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For most of us, <keyword id="6546574" type="General" weightage="80" keywordseo="octopus" source="Orion">octopus</keyword> mating is the kind of thing you'd bury deep beneath the incognito tab of your browser history. But for a crack team of researchers studying Antarctic <keyword id="1583699" type="General" weightage="20" keywordseo="ice-melt" source="Orion">ice melt</keyword>, it's a subject they can't get enough of – and not for the reasons you might think!<br /><br />Under the icy grip of <keyword id="19945467" type="General" weightage="100" keywordseo="antarctica" source="keywords">Antarctica</keyword>, where sunlight struggles to penetrate and temperatures plummet well below zero, thrives a fascinating creature: the <keyword id="19945468" type="General" weightage="20" keywordseo="turquet" source="Orion">Turquet</keyword>'s octopus. Its DNA, a tangled tale of past dalliances and daring encounters, holds the key to understanding a continent's precarious future.<br /><br />This half-foot wonder lays only a handful of oversized eggs on the seabed, investing heavily in their survival and growth. Coupled with the region's unpredictable currents, this means the species rarely strays far from its familiar haunts, dotting the icy landscape around Antarctica.<br /><br />Scientists, like modern-day octopus whisperers, have cracked the genetic code of these eight-legged time capsules. By studying the DNA of separate populations, they stumbled upon a remarkable truth: around 125,000 years ago, when Earth enjoyed a warmth akin to today, an ice-free corridor snaked across Antarctica. Through this watery highway, Turquet's octopuses embarked on scandalous intermingling with distant cousins they'd barely met before, their genes weaving a tapestry of shared ancestry.<br /><br />But before you start daydreaming about octopus rom-coms, this revelation throws up a chilling concern. If the West Antarctic Ice Sheet (WAIS) melted during a period similar to our current climate, it suggests its future stability is worryingly fragile. Studies show that a potential WAIS collapse could unleash a torrent of meltwater, raising sea levels by a staggering 3.3 to 5 metres.<br /><br />The study also uncovers a double whammy – two distinct periods of WAIS collapse, one in the mid-Pliocene and another during the Last Interglacial, a warm spell eerily similar to our own. This chilling coincidence serves as a stark reminder: the ice sheet has buckled before, and it could well do so again.<br /><br />The consequences of a WAIS collapse are nothing short of catastrophic. Coastal cities housing millions worldwide would be submerged, ecosystems shattered, and the map of our planet forever altered. The fate of the WAIS hangs in the balance, and the time to act is now – not just for ourselves, but for the octopuses, the penguins, the seals, and all the creatures who call Antarctica home.<br />

Octopus DNA gives scientists a glimpse into Antarctica's ancient past, and a possible highly unstable future

Unfavourable atmospheric conditions make it challenging to observe <keyword id="6354781" type="General" weightage="100" keywordseo="antarctica" source="Orion">Antarctica</keyword> from space. Nevertheless, while visualisations have portrayed the frosty continent as seemingly endless expanses of white ice, a new study has revealed that this is merely a facade for what lies beneath the surface.<br /><br />Antarctica might be a vast <keyword id="1352757" type="General" weightage="20" keywordseo="ice-sheet" source="Orion">ice sheet</keyword> today, but it wasn't always so. Portions of the southern continent once featured expansive trees, forests, and even animals. However, approximately 30 million years ago, shifting climate conditions encased the region in ice, leaving the landscape suspended in time.<br /><br />Comparing historical <keyword id="47552" type="General" weightage="20" keywordseo="radar" source="Orion">radar</keyword> data of the area with satellite images unveiled an ancient hidden paradise, located over two kilometres beneath the current surface. It includes extensive lakes and rugged river-carved hills and valleys. Stewart Jamieson, the principal author of the study, likened the 32,000-square-kilometre terrain to the Snowdonia region in northern Wales.<br /><br />The researchers estimate that this submerged land hasn't seen daylight for at least 14 million years, and a wealth of ancient landscapes remains to be unearthed. At present, this enigmatic subterranean landscape is even less familiar than the surface of Mars, as Jamieson points out.<br /><br />Despite remaining undiscovered for so long, <keyword id="6361617" type="General" weightage="20" keywordseo="climate-change" source="Orion">climate change</keyword> also poses a threat to this vast, Kerala-sized <keyword id="10265" type="General" weightage="20" keywordseo="snow" source="Orion">snow</keyword> globe world. However, the fact that it lies hundreds of kilometres inland from Antarctica's icy periphery and has remained untouched by previous warming events provides some hope.<br /><br />"We are now headed towards developing atmospheric conditions akin to those that prevailed between 14 to 34 million years ago when it was three to seven degrees Celsius warmer," the study cautions. Nevertheless, pinpointing the "tipping point" beyond which we will lose control over the thawing process is challenging.<br /><br />Comprehending the concealed landscape will enable researchers to fathom how ice behaves in Antarctica, providing us with more insights into how the continent might respond to future climate change. With melting rates in the region accelerating over recent decades, this knowledge is unquestionably valuable.<br /><br />The findings of this study have been published in <em>Nature Communications</em> and can be accessed <a href="https://dx.doi.org/10.1038/s41467-023-42152-2" data-type="tilCustomLink">here</a>.<br />

South Pole Secret! Massive network of prehistoric valleys, lakes and hills found deep under Antarctica

