Latest news with #BishakhdattaGayen
Yahoo
17-03-2025
- Science
- Yahoo
The 'heart' of the ocean is slowing down, study finds
When you buy through links on our articles, Future and its syndication partners may earn a commission. Melting Antarctic ice is slowing Earth's strongest ocean current, according to a new study. The influx of cold meltwater could slow the Antarctic Circumpolar Current by up to 20% by 2050, researchers reported March 3 in the journal Environmental Research Letters. The slowdown could affect ocean temperatures, sea level rise and Antarctica's ecosystem, the team said. The Antarctic Circumpolar Current, which swirls clockwise around Antarctica, transports around a billion liters (264 million gallons) of water per second. It keeps warmer water away from the Antarctic Ice Sheet and connects the Atlantic, Pacific, Indian and Southern oceans, providing a pathway for heat exchange between these bodies of water. Climate change has caused Antarctic ice to melt rapidly in recent years, adding an influx of fresh, cold water to the Southern Ocean. To explore how this influx will affect the Antarctic Circumpolar Current's strength and circulation, Bishakhdatta Gayen, a fluid mechanist at the University of Melbourne in Australia, and his colleagues used Australia's fastest supercomputer and climate simulator to model interactions between the ocean and the ice sheet. Related: Are Atlantic Ocean currents weakening? A new study finds no, but other experts aren't so sure. Fresh, cold meltwater likely weakens the current, the team found. The meltwater dilutes the surrounding seawater and slows convection between surface water and deep water near the ice sheet. Over time, the deep Southern Ocean will warm as convection brings less cold water from the surface. Meltwater also makes its way farther north before sinking. Together, these changes affect the density profile of the world's oceans, which drives the slowdown. Such a slowdown could allow more warm water to reach the Antarctic Ice Sheet, thereby exacerbating the melting that's already been observed. In addition to contributing to sea level rise, this could add even more meltwater to the Southern Ocean and weaken the Antarctic Circumpolar Current further. The Antarctic Circumpolar Current also acts as a barrier against invasive species by directing non-native plants — and any animals hitching a ride on them — away from the continent. If the current slows or weakens, this barrier could become less effective. RELATED STORIES —Zoom through a 'spectacular' chain of ancient underwater volcanoes on Antarctic ocean floor —'We are approaching the tipping point': Marker for the collapse of key Atlantic current discovered —Gulf Stream's fate to be decided by climate 'tug-of-war' "It's like a merry-go-round. It keeps on moving around and around, so it takes a longer time to come back to Antarctica," Gayen said. "If it slows down, what will happen is, things can migrate very quickly to the Antarctic coastline." It's difficult to say when we'll start to feel the effects — if we haven't started feeling them already. The Antarctic Circumpolar Current hasn't been monitored very long because it's in such a remote location, Gayen told Live Science. To better differentiate warming-induced changes from baseline conditions, "we need a long-term record," he said. The effects of the slowdown will be felt even in other oceans. "This is where the ocean heart sits," Gayen said. "If something stops there, or something different is happening, it's going to impact each and every ocean circulation."
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
Express Tribune
03-03-2025
- Science
- Express Tribune
Melting ice could slow vital Antarctic ocean current: study
The world's strongest ocean current could slow as melting Antarctic ice sheets flood it with fresh water, according to research published on Monday that warned of "severe" climate consequences. Scientists used one of Australia's most powerful supercomputers to model how melting ice sheets might change the Antarctic Circumpolar Current, which plays a major role in global climate patterns. If fossil fuel emissions increased over the next 25 years -- a so-called high emissions scenario -- the current could slow by around 20 percent, the peer-reviewed research found. "The ocean is extremely complex and finely balanced," said University of Melbourne scientist Bishakhdatta Gayen. "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 Antarctic Circumpolar Current acted as a kind of "ocean conveyor belt" shifting immense columns of water through the Indian, Atlantic and Pacific Oceans, Gayen said. Melting ice sheets would "dump vast quantities of fresh water" into the current, the modelling found. This would change the ocean's salt content, making it harder for cold water to circulate between the surface and the depths. Oceans play vital roles as climate regulators and carbon sinks. Cooler waters can absorb greater amounts of heat from the atmosphere. The strength of the current -- which flows clockwise around Antarctica -- also acts as a barrier that stops invasive species washing up on the continent's shores. Algae and molluscs could more easily colonise Antarctica if the current slowed down, the researchers wrote. Even if global warming was limited to a threshold of 1.5 degrees Celsius, the Antarctic current could still slow down. "The 2015 Paris Agreement aimed to limit global warming to 1.5 degrees Celsius above pre-industrial levels," said climate scientist and co-author Taimoor Sohail. "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." The research team, which included scientists from Australia, India and Norway, noted that their findings contrasted with previous studies that observed the current speeding up. They said further observation and modelling was needed to understand how the "poorly observed region" was responding to climate change. The research was published in the Environmental Research Letters journal.
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.'
