Researchers from New York University, McGill University and Pennsylvania State University found that the projected melting of Antarctic ice may be delayed or influenced by two things that are most often disregarded in present computer simulation models: ice gravity and Earth structure variations.
Significant unpredictability of anticipations about future sea level rise have been greatly influenced by the durability of Antarctic Ice Sheet (AIS) marine sectors in a warming climate. The decline of sea levels close to the grounding line of receding marine ice sheet has major effects on the ice sheets. Studies in the past have also confirmed the value of this feedback on the AIS evolution during the ice age.
In a new study, the authors used a model that connects ice sheet and sea levels to analyze the effects of the feedback mechanism on AIS fall back over a period of a century or millennium. Different emission schemes were also applied.
Gravity is most often associated with the force that enables people's feet to stay put on the ground. However, the concept actually pertains to the force that pulls two objects towards each other. The larger the object, the more forceful is the gravitational pull; such is the case in massive ice sheets, which attracts other bodies, including water.
As per analysis of their models, the researchers found that as the West Antarctic Ice Sheet (WAIS) melts, the gravitational pull also decreases. The decline is so significant that it is sufficient enough to lower sea levels close to the ice. Such effect would delay the anticipated pace of ice sheet retreat.
The researchers also found another vital factor in their computer model simulations. In case the ice sheet melts, the ice load would fall down, freeing the solid ground underneath it and causing a rebound upward effect.
The Earth's mantle has very viscous properties that make fluid movement notably slow. In the West Antarctic region, however, the mantle is less viscous compared to the other parts of the planet. With this, the land will emerge more rapidly than what scientists and other computer simulations could predict.
"We show that the combination of bedrock uplift and sea-surface drop associated with ice-sheet retreat significantly reduces AIS mass loss relative to a simulation without these effects included," the authors wrote.
The study was published in the journal Nature Communications on Tuesday, Nov. 10.
Photo: Bernt Rostad | Flickr
