Latest news with #AMOC
Time of India
16-07-2025
- Science
- Time of India
Scientists discover world's largest waterfall — but It's completely invisible, here's why
For decades, the title of the world's tallest waterfall belonged to Venezuela's Angel Falls. But now, scientists are pointing to an even more colossal cascade — one that plunges a staggering 11,500 feet. The twist? It's completely invisible to the human eye. Located deep beneath the ocean's surface between Greenland and Iceland, the Denmark Strait cataract is the largest waterfall on Earth — and no one will ever witness it in person. This underwater marvel moves over 3.2 million cubic meters of water per second, far more than any river on land. Yet its existence remained unknown until scientists began studying ocean temperatures, salinity, and currents in this icy part of the Atlantic. What makes Denmark Strait the world's largest waterfall and why it's invisible The Denmark Strait cataract is an undersea waterfall formed where cold, dense water from the Nordic Sea meets warmer, lighter water from the Irminger Sea. This dramatic temperature and salinity difference causes the heavier water to plunge downward in a massive cascade beneath the ocean surface. First identified through thermal and salinity mapping, this phenomenon doesn't roar or mist like terrestrial waterfalls. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Indonesia melirik jet tempur J-10 milik China. Mengapa para pakar memperingatkan untuk hati-hati? CNA Indonesia Baca Undo Instead, it silently flows through the darkness, shaped by a submerged ridge left behind by glaciers during the Last Ice Age approximately 11,500 years ago. In sheer height and volume, it surpasses all known waterfalls. Niagara Falls measures about 181 feet, and Angel Falls 3,212 feet, but the Denmark Strait cataract plunges nearly four times deeper. Its hidden nature makes it one of the most fascinating and powerful forces in Earth's ocean systems. A hidden force that regulates Earth's climate Beyond its jaw-dropping size, the Denmark Strait cataract plays a critical role in maintaining global climate stability. As the cold Arctic water descends into the Atlantic, it powers the Atlantic Meridional Overturning Circulation (AMOC), a massive oceanic conveyor belt that distributes heat and nutrients across the world's oceans. This deep-sea flow moderates temperatures in Europe, sustains marine biodiversity, and drives large-scale weather patterns. But the system is fragile. Climate change and warming Arctic waters are threatening the delicate balance of temperature and salinity that keeps this waterfall flowing. A disruption could weaken AMOC, raising ocean temperatures, intensifying hurricanes, and shifting climate zones worldwide. Marine scientists already see early signs of impact, such as the weakening of winter winds along the Catalan coast. Out of sight, yet incredibly influential, the world's largest waterfall is a silent engine behind the rhythms of Earth's climate.
Newsweek
09-07-2025
- Science
- Newsweek
Fact Check: Did an Ocean Current Reverse?
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. For years, climate experts have been sounding the alarm about the worsening impacts of global warming, and a report made by a European news wire agency over the weekend heightened the concerns in an alarming manner after reporting the first-ever reversal of an ocean current that could have "catastrophic" impacts. The Claim On July 5, IntelliNews published a report titled "Southern Ocean current reverses for first time, signaling risk of climate system collapse." The report states that the Deep Western Boundary Current (DWBC), a key component to the Atlantic Meridional Overturning Circulation (AMOC) that circulates water within the Atlantic Ocean, reversed direction for the first time ever, a "catastrophic" event that would accelerate global warming and disrupt global weather patterns. The alarming report cited a press release from El Institut de Ciències del Mar, a Spanish state research institute, which referenced a recent study published in the peer-reviewed Proceedings of the National Academy of Sciences (PNAS) by the University of Southampton. A stock photo of icebergs in Antarctica, where the Southern Ocean is located. A stock photo of icebergs in Antarctica, where the Southern Ocean is located. Oleksandr Matsibura/Getty The Facts What is the AMOC? The National Oceanic and Atmospheric Administration (NOAA) describes the AMOC as a "component of ocean circulation, which constantly moves water, heat, salt, carbon, and nutrients north-south within the ocean basins, and ultimately between the ocean basins and around the globe." The AMOC brings warm water north and cold water south. In a video about how the currents work, NOAA said that "as the ocean warms, the circulation may slow down, making it less effective at drawing carbon dioxide and especially heat out of the atmosphere." A reversal of the circulation would certainly