<ul class="summary-list"><li>Sea levels are rising steadily each year as the planet warms.</li><li>Melting ice could collapse suddenly, raising sea levels abruptly.</li></ul><p>The Earth's ice is, rightly, often in the news. As the planet and its oceans warm, our so-called cryosphere is quickly melting away.</p><p>There are <a href="https://climate.nasa.gov/vital-signs/sea-level/#:~:text=Sea%20level%20rise%20is%20caused,1993%2C%20as%20observed%20by%20satellites.">two factors</a> that lead to sea level rise: the water expanding as it gets warmer and added water from melting ice sheets and glaciers.</p><h4><br />Melting ice that could tip sea level rise into catastrophic levels</h4><span class="image-source-caption undefined" style="margin-top: -25px">                        <span class="image-source headline-regular">                                                Source: NASA Ice Viewer<br />Chart: Annie Fu/Insider                                                </span>                            </span><p>While it's easier to plan for a steady sea level rise, scientists are very concerned about what would happen if huge chunks of ice collapse and abruptly change sea levels. </p><p>Here are the sites around the world scientists are keeping a close eye on, and why they are important, according to Alex Brisbourne, a Glaciologist at the British Antarctic Survey, and Theodore Scambos, an Antarctic researcher at the University of Colorado.</p><h2><strong style="color: #000000;">Glaciers</strong></h2><p>Glaciers will be the first to go.</p><p>Though they will contribute comparatively little to sea level rise — adding about a foot to global mean sea levels if they melt completely — glaciers outside of Greenland and Antarctica have been the main contributors to higher seas over the past century, according to the UN's <a href="https://www.ipcc.ch/srocc/chapter/chapter-4-sea-level-rise-and-implications-for-low-lying-islands-coasts-and-communities/">Intergovernmental Panel on Climate Change (IPCC).</a></p><h4> </h4><h4><strong>Catastrophic collapse — Columbia Glacier in Alaska</strong></h4><p>Glaciers took centuries to freeze over, but they can disappear in a few years. When they start breaking apart, that triggers a negative feedback loop: the meltwater warms the glacier, which creates more meltwater.</p><div type="image" title="Columbia Glacier Alaska" height="2592" width="3456" msid="96665027" hostid="261"></div><p>The <a href="https://www.businessinsider.com/columbia-glacier-28-years-of-global-warming-2014-11">Columbia Glacier</a> in Alaska is one of the most recognizable examples of rapid glacier collapse. This glacier has almost completely disappeared today. </p><p>"It's an example of how this will play out for many coastal glaciers," Scambos told Insider in an email.</p><h4> </h4><h4><strong>Albedo — Presena Glacier in the Alps, Europe</strong></h4><p>Glaciers are not only important because they store water away from the oceans. Because they are light-colored, they bounce back a lot of light back into space. This effect, called the albedo of the ice, is crucial because it keeps sunlight from warming the earth. </p><div type="image" title="alps pink snow glacier" height="1532" width="2043" msid="96665029" hostid="261"></div><p>Scientists studying the albedo of the glaciers have discovered a peculiar effect of the melt. Colorful <a href="https://www.businessinsider.com/colorful-algae-blooms-may-be-speeding-up-glacier-melt-worldwide-2022-12">glacial and snow algae</a> have been growing in the glacier meltwater, creating <a href="https://www.businessinsider.com/greeland-ice-sheet-turned-black-melts-faster-because-of-algae-2021-3">pink and purple</a> spectacles on the ice, like at the Presena Glacier in the Alps. The problem is that reduces the albedo of the glacier, which again encourages warming and melting.</p><h4> </h4><h4><strong>Freshwater — Hindu Kush Himalayan glaciers, Central Asia</strong></h4><p>Glaciers are also a vital source of freshwater. Over a billion people living in central Asian countries rely on the Hindu-Kush Himalayan glaciers for drinking water, and scientists discovered recently that these glaciers are rapidly declining, causing <a href="https://e360.yale.edu/features/himalayas-glaciers-climate-change">concern</a>.</p><div type="image" title="A general view of the Chiatibo glacier in the Hindu Kush mountain range on October 16, 2019 in the Chitral District of Khyber-Pakhunkwa Province, Pakistan." height="1333" width="1777" msid="96665032" hostid="261"></div><p>"It's gonna peak in around 2050. Beyond that point, you start to get less melt," AB said.</p><p><a href="https://www.businessinsider.com/india-and-pakistan-potential-river-water-war-conflict-2019-2#fp-climate-change-threatens-tibetan-plateau-water-resources-in-a-couple-of-waysmore-rainfall-in-the-medium-term-but-also-quicker-glacial-melts-and-less-water-flow-in-the-future-how-much-could-climate-change-aggravate-the-already-tense-cross-border-water-situation-7">Geopolitical experts</a> are concerned this dwindling resource could cause tensions in neighboring countries.</p><h2><strong style="color: #000000;">Greenland and Antarctica</strong></h2><p>The ice sheets in Greenland and Antarctica are essentially humongous glaciers that cover the poles. They contain most of the freshwater on the Earth's surface. </p><p>The Antarctic ice sheet is much bigger than the ice sheet on Greenland. If they were to melt totally, the Greenland ice sheet would contribute about 23 feet to the sea levels, while the Antarctic ice sheet holds enough ice to raise sea levels by 190 feet. Of course, this <a href="https://climate.nasa.gov/interactives/global-ice-viewer/#/2/about/1316">isn't predicted</a> to happen for centuries.</p><p>The other big difference is that the Greenland ice sheet rests on solid land above sea level, whereas much of the Antarctic ice sheet is below sea level, which makes it more vulnerable to warming ocean temperatures.</p><h4> </h4><h4><strong style="color: #000000;">Greenland </strong></h4><p>Greenland is currently melting about twice as quickly as the Antarctic ice sheet, per <a href="https://www.ipcc.ch/srocc/chapter/chapter-4-sea-level-rise-and-implications-for-low-lying-islands-coasts-and-communities/">the IPCC.</a></p><p>As the atmosphere around the North Pole warms, any ice below about 2,000 meters altitude (about 6,500 feet) is at greater risk of melting, said Brisbourne. </p><p>"The problem here is that as you melt, you're thinning the ice and that brings more ice below 2,000 meters," he said.</p><p>This is happening over the entirety of the Greenland ice sheet, as can be seen in this <a href="https://www.businessinsider.com/terrifying-nasa-video-shows-greenland-changing-in-the-future-2019-8">NASA animation</a>.</p><p>The <a href="https://www.businessinsider.com/greenland-fast-melting-glacier-thickening-again-2019-3">Ilulissat</a> glacier, also known as <a href="https://www.businessinsider.com/jakobshavn-glacier-loses-huge-chunk-of-ice-2015-8">Jakobshavn</a> or its Innuit name Sermeq Kujalleq, is a glacier that scientists are following closely on the west coast of Greenland, where the ice sheet is melting more quickly.</p><h4><br />Ilulissat Glacier, also known as Jakobshavn</h4><p>Ice flows through ice sheets like very slow rivers. Carried by its weight, the ice falls from the top of the glacier to the lowest point. In a perfect equilibrium, there's enough snow fall to replenish the ice sheet, but that balance comes out of whack when the ice is melting away too quickly, snowfall is not sufficient, or <a href="https://www.businessinsider.com/greenland-summit-gets-rain-not-snow-first-time-on-record-2021-8">rain is falling</a> instead of snow. </p><p>When this happened, the ice sheet beings to thin and the glaciers at the edge of the sheet retreat, as can be seen below.</p><h4> </h4><h4><strong style="color: #000000;">Antarctica</strong></h4><p>The Antarctic ice sheet, found at the South Pole, is about eight times bigger than the Greenland sheet. </p><p>Because so much of this ice sheet is below sea level, it is much more affected by the temperature of the ocean, which has been warming. </p><p>Scientists break down this ice sheet into three parts: the peninsula, west Antarctica, and east Antarctica. </p><h4> </h4><h4>Antarctic Peninsula — Larsen-A and -B</h4><p>The peninsula is much more affected by the temperature of the atmosphere than other areas of the Antarctic, Brisbourne said.</p><p>In 2002, scientists watched helplessly as an ice shelf called Larsen-B collapsed into the ocean in a matter of weeks.</p><p>Between January 31 and April 13, 2002, about 500 billion tonnes of pack ice and snow disintegrated into the ocean. </p><p>This was less than a decade after another ice shelf in the area, Larsen-A, also disintegrated. </p><p>Ice shelves don't contribute to sea level rise when they melt. Because they float, they occupy the same volume in the sea, whether they are frozen or melted, just like an ice cube doesn't raise the water level in a glass when it melts. </p><p>However, ice shelves stabilize the glaciers and ice sheets that are behind them. Without their ice shelves, the glaciers that fed Larsen-A and -B glaciers started flowing much more quickly, releasing three times more ice into the ocean than they did before.</p><p>Larsen-B's collapse was likely caused by <a href="https://www.businessinsider.com/melting-antarctica-images-from-space-2014-8">melt ponds</a>, Brisbourne said.</p><p>Meltponds appear when the warming atmosphere causes meltwater to accumulate at the surface of the ice. As they grow, their weight cracks the ice and can lead to the collapse of the ice shelf, a process called hydrofracturing. </p><div type="image" title="melt ponds Antarctica" height="1000" width="1333" msid="96665035" hostid="261"></div><p>Because there wasn't much ice in the Antarctic peninsula to start, losing these ice shelves did not change global sea levels much. </p><p>But these losses are seen as "the canary in the coal mine" for Antarctica, said Brisbourne. </p><h4> </h4><h4>West Antarctica — The Doomsday (Thwaites) glacier and Pine Island</h4><p>Scientists are much more concerned about west Antarctica. The ice sheet in West Antarctica rests on bedrock under sea level, meaning it is much more vulnerable to the warming of the ocean. </p><p>West Antarctic ice flows into several ice shelves, including the Pine Island, Dotson, and Thwaites. These act as buffers between the ice sheet and the warming oceans.</p><p>Scientists are really concerned that Thwaites is holding on <a href="https://www.businessinsider.com/thwaites-doomsday-glacier-could-melt-faster-than-expected-study-2022-9">"by its fingernails."</a> This gives it its nickname — the "doomsday glacier." The ice shelf in front of Thwaites<a href="https://www.businessinsider.com/antarctica-thwaites-glacier-ice-shelf-will-shatter-scientists-say-2021-12"> is crackling</a> and it is thought the shelf could collapse within the decade.</p><p>"We think that potentially if we lose Thwaites area, this whole west Antarctica ice sheet part of Antarctica could follow," said Brisbourne. </p><p>That could add <a href="https://www.businessinsider.com/antarctica-sea-level-rise-could-be-higher-than-thought-study-2021-5">up to 10 feet</a> to global sea levels. </p><p>But there's still hope. </p><p>Pine Island was collapsing more quickly than Thwaites, but it slowed down, Brisbourne said. What scientists hadn't expected is that the ice sheet would catch on a small island off the coast of Antarctica, which has slowed the speed of its collapse.  </p><h4> </h4><h4>East Antarctica — Conger Ice Shelf</h4><p>The east side of Antarctica is thought to be fairly stable.</p><p>"East Antarctica is a bit more like Greenland in that it sits above sea level. So it's not been influenced much by the warming ocean and the atmosphere hasn't warmed as much," said Brisbourne. </p><p>East Antarctica has enough ice to raise sea levels by about 52 meters altogether, so if it were to collapse, it'd be fairly catastrophic. But Brisbourne says scientists don't expect that to happen for a very very long time. </p><p>Still, scientists were stunned to see an ice shelf called Conger <a href="https://www.businessinsider.com/Antarctica-ice-shelf-previously-thought-stable-collapses-2022-3">collapse</a> on the east side of Antarctica earlier this year. Conger was not under surveillance by most scientists. Indeed, Brisbourne said most of his colleagues had never heard of it. </p><p>"It's a very small ice shelf and it is fed by a glacier that drains a very small area. So in terms of the contribution sea level rise, it's actually gonna be very small," he said. </p><p>"But again, it's one of these warning signs that in this area we're starting to see processes that we know have affected other parts of the continent and led to a fairly dramatic loss of ice," said Brisbourne. </p><h2><strong style="color: #000000;">Other effects of ice melt</strong></h2><p>There are more indirect effects of the melting ice on sea level rise. </p><h4> </h4><h4>Arctic sea ice</h4><p>Every winter, water in the Arctic ocean freezes over, capping our planet in white over the winter and receding over the summer. </p><p>But the expanse of that white cap in the winter has been <a href="https://www.businessinsider.com/photos-reveal-extent-of-arctic-ice-loss-2020-9">getting smaller</a> every year. </p><div type="image" title="Animation shows Arctic sea ice getting smaller year on year, from 1979 to 2022" height="358" width="716" msid="96665038" hostid="261"></div><p>Because this ice is already in the sea, it won't raise the sea level if it melts. But, like the glaciers, its declining reflective albedo contributes to more warming within the atmosphere and the ocean.</p><h4> </h4><h4>Permafrost — Russian Tundra</h4><p>Permafrost, ground that is meant to stay frozen throughout the year, doesn't directly contribute to sea level rise when it thaws. But as the ground gets warmer, pools of water called thermokarsts start forming.</p><p>These are full of methane, a potent <a href="https://www.businessinsider.com/satellites-locate-source-of-methane-leaks-to-fight-climate-crisis-2022-7">climate-worsening gas</a>. It's not clear how much these pools could contribute to climate change. </p><h4> </h4><h4>Local sea level variation </h4><p>Global mean sea level rise is only a snapshot of the whole picture.</p><p>Because sea levels are influenced by the local environment, the sea level rise can be much higher locally than it is on a global scale.</p><p>The east coast of the US, for instance, is due to have <a href="https://www.businessinsider.com/day-after-tomorrow-was-right-and-wrong-about-climate-shifts-2019-3">higher sea levels</a> than the west coast, in part because of the slowing gulf stream.  </p><h4> </h4><h4>Local gravity variation — Antarctica's gravity pull</h4><p>Gravity is another important consideration when it comes to sea level rise.</p><p>Ice sheets are so big that they can <a href="https://www.antarcticglaciers.org/question/antarctic-ice-sheet-gravitational-effect-sea-level/">pull water</a> towards them, raising sea levels locally, Brisbourne said. </p><p>If Greenland melts, "sea-level rise will be greatest in the southern hemisphere, and if Antarctica melts then sea-level rise will be greatest in the northern hemisphere," wrote Pippa Whitehouse, a glaciologist from Durham University, <a href="https://www.antarcticglaciers.org/question/antarctic-ice-sheet-gravitational-effect-sea-level/">in a blog post. </a></p><p>The glaciers are also weighing down the planet, squishing the Earth's crust at the poles.</p><p>That pressure will disappear when the ice sheets melt, which will influence the rotation, shape, and gravity of the Earth. This effect, called <a href="https://www.nasa.gov/feature/goddard/glacial-rebound-the-not-so-solid-earth">post-glacial rebound</a>, has already started to appear. A study published in 2021 found that melting glaciers had already led to a small wobble of the <a href="https://www.businessinsider.com/earth-axis-shifted-melting-ice-climate-change-2021-4">Earth's axis.</a></p><p><strong><em>Correction: January 12, 2023</em></strong><em> — An earlier version of the story misstated the amount of sea level rise were ice on Antarctica to melt away completely. This is 58 meters (190 feet), not 58 feet. The earlier version also misspelled the name of an ice shelf, which is Dotson, not Dodson. Glaciers, ice shelves, and ice sheets were not always given the right designation. These have been corrected throughout.</em></p>

