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antarctic
For decades, the surface of the polar Southern Ocean (south of 50°S) has been freshening—an expected response to a warming climate. This freshening enhanced upper-ocean stratification, reducing the upward transport of subsurface heat and possibly contributing to sea ice expansion. It also limited the formation of open-ocean polynyas. Using satellite observations, we reveal a marked increase in surface salinity across the circumpolar Southern Ocean since 2015. This shift has weakened upper-ocean stratification, coinciding with a dramatic decline in Antarctic sea ice coverage. Additionally, rising salinity facilitated the reemergence of the Maud Rise polynya in the Weddell Sea, a phenomenon last observed in the mid-1970s.
Despite working on polar science for the British Antarctic Survey for 20 years, Louise Sime finds the magnitude of potential sea-level rise hard to comprehend
Antarctica's remote and mysterious current has a profound influence on the climate, food systems and Antarctic ecosystems. Can we stop it weakening by 2050?
The Antarctic Circumpolar Current (ACC) is the world's strongest ocean current and plays a disproportionate role in the climate system due to its role as a conduit for major ocean basins. This current system is linked to the ocean's vertical overturning circulation, and is thus pivotal to the uptake of heat and CO2 in the ocean. The strength of the ACC has varied substantially across warm and cold climates in Earth's past, but the exact dynamical drivers of this change remain elusive. This is in part because ocean models have historically been unable to adequately resolve the small-scale processes that control current strength. Here, we assess a global ocean model simulation which resolves such processes to diagnose the impact of changing thermal, haline and wind conditions on the strength of the ACC. Our results show that, by 2050, the strength of the ACC declines by ∼20% for a high-emissions scenario. This decline is driven by meltwater from ice shelves around Antarctica, which is exported to lower latit
If the global consumption of fossil fuels continues to grow at its present rate, atmospheric CO2 content will double in about 50 years. Climatic models suggest that the resultant greenhouse-warming effect will be greatly magnified in high latitudes. The computed temperature rise at lat 80° S could start rapid deglaciation of West Antarctica, leading to a 5 m rise in sea level.
A new declaration aims to make the southernmost continent an autonomous legal entity, akin to a nation-state, with inherent rights to participate in decision making that affects it.
As a six-year investigation into the Thwaites glacier in Antarctica wraps up, the scientists involved are pessimistic for the future of this glacier and the consequences for sea level rise
Ocean-driven melting of floating ice-shelves in the Amundsen Sea is currently the main process controlling Antarctica’s contribution to sea-level rise. Using a regional ocean model, we present a comprehensive suite of future projections of ice-shelf melting in the Amundsen Sea. We find that rapid ocean warming, at approximately triple the historical rate, is likely committed over the twenty-first century, with widespread increases in ice-shelf melting, including in regions crucial for ice-sheet stability. When internal climate variability is considered, there is no significant difference between mid-range emissions scenarios and the most ambitious targets of the Paris Agreement. These results suggest that mitigation of greenhouse gases now has limited power to prevent ocean warming that could lead to the collapse of the West Antarctic Ice Sheet. The authors use a regional ocean model to project ocean-driven ice-shelf melt in the Amundsen Sea. Already committed rapid ocean warming drives increased melt, regard
Antarctica’s sea ice levels are plummeting as extreme weather events happen faster than scientists predicted
Seafloor landforms reveal that ice sheets can collapse at 600 metres per day.
With the continent holding enough ice to raise sea levels by many metres if it was to melt, polar scientists are scrambling for answers
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Giant ice sheets, ocean currents and permafrost regions may already have passed point of irreversible change
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The rapid collapses of two ice shelves on the Antarctic Peninsula over the past quarter-century were most likely triggered by the arrival of huge plumes of warm, moisture-laden air that created extreme conditions and destabilized the ice, researchers said Thursday.
A chunk of Antarctic ice that was one of the biggest icebergs ever seen has met its end near South Georgia. Scientists will be studying its effects on the ecosystem around the island for some time.
Cracks and fissures stoke fears of breakup that could lead to half-metre rise in global sea levels – or more
The loss of its buttressing ice shelf could hasten the demise of the “Doomsday Glacier”
Emerging ice-sheet modeling suggests once initiated, retreat of the Antarctic Ice Sheet (AIS) can continue for centuries. Unfortunately, the short observational record cannot resolve the tipping points, rate of change, and timescale of responses. Iceberg-rafted debris data from Iceberg Alley identify eight retreat phases after the Last Glacial Maximum that each destabilized the AIS within a decade, contributing to global sea-level rise for centuries to a millennium, which subsequently re-stabilized equally rapidly.
It’s Beginning to Feel Like We’ve Finally Pushed the Planet Past its Final Tipping Point. We have “extreme events” the kind scientists have long feared. But they’ve even shocked scientists with how suddenly extreme and frequent they are. And “This is not a localised freak event, it is definitely part of a coherent global pattern.”