The Medieval Climate Anomaly in Antarctica

By Sebastian Lüning, Mariusz Gałka and Fritz Vahrenholt

Highlights

  • Opposing temperature trends of the Medieval Climate Anomaly (MCA) in Antarctica.
  • MCA warming found in Antarctic Peninsula and Victoria Land.
  • MCA cooling found in the Ross Ice Shelf region and probably in the Weddell Sea.
  • Spatial distribution of MCA cooling and warming follows modern dipole patterns.
  • Main drivers Southern Annular Mode (SAM) and El Niño-Southern Oscillation (ENSO).

Abstract

The Medieval Climate Anomaly (MCA) is a well-recognized climate perturbation in many parts of the world, with a core period of 1000–1200 CE. Here we are mapping the MCA across the Antarctic region based on the analysis of published palaeotemperature proxy data from 60 sites. In addition to the conventionally used ice core data, we are integrating temperature proxy records from marine and terrestrial sediment cores as well as radiocarbon ages of glacier moraines and elephant seal colonies. A generally warm MCA compared to the subsequent Little Ice Age (LIA) was found for the Subantarctic Islands south of the Antarctic Convergence, the Antarctic Peninsula, Victoria Land and central West Antarctica. A somewhat less clear MCA warm signal was detected for the majority of East Antarctica. MCA cooling occurred in the Ross Ice Shelf region, and probably in the Weddell Sea and on Filchner-Ronne Ice Shelf. Spatial distribution of MCA cooling and warming follows modern dipole patterns, as reflected by areas of opposing temperature trends. Main drivers of the multi-centennial scale climate variability appear to be the Southern Annular Mode (SAM) and El Niño-Southern Oscillation (ENSO) which are linked to solar activity changes by nonlinear dynamics.

This paywalled article appears on the Palaeogeography, Palaeoclimatology and Palaeoecology website at https://www.sciencedirect.com/science/article/pii/S0031018219303190?dgcid=author