Map shows the ice sheets and glaciers melting that scientists most fear will be the source of catastrophic rising sea levels

<ul class="summary-list"><li>Greenland's ice sheet disappeared at least once in the last million years, a <a href="https://www.pnas.org/content/118/13/e2021442118">new study</a> found. </li><li>The discovery came after fossilized plants were found deep below the ice.</li><li>The fossils were collected as part of a <keyword id="24525" type="ENTERTAINMENT" weightage="60" keywordseo="cold-war">Cold War</keyword> project but weren't analyzed until recently.</li></ul><p>During the Cold War, US Army scientists planned to hide hundreds of nuclear warheads underneath the <keyword id="664086" type="PERSON" weightage="60" keywordseo="Greenland-ice-sheet">Greenland ice sheet</keyword> in a covert mission known as "Project Iceworm."</p><p>It was 1960 and tensions were mounting between the US and Soviet Union. If nuclear war broke out, the US wanted to be close enough to strike the USSR with medium-range missiles.</p><p>But the top-secret project was abandoned after scientists realized that the ice sheet was moving too quickly: Within two years, the trenches dug by the military would be destroyed.</p><p>The work wasn't entirely fruitless, though, since geologists held onto samples of ancient soil from roughly 4,500 feet below the surface of the ice. The frozen chunks were stored in glass cookie jars for five decades, until researchers at the University of Vermont got hold of them, thawed the chunks, and began to rinse the sediment in the lab.</p><p>In doing so, one of those researchers, Paul Bierman, suddenly turned to his colleague, Andrew Christ: "What is that stuff floating in the water?" he asked.<br /><br />Christ sucked up the floating specs with a pipette, then placed them under a microscope.</p><p>"It was amazing," he told Insider. "They were these delicate little twigs and leaves that just started to unfurl when they were wet. They are so well-preserved that they look like they died yesterday."</p><div type="image" title="greenland ice study" height="1067" width="1600" msid="81555700" hostid="261"></div><p>The researchers knew that plants couldn't grow if the ice sheet was present. So they calculated the materials' age based on the rate of decay of isotopes in the soil.</p><p>Their results suggested there must have been an ice-free period in the region far more recently than scientists previously realized. In a <a href="https://www.pnas.org/content/118/13/e2021442118">new study</a>, they suggest that Greenland's ice sheet melted and reformed at least once in the last million years. Before that, scientists thought the current ice sheet had been around for up to 3 million years.</p><p>"Paul and I were just totally ecstatic," Christ said. "We were jumping up and down in the lab."</p><h2>Fossils between a few hundred thousand and a million years old</h2><h2><div type="image" title="andrew christ" height="960" width="1280" msid="81555702" hostid="261"></div></h2><p>Scientists first collected the frozen soil samples from northwestern Greenland in 1966. At the time, the samples gave researchers a never-before-seen peek at Earth's ancient climate.</p><p>"That was the first time anyone had drilled that deep into an ice sheet before, let alone recovered whatever's at the bottom," Christ said.</p><p>But in the 1960s, scientists didn't have the technology to determine the age of the soil. Now, researchers know that two isotopes, aluminum and beryllium, accumulate in rocks and sediment on Earth's surface when they're exposed to radiation from space. Over time, these isotopes decay.</p><p>"Because they're different isotopes, they decay at different rates," Christ said. "We can use that difference to tell us how long they've been buried."</p><p>Based on the ratio of aluminum to beryllium isotopes in the samples, the researchers concluded that the plant fossils collected by Project Iceworm were between a few hundred thousand and 1 million years old.</p><h2>The ice sheet is 'very sensitive' to climate shifts</h2><div type="image" title="greenland" height="998" width="1500" msid="81555703" hostid="261"></div><p>Christ said it's possible that the ice sheet vanished more than once in the last 3 million years.</p><p>"We still have 12 feet of this soil to analyze," he said. "That might tell us in greater detail how many times the ice has disappeared from this part of Greenland."</p><p>Already, he added, his study demonstrates that the Greenland ice sheet is "very sensitive to relatively minor changes in climate." </p><p>Now, Greenland's ice sheet is starting to shrink again. Snowfall is already insufficient to <a href="https://www.businessinsider.com/greenland-melting-ice-sheet-past-tipping-point-2020-8">keep up with the pace of the melting</a> - meaning the ice sheet could disappear even if global temperatures stop rising. By the year 2100, the melted ice could <a href="https://www.sciencedaily.com/releases/2020/12/201215112018.htm#:~:text=2-,The%20melting%20of%20the%20Greenland%20ice%20sheet%20could%20lead%20to,of%2018%20cm%20in%202100&amp;text=A%20new%20study%20applying%20the,in%20the%20next%20IPCC%20report.ort.">raise sea levels up to 7 inches</a>.</p><p>When the fossilized plants in the samples first bloomed, the concentration of carbon dioxide in the atmosphere <a href="https://today.tamu.edu/2019/09/25/humankind-did-not-live-with-a-high-carbon-dioxide-atmosphere-until-1965/">averaged just 230 parts per million</a>. By the time the ice samples were taken in the mid-1960s, atmospheric concentrations of carbon dioxide exceeded 320 parts per million. Today, those concentrations have topped 410 parts per million.</p><p>"That is a massive change in a really short amount of time," Christ said. "The worry is that: Are we pushing the Greenland ice sheet towards the point where it's going to start melting rapidly and adding to sea level rise?"</p><p>If the ice sheet were to melt completely again - which scientists predict could happen in the next millennium - the ocean would <a href="https://www.businessinsider.com/american-cities-disappear-sea-level-rise-2100-2019-3">swallow the coasts</a> across the globe.</p>

