Latest news with #GeophysicalResearchLetters
Yahoo
3 hours ago
- Science
- Yahoo
MIT scientists find first evidence that rivers form coral reef passes
In a new groundbreaking study out of MIT, researchers proved a theory that island rivers help shape and maintain the health of a reef rather than impacting it negatively. The findings stand to change conservation efforts for the better. In a paper published in the peer-reviewed journal Geophysical Research Letters, the MIT team described reef passes as "deep, navigable channels dissecting coral reefs around volcanic islands." These are basically wide channels that cut through the coral and serve as conduits for ocean water and nutrients to filter in and out. As many reef passes are found to form near large island river basins, researchers had previously assumed a relationship existed between the two. However, the theory remained unproven until now. The authors of the latest study showed "how coral reefs line up with where rivers funnel out from an island's coast." These water channels play a direct role as a freshwater body meets the sea, providing circulation throughout a reef and maintaining the health of corals by allowing saltwater and transporting key nutrients, a media release by MIT explained. The study impacts scientists' understanding of how coral reefs form and function, as much discussion has been brewing about this symbiotic interaction in recent years. MIT researchers focused on the Society Islands, a chain in the South Pacific Ocean around Tahiti and Bora Bora. However, the pandemic limited their ability to work onsite, needing to rely on satellite images and maps. Lead study authors professor Taylor Perron and graduate student Megan Gillen found that "reef passes are deep channels cutting through reef barriers and flats that facilitate wave- and tide-driven circulation. These passes regulate flow between lagoon and ocean." "It is well known that rivers discharging freshwater and sediment off islands affect reef structure and composition," study authors added. However, was there a direct connection between outlets of large island rivers and reef passes? Thanks to geospatial analysis of the archipelago, the researchers discovered that river basins drain to parts of the reef, essentially creating an underwater highway. River erosion actually shapes these coral formations. Rivers running towards the ocean created these eroded depressions in the coastline over time. The study authors identified two river-driven reef pass formation mechanisms: reef incision and reed encroachment. Incision refers to how "rivers cut passes into reefs exposed when the sea level is lower." Encroachment refers to where "old river channels on land are preserved as passes when sea level rises." "Reefs migrate toward the islands as sea levels rise, trying to keep pace with changing average sea level," observed Gillen. The study further states that the results "show how rivers may support reef health over geologic timescales by enhancing water circulation between lagoons and oceans." "A lot of discussion around rivers and their impact on reefs today has been negative because of human impact and the effects of agricultural practices," said Gillen. "This study shows the potential long-term benefits rivers can have on reefs, which I hope reshapes the paradigm and highlights the natural state of rivers interacting with reefs," she added Now, with this knowledge proven, Gillen will be exploring how rivers could be engineered to promote circulation and reef health. You can view the full study in the journal Geophysical Research Letters.
Yahoo
11-06-2025
- Science
- Yahoo
Scientists mapped what happens if a crucial system of ocean currents collapses. The weather impact would be extreme
The collapse of a crucial network of Atlantic Ocean currents could push parts of the world into a deep freeze, with winter temperatures plunging to around minus 55 degrees Fahrenheit in some cities, bringing 'profound climate and societal impacts,' according to a new study. There is increasing concern about the future of the Atlantic Meridional Overturning Circulation — known as the AMOC — a system of currents that works like a giant conveyor belt, pulling warm water from the Southern Hemisphere and tropics to the Northern Hemisphere, where it cools, sinks and flows back south. Multiple studies suggest the AMOC is weakening with some projecting it could even collapse this century as global warming disrupts the balance of heat and salinity that keeps it moving. This would usher in huge global weather and climate shifts — including plunging temperatures in Europe, which relies on the AMOC for its mild climate. What's less clear, however, is how these impacts will unfold in a world heated up by humans burning fossil fuels. 