Latest news with #NORCENorwayResearchCentre
Yahoo
05-03-2025
- Science
- Yahoo
World's strongest ocean current becoming weaker due to melting Antarctic ice: Study
Recent studies show the melting ice sheets surrounding Antarctica are having repercussions on the Antarctic Circumpolar Current (ACC), the world's strongest ocean current. This change could perturb integrated climate systems on a global scale, altering sea levels, ocean temperatures, or even marine ecosystems. According to a study conducted by the University of Melbourne and NORCE Norway Research Centre, if carbon emissions are not controlled, the ACC may decelerate by up to 20% by 2050. Increases in freshwater due to melting ice are changing patterns of saltiness and circulation in the ocean, and this is affecting the balance that allows currents to circulate around the globe. 'The ocean is extremely complex and finely balanced. If this current 'engine' breaks down, there could be severe consequences, including more climate variability, with greater extremes in certain regions, and accelerated global warming due to a reduction in the ocean's capacity to act as a carbon sink,' said Bishakhdatta Gayen, one of the study authors. The ACC is a major player in the world's ocean movement, acting as a key component of the "ocean conveyor belt," responsible for maintaining the movement of water between the Atlantic, Pacific, and Indian Oceans. Furthermore, it assists in climate control, including the distribution of heat, carbon dioxide, and nutrients to different ocean basins. The ACC is over four times as powerful as the Gulf Stream. As a result, the ACC significantly controls the migration of a number of species across the ocean. With the current weakening, there is a potential risk of certain species, such as bull kelp, shrimps, and mollusks, invading the Antarctic waters and putting the fragile ecosystems and food chains in grave danger. The possible shifts in available prey could affect the population of penguins, thereby affecting the biodiversity of the entire region. Researchers analyzed these microdetails through Australia's fastest supercomputer, GADI, using which they simulated the ocean currents and climatic changes. The model incorporated the change in monsoon patterns, intake of saline water, and other free atmospheric wind conditions to determine the ice melt effect on oceanic circulation. These findings contradict earlier research that said that the ACC had been accelerating owing to the growing range in temperature across oceanic latitudinal regions. The study's major finding, instead, was that large quantities of freshwater from melting ice sheets reduce the ocean's salinity, which weakens the process that drives cold, dense water to sink and circulate—a key mechanism behind ACC strength. The research reveals it isn't just the high emissions scare – even in a scenario predicated on weaker emissions where the ice continues to melt. The severity of change is still imminent. 'The 2015 Paris Agreement aimed to limit global warming to 1.5 degrees Celsius above pre-industrial levels. Many scientists agree that we have already reached this 1.5-degree target, and it is likely to get hotter, with flow-on impacts on Antarctic ice melting,' said Taimoor Sohail, one of the study authors. The scientists believe that there is more work required, such as climatograph modeling and animation simulations, to consider the complete ACC slowdown effects caused by climate change. 'Ocean models have historically been unable to adequately resolve the small-scale processes that control current strength. This model resolves such processes, and shows a mechanism through which the ACC is projected to actually slow down in the future. However, further observational and modelling studies of this poorly-observed region are necessary to definitively discern the current's response to climate change,' concluded Gayen. The study has been published in Environmental Research Letters.
Ammon
05-03-2025
- Science
- Ammon
Melting Antarctic ice sheets will slow Earth's strongest ocean current
Ammon News - Melting ice sheets are slowing the Antarctic Circumpolar Current (ACC), the world's strongest ocean current, researchers have found. This melting has implications for global climate indicators, including sea level rise, ocean warming and viability of marine ecosystems. The researchers, from the University of Melbourne and NORCE Norway Research Centre, have shown the current slowing by around 20 per cent by 2050 in a high carbon emissions scenario. This influx of fresh water into the Southern Ocean is expected to change the properties, such as density (salinity), of the ocean and its circulation patterns. University of Melbourne researchers, fluid mechanist Associate Professor Bishakhdatta Gayen and climate scientist Dr Taimoor Sohail, and oceanographer Dr Andreas Klocker from the NORCE Norwegian Research Centre, analysed a high-resolution ocean and sea ice simulation of ocean currents, heat transport and other factors to diagnose the impact of changing temperature, saltiness and wind conditions. Associate Professor Gayen said: "The ocean is extremely complex and finely balanced. If this current 'engine' breaks down, there could be severe consequences, including more climate variability, with greater extremes in certain regions, and accelerated global warming due to a reduction in the ocean's capacity to act as a carbon sink." The ACC works as a barrier to invasive species, like rafts of southern bull kelp that ride the currents, or marine-borne animals like shrimp or molluscs, from other continents reaching Antarctica. As the ACC slows and weakens, there is a higher likelihood such species will make their way onto the fragile Antarctic continent, with a potentially severe impact on the food web, which may, for example, change the available diet of Antarctic penguins. More than four times stronger than the gulf stream, the ACC is a crucial part of the world's "ocean conveyor belt," which moves water around the globe linking the Atlantic, Pacific and Indian Oceans and is the main mechanism for the exchange of heat, carbon dioxide, chemicals and biology across these ocean basins. Science Daily
Yahoo
03-03-2025
- Science
- Yahoo
Melting Antarctic ice sheets are slowing Earth's strongest ocean current: ‘There could be severe consequences'