Thanks to a secret Cold War project, researchers found fossilized plants 4,500 feet under Greenland's ice sheet

<ul class="summary-list"><li><keyword id="12329412" type="UNKNOWN" weightage="60" keywordseo="nepal" source="Orion">Nepal</keyword>'s base camp on <a href="https://www.businessinsider.com/mount-everest-stories-from-climbers-2019-6">Mount Everest</a> is being moved further down the mountain, due to <keyword id="11896311" type="UNKNOWN" weightage="60" keywordseo="climate-change" source="Orion">climate change</keyword>.</li><li>The site is located on top of the thinning Khumbu Glacier, which has become hazardous for climbers.</li></ul><p>In order to ascend <a href="https://www.businessinsider.com/mount-everest-death-zone-first-hand-account-2017-9">Mount Everest</a>, climbers have to pass through one of two starting points. But the southern site in Nepal — the most popular starting point to summit the world's tallest mountain — is located on top of a <a href="https://www.businessinsider.com/antarctica-thwaites-glacier-ice-shelf-will-shatter-scientists-say-2021-12">thinning glacier</a> that's becoming increasingly unsafe amid climate change.</p><p>As ice on the glacier close to the base camp slowly melts, Nepal is preparing to move the campsite down the mountain. <a href="https://www.businessinsider.com/climate-change-impacts-to-last-millennia-ipcc-report-2021-8">Glaciers and ice sheets are melting</a> at accelerated rates because of human-caused climate change: As temperatures rise, the glacier on the world's highest mountain, like other <keyword id="12737246" type="UNKNOWN" weightage="60" keywordseo="glaciers" source="Orion">glaciers</keyword> around the world, is retreating rapidly.</p><p>"We are now preparing for the relocation and we will soon begin consultation with all stakeholders," Taranath Adhikari, director general of Nepal's tourism department, told the <a href="https://www.bbc.com/news/science-environment-61828753">BBC</a>. "It is basically about adapting to the changes we are seeing at the base camp and it has become essential for the sustainability of the mountaineering business itself."</p><p>The potential relocation follows recommendations from a committee set up by the government, which oversees mountaineering at Everest. </p><p>A <a href="https://www.leeds.ac.uk/news/article/4327/warm_ice_in_worlds_highest_glacier">2018 study</a> found that the Khumbu Glacier close to the base camp was thinning at a rate of 1 meter — or 3 feet — per year. Now, according to Nepalese authorities, it's unsafe. Where the base camp currently stands, <a href="https://www.businessinsider.com/mount-everest-expeditions-climbing-companies-6-2019">mountain climbers</a> contend with cracks on the ice, erosion, and growing streams of water due to <a href="https://www.businessinsider.com/thwaites-glacier-melting-doomsday-sea-level-rise-2020-9">ice melt</a>. </p><p>"We see increased rock falls and movement of meltwater on the surface of the glaciers that can be hazardous," Scott Watson, a researcher at the University of Leeds, told the <a href="https://www.bbc.com/news/science-environment-61828753">BBC</a>. </p><div type="image" title=": A line of trekkers walk through fresh snow beside the Khumbu Glacier, near the base of Mount Everest and Everest Base Camp in the Solu-Khumbu region of Nepal, February 13, 2015" height="3330" width="4440" msid="92373242" hostid="261" sizebytes="1465608"></div><p>The sheer number of people passing through the camp, and the footprints, debris, and waste left on the mountain are a concern. The camp is used by around 1,500 climbers every year. People urinating at the camp, to the tune of 4,000 liters of pee every day during in peak season, along with runoff from kerosene and other waste products, also impact the glacier. </p><p>The base camp currently sits at an altitude of 5,364 meters (17,600 feet) above the mountain's snowline. Plans could shift it as much as 400 meters (1,310 feet) lower, to an ice-free area. A final decision has not been made, nor has a new base been identified, according to Nepalese authorities. Once plans are finalized, the relocation could come as soon as 2024.</p>

Nepal is planning to move its Everest base camp because of rapidly thinning glaciers and erosion from climbers