'What if the AMOC collapses and we have climate change? Does the cooling win or does the warming win?' asked René van Westen, a marine and atmospheric researcher at Utrecht University in the Netherlands and co-author of the paper published Wednesday in the Geophysical Research Letters journal. This new study is the first to use a modern, complex climate model to answer the question, he told CNN. The researchers looked at a scenario where the AMOC weakens by 80% and the Earth is around 2 degrees Celsius warmer than the period before humans began burning large amounts of fossil fuels. The planet is currently at 1.2 degrees of warming. They focused on what would happen as the climate stabilized post-collapse, multiple decades into the future. Even in this hotter world, they found 'substantial cooling' over Europe with sharp drops in average winter temperatures and more intense cold extremes — a very different picture than the United States, where the study found temperatures would continue to increase even with an AMOC collapse. Sea ice would spread southward as far as Scandinavia, parts of the United Kingdom and the Netherlands, the research found. This would have a huge impact on cold extremes as the white surface of the ice reflects the sun's energy back into space, amplifying cooling. The scientists have created an interactive map to visualize the impacts of an AMOC collapse across the globe. London, for example, could see winter cold extremes of minus 2.2 Fahrenheit , while Oslo could see temperatures as low as minus 55 Fahrenheit and endure maximum temperatures below 32 Fahrenheit for 46% of the year. Parts of Europe will also become stormier, the study found. The increased temperature difference between northern and southern Europe will strengthen the jet stream and increase storm intensity over northwestern Europe. It 'completely shifts the narrative, right?' van Westen said. 'Because now policy is planning for a warmer future, but maybe instead, we need to also prepare for a colder future.' While cooling on an ever-hotter planet may sound like good news, van Westen warns it's anything but. Society in many parts of the Northern Hemisphere 'is not built for these kind of cold extremes,' he said. Crops would die, threatening food security, and infrastructure could buckle. What's more, the impacts of an AMOC collapse would mostly be felt in Europe's winter; it would still endure increasingly deadly heat waves in the summer as the climate crisis intensifies. The Southern Hemisphere, meanwhile, is projected to experience increased warming. The scientists also looked at the impacts of an AMOC collapse in an even hotter world. If global temperatures reach around 4 degrees Celsius above pre-industrial levels, the heat outweighs the cooling impact of an AMOC collapse in Europe , van Westen said. 'The warming signal actually wins.' But, he added, an AMOC collapse won't only affect temperatures. Other impacts include increased sea level rise, which will particularly affect the US, where a weaker AMOC is already driving significantly increased flooding on the northeastern coast, according to recent research. Stefan Rahmstorf, a physical oceanographer at Potsdam University in Germany who was not involved in the latest research, said the study confirms 'an AMOC collapse would have massive impacts on European climate.' The research uses only one climate model; others will rely on different models and will likely come up with a variety of scenarios, he told CNN. What ultimately happens will depend on the how the two opposing trends play out: AMOC-induced cooling and climate change-induced heating. A 'large uncertainty' remains, he said. The study is 'by no means the last word' especially as huge questions remain over whether the AMOC could be on course to collapse, said Richard Allen, a climate science professor at the University of Reading, also not involved in the research. 'But even the mere possibility of this dire storyline unfolding over coming centuries underscores the need to forensically monitor what is happening in our oceans,' he said. What is crystal clear is that an AMOC collapse would be very bad for society, van Westen said. 'We want to avoid it at all costs.'
