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Why Antarctica Is Getting Taller (livescience.com)
An anonymous reader quotes a report from Live Science: Bedrock under Antarctica is rising more swiftly than ever recorded -- about 1.6 inches (41 millimeters) upward per year. And thinning ice in Antarctica may be responsible. That's because as ice melts, its weight on the rock below lightens. And over time, when enormous quantities of ice have disappeared, the bedrock rises in response, pushed up by the flow of the viscous mantle below Earth's surface, scientists reported in a new study. These uplifting findings are both bad news and good news for the frozen continent. The good news is that the uplift of supporting bedrock could make the remaining ice sheets more stable. The bad news is that in recent years, the rising earth has probably skewed satellite measurements of ice loss, leading researchers to underestimate the rate of vanishing ice by as much as 10 percent, the scientists reported. The findings were published in the journal Science.
Like the North American continent, Antartica is rising in response to the end of the last ice age. That's not due to AGW in any meaningful way. However, the recent loss of antartic ice may be more severe then measured, and the recent loss of ice is significantly impacted by climate change in the last 100 years, which appears to be strongly affected by human behavior.
Geophysicist here. Typically this sort of vertical place motion is slow. It is known as isostatic rebound, or post-glacial rebound, and it is pretty common. In fact, parts of north america and northern europe are still rebounding from when the glaciers melted after the last ice age. The uplift rate here is 41mm/year, which is high for this sort of thing, but it is not going have that great of an impact when you consider that the lithosphere (plate plus the upper solid mantle) is 50-150km thick. 41mm/ys is roughly the same rate fingernails grow. As far as I know an entire plate shearing off has never occcured, and seems pretty hard for me to imagine. Of the 6 plates it interacts with, 5 of those are ridges, where new plate is formed, and the last is a short section of subduction, where the antarctic plate is beaing pushed underneath the south american plate. Patagonian volcanoes are the result of this subduction, just like the volcanoes in the pacific northwest. While tsunamis can be generated here, they will happen the old fashioned way, where a large earthquake occurs and a small portion of the seafloor lifts up a bit.
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