Frozen icebergs

Frozen icebergs near Thwaites Glacier in West Antarctica.

NASA/Jim Yungel/Flickr (CC BY 2.0)

U.S. and U.K. plan ‘Thwaites invasion’ in Antarctica

STERLING, VIRGINIA—If there's one universal question that scientists working on the West Antarctic Ice Sheet hear from their friends and families, it's this: "How fast is the sea going to rise?"

The ice sheet is one of the biggest wild cards in sea-level projections for the next century, its durable uncertainty complicating efforts to adapt to human-driven climate change. Once thought stable for centuries, it has become clear from satellite and airplane observations that parts of the sheet are thinning and could become unstable. But when that might happen is uncertain, with estimates ranging from as soon as the next few decades to the next few centuries.

In a bid to refine these estimates, this month the National Science Foundation (NSF) and the United Kingdom's Natural Environment Research Council will announce a project to support coordinated fieldwork on the Thwaites Glacier, the emerging epicenter of potential melt on the West Antarctic Ice Sheet. Although NSF declined to disclose exact figures, the initiative will likely provide tens of millions of dollars for Antarctic research over 5 years, including spending on infrastructure.

The "Thwaites invasion" will be "the biggest thing to happen in our area of science for quite a long time," said David Vaughan, director of science at the British Antarctic Survey in Cambridge at an annual interdisciplinary workshop for West Antarctic scientists held here this week. The initiative will be expected to feed data directly into the sea-level forecasts produced by the Intergovernmental Panel on Climate Change. "We want real outcomes that improve projections," he said.

Several recent studies have found evidence of ice retreat and thinning at Thwaites and several other glaciers, alarming scientists and prompting concern that a slow collapse of the western sheets could be "irreversible." Such a melt, still projected to take centuries or millennia, could raise sea levels by 3.3 meters, inundating cities, with that rise 30% worse for the coastal United States thanks to a decline in Antarctica's gravitational pull.

Thwaites, a 182,000-square-kilometer glacier that abuts the Amundsen Sea, is a textbook example of the marine ice sheets that concern scientists. It has a wide front on the ocean's edge and sits on ground below sea level, where warming waters can slowly melt its base. This deep seawater is held back by a submerged ridge, but once water surmounts this grounding line, the land slopes downward into a basin of uncertain topography and slipperiness. With evidence coming from satellites, airplanes, and models, it remains difficult to say with certainty whether the melting at Thwaites represents a true tipping point for the planet or how fast it might happen.

Those alarming studies set the tone for the past 2 years, said Ted Scambos, a scientist at the U.S. National Snow and Ice Data Center in Boulder, Colorado, who helped devise the initiative. At a series of meetings, U.K. and U.S. scientists realized they were both focusing on Thwaites, which seemed to be changing faster than its neighboring Pine Island Glacier. Given tight budgets, a joint, targeted campaign made sense. "We already know what the right things to do are," Scambos said. They just have to do them.

The initiative will support a mix of land- and ocean-based field work on the ice sheet and its surrounding sea. This could include new automatic weather stations; sub–ice shelf moorings, gliders, and vehicles; shallow ice cores; and radar and seismic surveys, among other projects. It will also finance modeling, paleoclimate reconstruction, and research on glaciers deemed directly relevant to Thwaites. The project will support 5-year missions, beginning next October, with the primary field seasons expected between fall 2019 and spring 2021.

Thwaites is about as remote from existing infrastructure as one can get in Antarctica. It's not close to any U.S. station. Working there sits "at the limit of people's comfort level," says Chris Shuman, an Arctic scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. It has a gnarly, uneven surface and harsh weather. It will take a great deal of logistical support to make these campaigns happen, Vaughan said at the meeting. "We are committing a huge amount of our logistics resources to this."

Although NSF will continue to support investigator-driven research in Antarctica, it's unavoidable that this campaign will ding the financing for other projects, Eric Saltzman, head of NSF's Antarctic science program in Arlington, Virginia, told the meeting. "Will it have an impact? Yes."

Although it's possible the initiative could delay support for work elsewhere, the approach seems "sensible," says Martin Siegert, a polar scientist at Imperial College London who has worked on the East Antarctic Ice Sheet. Lessons learned on Thwaites will likely inform work on other ice sheets.

The initiative may represent the best chance Antarctic scientists have to make a tangible contribution to the world. Politicians are demanding better numbers, said Robin Bell, an Antarctic scientist at Columbia University. "This is a moral and social imperative."