CNN
11-06-2025
- Science
- CNN
Scientists mapped what happens if a crucial system of ocean currents collapses. The weather impact would be extreme
Climate changeFacebookTweetLink Follow The collapse of a crucial network of Atlantic Ocean currents could push parts of the world into a deep freeze, with winter temperatures plunging to around minus 55 degrees Fahrenheit in some cities, bringing 'profound climate and societal impacts,' according to a new study. There is increasing concern about the future of the Atlantic Meridional Overturning Circulation — known as the AMOC — a system of currents that works like a giant conveyor belt, pulling warm water from the Southern Hemisphere and tropics to the Northern Hemisphere, where it cools, sinks and flows back south. Multiple studies suggest the AMOC is weakening with some projecting it could even collapse this century as global warming disrupts the balance of heat and salinity that keeps it moving. This would usher in huge global weather and climate shifts — including plunging temperatures in Europe, which relies on the AMOC for its mild climate. What's less clear, however, is how these impacts will unfold in a world heated up by humans burning fossil fuels. 'What if the AMOC collapses and we have climate change? Does the cooling win or does the warming win?' asked René van Westen, a marine and atmospheric researcher at Utrecht University in the Netherlands and co-author of the paper published Wednesday in the Geophysical Research Letters journal. This new study is the first to use a modern, complex climate model to answer the question, he told CNN. The researchers looked at a scenario where the AMOC weakens by 80% and the Earth is around 2 degrees Celsius warmer than the period before humans began burning large amounts of fossil fuels. The planet is currently at 1.2 degrees of warming. They focused on what would happen as the climate stabilized post-collapse, multiple decades into the future. Even in this hotter world, they found 'substantial cooling' over Europe with sharp drops in average winter temperatures and more intense cold extremes — a very different picture than the United States, where the study found temperatures would continue to increase even with an AMOC collapse. Sea ice would spread southward as far as Scandinavia, parts of the United Kingdom and the Netherlands, the research found. This would have a huge impact on cold extremes as the white surface of the ice reflects the sun's energy back into space, amplifying cooling. The scientists have created an interactive map to visualize the impacts of an AMOC collapse across the globe. London, for example, could see winter cold extremes of minus 2.2 Fahrenheit , while Oslo could see temperatures as low as minus 55 Fahrenheit and endure maximum temperatures below 32 Fahrenheit for 46% of the year. Parts of Europe will also become stormier, the study found. The increased temperature difference between northern and southern Europe will strengthen the jet stream and increase storm intensity over northwestern Europe. It 'completely shifts the narrative, right?' van Westen said. 'Because now policy is planning for a warmer future, but maybe instead, we need to also prepare for a colder future.' While cooling on an ever-hotter planet may sound like good news, van Westen warns it's anything but. Society in many parts of the Northern Hemisphere 'is not built for these kind of cold extremes,' he said. Crops would die, threatening food security, and infrastructure could buckle. What's more, the impacts of an AMOC collapse would mostly be felt in Europe's winter; it would still endure increasingly deadly heat waves in the summer as the climate crisis intensifies. The Southern Hemisphere, meanwhile, is projected to experience increased warming. The scientists also looked at the impacts of an AMOC collapse in an even hotter world. If global temperatures reach around 4 degrees Celsius above pre-industrial levels, the heat outweighs the cooling impact of an AMOC collapse in Europe, van Westen said. 'The warming signal actually wins.' But, he added, an AMOC collapse won't only affect temperatures. Other impacts include increased sea level rise, which will particularly affect the US, where a weaker AMOC is already driving significantly increased flooding on the northeastern coast, according to recent research. Stefan Rahmstorf, a physical oceanographer at Potsdam University in Germany who was not involved in the latest research, said the study confirms 'an AMOC collapse would have massive impacts on European climate.' The research uses only one climate model; others will rely on different models and will likely come up with a variety of scenarios, he told CNN. What ultimately happens will depend on the how the two opposing trends play out: AMOC-induced cooling and climate change-induced heating. A 'large uncertainty' remains, he said. The study is 'by no means the last word' especially as huge questions remain over whether the AMOC could be on course to collapse, said Richard Allen, a climate science professor at the University of Reading, also not involved in the research. 'But even the mere possibility of this dire storyline unfolding over coming centuries underscores the need to forensically monitor what is happening in our oceans,' he said. What is crystal clear is that an AMOC collapse would be very bad for society, van Westen said. 'We want to avoid it at all costs.'