<ul class="summary-list"><li><a href="https://www.businessinsider.com/greenland-ice-loss-rate-7-times-higher-2019-12">Greenland's ice sheet</a> may have passed a point of no return, setting it on an irreversible path to disappearance, according to researchers at Ohio State University. </li><li>Snowfall can no longer replenish the ice lost as <keyword id="102244" type="COUNTRY" weightage="60" keywordseo="Greenland">Greenland</keyword>'s glaciers retreat, so it will keep melting and cause catastrophic sea-level rise, even if global temperatures stop rising.</li><li>The climate crisis could bring about other tipping points in the <a href="https://www.businessinsider.com/photos-how-global-warming-ravaged-arctic-threatens-reindeer-herds-2019-12">Arctic</a> and the <a href="https://www.businessinsider.com/amazon-rainforest-reaching-tipping-point-deforestation-experts-warn-2019-12">Amazon</a>, but there may still be time to avoid those.</li></ul><p>Greenland's ice sheet may have hit a tipping point that sets it on an irreversible path to completely disappearing.</p><p>Snowfall that normally replenishes Greenland's glaciers each year can no longer keep up with the pace of <keyword id="1583699" type="PERSON" weightage="60" keywordseo="Ice-melt">ice melt</keyword>, according to researchers at Ohio State University. That means that the <keyword id="664086" type="PERSON" weightage="60" keywordseo="Greenland-ice-sheet">Greenland ice sheet</keyword> — the world's second-largest ice body — would continue to lose ice even if global temperatures stop rising.</p><p>In their <a href="https://www.nature.com/articles/s43247-020-0001-2.pdf">study</a>, published Thursday in the journal Nature, the scientists reviewed 40 years of monthly satellite data from more than 200 large glaciers that are draining into the ocean across Greenland.</p><p>"What we've found is that the ice that's discharging into the ocean is far surpassing the snow that's accumulating on the surface of the ice sheet," Michalea King, the study's lead author and researcher at Ohio State University's Byrd Polar and Climate Research Center, said in a <a href="https://news.osu.edu/warming-greenland-ice-sheet-passes-point-of-no-return/">press release</a>.</p><p>Complete melting of the Greenland ice sheet could raise sea levels 23 feet by the year 3000. If that happens, the ocean would <a href="https://www.businessinsider.com/american-cities-disappear-sea-level-rise-2100-2019-3">swallow coastal cities</a> across the globe. Greenland's ice is already the world's largest single contributor to sea-level rise. In just the next 80 years, its current melt rate would add another 2.75 inches to global sea levels, according to a <a href="https://www.nature.com/articles/s41586-019-1855-2">study</a> published in December.</p><div type="image" title="greenland ice melt" height="1467" width="2200" msid="77568963" hostid="261"></div><p>"Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss," Ian Howat, a glaciologist and co-author on the paper, said in the release. "Even if the climate were to stay the same or even get a little colder, the ice sheet would still be losing mass."</p><p>But this is just one of many climate-change tipping points that human activity might bring about. There is still time to avoid irreversible pathways to other calamities.</p><h2>There are more points of no return</h2><p>The amount of ice Greenland loses each year has steadily increased in the last two decades. Before 2000, the researchers found, the ice sheet had an equal chance of gaining or losing mass each year. But in the climate of the last 20 years, it will only gain mass one in every 100 years, the researchers found.</p><p>Greenland dumped an unprecedented amount of ice and water into the ocean during the summer of 2019, when a heat wave from Europe washed over the island. The ice sheet lost 55 billion tons of water over five days — enough to cover the state of Florida in almost five inches of water.</p><div type="image" title="greenland ice melt" height="3456" width="4608" msid="77568965" hostid="261"></div><p>Melt brings about more melt, as water pooling across the ice sheet absorbs more sunlight and further heats everything around it. That's why tipping points like Greenland's accelerate ice loss so much.</p><p>Rising global temperatures and certain human activities can bring about tipping points in other parts of the world, too.</p><p>In the Arctic, ice melt is exposing permafrost — frozen soil that releases powerful greenhouse gases when it thaws. If warming thaws enough permafrost, the gases released will trap heat faster than humans' fossil-fuel emissions.</p><p>In the Amazon rainforest, humans have been cutting and burning trees for years, allowing moisture to escape the ecosystem. Enough deforestation could trigger <a href="https://www.businessinsider.com/amazon-rainforest-experiencing-record-breaking-deforestation-2019-7">a process called "dieback,"</a> in which the rainforest would dry up, burn, and become a savanna-like landscape, <a href="https://www.businessinsider.com/amazon-fires-may-help-dieback-emit-carbon-hurry-climate-change-2019-8">releasing up to 140 billion tons of carbon</a> into the atmosphere. Last year, leading rainforest scientists <a href="https://www.businessinsider.com/amazon-rainforest-reaching-tipping-point-deforestation-experts-warn-2019-12">warned that the Amazon is "teetering on the edge" of that threshold</a>.</p><div type="image" title="brazil amazon fire deforestation" height="3314" width="4419" msid="77568967" hostid="261"></div><p>Still, scientists say that switching to less carbon-intensive forms of energy, like solar power, and reducing unsustainable logging and mining can help us avoid those disasters.</p><p>Even for the Greenland ice sheet, the future holds more tipping points — degrees of collapse that will accelerate the glaciers' melt even more. Limiting global warming could delay those tipping points and give the world more time to prepare.</p><p>"We've passed the point of no return, but there's obviously more to come," Howat told <a href="https://www.cnn.com/2020/08/14/weather/greenland-ice-sheet/index.html">CNN</a>. "Rather than being a single tipping point in which we've gone from a happy ice sheet to a rapidly collapsing ice sheet, it's more of a staircase where we've fallen off the first step but there's many more steps to go down into the pit."</p>

Greenland's melting ice sheet has 'passed the point of no return,' scientists say, dooming it to disappear

<ul class="summary-list"><li>Ice algae that grow in extreme environments are darkening the ice sheet in <keyword id="102244" type="COUNTRY" weightage="60" keywordseo="Greenland">Greenland</keyword>.</li><li>Dark colors absorb more heat, which makes ice melt faster, adding to rising sea levels.</li><li>The increase in algae because of climate change, an expert told Insider.</li></ul><p>The <keyword id="664086" type="PERSON" weightage="60" keywordseo="Greenland-ice-sheet">Greenland ice sheet</keyword> is darkening due to algae growing on its surface - which in turn are making the diminishing expanse of ice melt even faster.</p><p>Over the past decade, scientists have discovered that these algae are a major contributor to the so-called "dark zone," a strip of darker ice on the South Western coastline of Greenland which can be seen from space.</p><p>An expert told Insider that the algae increase is a consequence of climate change, and part of a vicious cycle that will lead to the ice melting away faster and faster.</p><p>Darker ice reflects less heat from the sun, which means that it melts faster than whiter patches. </p><div type="image" title="dark zone" height="690" width="1381" msid="81777739" hostid="261"></div><p>These "snow" and "ice algae" have evolved to produce a range of colors to protect them from the <a href="https://phys.org/news/2020-02-glacier-algae-dark-zone-margins.html">intense sunlight</a> bouncing off the white snow or ice. </p><p>"There are different species of algae in the snow and the ice. The ones in the ice are purple-ish. The ones in the snow can be green, yellow, or red," Prof. Liane G. Benning told Insider.</p><p>Benning is an expert in geochemistry at the Freie Universität Berlin and GFZ Potsdam research center, and a lead scientist on the <a href="https://www.eurekalert.org/pub_releases/2019-10/ggph-dp-101119.php">DEEP PURPLE</a> project, which studies ice algae.  </p><p>Snow algae are the reason why "watermelon snow" can be seen on mountains and icebergs all around the world. In 2020, these algae turned the <a href="https://www.theguardian.com/world/2020/jul/06/algae-turns-italian-alps-pink-prompting-concerns-over-melting">Italian alps pink</a>. </p><div type="image" title="watermelon snow" height="1000" width="2000" msid="81777740" hostid="261"></div><p>A 2017 study found that watermelon snow contributed to <a href="https://www.businessinsider.com/watermelon-snow-is-making-glaciers-in-alaska-melt-faster-2017-9">icebergs in Alaska melting</a>. </p><p>In Greenland, the snow algae are present, and they cause watermelon snow inland, away from the coastline.</p><p>But it is the ice algae, which grow were the ice is melting, which are causing the most concern.</p><p>These algae produce the dark purple pigment when they bloom. "The moment you've got ice melting, bam! There they go," Benning said.</p><div type="image" title="melting surface ice core copyrigth Liane G Benning" height="1499" width="1999" msid="81777742" hostid="261"></div><p>Benning said that ice algae are proliferating because the ice is melting more quickly, and for longer. Ice in Greenland used to melt over a summer period of around 50 days, Benning said. "Now it's up to 75 days a year."</p><p>A study in 2019 <a href="https://www.businessinsider.com/greenland-ice-loss-rate-7-times-higher-2019-12">showed that</a> the Greenland ice sheet is melting seven times faster than it did in 1992. </p><p>"[Humans] increase the [global] temperature, there's more melting, there's more algae, there's more pigment. If there's more pigment, the ice is darker, it melts more."</p><div type="image" title="dark ice 3" height="1000" width="2000" msid="81777745" hostid="261"></div><p>"These algae are a consequence of the change in climate, not a cause," she says.</p><p>Benning says the algae are the biggest contributors to the darkness of Greenland's dark zone, though not the only one.</p><p>Other factors include mineral dust that is released as the ice sheet melts and soot from industrial production and wildfires that drift towards Greenland then settles.</p><p>Greenland ice melting is the <a href="https://www.nature.com/articles/s41467-020-20011-8">biggest contributor</a> to rising sea levels. Scientists warned in 2020 that it the situation has reached the <a href="https://www.businessinsider.com/greenland-melting-ice-sheet-past-tipping-point-2020-8">"point of no return"</a>, as the ice is vanishing faster than annual snowfalls can replenish it.</p><p>Scientists predict that Greenland melting could lead to a global sea level rise of between <a href="https://climate.nasa.gov/news/2883/study-predicts-more-long-term-sea-level-rise-from-greenland-ice/">1.5 feet and 5 feet</a> over the next 200 years.</p><div type="image" title="ice algae" height="1500" width="2000" msid="81777746" hostid="261"></div><p>But because models haven't taken into account the algae accelerating the process, their predictions could be off.</p><p>Understanding how the algae fit in this process could help scientists give a better estimate, Benning explained. </p><p>"We will not solve the equation of the world, but we will help put in one piece of the puzzle that, at the moment, is creating lots of uncertainties."</p>

