Eric Rignot, the glaciologist who maps where Antarctica is breaking

Eric Rignot has a way of describing Antarctica that sticks. Where warm ocean water reaches the ice, he says, the continent behaves like a balloon that has not been punctured everywhere, but where it has been punctured, the hole goes deep. Rignot is the scientist reporters call when a glacier is described as doomed, and the phrase he once attached to West Antarctica, the point of no return, has followed him for more than a decade. Yet his latest continent-wide survey found that most of Antarctica’s coastline has not moved at all. The alarm he raises was never that everything is melting. It concerns the few places that are, and the computer models that keep underestimating them.

He is a French engineer by training who became an American glaciologist by way of radar. Rignot grew up in Le Chambon-sur-Lignon, a village on the Haute-Loire plateau, and took his baccalauréat at its international school, the Collège-Lycée Cévenol. After the École Centrale in Paris and a master’s in astronomy at the Université Paris VI, he crossed to the University of Southern California for a doctorate in electrical engineering.

The degrees explain the method. Rignot joined NASA’s Jet Propulsion Laboratory in California in 1987 and has said plainly that he grew up with NASA. His instrument was satellite radar interferometry, which measures how fast ice moves across regions no field team could cross on foot; combined with ice-thickness surveys and snowfall models, it let him calculate how much ice the great sheets discharge into the sea along their entire perimeter. The European Geosciences Union, awarding him its Louis Agassiz Medal in 2017, credited that “flux-gate” approach with the first assessments of the mass balance of both the Antarctic and the Greenland ice sheets.

Greenland produced one of his starkest early findings. In 2006 he and Pannir Kanagaratnam published Changes in the velocity structure of the Greenland Ice Sheet in Science. The finding was blunt: faster-flowing outlet glaciers had roughly doubled the ice sheet’s mass deficit within a decade, from about 90 to 220 cubic kilometres a year. Rignot contributed to the fourth assessment of the Intergovernmental Panel on Climate Change, the body that shared the Nobel Peace Prize in 2007, and was a lead author of its fifth in 2013.

In 2007 he took a professorship at the University of California, Irvine, keeping his post at JPL. He was the land-ice science lead of Operation IceBridge, the NASA airborne mission that surveyed Greenland and Antarctica from 2009 to 2019, and deputy lead of Oceans Melting Greenland, which between 2015 and 2020 mapped Greenland’s fjords and the warm water entering them for the first time. Through NASA’s MEaSUREs programme his group released the first continent-wide map of Antarctic ice flow in 2011.

Then came the sentence. In May 2014 Rignot was lead author of a study of six glaciers draining into West Antarctica’s Amundsen Sea, among them Pine Island and Thwaites, which together hold enough ice to raise global sea level by 1.2 metres. The glaciers, he told reporters, had “passed the point of no return.” The phrase travelled faster than its fine print. Rignot himself estimated the loss would unfold over several centuries, a timescale that rarely survived into headlines about a collapsing continent, while Thwaites acquired the nickname Doomsday Glacier.

This is where the public figure and the working scientist part ways. To readers he brings the worst news about the ice; inside his field he is the one who keeps counting. In 2015 a NASA Goddard team led by Jay Zwally argued in the Journal of Glaciology that Antarctica was gaining more ice through snowfall than it was losing, a direct challenge to the record Rignot had assembled. Later measurements largely sided with loss. His own 2019 paper in the Proceedings of the National Academy of Sciences, Four decades of Antarctic Ice Sheet mass balance from 1979–2017, put the continent’s yearly loss at about 40 billion tonnes between 1979 and 1990 and 252 billion tonnes between 2009 and 2017. If there is a fair charge against him, it concerns compression rather than arithmetic. His most quoted phrases fold centuries into a single news cycle and leave the stable majority of Antarctica outside the frame he is known for.

In March 2026 he filled in that frame himself, leading a study in the same journal that tracked Antarctica’s grounding lines, where ice leaves the bedrock and begins to float, across thirty years of satellite radar. Seventy-seven percent of the coastline showed no migration since 1996. The rest had given up 12,820 square kilometres of grounded ice: Pine Island Glacier retreated 33 kilometres, Thwaites 26 and Smith 42. We should perhaps feel fortunate that all of Antarctica is not reacting right now, he said, “but that could be the next step.”

October brought the sharper result. A model published in Nature Communications, led by Mattia Poinelli, then a postdoctoral scholar at UC Irvine, treated the base of Thwaites not as a thin line but as a grounding zone kilometres wide, where warm, pressurised seawater reaches beneath ice still resting on the seafloor. It roughly doubled the projected contribution of Thwaites to sea level by 2100, to as much as 30 millimetres, and gave a 60 percent chance that the glacier comes loose from the Mouginot Ridge, the underwater high now holding it, before the century ends. Rignot, a co-author, said the mounting evidence from beneath glaciers like Thwaites was producing “an even greater sense of alarm.”

The work now runs against a tightening budget. In an interview with his university in October 2025, Rignot said MEaSUREs, which won a fourth five-year NASA grant in 2023, was rumoured to face termination under cuts to Earth science, and that NISAR, the NASA and Indian Space Research Organisation radar satellite launched that summer, faced threats of its own. He framed the stakes as a choice between deciding on knowledge and deciding on ideology.

Early in 2025 he spent twenty-four days on the King Baudouin Ice Shelf in East Antarctica, losing a drill head in a 350-metre borehole, then watching his doctoral student defend a thesis at Belgium’s Princess Elisabeth station. Elected to the US National Academy of Sciences in 2018 and the National Academy of Engineering in 2025, with a glacier in Ellsworth Land named after him, Rignot is now backing the University of Antarctica Research Center, an international consortium meant to be running by the next International Polar Year in 2032–33. NISAR is built to image the whole continent every twelve days. How long that data keeps coming will decide how much of the next retreat he gets to measure.

Tags: nasa, Antarctica, Eric Rignot, Thwaites Glacier, glaciologists, Mattia Poinelli

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