be cause for concern. However, the PNAS study does not mention reversing ocean currents or the AMOC. What the study found Instead, the study discusses surface salinity of the Southern Ocean. Between the 1980s and 2015, the surface of the polar Southern Ocean was freshening, or growing less salty. The study said this coincided with an expansion of Antarctic sea ice. New satellite data referenced in the study found a "marked increase in surface salinity" across the Southern Ocean over the past decade, which has "weakened upper-ocean stratification, coinciding with a dramatic decline in Antarctic sea ice coverage." "Our study found that surface salinity in the Southern Ocean has been increasing while sea ice has declined," the PNAS study's lead author Alessandro Silvano told Newsweek. "This was unexpected, as melting sea ice is generally thought to freshen the ocean surface. The results suggest that our understanding of the Antarctic system—and how it may evolve—is incomplete." Reports of an erroneous press release It is unclear if IntelliNet is referencing the June 30 PNAS study, considering it mentions a July 2 study in the report, although it doesn't cite the source. A report from German news site said the IntelliNet article was based on an erroneous press release from El Institut de Ciències del Mar about the June 30 study that allegedly included a flawed quote from study co-author Antonio Turiel regarding ocean circulation. Turiel told Newsweek that the flawed quote was partly a result of mistranslation. "Our original press note contained some wrong sentences, partly caused by mistranslation, partly caused by a wrong use of words on my side. That's the reason of the correction," he said. Turiel added that the paper also found evidence that "isopycnals have shoaled, so effectively there is a change in the structure of Southern Ocean." This doesn't indicate a change in direction for the current, Turial said, but that "it is likely that there is a change in the configuration of the currents." A spokesperson with El Institut de Ciències del Mar told Newsweek that the press release has been updated, and Turiel's quote was corrected. However, the IntelliNews report still claims the current has been reversed. Silvano told Newsweek the story has "several issues." "We do not talk about DWBC in our recently published work. The AMOC is not collapsing this year," Silvano said. "There have been issues over the social media and press," he added. The Ruling False. The recent PNAS study does not claim the DWBC is collapsing, as reported by IntelliNews. However, the study's findings are still concerning. "If this salinity increase continues, it could enhance vertical mixing, drawing heat from deeper ocean layers to the surface and further accelerating sea ice melt," Silvano told Newsweek. "This suggests the potential for a self-sustaining feedback loop, where reduced sea ice cover perpetuates further loss. Diminished sea ice coverage can have important consequences, including ocean warming, increased iceberg formation, and threats to marine wildlife." FACT CHECK BY Newsweek
Otago Daily Times
08-07-2025
- Science
- Otago Daily Times
'Unprecedented' changes around Antarctic
By Eloise Gibson of RNZ Researchers have found evidence of a major shift in the circulation of the Southern Ocean which could accelerate climate change for the whole planet. They say the finding has caught them off-guard and that the sea ice around Antarctica could be in "terminal decline". The study, led by the University of Southampton in the United Kingdom and helped by Spanish and other European researchers, found evidence of a change which has shocked other researchers, and which could explain the region's rapid loss of sea ice. The authors say the circulation of the Southern Ocean has reversed. Typically, as global heating melts the ice around Antarctica, climate scientists would expect saltier water at the surface of the ocean to be replaced by fresh water, because melting ice typically makes the ocean fresher. But new satellite data shows the opposite is happening. Because salt water draws up heat from the deep ocean and makes it harder for sea ice to regrow - as well as bringing up carbon dioxide from the depths - a reversal could accelerate ice loss and global heating. The authors - who published their findings in the peer-reviewed journal PNAS - say their salt content measurements "can now provide a coherent explanation for the rapid Antarctic sea ice loss that had puzzled the scientific community". However, the consequences are potentially disruptive for the planet. They say the Southern Ocean plays an essential role in regulating the Earth's heat and carbon and its disruption could trigger cascading effects on other ocean circulation systems, with potential consequences as far away as Europe. "We are witnessing a true change in ocean properties in the Southern Hemisphere - something we've never seen before," said Antonio Turiel, co-author of the study, published