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Showing posts with the label Sea level rise

Rebutting a Trump report, study shows U.S. sea-level rise is accelerating

By Brady Dennis . The Washington Post.  Excerpt: The rate of sea-level rise along U.S. coastlines has more than doubled over the past 125 years, according to  a new analysis  that examined data from scores of tide gauges from around the country. The findings stand in contrast to a wide-ranging, widely criticized  assessment  of climate science that the Trump administration released this summer. Chris Piecuch, a sea-level scientist at Woods Hole Oceanographic Institution, said he undertook his analysis in response to that Energy Department report, whichhe and others argue uses cherry-picked data to conclude that “U.S. tide gauge measurements reveal no obvious acceleration beyond the historical average rate of sea-level rise.” ...That assessment also underscores that some places, such as the Pacific Coast, have experienced little sea-level rise compared with places such as the gulf coast. Some spots in Alaska have even seen an overall decrease as sea-level rise is...

Antarctic glacier shows fastest retreat in modern history

By Hannah Richter , Science.  Excerpt: In 2022, something shocking happened to the Hektoria Glacier, a small river of ice that slips into the sea near the tip of the Antarctic Peninsula. Over 16 months, it retreated by 25 kilometers, and it lost a whopping 8 kilometers in just two of those months—the fastest glacial retreat in the modern record. Now, after  a forensic analysis of the event reported today in  Nature Geoscience , researchers say they have identified the worrisome mechanisms behind it: a combination of glacial earthquakes and a swath of thinned ice popping afloat and breaking apart in a geological instant. If the same processes were to occur at larger Antarctic glaciers, they could rapidly accelerate the retreat of ice sheets and raise global sea levels, says Jeremy Bassis, a glaciologist at the University of Michigan. The study is “telling us that those worst-case scenarios are maybe not as implausible as some people might have thought.” ...[Jeremy] Bassis ...

2025 State of the Climate Report: Our Planet’s Vital Signs are Crashing

By Grace van Deelen , Eos/AGU.  Excerpt: A yearly analysis of climate change’s progress and effects shows a “planet on the brink” of ecological breakdown and widespread crisis and suggests that only rapid climate mitigation can avoid the worst consequences. ...The sixth annual report, published in  BioScience ,  analyzes global data on Earth’s atmosphere, oceans, energy, ecosystems, food systems, and more. Researchers identified our planet’s so-called vital signs, including ocean temperature, surface temperature, sea ice extent, and carbon pollution. Of the 34 vital signs, 22 were at record levels, indicating a highly stressed Earth system. For example, 2024 surpassed 2023 as the hottest year on record.  Ocean heat  and  wildfire -related tree cover loss are both at all-time highs. Deadly weather disasters surged in 2024 and 2025, with floods, wildfires, and typhoons killing  hundreds in the U.S. alone . Atmospheric warming is showing signs of acc...

How Soon Will the Seas Rise?

By Evan Howell , Quanta Magazine.  Excerpt: In May 2014, NASA  announced(opens a new tab)  at a press conference that a portion of the West Antarctic Ice Sheet appeared to have reached a point of irreversible retreat. Glaciers flowing toward the sea at the periphery of the 2-kilometer-thick sheet of ice were losing ice faster than snowfall could replenish them, causing their edges to recede inland. With that, the question was no longer whether the West Antarctic Ice Sheet would disappear, but when. When those glaciers go, sea levels will rise by more than a meter, inundating land currently inhabited by  230 million people(opens a new tab) . And that would be just the first act before the collapse of the entire ice sheet, which could raise seas  5 meters(opens a new tab)  and redraw the world’s coastlines. ...If  greenhouse gas emissions  continue unabated, seas would rise a staggering  15 meters(opens a new tab)  by 2300. ...not all scie...

A Special ‘Climate’ Visa? People in Tuvalu Are Applying Fast

By Max Bearak , The New York Times.  Excerpt: As sea levels rise, Australia said it would offer a special, first-of-its-kind “climate visa” to citizens of Tuvalu, a Polynesian island nation of atolls and sandbars where waters are eating away at the land. The visa lottery opened last week, and already nearly half of Tuvalu’s population has applied....  Full article at https://www.nytimes.com/2025/06/27/climate/climate-visa-tuvalu.html . 

Sea level rise will cause ‘catastrophic inland migration’, scientists warn

By Damian Carrington , The Guardian.  Excerpt: Sea level rise will become unmanageable at just 1.5C of global heating and lead to “catastrophic inland migration”, the scientists behind a new study [ https://www.nature.com/articles/s43247-025-02299-w ] have warned. ...The loss of ice from the giant Greenland and Antarctic ice sheets has quadrupled since the 1990s due to the climate crisis and is now the principal driver of sea level rise. The international target to keep global temperature rise  below 1.5C is already almost out of reach . But the new analysis found that even if fossil fuel emissions were rapidly slashed to meet it, sea levels would be rising by 1cm a year by the end of the century, faster than the speed at which nations could build coastal defences. The world is  on track for 2.5C-2.9C  of global heating, which would almost certainly be beyond tipping points for the collapse of the Greenland and west Antarctic ice sheets. The melting of those ice shee...

Increased crevassing across accelerating Greenland Ice Sheet margins

By Thomas R. Chudley et al, Nature Geoscience.  Summary: The Greenland Ice Sheet, which measures more than 3 kilometers at its thickest point and covers an area three times the size of Texas, is the world’s second largest body of ice. If all of it were to melt, the world’s oceans would rise a whopping seven meters. And while such a complete meltdown would likely take thousands of years, Greenland—already one of the largest contributors to sea level rise—is poised to add up to 30 centimeters by 2100. Now, new research published in  Nature Geoscience  has revealed that  this enormous mass of ice is breaking apart faster than expected ....  Full article at https://www.nature.com/articles/s41561-024-01636-6 . 

Variable vertical land motion and its impacts on sea level rise projections

By https://www.science.org/doi/10.1126/sciadv.ads8163 et al, Science.  Abstract: Coastal vertical land motion (VLM), including uplift and subsidence, can greatly alter relative sea level projections and flood mitigations plans. Yet, current projection frameworks, such as the IPCC Sixth Assessment Report, often underestimate VLM by relying on regional linear estimates. Using high-resolution (90-meter) satellite data from 2015 to 2023, we provide local VLM estimates for California and assess their contribution to sea level rise both now and in future. Our findings reveal that regional estimates substantially understate sea level rise in parts of San Francisco and Los Angeles, projecting more than double the expected rise by 2050. Additionally, temporally variable (nonlinear) VLM, driven by factors such as hydrocarbon and groundwater extraction, can increase uncertainties in 2050 projections by up to 0.4 meters in certain areas of Los Angeles and San Diego. This study highlights the ...

A Seychelles Shoreline Resists the Rising Seas

By Caroline Hasler , Eos/AGU.  Excerpt: With global  sea levels  projected to rise 44 centimeters (17 inches) by the end of the century, atolls such as Aldabra—a  United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Site  in Seychelles and home to the world’s largest population of giant tortoises—may be at risk of sinking into the ocean. A new  study , however, shows that despite consistently rising sea levels, most of Aldabra’s shoreline hasn’t changed since 1960. ...An atoll forms when corals attach to the margins of a volcanic island or platform in the ocean. Over time, the volcano is eroded and subsides into the sea, leaving a ring-shaped reef. Winds and waves deposit crushed coral from surrounding reefs on top of the ring, ultimately forming islands that rise above sea level. ...“Our research shows that Aldabra’s resilience to sea level rise is likely linked to its high protection status. This serves as a crucial les...

Rising tides could wipe out Pacifica, but residents can’t agree on how to respond

By Connor Letourneau , San Francisco Chronicle.  Excerpt: “When people fight the ocean,” [Pacifica, City Council member Christine] Boles said, “the ocean always wins.” ...Pacifica, a picturesque surf town of roughly 35,000 just south of San Francisco, has become an important case study for the increasingly urgent questions  climate change  raises for many coastal communities. Should residents stay to defend their homes from rising tides that grow fiercer by the year? Or, should they admit defeat and cede the land back to nature? ...“Managed retreat” — a term coined by geologists to describe the process of removing people, homes and businesses from at-risk areas — is at the root of the debate. ...“We can’t build seawalls high enough to protect us forever,” said Gary Griggs, a professor of Earth and planetary sciences at UC Santa Cruz. “So, in the long run, it’s either going to be managed retreat or unmanaged retreat. It’s up to each community to decide.”...  Full...

