I keep vigil.
Climate Change is the real “national emergency” not an imaginary wall along the Mexican border.
An Antarctic ‘time bomb’ waiting to go off could wash away cities, scientists warn. Earth’ s sea levels should be 29 feet higher than they are now, according to historical data. It’s time to panic “because global temperatures today are the same as they were 115,000 years ago, a time when modern humans were only just beginning to leave Africa”. The bulk of that missing 29 feet of water will be in it’s frozen form.
Breaking news out of Antarctica.
Meltwater lakes on the ice shelves of Antarctica can cause them to buckle under the weight of the ponding water, possibly creating hydro-fractures resulting in ice shelf break up.
CIRES research scientists that studied an ice shelf near McMurdo Station have proven that these meltwater lakes are indeed capable of collapsing ice shelves similar to the break-up at Larsen B ice shelf.
For the first time, a research team co-led by CIRES-based scientists, has directly observed an Antarctic ice shelf bending under the weight of ponding meltwater on top, a phenomenon that may have triggered the 2002 collapse of the Larsen B ice shelf. And ice shelf flexure could potentially impact other vulnerable ice shelves, causing them to break up, quickening the discharge of ice into the ocean and contributing to global sea level rise.
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The team found that, at the center of each lake, the ice shelf moved down then up by around three to four feet in response to each lake filling then draining. But around 1500 feet from each lake there was virtually no vertical movement at all. Although this bending did not cause the McMurdo Ice Shelf to fracture, the team used modeling to predict that slightly larger lakes in closer proximity could trigger fracture. “That’s most likely what happened to Larsen B in 2002,” Banwell said.
Cartoon showing how a floating ice shelf bends (and may also fracture) in response to the filling and draining of a meltwater lake. Figure: Adapted from Fig 1. Banwell et al 2013. GRL“And climate models predict that there will be more melting across more ice shelves over the next few decades, leading to an increase in the occurrence of meltwater lakes,” added Willis.
“These observations are important because they help us better understand the triggers of ice shelf break up, which leads to sea level rise,” said Banwell. “Our results can be used to improve models to better predict which ice shelves are more vulnerable and are most susceptible to collapse.”
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