Late Holocene paleoecological and paleoclimatic data from moss peatbanks in the western Antarctic Peninsula

We used subfossil mosses and peats to document changes in regional climate, cryosphere, and terrestrial ecosystems in the western Antarctic Peninsula at ~65S latitude. We find that most peat-forming ecosystems have initiated since 2800 cal BP, in response to warmer summers and increasing summer insolation. The period at 900-600 cal BP was coldest as indicated by ice advance, abundance of kill ages from ice-entombed mosses exposed recently from retreating glacial ice, and apparent gap in peatbank initiation. Furthermore, the discovery of a novel Antarctic hairgrass (Deschampsia antarctica) peatland at 2300-1200 cal BP from the mainland Antarctic Peninsula suggests a much warmer climate than the present. A warming and wetting climate in the 1980s caused very high carbon accumulation in a Polytrichum strictum moss peatbank. Our results document dramatic transformations of landscape and ecosystems in response to past warmer climate, providing a telltale sign for what may come in the future.