A team of British climate scientists comparing today’s environment with the warm period before the last ice age has discovered a 65% reduction of Antarctic sea ice around 128,000 years ago. The finding is an important contribution towards the challenge of making robust predictions about the Earth’s future climate.
Reporting in the journal Nature Communications, scientists describe how, by reconstructing the Earth’s climate history through analysis of Antarctic ice cores, they can determine what environmental conditions were like during ice ages and past warm periods. This study focussed on sea-ice conditions during the most recent warm period – known as the last interglacial – when global temperatures were similar to today.
Sea ice in the Arctic and around Antarctica regulates climate as, in summer, vast areas of whiteness reflect heat from the Sun back into the atmosphere. In winter, the ice prevents heat from escaping from the warm ocean to the air. Current climate models forecast a reduction in Antarctic sea ice of up to about 60% by the end of the next century. Finding a 65% reduction in the climate record during a time when global climate conditions were similar to the present day is especially relevant.
The research team from British Antarctic Survey (BAS) and from the Universities of Bristol, Reading, Leeds and Cambridge studied data from ice cores drilled on the East Antarctic Ice Sheet. A climate model was then used in the analysis of these data. The ice core data and climate model simulations were combined using advanced statistical techniques to determine the state of Antarctic sea ice 128,000 years ago.
Antarctic last interglacial isotope peak in response to sea ice retreat not ice-sheet collapse
Holloway, Max D.; Sime, Louise C.; Singarayer, Joy S.; Tindall, Julia C.; Bunch, Pete; Valdes, Paul J.. 2016
Nature Communications, 7, 12293. 9, pp.