Findings suggest the West Antarctica glacier is very sensitive to environmental change
By Summit Voice
FRISCO — Antarctica’s Pine Island Glacier is likely to remain a significant factor in global sea level rise for decades to come, as a warming ocean melts the ice from beneath.
Geologists from the UK, USA and Germany used highly sensitive dating techniques, pioneered by one of the team, to track the thinning of the glacier through time, and to show that past thinning has lasted for several decades.
Rocks exposed by retreating or thinning glaciers provide evidence of past ice sheet change, which helps scientists to predict possible future change. The research results were published this week in Science.
By tracing the geological history of the Pine Island Glacier, the researchers were able to show that, about 8,000 years ago, it thinned as fast as it has in recent decades, providing an important model for its future behavior.
The Pine Island Glacier is currently experiencing significant acceleration, thinning and retreat that is thought to be caused by ocean-driven melting; an increase in warm ocean water finding its way under the ice shelf. After two decades of rapid ice loss, concerns are arising over how much more ice will be lost to the ocean in the future.
“Our geological data show us the history of Pine Island Glacier in greater detail than ever before,” said lead author Joanne Johnson of the British Antarctic Survey. “The fact that it thinned so rapidly in the past demonstrates how sensitive it is to environmental change; small changes can produce dramatic and long-lasting results. Based on what we know, we can expect the rapid ice loss to continue for a long time yet, especially if ocean-driven melting of the ice shelf in front of Pine Island Glacier continues at current rates,” Johnson said.
“This paper is part of a wide range of international scientific efforts to understand the behaviour of this important glacier,” said Professor Mike Bentley, a co-leader of the project based at Durham University.
“The results we’re publishing are the product of long days spent sampling rocks from mountains in Antarctica, coupled to some exceptionally precise and time-consuming laboratory analyses. The results are clear in showing a remarkably abrupt thinning of the glacier 8000 years ago,” he concluded.
This work was funded by the Natural Environment Research Council and Lamont-Doherty Earth Observatory, USA (through a Marie Tharp fellowship awarded to Joanne Johnson). Logistic support was provided by the Alfred Wegener Institute.