Nature & Environment
Achilles' Heel of Antarctic Ice Shelves is Underwater
Catherine Griffin
First Posted: Sep 16, 2013 11:06 AM EDT
What's the most vulnerable part of an ice shelf? It turns out that it's underwater. Scientists have discovered that more ice leaves Antarctica by melting from the underside of submerged ice shelves. In fact, it accounts for as much as 90 percent of ice loss in some areas.
Every year, about 2,800 cubic kilometers of ice leaves the Antarctic. In the past, many researchers believed that iceberg calving--which is the breaking off of chunks of ice at the edge of a glacier--was largely responsible for this ice-loss. While much of this is replaced by snowfall, any imbalance causes global sea levels to rise. This, in turn, can cause major issues for coastal communities into the future.
In order to examine this ice loss a bit more closely, though, the researchers used satellite and climate model data. They accurately measured the flow of the ice, its elevation and thickness. Then they combined this data with the output of a climate model for snowfall over the ice sheet. After, they compared how much snow was falling on the surface and accumulating against how much ice was leaving the continent, entering the ocean and calving.
It turns out that as much as 90 percent of mass loss from some ice shelves may be from underbelly melting. That's not true for all ice shelves, though. It accounts for just 10 percent in others. Even so, the findings are huge for understanding exactly how much this process could be impacting these ice shelves.
"Understanding how the largest ice mass on the planet loses ice to the oceans is one of the most fundamental things we need to know for Antarctica. Until recently, we assumed that most of the ice was lost through icebergs," said Jonathan Bamber, one of the researchers, in a news release. "Now we realize that melting underneath the ice shelves by the ocean is equally important and for some places, far more important. This knowledge is crucial for understanding how the ice sheets interact now, and in the future, to changes in the climate."
As our climate continues to warm and change, it's important to understand what might affect sea level rise. Over the last decade, the Antarctic ice sheet has been losing an increasing amount of its volume. Learning what factors are impacting this ice loss is an important part of creating future models of sea level rise.
The findings are published in the journal Nature.
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First Posted: Sep 16, 2013 11:06 AM EDT
What's the most vulnerable part of an ice shelf? It turns out that it's underwater. Scientists have discovered that more ice leaves Antarctica by melting from the underside of submerged ice shelves. In fact, it accounts for as much as 90 percent of ice loss in some areas.
Every year, about 2,800 cubic kilometers of ice leaves the Antarctic. In the past, many researchers believed that iceberg calving--which is the breaking off of chunks of ice at the edge of a glacier--was largely responsible for this ice-loss. While much of this is replaced by snowfall, any imbalance causes global sea levels to rise. This, in turn, can cause major issues for coastal communities into the future.
In order to examine this ice loss a bit more closely, though, the researchers used satellite and climate model data. They accurately measured the flow of the ice, its elevation and thickness. Then they combined this data with the output of a climate model for snowfall over the ice sheet. After, they compared how much snow was falling on the surface and accumulating against how much ice was leaving the continent, entering the ocean and calving.
It turns out that as much as 90 percent of mass loss from some ice shelves may be from underbelly melting. That's not true for all ice shelves, though. It accounts for just 10 percent in others. Even so, the findings are huge for understanding exactly how much this process could be impacting these ice shelves.
"Understanding how the largest ice mass on the planet loses ice to the oceans is one of the most fundamental things we need to know for Antarctica. Until recently, we assumed that most of the ice was lost through icebergs," said Jonathan Bamber, one of the researchers, in a news release. "Now we realize that melting underneath the ice shelves by the ocean is equally important and for some places, far more important. This knowledge is crucial for understanding how the ice sheets interact now, and in the future, to changes in the climate."
As our climate continues to warm and change, it's important to understand what might affect sea level rise. Over the last decade, the Antarctic ice sheet has been losing an increasing amount of its volume. Learning what factors are impacting this ice loss is an important part of creating future models of sea level rise.
The findings are published in the journal Nature.
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone