Why Greenland’s Ice Is Disappearing Faster Than You Think[Geography with Ben Description Deep-dive geography, geopolitics, and population trends — explained simply and visually. On YT since May 16, 2008]
Calving multiplier effect "until recently we never knew existed" amplifies ice loss in Greenland, 13-min film w transcript, Heating Planet blog The very act of a glacier shedding ice into the ocean triggers a process that accelerates its own-
If this is too dense for you, here is an EZ version of the science:EZ vlog Beckwith climate science lecture in previous post shortened to 2 min simple video- WATCH & READ at Heating Planet blog- Greenland Iceberg Calving Secrets: Underwater-
The countdown has begun. Greenland is melting, but it's not melting the way scientists thought it would. In August 2025, researchers made a discovery that changes everything we know about how glaciers die. Using a 10 km fiber optic cable laid on the seafloor of a Greenland fjord, they uncovered a hidden force that's been secretly accelerating ice loss this entire time.
Massive underwater waves, some as tall as skyscrapers, invisible from the surface, churning warm water upward and eating away at the glaciers from below. This isn't just about icebergs breaking off. This is about a vicious cycle that nobody saw coming. When ice crashes into the ocean, it creates these hidden waves that bring warmer water to the surface. That warmer water melts more ice at the glacier's edge, which causes more ice to break off, which creates more waves, which melts even more ice. It's a feedback loop, a cving multiplier effect, as researchers are calling it, that's pushing Greenland's ice sheet toward collapse faster than any climate model predicted.
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The implications are genuinely alarming. The Greenland ice sheet contains enough water to raise global sea levels by 7 m. 7 m. That's enough to submerge Miami, New York, London, and Shanghai. And if these hidden underwater waves are accelerating melt across Greenland's glaciers, which they almost certainly are, then current projections for sea level rise could be dangerously understated. We might be running out of time faster than we realized. Let's start with what scientists thought they knew.
Greenland's ice sheet has been losing mass for 27 consecutive years, every single year since 1998. It's currently the second largest contributor to sea level rise after ocean thermal expansion. Between 2006 and 2018 alone, Greenland contributed about 20% of global sea level rise. The mechanism seems straightforward. As temperatures rise, more ice melts on the surface during summer.
That melt water flows into the ocean or drains through the ice sheet. Meanwhile, at the edges, chunks of ice break off through a process called calving, where huge icebergs split from the glacier front and crash into the sea. Scientists knew that warm seawater was melting glaciers from below, a process called submarine melting. They knew calving was important. They just didn't fully understand how these processes interacted. The numbers tell a complicated story.
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In 2024, Greenland actually experienced its lowest annual ice loss since 2013, losing just 55 gigaatons of mass according to gray satellite data. That might sound like good news, but it's misleading. The low loss was driven primarily by above average snowfall and below average surface melting thanks to persistent low pressure over southern Greenland that brought cooler conditions and cloudiness.
But here's what's concerning. Even with all that extra snow and reduced melting glacier discharge rates, the amount of ice flowing into the ocean through calving and submarine melt remained substantially above the 1991 to 2020 average. The ice kept pouring into the ocean even when conditions at the surface improved. Something else was driving the loss, something that wasn't captured in the models.
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According to annual reviews going back years, Greenland lost approximately 80 billion tons of ice from September 2023 to August 2024. When you account for both surface melt and marine mass balance, the last year Greenland saw a net gain of ice was 1996, nearly 30 years ago. The trend is clear, relentless, and apparently irreversible. And now we're learning that the problem might be even worse than the data suggests.
This is where the breakthrough happened. As part of the green fjord project, an international research team led by the University of Zurich and the University of Washington deployed a fiber optic cable across the fjord in front of the Echolarit Kangilit Seriat Glacier in southern Greenland. This wasn't just any glacier. It's a massive fast-moving beast that releases approximately 3.6 cubic kilm of ice into the ocean every single year. almost three times the annual volume of Switzerland's Rhone glacier. The cable stretched across the seafloor, sitting a few hundred meters from the towering m high wall of ice at the glacier's face in water 80 m deep. The researchers used a technology called distributed acoustic sensing or DAS, which detects tiny vibrations and strain along the cable caused by various events.
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Cravasses forming in the ice, falling ice blocks, ocean waves, temperature changes. The fiber optic cable essentially became a massive ultra sensitive listening device for everything happening in the fjord. Lead author Dominic Greff, a post-doal researcher at the University of Washington who completed his doctorate at ETHZurich described what they witnessed.
The team observed a large calving event every few hours when massive chunks of ice broke away from the glacier and crashed into the ocean. The impact was dramatic and violent. Icebergs are breaking off and exciting all sorts of waves, Greff explained. First came the surface waves, calving induced tsunamis, walls of water that surged through the fjord following the initial impact. Anyone who has seen video of a calving event knows how spectacular this looks. A wave rushing away from the ice like a miniature tsunami. But the fiber optic cable detected something else. Something invisible from above. Long after the surface had calmed and the visible waves had dissipated, other waves continued moving beneath the surface. These were internal gravity waves propagating between different density layers of water, and they were enormous, some reaching heights comparable to skyscrapers. Here's why this matters. The water in Greenland's fjords is stratified by temperature and salinity. Warm, salty seawater is denser than cold, fresh glacial meltwater, so it naturally sinks to the bottom. The glacial meltwater sits at the surface, creating a cool, insulating layer around the glacier's edge. This layer actually protects the ice, preventing more rapid melting. Greff compared this to ice cubes in a drink. If you drop ice cubes into warm water and don't stir, a cool layer forms around each cube, insulating it and slowing the melt. But if you stir the drink, disrupting that protective layer, the ice melts much faster. The same principle applies to glaciers, except the stirring mechanism wasn't well understood until now. The fiber optic cable revealed exactly how powerful this stirring is. When an iceberg crashes into the fjord, it doesn't just create visible surface waves. It generates these massive underwater waves that continue moving between density layers long after the splash. These internal waves bring warm water from the depths up to the glacier's edge, constantly disrupting the protective cold layer and dramatically accelerating underwater melt. But it doesn't stop there. As the iceberg drifts away from the glacier, it creates its own wake, like a boat moving through water. Except this wake is invisible beneath the surface. This continued stirring brings even more warm water upward, further intensifying the melt at the glacier's base. The fiber optic cable allowed us to measure this incredible calving multiplier effect which wasn't possible before. Graph said this is the key phrase multiplier effect. It's not just that calving removes ice directly. It's that each calving event accelerates future calving by creating conditions that melt the glacier faster from below. The process becomes self-reinforcing. More calving creates more underwater waves. More waves bring more warm water to the surface. More warm water melts more ice at the glacier's base. This makes the glacier unstable and topheavy, triggering more calving. The cycle accelerates and there's no natural break to stop it. So, what does this mean for Greenland as a whole? The echolorit kangaliteriat glacier is just one of hundreds of glaciers around Greenland's coast. If this calving multiplier effect operates at this one glacier, it almost certainly operates at others, too. And that means current climate models, which don't fully account for this underwater wave mixing, are likely underestimating how fast Greenland is losing ice. Matio Morajam, a glaciologist at Dartmouth College who wasn't involved in the research, put it bluntly. Maybe this study is the key to why in practice in real life we have much higher melt rates than what we would expect. They are able to capture a lot of the physics that we didn't even know was happening. This is a critical admission. Scientists have long known that their models couldn't fully explain observed melt rates. Glaciers were retreating faster than predictions suggested they should. The mismatch was concerning but not fully understood. Now there's a potential explanation. The models weren't accounting for the continuous stirring caused by calving induced waves bringing warm water to the surface. The Greenland ice sheet covers an area roughly times the size of Switzerland. If it melted completely, global sea levels would rise by approximately m. That's not a distant theoretical possibility. Parts of Greenland are already believed to be at a tipping point of irreversible melting, and the consequences extend far beyond sea level rise. The massive volumes of fresh water flowing from Greenland's melting glaciers are already disrupting ocean currents. The Atlantic meridian overturning circulation, which includes the Gulf Stream, circulates water from the North Atlantic to the south and back again in a massive conveyor belt. This current system regulates climate across much of Europe and North America. Recent studies have shown that AO is already at its weakest point in , years. In worst case scenarios, some models suggest it could reach a tipping point as early as . Though most scientists consider that timeline too extreme, but the underlying concern is real. If Greenland continues pouring fresh water into the North Atlantic at accelerating rates, it could eventually collapse the Sea entirely. The consequences would be catastrophic for Europe's climate. The Gulf Stream brings warm water from the tropics northward, keeping Western Europe much warmer than it would otherwise be at those latitudes. If the Amosi collapses, temperatures across Europe could drop dramatically. Meanwhile, sea levels along the US east coast could rise even faster as water that's currently pulled northward by the current instead piles up along American shores. And the retreat of Greenland's cving glaciers affects local ecosystems within the fjords themselves. As Andreas Vielli, a professor at the University of Zurich's Department of Geography and co-author of the study, warned, "Our entire Earth system depends, at least in part, on these ice sheets. It's a fragile system that could collapse if temperatures rise too high." The timing of this discovery is particularly significant. For years, scientists have struggled to understand why Greenland appears to be melting faster than their models predict. A study published in Nature found that Greenland's ice sheet is losing ice % faster than previously estimated when researchers accounted for calving at the edges of glaciers. Something earlier estimates had missed or underestimated. Between and , researchers found that Greenland lost approximately , km of ice, averaging about km per year. Almost every glacier in Greenland experienced some level of loss during that period. The study combined over , observations of glacier terminus positions from various data sets to capture monthly ice melt patterns, revealing that the problem