{"id":603620,"date":"2026-04-14T15:06:11","date_gmt":"2026-04-14T15:06:11","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/603620\/"},"modified":"2026-04-14T15:06:11","modified_gmt":"2026-04-14T15:06:11","slug":"antarcticas-most-vulnerable-regions-called-the-nightmare-scenario-have-reached-a-melting-phase-with-no-point-of-return","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/603620\/","title":{"rendered":"Antarctica’s Most Vulnerable Regions Called “The Nightmare Scenario” Have Reached a Melting Phase with No Point of Return"},"content":{"rendered":"

The ice beneath West Antarctica has been retreating for decades. Satellites have tracked it. Researchers have modeled it. But for years, the central question remained unanswered: had any part of that retreat crossed a threshold from which recovery was no longer possible? A new study published in\u00a0Nature Climate Change<\/a>\u00a0now provides the most detailed answer yet, and for some of the continent\u2019s most vulnerable basins, the conclusion is sobering.<\/p>\n

The Potsdam Institute for Climate Impact Research led the analysis, mapping\u00a0critical temperature thresholds\u00a0across all 18 of Antarctica\u2019s major drainage basins. What they found was not a single tipping point for the continent, but a network of individual systems, each with its own threshold, its own bedrock geometry, and its own potential contribution to rising seas. Some of those systems sit in territory that current warming levels may already have reached.<\/p>\n

Global mean temperatures have climbed to approximately\u00a01.3 degrees Celsius above pre-industrial levels. That number, familiar from climate policy discussions, takes on a different weight when placed against the study\u2019s modeling results. For the most vulnerable basins in West Antarctica<\/a>, the threshold for irreversible long-term ice loss sits as low as 1 to 2 degrees Celsius. The gap between where the world is now and where those thresholds begin is narrow, and for some basins, it may already be closed.<\/p>\n

The Glaciers at the Center of the Risk Map<\/p>\n

The\u00a0Thwaites and Pine Island glaciers, which together drain roughly 5 percent of the entire Antarctic Ice Sheet <\/a>into the Amundsen Sea, sit in the basin the study identifies as most immediately at risk. According to the modeling results, once that basin crosses its tipping threshold, it faces the eventual loss of approximately 70 percent of its sea-level relevant ice volume, a commitment that would translate to around 0.9 meters of\u00a0long-term sea-level rise.<\/p>\n

\"ThwaitesThwaites and Pine Island Glaciers lie in West Antarctica. Pine Island Glacier is one of the largest ice streams in Antarctica. It flows, together with Thwaites Ice Stream, into the Amundsen Sea, and the two ice streams together drain about 5% of the Antarctic Ice Sheet. Credit: ESA<\/p>\n

The mechanism driving this behavior is\u00a0marine ice sheet instability, a feedback process where ocean-driven melting causes grounding lines to retreat into progressively deeper inland basins. Because the bedrock beneath Thwaites and Pine Island slopes downward away from the coast, retreat tends to accelerate once it begins rather than slow. Reversing that retreat, the study finds, would require cooling temperatures below pre-industrial levels, a condition no current climate pathway anticipates.<\/p>\n

The Ross West basin, also known as the Siple Coast, shares a similarly low threshold. The study groups it alongside Thwaites and Pine Island as already at risk of substantial long-term ice loss <\/a>below 1 degree Celsius of warming above pre-industrial levels. Together, these three systems represent about 40 percent of West Antarctica\u2019s\u00a0marine ice volume, all of it potentially committed to loss at warming levels that exist today.<\/p>\n

East Antarctica Faces Its Own Thresholds<\/p>\n

West Antarctica draws most of the attention, but the study makes clear that\u00a0East Antarctica\u00a0is not immune. The Cook, Ninnis, and Mertz basin, associated with the Wilkes Subglacial Basin, faces a critical threshold between 2 and 3 degrees Celsius of warming. Crossing it would commit the basin to losing around 40 percent of its ice above flotation, contributing approximately 1.2 meters to global mean sea level over time.<\/p>\n

\"RiskRisk map of Antarctic ice catchment basins. Credit: Nature Climate Change<\/p>\n

As reported by\u00a0The Daily Galaxy<\/a>, marine-based sectors in East Antarctica representing roughly 5 meters of potential\u00a0sea-level commitment\u00a0are at risk of losing stability between 2 and 5 degrees Celsius. Beyond 6 degrees, threshold behavior appears across almost all East Antarctic regions, with a combined sea-level commitment exceeding 26 meters. Those extreme warming levels are only reached under the highest-emission scenarios, but they underscore how much ice the continent holds in reserve.<\/p>\n

The fundamental reason East Antarctica\u2019s thresholds are higher is geography. Many of its basins sit on bedrock configurations that require greater ocean heat delivery before instability takes hold. But the Wilkes Subglacial Basin is an exception. A comparably small perturbation at its coastal outlet glaciers can trigger large-scale, self-amplified retreat inland, a process the study describes as an\u00a0ice plug mechanism\u00a0that, once removed, allows the basin behind it to drain.<\/p>\n

A Network of Systems, Not a Single Switch<\/p>\n

One of the study\u2019s most significant contributions is its reframing of how\u00a0Antarctic ice sheet stability\u00a0should be understood. Previous analyses often treated the continent as a single tipping element. This research treats it as a network of 18 interacting drainage basins, each exhibiting its own dynamic behavior, some losing ice gradually with warming, others displaying sharp nonlinear transitions.<\/p>\n

\"Ice<\/a>An illustration of most of Earth\u2019s ice features, including the ice sheet. Credit: NASA<\/p>\n

The team used the\u00a0Parallel Ice Sheet Model, calibrated against paleoclimate records and present-day satellite observations, running quasi-static warming experiments that allowed the ice sheet to reach equilibrium at each temperature increment. This approach is designed to identify genuine stability thresholds rather than transient fluctuations driven by short-term climate variability. The results showed that even among basins with similar geographic settings, the difference of a fraction of a degree in threshold temperature could determine whether long-term collapse was triggered.<\/p>\n

The concept of\u00a0hysteresis\u00a0runs through the entire analysis. It describes the asymmetry between the warming required to initiate ice loss and the cooling required to undo it. For the Thwaites and Pine Island basin, the model shows that once retreat begins in earnest, restoring the original ice configuration would require temperatures below anything seen since the pre-industrial era. The ice, in other words, does not simply reverse when conditions improve.<\/p>\n

What the Study Does and Does Not Say<\/p>\n

The research is explicit about its scope. It describes\u00a0long-term equilibrium behavior, not near-term projections. Committed ice loss, once a threshold is crossed, unfolds over centuries to millennia, not decades. The paper does not project multi-meter sea-level rise within this century. Its central claim is that decisions made today, about emissions and warming trajectories, lock in outcomes that future generations will inherit regardless of what they do.<\/p>\n

The study also acknowledges its limitations. It uses a reduced-complexity model ensemble rather than high-resolution three-dimensional simulations, which constrains its ability to capture localized feedbacks.\u00a0Marine ice cliff instability, a process by which tall exposed ice faces mechanically collapse, is not included in the simulations. The authors note that including it could push some thresholds lower, though significant uncertainty remains around that mechanism.<\/p>\n","protected":false},"excerpt":{"rendered":"The ice beneath West Antarctica has been retreating for decades. Satellites have tracked it. Researchers have modeled it.…\n","protected":false},"author":2,"featured_media":603621,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[49,48,295,66],"class_list":{"0":"post-603620","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-ca","9":"tag-canada","10":"tag-environment","11":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/603620","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=603620"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/603620\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/603621"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=603620"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=603620"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=603620"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}