Science1 publisher2 min readPublished
East Antarctica's Wilkes Basin holds 3 to 4 meters of sea-level rise in ice too poorly observed to forecast
Researchers from 14 countries say the Wilkes Basin's ice could raise seas 3 to 4 meters, though its pace of retreat and its trigger are still unknown. Until someone measures the sea floor and ocean at its glacier fronts, the basin's share of future sea-level rise cannot be dated.
The Scientist · Science desk
Drafted by a language model from the sources cited here and checked against its claim ledger before publication. How we use AISend a correction
What happened
- Matt King, a University of Tasmania professor and chief investigator at the Australian Centre for Excellence in Antarctic Science, led the review.
- According to King, no ship has ever come within 150 kilometers of the front of the Cook Glacier, one of the basin's key glaciers.
- Most of the Wilkes Subglacial Basin lies within Australian Antarctic Territory.
- The authors call for an urgent international effort to map the region and improve its ocean and ice-sheet observations.
Compiled by The ScientistSomething wrong?How this is made
Why it matters
- exposure King names coastal communities and infrastructure in Australia and the Pacific as the places at risk, and the present record cannot say how fast this basin could add to their sea-level rise.
- constraint With no in situ sea-floor maps and little ocean data, ice-sheet models of the basin have nothing local to check against, so better modeling alone cannot close the gap the review describes.
- decision Narrowing the range now depends on fieldwork. Governments would have to pay for ships and ocean instruments at glacier fronts that vessels have never reached.
The paper, published in Nature Reviews Earth & Environment [1] under the title "Dynamic instability of the Wilkes Subglacial Basin Ice Sheet, East Antarctica" [15], is a review. It puts the geology, oceanography, climate science, satellite observations and ice-sheet modeling side by side to sort out what is known about the basin and what is not [4]. Its main finding is about data that has never been collected. "There's no in situ mapping data of the sea floor, and we have very limited information about the ocean conditions that could drive future melting," King said [8].
For forecasting, the second half of that sentence matters most. King identifies the ocean as the thing that could drive future melting [8], and the water next to these glaciers is where information is scarcest. He called the basin "arguably the last unexplored place in Antarctica" [6].
The reason for concern is old. Geological records suggest the basin retreated substantially during past warm periods [9]. So the ice has moved before in a warm climate. But that is a correlation across geological time, and the authors do not turn it into a forecast. They conclude that the climate threshold for large-scale retreat cannot yet be predicted with confidence [5]. "The evidence from past warm periods is enough to ring an alarm bell that this is a region we need to understand much better, but it's hard to find a living scientist who's been there," King said [11].
The phys.org account of the review does not say how existing sea-level projections handle the Wilkes Basin, or what share of its estimated 3 to 4 meters they assume [2]. In my view, anyone planning against those projections should treat this basin's contribution as only loosely tied to observation, since nobody has mapped the region's sea floor in situ [8]. Planners are the audience King had in mind. "If we can better understand this region and its trajectory more accurately, we'll be better prepared for future sea-level rise, climate impacts and the consequences for coastal communities and vulnerable infrastructure in Australia, the Pacific and around the world," he said [14].
What to watch
- Whether any national Antarctic program commits a ship to survey the sea floor and ocean at the Cook Glacier front.
- Whether ice-sheet modelers publish revised retreat-rate ranges for the Wilkes Basin once in situ ocean data exist.
- Whether the 14-country author group turns its call into a funded campaign with dates and named vessels.