is more widespread than anyone realized. Seasonal variability turns out to be a powerful predictor of long-term ice loss. During summer, ocean warming and influxes of surface melt water raise ice melting rates and alter glacial thickness. During winter, a mlange of sea ice and icebergs can modify melt rates. But the underlying trend is clear. Retreat and loss. What's particularly alarming is the feedback loop that climate change creates. As temperatures rise, more surface melting occurs. That meltwater flows underneath glaciers, lifting and lubricating them. It can actually affect how fast the ice flows, explained Mikalia King, a senior research scientist at the University of Washington's Polar Science Center. So, not only do you have the loss of mass from the melt directly at the surface, but then you're also impacting how rapidly these big conveyor belts of ice, these big outlet glaciers are flowing. The ice moves faster, reaches the ocean sooner, and calves more frequently. Each calving event then triggers the underwater wave process that the fiber optic study documented, bringing warm water up and melting even more ice. It's multiple feedback loops operating simultaneously, all pushing toward faster ice loss. And here's what makes the new fiber optic findings so important. This underwater mixing process operates regardless of what's happening at the surface. Even in years like , when surface melting was below average due to cooler conditions and above average snowfall, the discharge of ice into the ocean remained high. The calving and submarine melting continued, driven, at least in part, by these hidden underwater waves that keep churning warm water to the glacier fronts. The research team's methodology opens new possibilities for monitoring glaciers. Fiber optic cables are relatively cheap, passive, and safe compared to traditional field measurements. Researchers don't have to navigate through icebergs or get dangerously close to unstable cving fronts. The cable just sits on the seafloor collecting data continuously. There is a fiber sensing revolution going on right now, said Bradley Paul Leovsky, a co-author from the University of Washington. It's become much more accessible in the past decade, and we can use this technology in these amazing settings. And the team collected data for weeks during their field campaign, but they're planning longerterm deployments that could monitor changes throughout entire seasons or even multiple years. This would capture not just individual cving events, but the cumulative effects over time, revealing how the process varies with seasons and climate conditions. The data could also improve forecasting models. If scientists can incorporate this cving multiplier effect into climate simulations, they'll get more accurate predictions of how much ice will melt and how quickly seas will rise. That has enormous implications for coastal planning, infrastructure development, and climate adaptation policies. Right now, hundreds of millions of people live in coastal areas that would be inundated by significant sea level rise. Cities like Miami, New York, Shanghai, London, Mumbai, and Bangkok all face existential threats. Even a meter or two of sea level rise would displace tens of millions of people, cause trillions of dollars in damage, and force massive relocations. If Greenland is melting faster than current models predict, those impacts could arrive sooner than expected. The fiber optic study also revealed that the meltwater pools and streams sitting on top of Greenland's ice sheet are absorbing more heat than previously realized. A separate study published in Nature Communications found that thousands of small ponds of melted water on the ice surface absorb significantly more solar energy because of their dark color compared to white ice and snow. This creates yet another feedback loop. As ice melts and forms surface ponds, those dark ponds absorb more heat, which melts more ice, which creates more ponds. Combined with the underwater wave process accelerating submarine melt and the meltwater lubrication speeding up glacier flow, you have multiple reinforcing mechanisms all working in the same direction, faster ice loss. So, where does this leave us? The uncomfortable truth is that Greenland's ice loss appears to be accelerating through processes that weren't fully understood until very recently. The data showing lower ice loss might seem encouraging, but it's driven by temporary weather conditions, not any fundamental change in the underlying dynamics. Greenland has been losing ice every year for consecutive years. The trend is clear and now we know that one of the major drivers of that loss. Calvin induced submarine melting amplified by underwater waves has been operating in the shadows literally beneath the surface where satellites can't see and traditional measurements couldn't detect it. Climate models will need to be updated to incorporate these findings. Current projections for sea level rise already paint a concerning picture. But if they're missing a major acceleration mechanism, the reality could be worse. Some estimates suggest that if current trends continue, Greenland could contribute one to two meters of sea level rise this century with catastrophic consequences for coastal cities worldwide. The researchers emphasize that their entire Earth system depends, at least in part, on ice sheets like Greenlands. It's a fragile system that could collapse if temperatures rise too high. The problem is that temperatures are rising and they're showing no signs of slowing down without dramatic reductions in greenhouse gas emissions. Greenland's fate isn't sealed. In theory, if global temperatures could be stabilized and even reduced, the ice loss could slow, but the feedback loops now being discovered make that increasingly difficult. Each process reinforces the others, creating momentum that's hard to reverse. The fiber optic study revealed one piece of a larger puzzle, but it's a crucial piece. Understanding how icebergs stir up warm water and accelerate melt helps explain why Greenland is losing ice faster than models predicted. And it suggests that unless something changes dramatically, the ice sheet will continue its retreat, potentially passing points of no return, where collapse becomes inevitable regardless of what humans do. For the millions of people living in coastal cities, for the island nations facing complete inundation, for the ecosystems that depend on stable ocean currents, Greenland's hidden underwater waves represent more than just a scientific curiosity. They're a warning sign that the ice is melting faster than we thought through mechanisms we're only now beginning to understand. And the countdown has already begun
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