Researchers have announced a significant scientific achievement: they have penetrated deeper than previously accomplished beneath the West Antarctic Ice Sheet. This deep-sea exploration has yielded insights dating back millions of years, indicating that at least portions of this region were once open ocean.
An international contingent of 29 scientists has estimated that this immense ice mass contains sufficient frozen water to elevate global sea levels by an estimated four to five meters (approximately 13 to 16 feet).
Through the process of drilling through the ice and the underlying sediment layers, researchers successfully retrieved specimens that illuminate the environmental conditions present up to 23 million years ago.
The primary objective of this research is to comprehend the historical melting patterns of this ice sheet. By understanding the factors that precipitated its past retreats, scientists aim to identify drivers such as oceanic temperatures prevalent during those epochs.
This knowledge is anticipated to contribute to more precise projections regarding the rate at which the ice sheet might diminish in the future, in the context of a progressively warming global climate.
“Decades of satellite monitoring have revealed an accelerating rate of mass loss from the ice sheet, yet considerable conjecture persists regarding the precise temperature threshold that could instigate rapid glacial ablation,” stated the researchers in a report detailing their preliminary findings, issued on Wednesday. “Prior to this endeavor, ice sheet modelers were constrained to utilizing geological records sourced from more distant locations.”
The drilling operation, executed at Crary Ice Rise on the Ross Ice Shelf, extended through 523 meters of ice followed by 228 meters of ancient rock and mud. This undertaking was spearheaded by a collaborative effort involving Earth Sciences New Zealand, Victoria University of Wellington, and Antarctica New Zealand.
‘Marine organisms’
“A portion of the recovered sediment exhibited characteristics consistent with depositional environments found beneath an ice sheet, similar to the conditions presently observed at Crary Ice Rise,” commented co-chief scientist Molly Patterson, affiliated with Binghamton University in the United States.
However, the team also unearthed shell fragments and the remnants of marine life requiring sunlight. This type of material is more indicative of open ocean conditions, a floating ice shelf, or the edge of an ice shelf where icebergs are breaking off, Patterson explained.
Existing scientific understanding already suggested that this region was at one point an open ocean, implying a recession of the Ross Ice Shelf and a potential destabilization of the West Antarctic Ice Sheet.
Nevertheless, definitive information regarding the timing of these events remained elusive.
The newly acquired data provides a chronological sequence of past environmental states and offers concrete evidence of open ocean presence within this geographical area, according to Patterson.
Huw Horgan, a fellow co-chief scientist on the project from Victoria University of Wellington, indicated that initial analyses suggest the retrieved samples encompass a timeframe of the past 23 million years.
This period includes intervals when Earth’s global average temperatures were substantially higher, exceeding pre-industrial levels by more than two degrees Celsius, Horgan noted.
The drilling concluded in January, and the extracted core samples have been transported over 1,100 kilometers (approximately 680 miles) across the Ross Ice Shelf from Crary Ice Rise to Scott Base. From Scott Base, the samples will be dispatched to New Zealand for comprehensive further examination.