As Seas Rise, Marshes May Still Trap Carbon—and Cool the Planet

By Rambo Talabong , Eos/AGU.  Excerpt: Coastal wetlands have long been seen as one of the casualties of climate change, doomed by the rising seas that are steadily swallowing their ecosystems. ...New research by Virginia Institute of Marine Science coastal geomorphologist  Matthew Kirwan  has revealed that some marshes, migrating as they adapt to changing conditions, may release carbon (primarily as carbon dioxide) but gain an enhanced capacity to store methane.  Methane  is a more potent greenhouse gas than carbon dioxide, and sequestering it may have an atmospheric cooling effect. As sea level rises, freshwater marshes get saltier and turn into salt marshes. Conventional wisdom has long held that as freshwater marshes shrink, they release carbon stored in their soil and biomass. But Kirwan pointed out that as freshwater marshes degrade and salinize, their microbial populations are affected in a way that causes the marshes to  emit less methane . “Even deg...

A Radical Approach to Flooding in England: Give Land Back to the Sea

By Rory Smith , The New York Times.  Excerpt: In September, a  month’s rain fell in a single day  in some parts of England. The 18 months to March 2024 were England’s  wettest in recorded history . Even on an island that has built at least part of its identity around tolerating inclement weather, it has been impossible to ignore the deluge.  Flooding  has submerged  fields ,  ruined homes , and at times,  cut off whole villages . As sea levels rise and extreme weather becomes more common, experts say that Britain’s traditional defenses — sea walls, tidal barriers and sandbanks — will be insufficient to  meet the threat . It is not alone: in September,  deadly floods in Central Europe  led to the deaths of at least 23 people. ...But on a tendril of land curling out from the coast of Somerset, in southwestern England, a team of scientists, engineers and conservationists have embraced a radical solution. ...In a project costing 20...

Doomsday may be delayed at Antarctica’s most vulnerable glacier

By Paul Voosen , Science.  Excerpt: Antarctica’s Thwaites Glacier isn’t called the Doomsday Glacier for nothing. Were the Florida-size ice sheet to melt away, it could raise global sea levels by 65 centimeters. And because it is a keystone that holds back other ice sheets from flowing into the ocean, its disappearance could unlock a total of more than 3 meters of global sea level rise. In 2018, U.S. and U.K. funders created the 100-person International Thwaites Glacier Collaboration (ITGC) to probe the ice—and its future.... ...one conclusion is that some of the worst-case scenarios—such as the runaway collapse of the iceberg-calving front of the glacier, which juts into the ocean as an ice shelf—are unlikely this century, says Robert Larter, a BAS marine geophysicist and co-lead of the project. That worry, he says, “is not the huge monster it might have been 10 years ago.” ...preliminary results from one of ITGC’s modeling groups suggest that in coming decades Thwaites will steadi...

‘Worst-Case’ Disaster for Antarctic Ice Looks Less Likely, Study Finds

By Raymond Zhong , The New York Times.  Excerpt: For almost a decade, climate scientists have been trying to get their heads around a particularly disastrous scenario for how West Antarctica’s gigantic ice sheet might break apart, bringing catastrophe to the world’s coasts. ...Once enough of the ice sheet’s floating edges melt away, what remains are immense, sheer cliffs of ice facing the sea. ...Great chunks of ice start breaking away from them, exposing even taller, even more-unstable cliffs. Soon, these start crumbling too, and before long you have runaway collapse. As all this ice tumbles into the ocean, and assuming that nations’ emissions of heat-trapping gases climb to extremely high levels, Antarctica could contribute more than a foot to worldwide sea-level rise before the end of the century. This calamitous chain of events is still hypothetical, yet scientists have taken it seriously enough to include it as a “low-likelihood, high-impact” possibility in  the United Na...

Radar Data Show Thwaites Gets a Daily Bath of Warm Seawater

By Anupama Chandrasekaran , Eos/AGU.  Excerpt: Daily tides bring warm ocean water farther in beneath West Antarctica’s Thwaites Glacier than previously thought, potentially causing ice to melt faster than expected, according to a new study. The finding could help scientists make better predictions about the fate of one of the world’s most closely watched glaciers. Thwaites ...is about the size of Florida. It currently  contributes about 4%  to global annual sea level rise. ...  recent research on Thwaites  and  other glaciers  has shown that these boundaries between floating ice and ice that is grounded on the seafloor shift with the daily tide. ...The team found that the ice rose and sank in sync with the tides. The data suggested that the grounding line migrated up to 6 kilometers (3.7 miles) inland during an average high tide. ...The  study  was published in the  Proceedings of the National Academy of Sciences of the United States of ...

The Vanishing Islands That Failed to Vanish

By Raymond Zhong , The New York Times.  Excerpt: The very existence of low-slung tropical islands seems improbable, a glitch. ...when the world began paying attention to global warming decades ago, these islands, which form atop coral reefs in clusters called atolls, were quickly identified as some of the first places climate change might ravage in their entirety. As the ice caps melted and the seas crept higher, these accidents of geologic history were bound to be corrected and the tiny islands returned to watery oblivion, probably in this century. Then, not very long ago, researchers began sifting through aerial images and found something startling. They looked at a couple dozen islands first, then several hundred, and by now close to 1,000. They found that over the past few decades, the islands’ edges had wobbled this way and that, eroding here, building there. By and large, though, their area hadn’t shrunk. In some cases, it was the opposite: They grew. The seas rose, and ...

More than a Third of Coastal Alaska Structures May Be at Risk of Flooding by 2100

By Grace van Deelen , Eos/AGU.  Excerpt: As climate change continues to spur  sea level rise  and increase  hurricane intensity , mapping possible future flooding is crucial. A new  study , published in  Scientific Reports , used community accounts of past floods to show how sea level rise is likely to make future floods worse. The work adds to scientists’ understanding of how climate change could affect Alaska’s coastal communities as part of a broader effort to improve flood modeling in the state. ...In the new study, researchers used the historical accounts to estimate current and future flood exposure. They compared record flooding to topography and the locations of buildings in 46 communities under two scenarios: 0.5 meter (1.6 feet) and 1.0 meter (3.3 feet) of sea level rise by 2100. NOAA  estimates  that global sea level will rise between 0.3 meter (1 foot) and 2 meters (6.6 feet) by 2100.  The team found that currently, 22% ...

As the Ferry Building shakes off the pandemic, major uncertainties surround its future

By John King , San Francisco Chronicle.  Excerpt: Throughout its 125-year history, there have been times when the formidable elegance of  San Francisco’s Ferry Building  was shadowed by uncertainties — from fears early on that it wouldn’t survive a major earthquake to the question, after the opening of the Bay Bridge, of whether it should be torn down. ...The most ominous element, though, is the U.S. Army Corps of Engineers’ desire to elevate the huge structure by at least 3½ feet as part of a larger multi-decade effort  to protect the bay shoreline  from floods and sea level rise....  Full article at https://www.sfchronicle.com/sf/article/ferry-building-business-pandemic-19462543.php . 

Warm ocean tides are eating away at ‘doomsday glacier’ in Antarctica

By ELI KINTISCH , Science.  Excerpt: Ocean tides are burrowing beneath a thick sheet of Antarctic ice—dubbed the “doomsday glacier” for its threat to global sea levels—and melting it from below. The daily intrusions of seawater, detected by satellites, mean the Thwaites Glacier may be disintegrating “much faster” than previously thought, scientists say in a study  published today  in the Proceedings of the National Academy of Sciences. Melting at Thwaites, an expanse of ice bigger than Florida that stores enough water to raise sea levels by 0.6 meters, already accounts for 4% of global sea level rise. Because the glacier rests on bedrock that dips inland into a deep basin, its underbelly is vulnerable to relatively warm seawater, which melts the ice and, by loosening it from bedrock, hastens its flow into the ocean. And because other West Antarctic glaciers drain into the same basin, scientists believe Thwaites acts as a keystone. Its removal could accelerate the oth...

Where Seas Are Rising At Alarming Speed

By Chris Mooney ,  Brady Dennis ,  Kevin Crowe  and  John Muyskens , The Washington Post. Excerpt: One of the most rapid sea level surges on Earth is besieging the American South, forcing a reckoning for coastal communities across eight U.S. states, a Washington Post analysis has found. At more than a dozen tidegauges spanning from Texas to North Carolina,sea levels are at least 6 inches higher than they were in 2010 — a change similar to what occurred over the previous five decades. ...The Gulf of Mexico has experienced twice the global average rate of  sea level rise since 2010 , a Post analysis of satellite data shows. ...As waters rise, Louisiana’s wetlands — the state’s natural barrier against major storms — are in a  state of “drowning.”  Choked septic systems are  failing  and threatening to contaminatewaterways.  Insurance companies  are raising rates,  limiting policies  or even bailing  in some places, ...