The Thwaites Glacier is a large, dynamic portion of the West Antarctic Ice Sheet.

Researchers Find Major Glacier Melting Due to Geothermal Heat

A study by scientists at UT’s Institute for Geophysics finds that the flow of geothermal heat below the Thwaites Glacier is much more variable, widely distributed and hotter than previously believed. This melting can contribute to global sea level rise.

A recent study from University of Texas at Austin researchersindicates that the Thwaites Glacier, a large, dynamic portion of the West Antarctic Ice Sheet, is melting, in large part due to the geothermal heat flowing below the glacier.Scientists use ice sheet modeling to attempt to understand the rate at which glaciers are moving and melting, and predict the rate of sea level rise."Geothermal flux is the heat that flows from the earth beneath an ice sheet into the bottom of the ice," said Dusty Schroeder, lead author of the study. "So, if part of an ice sheet is located in a region of high geothermal flux, for example in a region with thin crust or nearby volcanism due to rifting, then it will lead to more melting at the bottom of the ice sheet than if that that ice sheet was located in a region with lower geothermal flux.”It was previously thought that the flow of geothermal heat beneath the glacier was uniform. This study, however, has shown that this is not the case."Before our paper, models tended to just assume a uniform geothermal flux value beneath the glacier because it was the best you could do with the observations available," Schroeder said. "Our results provide an observation-based set of geologically realistic geothermal flux values that modelers can use to make much more realistic simulations of the future behavior, and sea level contribution of Thwaites Glacier."Schroeder and his team found that the flow of geothermal heat is much more variable, widely distributed and hotter than previously believed. This variable distribution could be due to magma flow and volcanic activity in the area.“It’s the most complex thermal environment you might imagine,” said co-author Don Blankenship, who was Schroeder’s Ph.D. adviser. “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.”The Thwaites Glacier is the focus of recent studies because scientists are predicting that the glacier has begun to collapse, due to global warming. This collapse, scientists warn, will contribute to a global sea level rise.Although many scientists speculate that global warming is the cause of increased melting rates and therefore rising ocean levels, Schroeder and his team emphasize that their study did not examine this issue."Our study has no bearing on whether or not anthropogenic global warning is occurring," Schroeder's team said in a statement.Schroeder and his team used radar techniques in order to map water flow under the ice sheets. This allowed the researchers to identify the melting rate and cause of geothermal heat."We used a combination of ice penetrating radar data analysis and subglacial hydrologic modeling to constrain the melt rates in an area where the configuration of the subglacial water system was well understood," Schroeder said.Scientists place great emphasis on modeling heat distribution and glacier behavior in order to predict how glaciers respond to warming ocean temperatures.Schroeder believes that this study has important developments for future research.“That's one of the exciting things about the technique developed in this paper,” Schroeder said. “We can apply it to other areas where we expect that high, and spatially varying, geothermal heat flow might be playing a significant role. The most likely candidates are other areas in West Antarctica near to the West Antarctic Rift System.”

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