Glacier fluctuations in the southern Andes (17°-55°S) during the past millennium

MASIOKAS, M.H.; RIVERA, A.; ESPIZUA, L.E.; VILLALBA, R.; LUCKMAN, B.H.; ARAVENA, J.C.

Perth

Conferencia; Perth II: Global Change and the World's Mountains; 2010

Southern South America contains an impressive diversity of glaciers covering over 20,000 km2 across the Andes. Reliable glacier chronologies from this region could provide important, complementary information for comparison with other glacierized areas and/or higher-resolution palaeoenvironmental indicators for regional, hemispheric or global analyses. We focus on glacier variations over the last 1000 years for which, despite recent efforts, relatively little is known. The available evidence indicates that glaciers in the southern Andes reached their maximum extent sometime between the 16th and 19th centuries during the Little Ice Age. The data shows considerable variability in the extent and timing of events, and precisely dated advances have only been identified at very few sites. Over the past century several readvances have been identified but glacier recession has dominated and is clearly evident throughout the region. A growing body of information is also showing glacier advances during the first half of the past millennium. Differences in glacier histories probably reflect inherent limitations in the glacier records and/or the dating techniques used in each case together with the varying dominance of climatic and non-climatic factors on glacier mass balance and glacier dynamics. A better understanding of these factors and a significantly larger number of detailed, well-dated records of glacier fluctuations is needed if we are to use these records as reliable palaeoclimatic indicators.