Peter 1st Island is situated in the Bellingshausen Sea, a region that has experienced considerable climate change in recent decades. Here we present data from the first firn core drilled on Peter 1st Island, spanning the period 2002-2017 CE. The record includes major ion chemistry (Br-, Cl-, SO42-, Na+, Ca2+, Mg2+) used to annual layer count the ice core and calculate the annual snow accumulation. The stable water isotope record is presented as annual averages, which are related to surface air temperatures across the Amundsen-Bellingshausen Seas, and the adjacent Antarctic Peninsula.

The ice core drilling and analysis were funded by Ecole Polytechnique Federale de Lausanne, the Swiss Polar Institute, and Ferring Pharmaceuticals Inc and the British Antarctic Survey, Natural Environment Research Council (NERC, Cambridge, UK).