Greenland's vast ice sheet is being turned black by algae, part of a vicious cycle making it melt faster

<ul class="summary-list"><li>Study shows for the first time that Greenland wasn't covered in ice in the recent past.</li><li>The data comes from long-lost ice cores obtained during a secret army mission during the Cold War.</li></ul><p>Drilling thousands of feet down through a giant layer of ice isn't an easy task, but that's what the army liked about it.</p><p>Grabbing ice cores for scientists to study served as a perfect cover for their real intention, <a href="https://www.businessinsider.com/project-iceworm-toxic-nuclear-waste-2016-8">burying nuclear missiles within</a> Greenland's ice sheet, in a scheme known as <a href="https://www.businessinsider.com/cold-war-project-greenland-ice-sheet-plant-fossils-2021-3">Project Iceworm</a>.</p><p>The project, which took place during the height of the Cold War, didn't yield the results the army wanted. But by the time they <a href="https://www.uvm.edu/news/story/secrets-under-ice" target="_blank" rel="noopener">abandoned it in 1967</a>, scientists had gathered enough ice cores to help them understand Greenland's ancient climate. </p><p>Along with the ice, scientists grabbed 12 feet of sediment that sat beneath the ice sheet. Most scientists were only interested in the ice, so the sediment cores were labeled, stored away in a bunch of cookie jars, and forgotten.</p><p>Not unlike that bag of peas fossilizing at the back of your freezer.</p><p>That is until Danish scientists <a href="https://www.uvm.edu/news/story/secrets-under-ice" target="_blank" rel="noopener">re-discovered the sediment cores in 2018</a> and shipped them to Paul Bierman, a geologist at the University of Vermont. There, Bierman's then PhD candidate Andrew Christ found something unexpected — signs of life. </p><p>They discovered that Greenland's ice had melted in the recent past, which was incredibly surprising, Christ said. </p><p>This initial discovery took place <a href="https://www.pnas.org/doi/10.1073/pnas.2021442118" target="_blank" rel="noopener">over two years ago</a>, but the scientists just now pinpointed when the country's ice sheet had melted. The team of 21 researchers published their findings last week in the <a href="https://www.science.org/doi/10.1126/science.ade4248" target="_blank" rel="noopener">journal Science</a>. </p><h2><div type="image" title="A small deposit of snowy ice sits in a larger pool of clear, melted water amid a wide view of the Greenland tundra. The Earth below it is yellow and green and the sky, which takes up half the frame, is right blue where it peaks through the thick blanket of clouds." height="3036" width="4048" msid="102251513" hostid="261" sizebytes="890502"></div></h2><p>Their paper shows that only 416,000 years ago, Greenland's ice sheet had melted and sea levels were between five and 20 feet higher compared to when the sheet was frozen. This means that the current ice sheet is much more sensitive to global warming than previously thought, the scientists reported.</p><p>"The ancient frozen soil from beneath Greenland's ice sheet warns of trouble ahead," Bierman and co-author Tammy Rittenour wrote in <a href="https://theconversation.com/when-greenland-was-green-ancient-soil-from-beneath-a-mile-of-ice-offers-warnings-for-the-future-209018" target="_blank" rel="noopener">The Conversation</a>.</p><h2>More sensitive to warming </h2><p>The melting occurred way earlier than scientists had predicted. Previous estimates had put a wide window on the thawing, saying it occurred sometime in the last <a href="https://www.businessinsider.com/cold-war-project-greenland-ice-sheet-plant-fossils-2021-3">million years</a>.</p><p>The Earth naturally cycles through warmer phases and <a href="https://www.businessinsider.com/300000-year-giant-hand-axes-ice-age-sediments-england-mystery-2023-7">cooler phases</a>, per the <a href="https://www.fs.usda.gov/ccrc/education/climate-primer/natural-climate-cycles#:~:text=The%20mechanisms%20that%20cause%20these,2008)." target="_blank" rel="noopener">Climate Change Resource Center</a>. Shooting back to 416,000 years ago then, we were in a warmer period. </p><p>The researchers know this warmer period was caused by normal cycles because they can measure the amount of gases that were present in the atmosphere back then by looking at the molecules that were frozen in the samples. </p><div type="image" title="An old black and white photo ofJ. Kasl and D. Garfield viewing a retrieved core at Camp Century in 1966 The researchers are wearing thick down jackets with fur hoods and standing near complex looking metal tables bearing scientific machines." height="2283" width="3045" msid="102251514" hostid="261" sizebytes="477450"></div><p>They determined that greenhouse gas levels were much lower back then <a href="https://www.businessinsider.com/carbon-dioxide-record-human-health-effects-2018-5">than they are today</a>, Christ told Insider.</p><p>So if the natural, moderate warming caused the ice to melt, it means the country's ice sheet is more sensitive to temperature changes than scientists originally thought, Christ explained. He and Bierman further said their findings mean the ice sheet is likely going to be sensitive to the changes we've caused to our climate. </p><p>Essentially, in the coming centuries, climate change will cause the Greenland ice sheet to melt completely, the researchers said. "It's not going to happen tomorrow. But it's going to happen faster and faster," Bierman said. </p><p>This will cause anywhere from five feet of sea level rise to 20 plus feet, the paper reported. What would that amount of water do to a city like Miami, or the island of Manhattan, for example?</p><p>Using the National Oceanic and Atmospheric Administration's <a href="https://coast.noaa.gov/slr/" target="_blank" rel="noopener">sea level rise viewer</a>, Bierman showed Insider the consequences.</p><p>Slowly, the water eats ups streets, then blocks, then neighborhoods. The viewer maxes out at ten feet, he said, adding: imagine if the water rises higher than that.</p>

Lost samples from a secret army base reveal that Greenland's ice vanished 416,000 years ago. That means it could melt way faster than expected.