CNN
11-06-2025
- Science
- CNN
Scientists mapped what happens if a crucial system of ocean currents collapses. The weather impact would be extreme
Climate changeFacebookTweetLink Follow The collapse of a crucial network of Atlantic Ocean currents could push parts of the world into a deep freeze, with winter temperatures plunging to around minus 55 degrees Fahrenheit in some cities, bringing 'profound climate and societal impacts,' according to a new study. There is increasing concern about the future of the Atlantic Meridional Overturning Circulation — known as the AMOC — a system of currents that works like a giant conveyor belt, pulling warm water from the Southern Hemisphere and tropics to the Northern Hemisphere, where it cools, sinks and flows back south. Multiple studies suggest the AMOC is weakening with some projecting it could even collapse this century as global warming disrupts the balance of heat and salinity that keeps it moving. This would usher in huge global weather and climate shifts — including plunging temperatures in Europe, which relies on the AMOC for its mild climate. What's less clear, however, is how these impacts will unfold in a world heated up by humans burning fossil fuels. 'What if the AMOC collapses and we have climate change? Does the cooling win or does the warming win?' asked René van Westen, a marine and atmospheric researcher at Utrecht University in the Netherlands and co-author of the paper published Wednesday in the Geophysical Research Letters journal. This new study is the first to use a modern, complex climate model to answer the question, he told CNN. The researchers looked at a scenario where the AMOC weakens by 80% and the Earth is around 2 degrees Celsius warmer than the period before humans began burning large amounts of fossil fuels. The planet is currently at 1.2 degrees of warming. They focused on what would happen as the climate stabilized post-collapse, multiple decades into the future. Even in this hotter world, they found 'substantial cooling' over Europe with sharp drops in average winter temperatures and more intense cold extremes — a very different picture than the United States, where the study found temperatures would continue to increase even with an AMOC collapse. Sea ice would spread southward as far as Scandinavia, parts of the United Kingdom and the Netherlands, the research found. This would have a huge impact on cold extremes as the white surface of the ice reflects the sun's energy back into space, amplifying cooling. The scientists have created an interactive map to visualize the impacts of an AMOC collapse across the globe. London, for example, could see winter cold extremes of minus 2.2 Fahrenheit , while Oslo could see temperatures as low as minus 55 Fahrenheit and endure maximum temperatures below 32 Fahrenheit for 46% of the year. Parts of Europe will also become stormier, the study found. The increased temperature difference between northern and southern Europe will strengthen the jet stream and increase storm intensity over northwestern Europe. It 'completely shifts the narrative, right?' van Westen said. 'Because now policy is planning for a warmer future, but maybe instead, we need to also prepare for a colder future.' While cooling on an ever-hotter planet may sound like good news, van Westen warns it's anything but. Society in many parts of the Northern Hemisphere 'is not built for these kind of cold extremes,' he said. Crops would die, threatening food security, and infrastructure could buckle. What's more, the impacts of an AMOC collapse would mostly be felt in Europe's winter; it would still endure increasingly deadly heat waves in the summer as the climate crisis intensifies. The Southern Hemisphere, meanwhile, is projected to experience increased warming. The scientists also looked at the impacts of an AMOC collapse in an even hotter world. If global temperatures reach around 4 degrees Celsius above pre-industrial levels, the heat outweighs the cooling impact of an AMOC collapse in Europe, van Westen said. 'The warming signal actually wins.' But, he added, an AMOC collapse won't only affect temperatures. Other impacts include increased sea level rise, which will particularly affect the US, where a weaker AMOC is already driving significantly increased flooding on the northeastern coast, according to recent research. Stefan Rahmstorf, a physical oceanographer at Potsdam University in Germany who was not involved in the latest research, said the study confirms 'an AMOC collapse would have massive impacts on European climate.' The research uses only one climate model; others will rely on different models and will likely come up with a variety of scenarios, he told CNN. What ultimately happens will depend on the how the two opposing trends play out: AMOC-induced cooling and climate change-induced heating. A 'large uncertainty' remains, he said. The study is 'by no means the last word' especially as huge questions remain over whether the AMOC could be on course to collapse, said Richard Allen, a climate science professor at the University of Reading, also not involved in the research. 'But even the mere possibility of this dire storyline unfolding over coming centuries underscores the need to forensically monitor what is happening in our oceans,' he said. What is crystal clear is that an AMOC collapse would be very bad for society, van Westen said. 'We want to avoid it at all costs.'
Washington Post
01-06-2025
- Science
- Washington Post
Satellite measures river flow waves for the first time
Long river waves, known as flow waves, have been measured by satellite for the first time, researchers announced May 14, a breakthrough that could expand understanding of river dynamics, floods and the other hazards sometimes present when the waves form. In a study in Geophysical Research Letters, the researchers found that the long waves can be spotted and studied using data from a NASA-French space agency satellite designed to study Earth's water.
