At the tide gauge on Grand Isle, Louisiana, the water has climbed more than 2 feet since 1947. That works out to about 3.6 inches every decade, the fastest rate of any long-running tide gauge in the Lower 48, according to the National Oceanic and Atmospheric Administration. The number is not just about the ocean rising. The agency measures relative sea level, which combines the water getting higher with the land getting lower, and along much of the Gulf Coast, the ground itself is sinking. That is why the fastest-rising US coastlines cluster in Louisiana, Texas, and Virginia, while parts of Alaska are seeing sea level fall. Grand Isle, Louisiana Grand Isle is Louisiana's only inhabited barrier island, a thin strip of sand at the edge of the Mississippi River Delta. The delta was built over thousands of years by river mud, and that mud naturally settles and compacts over time. In the past, spring floods spread fresh sediment across the delta to make up the difference. Today, levees keep the river in its channel, so little new mud reaches the coast, while the old ground keeps sinking. Add rising seas, and Grand Isle's tide gauge has recorded one of...

At the tide gauge on Grand Isle, Louisiana, the water has climbed more than 2 feet since 1947. That works out to about 3.6 inches every decade, the fastest rate of any long-running tide gauge in the Lower 48, according to the National Oceanic and Atmospheric Administration. The number is not just about the ocean rising. The agency measures relative sea level, which combines the water getting higher with the land getting lower, and along much of the Gulf Coast, the ground itself is sinking. That is why the fastest-rising US coastlines cluster in Louisiana, Texas, and Virginia, while parts of Alaska are seeing sea level fall. Grand Isle, Louisiana Grand Isle is Louisiana's only inhabited barrier island, a thin strip of sand at the edge of the Mississippi River Delta. The delta was built over thousands of years by river mud, and that mud naturally settles and compacts over time. In the past, spring floods spread fresh sediment across the delta to make up the difference. Today, levees keep the river in its channel, so little new mud reaches the coast, while the old ground keeps sinking. Add rising seas, and Grand Isle's tide gauge has recorded one of...

The findings, published in Nature Communications, reveal why earlier models may have underestimated the glacier's retreat. Instead of treating the boundary between grounded and floating ice as a narrow line, researchers accounted for a much broader area where ocean water can reach beneath the glacier. With this change, the model reproduced historical changes in Thwaites from the 1990s to the present that were four times more pronounced than those represented by conventional models. Warm Ocean Water Is Melting Antarctica's Ice From Below "Glaciologists have long based their assumptions of ice sheet dynamics on the 'grounding line,' a discreet, narrow and mostly stable demarcation where ice leaves the land and begins floating on water," said lead author Mattia Poinelli, who was a UC Irvine postdoctoral scholar in Earth system science when the research was conducted. "We have come to acknowledge a different arrangement beneath Earth's major ocean-terminating glaciers. Satellite observations demonstrate the existence of a 'grounding zone,' sometimes kilometers wide, where warm ocean water is reaching deep underneath the ice sheets and causing vigorous melting." Thwaites Glacier lies in West Antarctica's Amundsen Sea Embayment, a region responsible for approximately one third of the Antarctic Ice Sheet's total mass loss. Over recent...

The findings, published in Nature Communications, reveal why earlier models may have underestimated the glacier's retreat. Instead of treating the boundary between grounded and floating ice as a narrow line, researchers accounted for a much broader area where ocean water can reach beneath the glacier. With this change, the model reproduced historical changes in Thwaites from the 1990s to the present that were four times more pronounced than those represented by conventional models. Warm Ocean Water Is Melting Antarctica's Ice From Below "Glaciologists have long based their assumptions of ice sheet dynamics on the 'grounding line,' a discreet, narrow and mostly stable demarcation where ice leaves the land and begins floating on water," said lead author Mattia Poinelli, who was a UC Irvine postdoctoral scholar in Earth system science when the research was conducted. "We have come to acknowledge a different arrangement beneath Earth's major ocean-terminating glaciers. Satellite observations demonstrate the existence of a 'grounding zone,' sometimes kilometers wide, where warm ocean water is reaching deep underneath the ice sheets and causing vigorous melting." Thwaites Glacier lies in West Antarctica's Amundsen Sea Embayment, a region responsible for approximately one third of the Antarctic Ice Sheet's total mass loss. Over recent...

El Niño Lifts the Pacific: A Bathtub the Size of an Ocean

Even without further warming, Thwaites Glacier could contribute twice as much to sea level rise by 2100 as previously estimated, according to a revised ice sheet model. Thwaites Glacier in West Antarctica has been retreating and thinning rapidly, while satellites show substantial acceleration in its ice flow. Traditional ice sheet models have depicted slower movement, leaving scientists struggling to reconcile their simulations with the observations. The glacier lies in the Amundsen Sea Embayment, a sector responsible for roughly one-third of the Antarctic Ice Sheet’s mass loss. A new ice sheet model developed by glaciologists at the University of California, Irvine and NASA’s Jet Propulsion Laboratory projects that melting at Thwaites could contribute up to 30 millimeters, or about 1.2 inches, to sea level rise by 2100. That is twice previous estimates, even without additional climate warming. The study was published in Nature Communications. Warm seawater reaches beneath grounded ice “Glaciologists have long based their assumptions of ice sheet dynamics on the ‘grounding line,’ a discreet, narrow and mostly stable demarcation where ice leaves the land and begins floating on water,” said lead author Mattia Poinelli, who was a UC Irvine postdoctoral scholar in Earth system science when the study was...

Sea-level rise driven by climate change could help invasive marine species spread into newly flooded coastal areas, threatening biodiversity and some economic activities, researchers warned in a study published recently. The findings in Nature Ecology & Evolution highlight the links between the climate and bio- diversity crises, with global warming altering ecosystems and creating new opportunities for non-native species to thrive. That could “potentially expose ecosystems and human activities that have not previously been affected by these species”, said study co-author Xuan Liu of Beijing Normal University. The researchers modelled the potential future spread of 122 established non-native marine animals, including fish, crustaceans, molluscs and sea stars, under different climate and sea-level scenarios. Climate change causes sea levels to rise through thermal expansion – ocean water increases in volume as it warms – and the melting of glaciers and ice sheets. Global sea levels are projected to rise by about 20cm by 2050 and 56cm by 2100 under a scenario of moderate growth in greenhouse gas emissions. That would see around 360,000sq km of coastal land flooded by mid-century, rising to 550,000sq km by the end of the century. More than two-thirds of the newly flooded coastal land – roughly...

Scientists say a “multi-headed monster” train of Kelvin waves is quietly lifting sea levels and priming California for more erosion, flooding and chaos.

Climate scientists warn that the heat expansion already raising some Pacific sea levels by 1.3 feet this El Niño season will become even more deadly thanks to the Moon itself.