by the Spanish marine research institute Institut de Ciències del Mar. "While the world is debating the potential collapse of the AMOC (Atlantic Meridional Overturning Circulation) in the North Atlantic, we're seeing that the Southern Ocean is drastically changing, as sea ice coverage declines and the upper ocean is becoming saltier. This could have unprecedented global climate impacts." "What we found was astonishing," said co-author Alessandro Silvano, an oceanographer at University of Southampton in a piece for The Conversation. "By combining satellite observations with data from underwater robots, we built a 15-year picture of changes in ocean salinity, temperature and sea ice," he said. "Around 2015, surface salinity in the Southern Ocean began rising sharply - just as sea ice extent started to crash. This reversal was completely unexpected." The fleet of underwater robots used in the study are Argo floats, many of them deployed by New Zealand scientists, which drift with ocean currents and return data that any scientist can use. More work urgently needed: NZ researchers The new paper does not explain why the reversal is happening, and New Zealand scientists say more work is urgently needed to complete the puzzle. For decades, the surface of the Southern Ocean was getting fresher and colder, helping sea ice expand - seemingly in defiance of global heating. At the same time, sea ice in the Arctic at the opposite pole was in freefall. Now Antarctic sea ice is also shrinking, contributing to a feedback loop where larger areas of darker open ocean reflect less of the sun's heat back than ice would have - further increasing the heating and melting. Professor Wolfgang Rack, a glaciologist at University of Canterbury and Director of Gateway Antarctica, said the growth of sea ice in the Southern Ocean was seen as climate paradox until it stopped around 2015. "Many scientists expected the trend to reverse at some point, but the rate of the current retreat is completely unexpected and mind boggling," he said. He said the ocean south of Wellington was the "most under-surveyed region globally" and more and urgent work was needed. Associate Professor Inga Smith, a sea ice physicist at the University of Otago, said the new results were "shocking" for those researching Antarctic sea ice. "In a warming world, fresher water from melting of land-based ice sheets and floating ice shelves would be expected to dominate at the ocean surface." Instead, the ocean surface was getting warmer and more salty right at the time the extent of the sea ice shrank. She said although the paper didn't explore why, "the authors will no doubt explore this in a longer paper sometime soon". Dr Ken Hughes, a senior lecturer in coastal processes at the University of Waikato, says when he first began research in 2012 scientists assumed that the ocean and big ice shelves buffered the Antarctic system in some way so that the warming climate was not wrecking havoc on the ice extent in the same way it was for the Arctic. That security could no longer be taken for granted, he said, and the most difficult question was whether the decline would continue. Professor James Renwick, a climate scientist at Victoria University of Wellington, said other research had shown how upper-ocean heat content and westerly winds were changing in the Southern Ocean. The new paper provided more evidence that climate change was causing a "major change" in the way the ocean was working, he said. "The implications are very worrying. "Antarctic sea ice extent will likely continue to trend downwards from here (with ups and downs from year to year). That will accelerate the melting of ice shelves and land-based ice, increasing the rate of sea level rise and pushing us closer to the irreversible loss of the West Antarctic ice sheet. It will also reduce the reflectivity of the planet, bringing more warming." Natalie Robinson, a marine physicist at Earth Sciences New Zealand (formerly NIWA) and associate professor at Victoria University, said despite covering only 17% of the planet, the Southern Ocean was a critical player in the global climate. The annual cycle of sea ice forming and shrinking was a major player in stabilising the climate, especially for New Zealand. "We are moving into uncharted climate territory," she said. "What happens in Antarctica has implications for the entire globe, but here in New Zealand we are impacted by changes to Antarctic sea ice more directly than most. "Early indications are that a warmer Southern Ocean, exacerbated by retreat of the sea ice edge, contributes to increased storminess for New Zealand. "When combined with the steadily warming waters of New Zealand's Exclusive Economic Zone, we should expect to see more of the intense rainfall events we've experienced recently, since warmer air can hold more moisture. "In order to secure a liveable future for ourselves and our children, it is imperative that we drastically reduce our reliance on fossil fuels."
