Spatial and Temporal Changes in Marine-terminating Glaciers on the Antarctic Peninsula since the 1940s
The numerous glaciers on the Antarctic Peninsula are highly sensitive to environmental changes, with potential to make a significant contribution to sea-level rise, and yet they have been distinctly under studied. An absence of fundamental details on glacier characteristics and behaviour is due in part to the inaccessibility of the region. In this research, the production of a new topographic model and an inventory of 1590 glacier drainage basins between 63-70° S have enabled detailed analysis of these glaciers for the first time. Area change measurements since the 1940s reveal that 90% of the 860 marine-terminating glaciers have retreated. Greatest glacier area loss has occurred in the north-east, primarily due to the demise of ice shelves. In the west, an increasing gradient of overall ice loss from north to south is observed, as well as a distinct region in the north-west where glaciers have remained stable. There are also clear trends over time, such as reduction in glacier retreat rates in the late 1980s, and acceleration in retreat since the late 1990s. These statistically significant trends indicate that there are external control factors currently outweighing local glaciological controls on glacier extent. Analysis of atmospheric and ocean temperature data reveals that, to the west of the peninsula, patterns in ocean temperatures have a strong synchroneity with glacier area change. An increasing ocean temperature gradient from north to south, which strengthens with depth, is closely correlated with glacier front changes. Furthermore, a warming at mid ocean depths has occurred since the 1990s. This research suggests that although the atmosphere is rapidly warming, melt by the ocean is the primary cause of glacier retreat along the western peninsula. With persistent warm ocean temperatures, glacier retreat and associated mass loss is set to continue, leading to an increasing contribution to sea-level rise.
Authors: Cook, Alison
6 July, 2015