Melting ice sheets are slowing the world's strongest ocean current, researchers said Monday. An influx of fresh water from the melting sheets is changing the properties of the ocean and its circulation patterns, altering the water's salinity which determines the density of the water. Freshwater is less dense than saltwater, interrupting the natural sinking of the denser water that helps to power ocean currents. Also driven by temperature and wind, ocean currents help to regulate the planet's climate, transporting warm and cold water around the planet. They're also critical for marine life, redistributing oxygen and nutrients. But, slowing currents will come with consequences on land and in the ocean, like sea level rise and ocean warming. 'The ocean is extremely complex and finely balanced. If this current 'engine' breaks down, there could be severe consequences, including more climate variability, with greater extremes in certain regions, and accelerated global warming due to a reduction in the ocean's capacity to act as a carbon sink,' University of Melbourne Associate Professor Bishakhdatta Gayen said in a statement. Gayen was one of the researchers who reported the impact to the Antarctic Circumpolar Current. Findings from the university and NORCE Norway Research Centre were published on Monday in the journal Environmental Research Letters. They say that the largest wind-driven current on Earth — which is the only current that moves around the planet and connects the Atlantic, Pacific, and Indian Oceans — could slow by around 20 percent by 2050 in a high carbon emissions scenario. Should it slow and weaken, its role as a barrier to invasive species will be tested, with a potentially severe impact on the food web that could change the available diet for Antarctic penguins To reach these conclusions, they analyzed a simulation of ocean currents, ocean heat transport, and other factors to 'diagnose the impact of changing temperature, saltiness and wind conditions.' using Australia's fastest supercomputer and climate simulator, a team at the University of New South Wales found that the transport of ocean water from the surface to the deep – the colder and saltier water sinks – may also slow. 'The 2015 Paris Agreement aimed to limit global warming to 1.5 degrees Celsius above pre-industrial levels. Many scientists agree that we have already reached this 1.5 degree target, and it is likely to get hotter, with flow-on impacts on Antarctic ice melting,' climate scientist Dr. Taimoor Sohail said. The research comes as other scientists have warned about the possible collapse of other critical ocean circulation, and as the world's ice sheets continue to dwindle. Earlier this month, scientists said that the Greenland Ice Sheet – the world's second largest body of ice – is cracking open quicker than ever before. Ultimately, the authors said that the impact of ice melting and ocean warming on the current is more complex than previously believed. And, they said that their research contrasts with other previous studies that suggest it may be accelerating because of steeper temperature differences in different latitudes of the ocean caused by climate change. 'Ocean models have historically been unable to adequately resolve the small-scale processes that control current strength. This model resolves such processes, and shows a mechanism through which the ACC is projected to actually slow down in the future,' Gayen said. 'However, further observational and modelling studies of this poorly-observed region are necessary to definitively discern the current's response to climate change.'
The Independent
03-03-2025
- Science
- The Independent
Melting Antarctic ice sheets are slowing Earth's strongest ocean current: ‘There could be severe consequences'
Melting ice sheets are slowing the world's strongest ocean current, researchers said Monday. An influx of fresh water from the melting sheets is changing the properties of the ocean and its circulation patterns, altering the water's salinity which determines the density of the water. Freshwater is less dense than saltwater, interrupting the natural sinking of the denser water that helps to power ocean currents. Also driven by temperature and wind, ocean currents help to regulate the planet's climate, transporting warm and cold water around the planet. They're also critical for marine life, redistributing oxygen and nutrients. But, slowing currents will come with consequences on land and in the ocean, like sea level rise and ocean warming. 'The ocean is extremely complex and finely balanced. If this current 'engine' breaks down, there could be severe consequences, including more climate variability, with greater extremes in certain regions, and accelerated global warming due to a reduction in the ocean's capacity to act as a carbon sink,' University of Melbourne Associate Professor Bishakhdatta Gayen said in a statement. Gayen was one of the researchers who reported the impact to the Antarctic Circumpolar Current. Findings from the university and NORCE Norway Research Centre were published on Monday in the journal Environmental Research Letters. They say that the largest wind-driven current on Earth — which is the only current that moves around the planet and connects the Atlantic, Pacific, and Indian Oceans — could slow by around 20 percent by 2050 in a high carbon emissions scenario. Should it slow and weaken, its role as a barrier to invasive species will be tested, with a potentially severe impact on the food web that could change the available diet for Antarctic penguins To reach these conclusions, they analyzed a simulation of ocean currents, ocean heat transport, and other factors to 'diagnose the impact of changing temperature, saltiness and wind conditions.' using Australia's fastest supercomputer and climate simulator, a team at the University of New South Wales found that the transport of ocean water from the surface to the deep – the colder and saltier water sinks – may also slow. 'The 2015 Paris Agreement aimed to limit global warming to 1.5 degrees Celsius above pre-industrial levels. Many scientists agree that we have already reached this 1.5 degree target, and it is likely to get hotter, with flow-on impacts on Antarctic ice melting,' climate scientist Dr. Taimoor Sohail said. The research comes as other scientists have warned about the possible collapse of other critical ocean circulation, and as the world's ice sheets continue to dwindle. Earlier this month, scientists said that the Greenland Ice Sheet – the world's second largest body of ice – is cracking open quicker than ever before. Ultimately, the authors said that the impact of ice melting and ocean warming on the current is more complex than previously believed. And, they said that their research contrasts with other previous studies that suggest it may be accelerating because of steeper temperature differences in different latitudes of the ocean caused by climate change. 'Ocean models have historically been unable to adequately resolve the small-scale processes that control current strength. This model resolves such processes, and shows a mechanism through which the ACC is projected to actually slow down in the future,' Gayen said. 'However, further observational and modelling studies of this poorly-observed region are necessary to definitively discern the current's response to climate change.'
