An analysis of the expansion of cracks in the Thwaites Glacier over the past 20 years suggests that a total collapse could be only a matter of time. Known as the "Doomsday Glacier," the Thwaites Glacier in Antarctica is one of the most rapidly changing glaciers on Earth, and its future evolution is one of the biggest unknowns when it comes to predicting global sea level rise. The eastern ice shelf of the Thwaites Glacier is supported at its northern end by a ridge of the ocean floor. However, over the past two decades, cracks in the upper reaches of the glacier have increased rapidly, weakening its structural stability. A new study by the International Thwaites Glacier Collaboration (ITGC) presents a detailed record of this gradual collapse process.

Environment Conservation Ocean Underwater robot survives voyage to'never-accessed region of the planet' An Argo float delivered unprecedented data after eight months beneath Antarctic ice. Breakthroughs, discoveries, and DIY tips sent every weekday. Thanks to an underwater survey robot, oceanographers are getting the first-ever readings collected from underneath East Antarctic's vast ice shelves . But for a moment, it wasn't clear when(or if) the bright yellow float would return to the ocean's surface after it dove underneath the ice. "We got lucky," Steve Rintoul, an oceanographer with Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO), said in a statement .

Environment Animals Wildlife Fish The quest to find Shackleton's ship uncovered an Antarctic mystery Beneath the ice, an underwater robot discovered something far stranger than the'Endurance' shipwreck. Breakthroughs, discoveries, and DIY tips sent every weekday. The Antarctic Ocean's brutal conditions ultimately doomed Ernest Shackleton's famed 1915 expedition aboard the . Although the icy environment has quickly turned fatal for many unfortunate explorers, it's not an entirely inhospitable place . While attempting to locate Shackleton's sunken ship in 2019, researchers unexpectedly documented a strange sight-a sprawling, geometric complex of over 1,000 icefish nests .

James Cameron wasn't near the penguins this time around, but he is extremely familiar with their environment. "When I went to Antarctica myself, I had a Nikon still camera adapted to the cold with special lubricants," he tells Popular Science. "I went to the South Pole and the film shattered in my hand when I tried to change it. I took a video camera, I wrapped it in a heating pack and it [died] in two minutes. I have a good sense of what it takes to take conventional equipment into that environment and survive."

We propose a novel technique for guidance of buoyancy-controlled vehicles in uncertain under-ice ocean flows. In-situ melt rate measurements collected at the grounding zone of Antarctic ice shelves, where the ice shelf meets the underlying bedrock, are essential to constrain models of future sea level rise. Buoyancy-controlled vehicles, which control their vertical position in the water column through internal actuation but have no means of horizontal propulsion, offer an affordable and reliable platform for such in-situ data collection. However, reaching the grounding zone requires vehicles to traverse tens of kilometers under the ice shelf, with approximate position knowledge and no means of communication, in highly variable and uncertain ocean currents. To address this challenge, we propose a partially observable MDP approach that exploits model-based knowledge of the under-ice currents and, critically, of their uncertainty, to synthesize effective guidance policies. The approach uses approximate dynamic programming to model uncertainty in the currents, and QMDP to address localization uncertainty. Numerical experiments show that the policy can deliver up to 88.8% of underwater vehicles to the grounding zone -- a 33% improvement compared to state-of-the-art guidance techniques, and a 262% improvement over uncontrolled drifters. Collectively, these results show that model-based under-ice guidance is a highly promising technique for exploration of under-ice cavities, and has the potential to enable cost-effective and scalable access to these challenging and rarely observed environments.

The ice shelves buttressing the Antarctic ice sheet determine the rate of ice-discharge into the surrounding oceans. The geometry of ice shelves, and hence their buttressing strength, is determined by ice flow as well as by the local surface accumulation and basal melt rates, governed by atmospheric and oceanic conditions. Contemporary methods resolve one of these rates, but typically not both. Moreover, there is little information of how they changed in time. We present a new method to simultaneously infer the surface accumulation and basal melt rates averaged over decadal and centennial timescales. We infer the spatial dependence of these rates along flow line transects using internal stratigraphy observed by radars, using a kinematic forward model of internal stratigraphy. We solve the inverse problem using simulation-based inference (SBI). SBI performs Bayesian inference by training neural networks on simulations of the forward model to approximate the posterior distribution, allowing us to also quantify uncertainties over the inferred parameters. We demonstrate the validity of our method on a synthetic example, and apply it to Ekstr\"om Ice Shelf, Antarctica, for which newly acquired radar measurements are available. We obtain posterior distributions of surface accumulation and basal melt averaging over 42, 84, 146, and 188 years before 2022. Our results suggest stable atmospheric and oceanographic conditions over this period in this catchment of Antarctica. Use of observed internal stratigraphy can separate the effects of surface accumulation and basal melt, allowing them to be interpreted in a historical context of the last centuries and beyond.

Icefin the robot is designed to go where no human can, swimming off the coast of Antarctica under 2,000 feet of ice. Lowered through a borehole drilled with hot water, the torpedo-shaped machine takes readings and--most strikingly--video of Thwaites Glacier's vulnerable underbelly. This Florida-sized chunk of ice is also known as the Doomsday Glacier, and for good reason: It's rapidly deteriorating, and if it collapses, global sea levels could rise over a foot. It could also tug on surrounding glaciers as it dies, which would add another 10 feet to rising seas. In a pair of papers published today in the journal Nature, scientists describe what Icefin and other instruments have discovered underneath all that ice.

Forecasting rates of sea level change in polar ice shelves: Polar scientists, along with atmospheric and ocean scientists, face an urgent need to understand sea level rise around the globe. Ice-shelf environments represent extreme environments for sampling and sensing. Current efforts to collect sensed data are limited and use tethered robots with traditional sampling frequency and collection limitations. The ability to collect extensive data about conditions at or near the ice shelves will inform our understanding about changes in ocean circulation patterns, as well as feedbacks with wind circulation. New research on intelligent sensors would support selective data collection, onboard data analysis, and adaptive sensor steering.

This story was originally published by Wired and is reproduced here as part of the Climate Desk collaboration. Two Decembers ago, Erin Pettit layered up, slapped on goggles, cued up an audio book, and went on a hike--across Thwaites Glacier in Antarctica. Behind her, she dragged a sled loaded with a ground-penetrating radar, which fired pulses through a thousand feet of ice and analyzed the radio waves that bounced off the seawater below, thus building a detailed image of the glacier beneath her feet. Pettit--a glaciologist and climate scientist at Oregon State University--hiked alone through the snow, sometimes eschewing headphones for the absolute auditory stillness of the most remote landscape on Earth. "It was actually kind of an amazing, meditative field season," she says, "I just bundled up, I went out there and pulled my sled, and just walked for miles and miles."

Two Decembers ago, Erin Pettit layered up, slapped on goggles, cued up an audio book, and went on a hike--across Thwaites Glacier in Antarctica. Behind her, she dragged a sled loaded with a ground-penetrating radar, which fired pulses through a thousand feet of ice and analyzed the radio waves that bounced off the seawater below, thus building a detailed image of the glacier beneath her feet. Pettit--a glaciologist and climate scientist at Oregon State University--hiked alone through the snow, sometimes eschewing headphones for the absolute auditory stillness of the most remote landscape on Earth. "It was actually kind of an amazing, meditative field season," she says, "I just bundled up, I went out there and pulled my sled, and just walked for miles and miles." In case you were worried, her colleagues always knew where Pettit was; every so often someone would roll out on a snow machine to bring her supplies or to swap out the radar's battery.