The record shows a long term cooling of 3-4 degrees Celsius over this time period. This long term cooling related to local insolation is interrupted by short term variability that is influenced by the strength of the westerly winds. In the most recent part of the record, sea surface temperatures show a warming trend that matches the rate of change observed in the Antarctic Peninsula of -3.4 degrees Celsius per century.
The results are published in Nature (v.470, 250-254 (2011)), the methods and broader impacts discussed in a News and View article by James Bendle in the same volume, and highlighted in the news media.
Scientists have reconstructed sea-surface temperatures from near the tip of the Antarctic Peninsula for the past twelve thousand years. The record, reported in Nature this week, could help understanding of climate feedbacks and improve models of how the Antarctic ice sheet responds to climate change.
The Antarctic Peninsula is one of the fastest-warming places on Earth, experiencing dramatic regional climate change in recent decades, especially during La Niña years. But the long-term variability of the peninsula’s climate has remained unclear, and this has limited our ability to evaluate ongoing changes in a historical context and to understand what part underlying forcing mechanisms might play. Amelia Shevenell and colleagues present data from a marine sediment core, which they use to reconstruct sea surface temperatures for the past twelve thousand years. The data show that long-term cooling of 3 to 4 degrees Celsius occurred in waters near the tip of the peninsula and was related to changes in local insolation, but short-term variability was strongly influenced by westerly winds. They propose that the present influence of the El Niño/Southern Oscillation (ENSO) system on the Antarctic Peninsula may have developed only over the past two thousand years. The authors suggest that if ENSO increases in strength and frequency and the westerly winds move south and intensify, as expected from future climatic warming, this connection may strengthen, with implications for Antarctic ice-sheet stability and sea-level rise.
Amelia Shevenell (University College London, UK) Tel: +44 20 7679 0671;
James Bendle (University of Glasgow, UK) N&V author Tel: +44 141 330 6864; E-mail: firstname.lastname@example.org