West Antarctica is in a lot of trouble, which means that we too, are in a lot of trouble from sea level rise.
The West Antarctic Ice Sheet (WAIS) is the largest mass of ice on the planet.covering an area of 5,405,430 square miles and holding 30 million cubic km of ice. That represents 90% of the world’s fresh water and also holds 230 feet of sea level rise. East Antarctica rests on the bedrock. In West Antarctica the bed can extend to more than 8200 feet below sea level.
Washington University in Saint Louis reports on the geography of West Antarctica.
"Our understanding of what's going on is really hampered because we can't see the geology," said Andrew Lloyd, a graduate student in earth and planetary sciences in Arts & Sciences at Washington University in St. Louis. "We have to turn to geophysical methods, such as seismology, to learn more," he said.
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The old rock of East Antarctica rises well above sea level, but west of the Transantarctic Mountains, extension has pulled the crust into a broad saddle, or rift valley, much of which lies a kilometer below sea level.
“If you removed the ice, West Antarctica would rebound, and most of it would be near sea level. But the narrower and deeper basins might remain below it,” Lloyd said. “The Bentley Subglacial Trench, which is the lowest point on Earth not covered by an ocean, would still be a kilometer and a half below sea level if the ice were removed.”
Scientists have not detected earthquakes which means the rift is inactive. But heat was found that suggests that the rifting had stopped only recently.
The rift system is thought to have a major influence on ice streams in West Antarctica. “Rifting and ice flow occur on completely different time scales,” Lloyd said, “so rifting is not going to suddenly make the ice sheet unstable.
“But to accurately model how quickly the ice is going to flow or the rock to rebound, we need to understand the ‘boundary conditions’ for ice models, such as heat flow from the mantle,” he said.
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