Uninhabited, desolate, and unbearably cold, Antarctica is the largely forgotten continent situated in the Southern Ocean over the global South Pole. Antarctica is home to many glaciers and provides habitat for a number of species of marine wildlife and birds, including 18 species of penguins. As a result, this continent is a primary research destination for determining the drastic ecological and geophysical impacts of climate change.

Two of Antarctica’s fastest shrinking glaciers, Pine Island and Thwaites, are feared to be undergoing a natural phenomenon known as “runaway retreat”. Runaway retreat occurs when a glacier is receding beyond any previous historical marker of melting and is unlikely to re-advance. This could lead to ice shelf collapse and cause a rise in sea level as high as one meter. To determine whether the current ice recession may be reversible, scientists at the University of Maine set out to measure the ages and heights of newly uncovered shorelines while taking samples of bones left by ancient penguin inhabitants.

First author Scott Braddock and additional members of Dr. Brenda Hall’s lab used inflatable boats to collect samples from rocky shorelines and emerging islands throughout Antarctica where they collected measurements of shoreline age and height to calculate how fast the islands had risen. The collected penguin bones, along with additional shells, were transported back to the University of Maine where they were carbon dated to provide biological evidence of shoreline age. Results showed that the land near Pine Island and Thwaites is currently rising at a rate of 20 to 40 mm per year, much faster than the previous rate of 3.5 mm per year. The increasing rate is directly attributed to anthropogenic climate change and subsequent increasing global temperatures. While understanding if these glaciers are entering runaway retreat is still unconfirmed, this provides greater evidence of the harmful effects of continued global warming.

Scott Braddock is a PhD Candidate at the University of Maine in the School of Earth and Climate Sciences and the Climate Change Institute. His research uses ground penetrating radar to determine ice-volume changes in glaciers of Alaska, Antarctica, and Patagonia. He is also part of the International Thwaites Glacier Collaboration to evaluate ice changes within a historical context.

Managing Correspondent: Samantha Tracy
Press Article: “Ancient penguin bones reveal unprecedented shrinkage in key Antarctic glaciers
Journal Article: “Relative sea-level data preclude major late Holocene ice-mass change in Pine Island Bay
Photo Credit: Pixabay

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