<ul class="summary-list"><li><a href="https://www.businessinsider.com/photos-show-rare-total-solar-eclipse-over-antarctica-2021-12">Antarctica</a>'s <a href="https://www.businessinsider.com/thwaites-glacier-melting-doomsday-sea-level-rise-2020-9#this-rapid-melting-is-happening-in-part-because-natural-buffers-holding-the-thwaites-and-pine-glaciers-in-place-are-breaking-apart-according-to-new-research-3">Thwaites Glacier</a> is melting quickly, fueling 4% of <a href="https://www.businessinsider.com/antarctica-sea-level-rise-could-be-higher-than-thought-study-2021-5">sea-level rise</a> each year.</li><li>The eastern region of Thwaites is shielded from <a href="https://www.businessinsider.com/atlantic-ocean-water-circulation-weakening-climate-shift-2021-8">warming</a> <a href="https://www.businessinsider.com/photos-show-coral-spawning-in-great-barrier-reef-2021-11">ocean waters</a> by a dam-like <a href="https://www.businessinsider.com/one-of-antarcticas-largest-glaciers-danger-as-ice-shelf-collapses-2021-6">ice shelf</a>.</li></ul><p>A crucial <a href="https://www.businessinsider.com/one-of-antarcticas-largest-glaciers-danger-as-ice-shelf-collapses-2021-6">ice shelf</a> on <a href="https://www.businessinsider.com/antartica-working-sometimes-means-using-pee-bottles-amundsen-scott-aro-2021-6">Antarctica</a>'s <keyword id="12737244" type="UNKNOWN" weightage="60" keywordseo="thwaites-glacier" source="Orion">Thwaites Glacier</keyword> is on track to collapse within five years, accelerating the melting of the notorious "doomsday glacier."</p><p>Thwaites, which is the size of Florida, is already melting quickly, losing about 50 billion tons of ice per year. The glacier earned its grim nickname because its total collapse would raise global sea levels by about two feet and expose other Antarctic <keyword id="12737246" type="UNKNOWN" weightage="60" keywordseo="glaciers" source="Orion">glaciers</keyword> to the same melt process.</p><p>While scientists don't expect that catastrophe for at least 200 years, <keyword id="12737245" type="UNKNOWN" weightage="60" keywordseo="ice-melt" source="Orion">ice melt</keyword> from Thwaites currently fuels about 4% of annual sea-level rise. <a href="https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level">Rising ocean levels</a> can cause flooding in coastal areas that are home to millions of people and many of the world's largest cities, <a href="https://www.businessinsider.com/photos-landmarks-flooding-sea-level-rise-2021-10">damaging</a> <a href="https://www.businessinsider.com/homeowners-lift-home-sea-wall-house-lifting-hurricane-flooding-insurance-2021-9">property</a> and infrastructure, and leading to more <a href="https://www.businessinsider.com/working-through-hurricane-ida-covid-as-a-louisiana-nurse-2021-9">catastrophic storms</a>.</p><p>For now, Thwaites's eastern region is somewhat stable, melting more slowly than the rest of the glacier. That's because an ice shelf — a floating extension of the glacier propped up on an underwater mountain — shields it from warm ocean waters and holds the glacier in place.</p><p>"As it's structured right now, this ice shelf acts like a dam. But it's not going to for very long," Erin Pettit, a glaciologist at Oregon State University, said in a press briefing at the meeting of the American Geophysical Union on Monday.</p><p>Cracks are spiderwebbing across the protective eastern ice shelf, which is likely to disintegrate into hundreds of icebergs within the next five years, "like the shattering of your car's window," Pettit said.</p><p>Once that happens, a wider stretch of ice from the landlocked Thwaites Glacier will be flowing into the ocean — melting into water, calving away from cliffs, or breaking off as icebergs.</p><h2>Thwaites is changing rapidly — and getting more dangerous</h2><div type="image" title="water heaters tents in antarctica snow ice" height="675" width="1200" msid="88283663" hostid="261"></div><p>It's unsettling to see new satellite images of the eastern ice shelf each week, Pettit said, adding, "Each new satellite image we get, we see deeper and longer fractures."</p><p>Pettit and her team are monitoring the ice shelf as part of the International Thwaites Glacier Collaboration (ITGC), a team of nearly 100 scientists. The US National <keyword id="11896083" type="UNKNOWN" weightage="100" keywordseo="science" source="Orion">Science</keyword> Foundation and UK Natural Environmental Research Council have deemed Thwaites so important to immediate sea-level rise that they gave the collaboration $25 million to study the glacier over five years.</p><p>As they near the midpoint of their five-year project, the ITGC scientists' data reveal a glacier growing increasingly volatile.</p><p>"There's going to be a dramatic change in the front of the glacier, probably within less than a decade," Ted Scambos, a senior research scientist leading Pettit's team, who called in from <keyword id="12266096" type="UNKNOWN" weightage="60" keywordseo="antarctica" source="Orion">Antarctica</keyword>'s McMurdo Station, said during the briefing.</p><p>"It may still take a few decades before some of the other processes that accelerate the ice flow and the retreat take hold. It will, though, accelerate the pace and effectively widen the dangerous part of the glacier."</p><h2>If the ice shelf doesn't shatter, it will come unmoored</h2><div type="image" title="penguin stands on iceberg in ocean" height="1667" width="2500" msid="88283664" hostid="261"></div><p>As the critical eastern ice shelf fractures, warming ocean waters are melting it from below. The diminishing ice is slowly pulling away from the underwater mountain that props it up against the Thwaites glacier.</p><p>Within a decade, Pettit said, the ice will completely lose its grip on the undersea mountain. Her team thinks the fracturing will completely shatter the ice shelf before that, but it's hard to be sure.</p><p>Either way, once the ice shelf collapses, the new exposure to warm ocean waters could triple the speed of ice loss in the eastern third of Thwaites. That will send new volumes of water and ice pouring into the ocean each year, growing Antarctica's contribution to rising seas.</p><p>The researchers are not sure how quickly that acceleration will happen. It could take decades, or it could take centuries, Pettit said.</p><p>"It's daunting. It's a bit unsettling, especially standing on the ice and looking onto the ice sheet, and seeing that this huge area from one side of the horizon to the other is moving at you at about a mile every year," Scambos said. "All by itself, this one glacier is big enough to impact sea level significantly."</p>

Key ice shelf on Antarctica's doomsday glacier will probably shatter like a car windshield within 5 years, scientists say

<ul class="summary-list"><li>Scientists say if the West Antarctica Ice sheet were to collapse, global sea levels could rise by about 10 feet.</li><li>But a new study says that this figure could be about 3.3 feet higher.</li><li>That is because as the glaciers melt, the bedrock under the ice sheet could rise out of the ocean.</li></ul><p>The global sea-level rise due to the melting of <keyword id="74074" type="ORGANIZATION" weightage="60" keywordseo="Antarctic">Antarctic</keyword> <keyword id="1331041" type="PERSON" weightage="60" keywordseo="ice-sheets">ice sheets</keyword> in the next 1,000 years could have been underestimated by about 30%, a new study says.</p><p>Previous studies had estimated that if the West Antarctic ice sheet were to collapse, the sea levels would increase by <a href="https://www.businessinsider.com/thwaites-glacier-melting-doomsday-sea-level-rise-2020-9">about 10 feet</a>.</p><p>But the new study, which was published in the peer-reviewed <a href="https://advances.sciencemag.org/content/7/18/eabf7787">Science Advances</a> journal on Friday, suggests that an effect called the "water-expulsion mechanism" had been underestimated.</p><p>The effect refers to the bedrock beneath the West Antarctic ice sheet, which scientists predict will rise above sea levels when the ice sheet melts.</p><p>The new calculation of this effect shows that over the next 1,000 years, the world's sea level could rise by one meter -about 3.3 feet - higher than previously predicted.</p><p>Scientists had previously "dismissed it as inconsequential," Linda Pan, a lead author on the study, <a href="https://www.eurekalert.org/pub_releases/2021-04/hu-aim042921.php">said in a press release</a>. </p><p>Dr. Andy Smith, a <keyword id="41551" type="ENTERTAINMENT" weightage="100" keywordseo="science">science</keyword> leader at the British Antarctic Survey who wasn't involved in the study, told Insider: "This paper is another incremental improvement to our ability to project what the melting ice sheets will contribute to sea level in the future."</p><p>Because the bedrock underneath the West Antarctic ice sheet is somewhat elastic, scientists believe it will lift above sea level when the ice sheet melts. As this happens, it could push the water around the glacier into the surrounding ocean, adding to the global sea-level rise.</p><p>Scientists already knew this. But the new evidence suggests the underlying Earth is less viscous than previously thought, so the bedrock could rise faster than first expected, Smith, of the British Antarctic Survey, told Insider.</p><p>Pan added in a press release: "No matter what scenario we used for the collapse of the West Antarctic Ice Sheet, we always found that this extra one meter of global sea level rise took place."</p><p>"The magnitude of the effect shocked us," Pan said.</p><p>Every single estimate of sea level rise "is going to have to be revised upward" because of this work, Jerry X. Mitrovica, a professor of geophysics at Harvard and an author on the paper, <a href="https://www.eurekalert.org/pub_releases/2021-04/hu-aim042921.php">said in a Friday statement</a>.</p><p>Scientists are concerned that the <a href="https://www.businessinsider.com/nasa-west-antarctic-ice-sheet-results-2014-5">collapse of the West Antarctic ice sheet could be unstoppable</a>.</p><p>One glacier on the ice sheet, the Thwaites Glacier - which is <a href="https://www.businessinsider.com/cavity-underneath-antarctica-ice-sheet-melting-fast-2019-2">two-thirds the size of Manhattan</a> - <a href="https://www.businessinsider.com/thwaites-glacier-melting-doomsday-sea-level-rise-2020-9">is receding by about half a mile per year</a>, and warming waters have created a cavity underneath.</p><p>Scientists have nicknamed this glacier the "Doomsday Glacier" because it is acting as a buffer between the ice sheet and warming waters.</p><p>As it melts away, scientists predict it will trigger a cascading effect taking the neighbouring glaciers along, <a href="https://www.businessinsider.com/thwaites-glacier-melting-doomsday-sea-level-rise-2020-9">Insider's Aylin Woodward reported last year.</a></p>