Otago Daily Times
08-07-2025
- Science
- Otago Daily Times
Warning Southern Ocean changes will affect planet
By Eloise Gibson of RNZ Researchers have found evidence of a major shift in the circulation of the Southern Ocean which could accelerate climate change for the whole planet. They say the finding has caught them off-guard and that the sea ice around Antarctica could be in "terminal decline". The study, led by the University of Southampton in the United Kingdom and helped by Spanish and other European researchers, found evidence of a change which has shocked other researchers, and which could explain the region's rapid loss of sea ice. The authors say the circulation of the Southern Ocean has reversed. Typically, as global heating melts the ice around Antarctica, climate scientists would expect saltier water at the surface of the ocean to be replaced by fresh water, because melting ice typically makes the ocean fresher. But new satellite data shows the opposite is happening. Because salt water draws up heat from the deep ocean and makes it harder for sea ice to regrow - as well as bringing up carbon dioxide from the depths - a reversal could accelerate ice loss and global heating. The authors - who published their findings in the peer-reviewed journal PNAS - say their salt content measurements "can now provide a coherent explanation for the rapid Antarctic sea ice loss that had puzzled the scientific community". However, the consequences are potentially disruptive for the planet. They say the Southern Ocean plays an essential role in regulating the Earth's heat and carbon and its disruption could trigger cascading effects on other ocean circulation systems, with potential consequences as far away as Europe. "We are witnessing a true change in ocean properties in the Southern Hemisphere - something we've never seen before," said Antonio Turiel, co-author of the study, published by the Spanish marine research institute Institut de Ciències del Mar. "While the world is debating the potential collapse of the AMOC (Atlantic Meridional Overturning Circulation) in the North Atlantic, we're seeing that the Southern Ocean is drastically changing, as sea ice coverage declines and the upper ocean is becoming saltier. This could have unprecedented global climate impacts." "What we found was astonishing," said co-author Alessandro Silvano, an oceanographer at University of Southampton in a piece for The Conversation. "By combining satellite observations with data from underwater robots, we built a 15-year picture of changes in ocean salinity, temperature and sea ice," he said. "Around 2015, surface salinity in the Southern Ocean began rising sharply - just as sea ice extent started to crash. This reversal was completely unexpected." The fleet of underwater robots used in the study are Argo floats, many of them deployed by New Zealand scientists, which drift with ocean currents and return data that any scientist can use. More work urgently needed: NZ researchers The new paper does not explain why the reversal is happening, and New Zealand scientists say more work is urgently needed to complete the puzzle. For decades, the surface of the Southern Ocean was getting fresher and colder, helping sea ice expand - seemingly in defiance of global heating. At the same time, sea ice in the Arctic at the opposite pole was in freefall. Now Antarctic sea ice is also shrinking, contributing to a feedback loop where larger areas of darker open ocean reflect less of the sun's heat back than ice would have - further increasing the heating and melting. Professor Wolfgang Rack, a glaciologist at University of Canterbury and Director of Gateway Antarctica, said the growth of sea ice in the Southern Ocean was seen as climate paradox until it stopped around 2015. "Many scientists expected the trend to reverse at some point, but the rate of the current retreat is completely unexpected and mind boggling," he said. He said the ocean south of Wellington was the "most under-surveyed region globally" and more and urgent work was needed. Associate Professor Inga Smith, a sea ice physicist at the University of Otago, said the new results were "shocking" for those researching Antarctic sea ice. "In a warming world, fresher water from melting of land-based ice sheets and floating ice shelves would be expected to dominate at the ocean surface." Instead, the ocean surface was getting warmer and more salty right at the time the extent of the sea ice shrank. She said although the paper didn't explore why, "the authors will no doubt explore this in a longer paper sometime soon". Dr Ken Hughes, a senior lecturer in coastal processes at the University