Study: West Antarctic Glacier Melt Due To Volcanoes, Not Global Warming

An Adelie penguin stands atop a block of melting ice near the French station at Dumont d’Urville in East Antarctica January 23, 2010. REUTERS/Pauline Askin



A new study by researchers at the University of Texas, Austin found that the West Antarctic Ice Sheet is collapsing due to geothermal heat, not man-made global warming.

Researchers from the UTA’s Institute for Geophysics found that the Thwaites Glacier in western Antarctica is being eroded by the ocean as well as geothermal heat from magma and subaerial volcanoes. Thwaites is considered a key glacier for understanding future sea level rise.

UTA researchers used radar techniques to map water flows under ice sheets and estimate the rate of ice melt in the glacier. As it turns out, geothermal heat from magma and volcanoes under the glacier is much hotter and covers a much wider area than was previously thought.

“Geothermal flux is one of the most dynamically critical ice sheet boundary conditions but is extremely difficult to constrain at the scale required to understand and predict the behavior of rapidly changing glaciers,” UTA researchers wrote in their study, which was published in the Proceedings of the National Academy of Sciences.

The geothermal heat under the glaciers is likely a key factor in why the ice sheet is currently collapsing. Before this study, it was assumed that heat flow under the glacier was evenly distributed throughout, but UTA’s study shows this is not the case. Heat levels under the glacier are uneven, with some areas being much hotter than others.

“The combination of variable subglacial geothermal heat flow and the interacting subglacial water system could threaten the stability of Thwaites Glacier in ways that we never before imagined,” lead researcher David Schroeder said in a press release.

“It’s the most complex thermal environment you might imagine,” echoed co-author Don Blankenship “And then you plop the most critical dynamically unstable ice sheet on planet Earth in the middle of this thing, and then you try to model it. It’s virtually impossible.”

Scientists and environmentalists have been pointing to Antarctica’s collapsing western ice sheet as further evidence the planet is warming. NASA glaciologist Eric Rignot recently found that the western ice sheet collapse is “unstoppable” and could dramatically raise sea levels.

“The highest storm surge from Hurricane Sandy, or Superstorm Sandy, was just under 13 feet, and a whole lot of places it was 10 feet or less,” Penn State University glaciologist Richard Alley told Mother Jones’ Chris Mooney in a podcast.

“And we’re looking at 11 feet, or something like that, from West Antarctica,” Alley said. “Plus a little thermal expansion [water expanding as it gets warmer] and some mountain glacier melting that are already on the table. And so you can sort of think of the storm surge of Hurricane Sandy, something vaguely in that neighborhood for most of the coastline of the world.”

But reports of the western ice sheet’s collapse comes as Antarctic ice sheets continue to break records. At the end of May, Antarctic sea ice extent reached the highest level since measurements began in 1979.

Sea ice extent reached nearly 13 million square kilometers — 10.3 percent above the 1981-2010 climatological average of 11.7 million square kilometers. The previous record was 12.7 million square kilometers set in 2010.

Previous studies have also shown that the collapse of the continent’s western ice sheet is nothing new. The British Antarctic Survey (BAS) has released two major studies in the last year showing that the thinning south pole ice is nothing new.

A BAS study from February found that Antarctica’s Pine Island glacier thinned just as fast 8,000 years ago as it has in recent times — it also was able to reverse the collapse.

Another BAS study from last year says western Antarctic thinning is within the “natural range of climate variability” of the last 300 years.

“The record shows that this region has warmed since the late 1950s, at a similar magnitude to that observed in the Antarctic Peninsula and central West Antarctica,” said a BAS study published in the journal Geophysical Research Letters last year, “however, this warming trend is not unique.”

“More dramatic isotopic warming (and cooling) trends occurred in the mid-19th and 18th centuries, suggesting that at present the effect of anthropogenic climate drivers at this location has not exceeded the natural range of climate variability in the context of the past ~300 years,” the study said.


Brophy Saturday 14 June 2014 - 12:19 am | | Brophy Blog, Global Warming

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