Published on November 26th, 2016 | by James Ayre0
Retreat Of Pine Island Glacier In West Antarctica Began In 1940s, Through Ocean-Driven Thinning & Retreat Of Sea-Ice Shelves (Climate Change), Research Finds
November 26th, 2016 by James Ayre
The retreat and thinning of Pine Island Glacier in West Antarctica, which had been known to go back at least as far as satellite monitoring of the region in the early 1990s, began all the way back in the 1940s — owing to ocean-driven thinning and retreat of sea-ice shelves, thereby leading to inland-glacier acceleration and ice-sheet thinning (climate change associated, and very likely induced at least partly by industrial activity before then) — new research has found.
The terminology of “ocean-driven thinning and retreat of ice-shelves” refers to the fact that the waters of the region became warm enough to begin melting the sea ice that they were in contact with (not non-stop, but periodically). Notably, since this trend was jump started, it has continued apace despite periodic changes in climate forcing.
“Our results suggest that, even when climate forcing (such as El Ninos, which create warmer water) weakened, ice-sheet retreat continued,” stated lead author James Smith of the British Antarctic Survey.
“Despite a return to pre-1940s climatic conditions in the ensuing decades, thinning and glacier retreat has not stopped and is unlikely to be reversible without a major change in marine or glaciological conditions,” Smith continued. “A period of warming in the Antarctic shelf waters triggered a substantial change in the ice sheet, via the mechanism that we see today — that is, ocean-driven thinning and retreat of ice shelves leads to inland glacier acceleration and ice-sheet thinning.”
So, despite some of the more twisted around headlines for this research out there now, what this means is that retreat of the ice shelves in West Antarctica has been going on since not that long after industrial anthropogenic climate forcing began in earnest.
This is highly relevant as the West Antarctic ice-sheet contains enough water to raise sea levels by an enormous degree — making useless many of the primary deep water sea ports of the current world, which would be incredibly expensive to relocate (and would require periodic relocation of sea level were to continue rising after relocation, as would happen). This would impact the economic spheres of the world more than is generally acknowledged. And would bring with it the typical social problems that always accompany groups of primates that have had something they consider to be theirs taken away from them.
While some may say well then we’ll also have a new continent filled with untapped mineral resources, the continent will also (once de-iced, centuries or millennia from now) be nearly devoid of soil, scoured down to the bedrock almost everywhere, and offer few means of self-support. Eventually, West Antarctica will no doubt end up greened to some degree or other, as it is colonized, whether by the surviving Antarctic Flora, Meyer Desert Formation biota, or otherwise, but this will be a relatively slow process following accelerated climate change.
Anyways, back to the new research… the press release provides details: “Over the past 40 years, glaciers flowing into the Amundsen Sea sector of the ice sheet have thinned at an accelerating rate, and several numerical models suggest that unstable and irreversible retreat of the grounding line — which marks the boundary between grounded ice and floating ice shelf — is underway.”
Continuing: “The team… analyzed sediment cores recovered beneath the floating Pine Island Glacier ice shelf. The team concluded the date at which the grounding line retreated from a prominent seafloor ridge was in 1945 at the latest. The team also found that final ungrounding of the ice shelf from the ridge occurred in 1970. For the study, the team drilled three 20-centimeter holes through the Pine Island Glacier ice shelf during December 2012 and January 2013 to access the ocean cavity below. Sediment cores were recovered at each site. Changes in the lithology and composition of sediment deposited beneath the glacier record the transition from grounded glacier to freely floating ice. Measurements of lead and plutonium in the sediment were used to determine when the ice retreat began. Analyses of trace levels of global fallout plutonium in the sediment were performed by high-precision mass spectrometry at LLNL. The appearance of plutonium in the sediment marks the onset of above-ground testing of nuclear weapons in the 1950s, and indicates that ice-sheet retreat began before this time.”
Regardless of the endless spinning of climate change related findings in the news, the truth is that the course has essentially already been set — denial, or tacit acceptance but a lack of strong action, lead to the same place after all.
The actions necessary to truly deal with the coming changes would require a fundamental restructuring of the current world paradigm, which given the inertia inherent in large groups of primates, and the stupefying effects of the modern stimuli, and drug-addled culture, is unlikely. Too bad then, because most predictions to date seem to be underestimating what’s in store, not overestimating.
The new research is detailed in a paper published in the November 23 issue of the journal Nature.
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