of Waikato, says when he first began research in 2012 scientists assumed that the ocean and big ice shelves buffered the Antarctic system in some way so that the warming climate was not wrecking havoc on the ice extent in the same way it was for the Arctic. That security could no longer be taken for granted, he said, and the most difficult question was whether the decline would continue. Professor James Renwick, a climate scientist at Victoria University of Wellington, said other research had shown how upper-ocean heat content and westerly winds were changing in the Southern Ocean. The new paper provided more evidence that climate change was causing a "major change" in the way the ocean was working, he said. "The implications are very worrying. "Antarctic sea ice extent will likely continue to trend downwards from here (with ups and downs from year to year). That will accelerate the melting of ice shelves and land-based ice, increasing the rate of sea level rise and pushing us closer to the irreversible loss of the West Antarctic ice sheet. It will also reduce the reflectivity of the planet, bringing more warming." Natalie Robinson, a marine physicist at Earth Sciences New Zealand (formerly NIWA) and associate professor at Victoria University, said despite covering only 17% of the planet, the Southern Ocean was a critical player in the global climate. The annual cycle of sea ice forming and shrinking was a major player in stabilising the climate, especially for New Zealand. "We are moving into uncharted climate territory," she said. "What happens in Antarctica has implications for the entire globe, but here in New Zealand we are impacted by changes to Antarctic sea ice more directly than most. "Early indications are that a warmer Southern Ocean, exacerbated by retreat of the sea ice edge, contributes to increased storminess for New Zealand. "When combined with the steadily warming waters of New Zealand's Exclusive Economic Zone, we should expect to see more of the intense rainfall events we've experienced recently, since warmer air can hold more moisture. "In order to secure a liveable future for ourselves and our children, it is imperative that we drastically reduce our reliance on fossil fuels."
India Today
07-07-2025
- Science
- India Today
A blob in Atlantic Ocean is mysteriously cooling while the world warms
While much of the planet experiences record-breaking warmth, a patch of the Atlantic Ocean south of Greenland remains stubbornly cold, a phenomenon scientists have dubbed the 'cold blob.'This anomaly, which has cooled even as surrounding waters have warmed, is now better understood thanks to new research led by Penn State cold blob's origin is closely tied to a slowdown in the Atlantic Meridional Overturning Circulation (AMOC), a vast system of ocean currents that acts like a conveyor belt, transporting warm, salty water from the tropics northward, where it cools, sinks, and returns south at This circulation is crucial for regulating global climate, particularly in Europe and North the past century, while most of the globe has warmed, this subpolar region of the North Atlantic has cooled by up to 0.5 degrees Fahrenheit (0.3 degrees Celsius). Understanding the cold blob is critical, as it can disrupt the jet stream and storm patterns. Scientists have long debated whether this was due solely to changes in ocean currents or if the atmosphere played a role. The latest study, published in Science Advances, finds that both ocean and atmospheric processes are equally responsible for the persistent cold spot.'We found that the contribution from the atmosphere is comparable to that from ocean transport itself, which has never been found before,' said Yifei Fan, lead author of the the AMOC weakens, largely due to an influx of freshwater from melting Greenland ice, which dilutes salty ocean water and makes it less dense, the conveyor belt slows. This reduces the northward transport of heat, cooling the the ocean isn't acting alone. Cooler surface waters mean less evaporation, reducing atmospheric moisture and water vapour, a greenhouse gas that helps trap heat. This drier, cooler atmosphere feeds back to the ocean, amplifying and prolonging the cold anomaly.'Reducing the greenhouse effect, to put it simply, will feed back to the surface and amplify the pre-existing cold anomaly,' Fan the cold blob is critical, as it can disrupt the jet stream and storm patterns, affecting extreme weather in North America and finding highlights the delicate balance between the ocean and atmosphere in shaping the climate, and the far-reaching consequences that occur when this balance is disturbed.- EndsTrending Reel