The sea-level rise from Antarctica's melting ice sheet could be 30% higher than estimated due to an effect scientists previously thought was 'inconsequential,' new study says

<ul class="summary-list"><li>In the movie <a href="https://www.businessinsider.com/day-after-tomorrow-was-right-and-wrong-about-climate-shifts-2019-3">"The Day After Tomorrow,"</a> an ice age happens after <a href="https://www.businessinsider.com/climate-change-amoc-day-after-tomorrow-2017-1">currents in the Atlantic suddenly stop</a>.</li><li>The Atlantic's <a href="https://www.businessinsider.com/climate-change-could-shut-down-the-current-that-carries-warm-water-2017-9">current system</a> is responsible for Europe's warm climate, but <a href="https://www.businessinsider.com/climate-ipcc-report-temperature-rise-20-years-15-degrees-2021-8">it may be weakening</a>.</li><li>Slower circulation may bring droughts to west Africa and colder weather to Europe and North America.</li></ul><p>In the 2004 film "The Day After Tomorrow," a climatologist played by Dennis Quaid warns world leaders about a rapid climate shift.</p><p>The key factor is an ocean current system called the Atlantic Meridional Overturning Circulation (AMOC), which moves warm water from the equatorial tropics up to Europe and the north Atlantic. This influx of warmer water contributes to western Europe's mild, temperate climate.</p><p>In the movie, the AMOC stops completely, causing an ice age to begin almost overnight. While the speed and intensity of that cold snap are hyperbolized in the film, the AMOC is very real, and research suggests a slow down of its circulation is a <a href="https://www.businessinsider.com/day-after-tomorrow-was-right-and-wrong-about-climate-shifts-2019-3">likely consequence of climate change</a>. </p><p>In <a href="https://www.nature.com/articles/s41558-021-01097-4">a paper</a> published last week, climate scientist Niklas Boers concluded that the AMOC is approaching a tipping point. If enough fresh water from melting polar ice enters the ocean, the current system will experience an "abrupt weakening," and destabilize, he told Insider.   </p><p>A new climate report from the UN's Intergovernmental Panel on <keyword id="6361617" type="UNKNOWN" weightage="60" keywordseo="climate-change">Climate Change</keyword> (IPCC) similarly suggests that the AMOC will very likely weaken by the end of the century.</p><p>According to Boers, a researcher at the Potsdam Institute for Climate Impact Research in Germany, this weakening would cause temperatures in Europe to fall, and "the cooling effect would be stronger the further north you go."</p><p>On the US East Coast, meanwhile, sea levels would rise. Parts of central and west Africa would experience persistent drought conditions, since those areas also benefit from the AMOC's circulation.</p><h2>An on/off switch for the Atlantic's currents</h2><div type="image" title="ocean currents" height="900" width="1200" msid="85210390" hostid="261"></div><p>When the AMOC is flowing quickly, western Europe enjoys a wet and warm climate. Scientists have likened the system to a conveyor belt: Once warmer water reaches the area around the UK, it cools and sinks to the bottom of the Labrador and Nordic Seas. Then that cold water makes a U-turn and snakes along the ocean floor, down to Antarctica's Southern Ocean.</p><p>But if this circulation is sluggish and weak, warm tropical waters don't get moved up, and the north Atlantic cools.</p><p>The AMOC's speed is determined by a delicate balance of salt and fresh water. Salty water is dense, so it sinks easily. But as Greenland's ice sheet and glaciers continue to melt, more fresh water is joining the AMOC's salty surface water, making it lighter and less likely to sink. That clogs up <a href="https://www.scientificamerican.com/article/slow-motion-ocean-atlantics-circulation-is-weakest-in-1-600-years/">the circulation's flow</a>.</p><p>Prior <a href="https://www.nature.com/articles/s41467-019-09237-3">research</a> suggests that a change in the strength of water circulation in the Atlantic really does precede abrupt climate changes. By examining ice cores dated to Earth's last ice age, scientists have found that the AMOC alternates between two states - a strong "on" state, where the current system runs quickly, and a weak "off" state where that circulation decelerates. </p><p>"A shutdown of the AMOC is the easiest, most efficient way to disrupt the climate system," Francesco Muschitiello, a geographer specializing in paleoclimatology at the University of Cambridge told Insider, adding, "95% of time when we talk about rapid climate change, it's associated with AMOC."</p><p>Still, Boers said, any cooling related to the AMOC wouldn't look like "The Day After Tomorrow" - it "would take a few decades," and North America "won't get as cold as the movie suggests."</p><h2>It would take at least a few hundred years for the AMOC to re-strengthen</h2><div type="image" title="greenland" height="998" width="1500" msid="85210391" hostid="261"></div><p>In the past, when the AMOC reached a tipping point, the transition from strong to weak took a couple of decades, Boers said. But it takes much longer for the system to switch back.</p><p>"It typically took a few hundred to a few thousand years for the AMOC to go back to the strong mode," he said, adding, "if the AMOC were to collapse to the weak mode at some point in the future, it would indeed be very hard to bring it back to the strong mode."</p><p>According to the IPCC report, it's possible that the AMOC will experience an abrupt collapse by 2100. That collapse, the report authors said, could be triggered by an unexpected additional melted ice from the Greenland Ice Sheet, which has been thawing at an unprecedented rate. A 2019 study found the ice sheet was <a href="https://www.businessinsider.com/greenland-approaching-threshold-of-irreversible-melting-2019-1]">melting six times faster</a> than it was 40 years ago. </p><div type="image" title="Ocean" height="1336" width="1781" msid="85210392" hostid="261"></div><p>It's unlikely, however, that the Greenland Ice Sheet will ever melt quickly enough to completely stop the AMOC.</p><p>A full halt like the one depicted in "The Day After Tomorrow," would only happen "if the Greenland ice sheet was to melt over the course of a few days," Muschitiello previously told Insider.</p><p>That said, some studies suggest that the AMOC has stopped entirely in the past.</p><p>"These major distortions of the AMOC led to the coldest events ever recorded," Muschitiello said.</p><p>In those cases, the cold events may have lasted for up to 1,000 years. If the AMOC were to shut down completely again, Boers said, the only way to undo it would be "to reverse the global temperature trend and get back to pre-industrial conditions."</p>

You Searched For "ice sheet melt" and got 11 results

Octopus DNA gives scientists a glimpse into Antarctica's ancient past, and a possible highly unstable future

Ankush Banerjee

South Pole Secret! Massive network of prehistoric valleys, lakes and hills found deep under Antarctica

Ankush Banerjee

Map shows the ice sheets and glaciers melting that scientists most fear will be the source of catastrophic rising sea levels

Marianne Guenot,Annie Fu

Thanks to a secret Cold War project, researchers found fossilized plants 4,500 feet under Greenland's ice sheet

Aria Bendix

Nepal is planning to move its Everest base camp because of rapidly thinning glaciers and erosion from climbers

Paola Rosa-Aquino

Greenland's melting ice sheet has 'passed the point of no return,' scientists say, dooming it to disappear

Morgan McFall-Johnsen

Greenland's vast ice sheet is being turned black by algae, part of a vicious cycle making it melt faster

Marianne Guenot

Lost samples from a secret army base reveal that Greenland's ice vanished 416,000 years ago. That means it could melt way faster than expected.

Maiya Focht

Key ice shelf on Antarctica's doomsday glacier will probably shatter like a car windshield within 5 years, scientists say

Morgan McFall-Johnsen

The sea-level rise from Antarctica's melting ice sheet could be 30% higher than estimated due to an effect scientists previously thought was 'inconsequential,' new study says

Marianne Guenot

'The Day After Tomorrow' film foretold a real and troubling trend: The Atlantic ocean's circulation system is weakening

Aylin Woodward

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