Antarctic Climate Variability During the Past Few Centuries Based on Ice Core Records from Coastal Dronning Maud Land and Its Implications on the Recent Warming

Abstract

Instrumental and proxy records have revealed that the Antarctic climate system experienced remarkable changes in the past. In order to reconstruct the recent Antarctic climate change during the past centuries with annual to seasonal resolution and to understand its spatial variability, two well-dated ice cores (IND-22/B4 – 62 m and IND-25/B5 – 65 m) from the coastal Dronning Maud Land region of East Antarctica were studied for stable oxygen and hydrogen isotope ratio variability. Of these, the IND-25/B5 provided high-resolution records of the past 100 years (1905–2005) and the IND-22/B4 core represented the past ~470 years (1530–2002) of climate change. The considerable variations in δ18O records on an interannual to decadal scale seems to be associated with changes in low and mid latitude climatic modes like the Southern Annular Mode (SAM) and El Nino Southern Oscillation (ENSO). The extended records of IND-22/B4 exhibited relatively more negative δ18O values during periods of reduced solar activity like the Dalton and Maunder Minima, indicating manifestations of solar activity on Antarctic climate. The estimated surface air temperatures using the δ18O profiles of two ice cores revealed a significant warming by 0.6–1°C per century, with greatly enhanced warming during the past several decades (~0.4°C per decade). Complimentary to the recent findings, it is proposed that the coastal areas of Dronning Maud Land are experiencing significant warming in the recent centuries and further support for a detailed evaluation on actual rates of Antarctic warming through a combination of instrumental and proxy records.