February 21, 2014
Pine Island Glacier Thinning Possible Indicator Of Future Ice Loss
redOrbit Staff & Wire Reports - Your Universe Online
Previous instances of rapid thinning of Pine Island Glacier suggests that current ice loss in the Antarctic could continue for several more decades, a team of geologists from the US, UK and Germany report in this week’s edition of the journal Science.
Pine Island Glacier, which is part of the West Antarctic Ice Sheet, is rapidly accelerating, thinning and retreating, and the researchers report that it has thinned rapidly in the past. Their research suggests that the glacier could continue thinning for decades to come, officials from the British Antarctic Survey (BAS) said in a statement Thursday.
As part of their research, the study authors found that 8,000 years ago, this so-called “largest single contributor to global sea level rise” thinned as quickly as it has in recent decades. This behavior provides an important model for how the glacier will behave in the foreseeable future.
Currently, Pine Island Glacier is experiencing a significant amount of acceleration, thinning and retreat that experts believe is caused by an increase in warm ocean water finding its way beneath the ice shelf – a phenomenon known as ocean-driven melting. Following roughly 20 years of rapid ice loss, scientists are becoming concerned about how much more ice will be lost to the ocean in the years ahead.
“Our geological data show us the history of Pine Island Glacier in greater detail than ever before,” said lead author Dr. Joanne Johnson. “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.”
Furthermore, projections of the glacier’s future based on models illuminate uncertainty surrounding the rate, timing and persistence of future sea level rise, the BAS said. Evidence of previous ice sheet changes surfaced in the form of rocks exposed by retreating or thinning glaciers, and this helps scientists predict potential changes yet to come.
By using extremely sensitive dating techniques, pioneered by a member of the investigative team behind the study, the authors were able to track the thinning of Pine Island Glacier over the years. These techniques revealed that the thinning of the glacier lasted over a period of several decades.
“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,” Dr. Johnson said.
“This paper is part of a wide range of international scientific efforts to understand the behavior of this important glacier. 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,” added study co-leader and Durham University professor Mike Bentley. “The results are clear in showing a remarkably abrupt thinning of the glacier 8000 years ago.”
BAS team members began their ambitious iStar Antarctic science mission, which was designed to determine why the Pine Island Glacier was rapidly diminishing, last September. The goal of the four-part project, which officially kicked off when the Antarctic summer season began in late 2013, was to determine whether or not the glacier’s rapid ice loss would continue to increase, or if it would slow down.
Image 2 (below) Credit: Florian Wobbe