor, Philip Gibbard, awarded the Digby McLaren Medal

Congratulations to SPRI Emeritus Professor Philip Gibbard, who was awarded the Digby McLaren Medal, at the International Commission on Stratigraphy's STRATI 2019 Congress in Milano, Italy on 4th July 2019.

The Medal is awarded to honour a significant body of internationally important contributions to stratigraphy sustained over a number of years. Contributions can be in research (through publication of papers, monographs or books) or in education (through development of influential educational material or resources. It is expected that a major proportion of the work will have been published in an international language.

Past water flow beneath Pine Island and Thwaites glaciers

A team of researchers at the Scott Polar Research Institute along with collaborators at the British Antarctic Survey, Lamont‑Doherty Earth Observatory, and Victoria University of Wellington have published a paper investigating subglacial water flow beneath Pine Island and Thwaites glaciers in West Antarctica.

The study combines geomorphological mapping and numerical modelling of water flow beneath the West Antarctic Ice Sheet 20,000 years ago. The authors find that water discharged from a system of subglacial lakes carved out huge channels beneath the glaciers over several glacial cycles. The results are reported in the journal The Cryosphere.

The team includes PhD student James Kirkham, Professor Julian Dowdeswell, Dr Neil Arnold and Dr Kelly Hogan and Dr Robert Larter at the British Antarctic Survey.