Scientists Map What Lies Beneath Antarctica’s Ice Sheet

(CN) – Scientists have revealed the most detailed map of the land beneath the massive ice sheets of Antarctica – a map that offers significant insight into how the continent will respond to climate change and contribute to rising sea levels, according to a new scientific study.

A topographical map of Antarctica reveals a mixed picture: Ice streams in some areas are protected by ground features underneath, while others on retrograde beds are more at risk from possible instability of the ice sheet. (Mathieu Morlighem / UCI)

The study, published in Nature Geoscience on Thursday, details how a group of glaciologists assembled the most detailed map to date of the topography hidden beneath Antarctic ice. The group, led by a research team from the University of California, Irvine, used Antarctic ice thickness data that dates back to the late 1960s, comprehensive bathymetry measurements of ice shelves, and several other research tools in their cartography.

The new map, known as the BedMachine project, unearthed several land features that were previously either unknown or poorly understood, according to the study. Significantly, the map revealed icy ridges that help to naturally stabilize ice flow across and around the Transantarctic Mountains, some of the oldest and most expansive mountains in Antarctica. Researchers also gained detailed information on an East Antarctic canyon underneath the Denman Glacier – the deepest land canyon on Earth.

Researchers say that perhaps the most valuable insight that can be gained by this new understanding of Antarctic topography is how the continent could react to continually shifting climate conditions as a result of climate change. The new details on the earth beneath Antarctica’s ice sheets could help researchers better understand which areas of the continent are more vulnerable land loss and which sections of the continent could contribute the most sea level rise.

Mathieu Morlighem, associate professor of Earth system science at the University of California, Irvine, said the complexity and changing nature of Antarctica’s ice sheets make it necessary to better understand the dynamics of the land underneath the sheets themselves, which is exactly what this new map helps make possible.

“A high-resolution description of the shape of the bedrock underneath the ice sheet is absolutely critical if we want to reduce the uncertainty in sea level rise projections,” Morlighem said. “Ice sheets are dynamic systems: snow accumulates in the interior and never melts, forming ice as it gets more and more compact. It then starts to deform under its own weight forming rivers of ice that discharge icebergs into the ocean.”

“What we are observing today is that these ice streams flow faster and therefore discharge more icebergs into the ocean than they receive snowfall, leading to an overall mass loss and therefore sea level rise,” he added.

Researchers suggest that with each new discovery made about the geographic makeup of what is under the Antarctic ice sheets, scientists become increasingly well-equipped with the kind of knowledge needed to anticipate and understand how Antarctica will be influenced by climate change in the coming years.

Morlighem said these discoveries were never made by previous radar mapping efforts of Antarctica, and that a newer, more detailed approach was needed in order to make these vital geographic observations.

“The last version of the bed topography under Antarctica was released 7 years ago, and many, many radar surveys have been conducted all over the ice sheet to try to fill in the gaps where we did not have data, or improve the accuracy of the bed where we know it matters for sea level rise projections,” Morlighem said. “Here, we have not only compiled all the radar surveys we could find, we also used a new mapping technique to ‘fill in the blanks’ in between flight lines based on physics.”

The study notes that while this new map is the most detailed picture scientists have of Antarctica, further efforts to map the landmass could yield even more enlightening results.

The study suggests that data-collecting flights track areas where ice flow is at its fastest – such as the area around the Ross Ice Shelf, which is the largest ice shelf in Antarctica – could shed further light on the continent’s structural nature, and what role it will play in the problem of sea level rise.

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