By Kenneth Richard on 29. May 2023
Map of the central Amundsen Sea coast generated using data sets from Quantarctica version 3 (Matsuoka et al., 2021) and showing major glaciers, the drill site at Kay Peak Ridge, and historical grounding line positions in the Thwaites–Pope–Smith Glacier region. The 1992–1995 and 2020 grounding line positions are from Rignot et al. (2011) and Milillo et al. (2022), respectively. The blue shading is a qualitative representation of ice flow velocity and is intended to highlight major glaciers.
Scientists have determined there is no measured data to “indicate thicker than present ice after 4ka” at a West Antarctic study site near the Thwaites “Doomsday” Glacier. Any ice melt observed today is thus “reversible”… and natural.
Synthetic oblique view of the drill site at the north ridge of Kay Peak generated from WorldView imagery (© 2018, Maxar) and the Reference Elevation Model of Antarctica (REMA) digital elevation model (Howat et al., 2019). View direction is to the south, as indicated in Fig. 1, from the position of a viewer located over the Crosson Ice Shelf and looking up Pope Glacier. The overlay is an elevation profile along the axis of Kay Peak Ridge showing the relationship between samples collected from the exposed portion of the ridge, drill sites, and subglacial bedrock samples. Note that the vertical scale of the inset profile excludes many samples collected from above 170 m elevation on the ice-free portion of the ridge; Fig. 4 shows the elevation distribution of the entire sample set.
The Thwaites, Pine Island, and Pope Glaciers in the Amundsen Sea region of West Antarctica are all situated on a hotbed of active geothermal heat flux, which has led to anomalously high regional melt rates. Indeed, “there is a conspicuously large amount of heat from Earth’s interior beneath the ice” in the very locations where the ice melt is most pronounced.
While the Earth’s crust has an average thickness of about 40 km, in the Thwaites-Pine Island-Pope Glacier region the anomalously thinner crust (10 to 18 km) more readily exposes the base of the ice to 580°C tectonic trenches. The “elevated geothermal heat flow band is interpreted as caused by an anomalously thin crust underlain by a hot mantle,” which is exerting a “profound influence on the flow dynamics of the Western Antarctic Ice Sheet” (Dziadek et al., 2021).
Despite the established natural causes of ice melt this region (see also Schroeder et al., 2014, Loose et al., 2018), it has nonetheless become commonplace for those who believe human behaviors are the climate’s “control knob” to claim the melting of the Thwaites Glacier – dubbed the “Doomsday Glacier” by alarmists – is caused by humans driving gasoline-powered trucks or using natural gas for energy.
But a new study categorically undermines claims that the ice melt occurring in the Thwaites-Pine Island-Pope Glacier region is unusual, unprecedented, or unnatural.
The thickness of the ice sheet at this Amundsen Sea region site averages about 40 m today.
Scientists (Balco et al., 2023) have used cosmogenic-nuclide concentrations and bedrock cores to determine the ice sheet is presently around 8 times thicker than it was for most of the last 8,000 years of the Holocene, when the ice thickness ranged between 2 m and 7 m.
“…the West Antarctic Ice Sheet (WAIS) at a site between Thwaites and Pope glaciers was at least 35m thinner than present in the past several thousand years”
Image Source: Balco et al., 2023
Even more interesting, the scientists found there are “no exposure-age data in the Amundsen Sea region indicating thicker than present ice after 4 ka,” suggesting that the present thickness is close to the most pronounced it has been over the last 4,000 years.
Any ice melt from this region, then, is not only natural, but the opposite of “unprecedented.” The scientists thus characterize modern changes to the West Antarctic ice sheet as “reversible” instead.