Japan has told the World Trade Organization (WTO) that China’s ban on Japanese seafood after the release of treated water from the Fukushima nuclear plant was “totally unacceptable”, the Japanese foreign ministry said late on Monday.
In a counterargument to China’s Aug. 31 notification to WTO on its measures to suspend Japanese aquatic imports, which started last month, Japan said it would explain its positions in relevant WTO committees and urged China to immediately repeal the action.
Some Japanese officials have signaled the country may file a WTO complaint, which the U.S. ambassador to Japan said last week the United States would support.
Japan will explain the safety of the released water at diplomatic forums, including the ASEAN Summit in Indonesia and G20 Summit in India this month, chief cabinet secretary Hirokazu Matsuno told reporters on Tuesday.
“Nothing is decided about a Japan-China leaders’ meeting,” added Matsuno, Tokyo’s top government spokesperson. Japanese Prime Minister Fumio Kishida and China’s Premier Li Qiang will attend the ASEAN and G20 summits, while Chinese President Xi Jinping is skipping both conferences.
In a separate statement on Monday, Tokyo’s foreign ministry said Japan has also asked China to hold discussions over the import ban based on the provisions of the Regional Comprehensive Economic Partnership (RCEP) trade pact.
Although marine products make up less than 1% of Japan’s global trade, which is dominated by cars, Japan exported about $600 million worth of aquatic products to China in 2022, making it the biggest market for Japanese exports, followed by Hong Kong.
Data on Tuesday showed China-bound exports of aquatic products fell for the first time in 2 1/2 years in July, dropping 23% year-on-year to 7.7 billion yen ($52.44 million).
Goods bound for China have faced stricter inspections since Japan announced its plan to release the treated Fukushima water, slowing down shipments.
To ease the pain of losing that seafood demand, Japan will spend more than 100 billion yen ($682 million) to support the domestic fisheries industry.
The Panama Canal’s water levels have not recovered enough as the end of the rainy season approaches and limits on daily transit and vessel draft will stay in place for the rest of the year and throughout 2024, the waterway’s authority said on Tuesday.
The restrictions, implemented earlier this year to conserve water amid prolonged drought, triggered a backlog of ships waiting to pass the key global waterway, which handles an estimated 5% of world trade, contributing to more expensive freight costs ahead of the approaching Christmas season.
The bottleneck at the canal connecting the Pacific and Atlantic Oceans has eased about 20% since last week, but waiting times to transit the waterway doubled last month from July in some vessel categories, while many ship owners have opted for alternate routes to avoid costly delivery delays.
The authority that manages the canal added in a statement that this week’s ship traffic represents a “normal” level for this season.
It noted that a month before the end of its 2023 fiscal year, the canal’s total vessel crossings already total nearly 800 more that what the canal authority’s budget had forecast.
The additional vessel crossings, which contribute to a total of more than 13,000 transits so far during the fiscal year, show strong demand by vessel owners.
But insufficient rainfall continues to negatively impact the Gatun Lake, which feeds the canal, lowering its water level to 24.2 meters (79.7 feet), versus 26.6 meters (87.41 feet) for the month of September in recent years.
Each vessel passing through the 50-mile (80-km) trans-oceanic waterway uses some 51 million gallons (193 million litres) of water from the lake.
At the end of the rainy season in November, the lake’s water level typically reaches some 27 meters (89 feet) and then drops to slightly below 26 meters (85 feet) after the dry season ends in April, according to the canal authority.
Experts have warned about maritime trade disruptions ahead of what is shaping up to be an even drier period next year. They argue that a potential early start to Panama’s dry season and hotter-than-average temperatures could increase evaporation and result in near-record low water levels by April.
Published today in Nature Geoscience, the study shows that glacier ice, characterized by pockets of pressurized air, melts much more quickly than the bubble-free sea ice or manufactured ice typically used to research melt rates at the ocean-ice interface of tidewater glaciers.
Tidewater glaciers are rapidly retreating, the authors say, resulting in ice mass loss in Greenland, the Antarctic Peninsula and other glacierized regions around the globe.
“We have known for a while that glacier ice is full of bubbles,” said Meagan Wengrove, assistant professor of coastal engineering in the OSU College of Engineering and the leader of the study. “It was only when we started talking about the physics of the process that we realized those bubbles may be doing a lot more than just making noise underwater as the ice melts.”
Glacier ice results from the compaction of snow. Air pockets between snowflakes are trapped in pores between ice crystals as the ice makes its way from the upper layer of a glacier to deep inside it. There are about 200 bubbles per cubic centimeter, meaning glacier ice is about 10% air.
“These are the same bubbles that preserve ancient air studied in ice cores,” said co-author Erin Pettit, glaciologist and professor in the OSU College of Earth, Ocean, and Atmospheric Sciences. “The tiny bubbles can have very high pressures — sometimes up to 20 atmospheres, or 20 times normal atmospheric pressure at sea level.”
When the bubbly ice reaches the interface with the ocean, the bubbles burst and create audible pops, she added.
“The existence of pressurized bubbles in glacier ice has been known for a long time but no studies had looked at their effect on melting where a glacier meets the ocean, even though bubbles are known to affect fluid mixing in multiple processes ranging from industrial to medical,” Wengrove said.
Lab-scale experiments performed in this study suggest bubbles may explain part of the difference between observed and predicted melt rates of tidewater glaciers, she said.
“The explosive bursts of those bubbles, and their buoyancy, energize the ocean boundary layer during melting,” Wengrove said.
That carries huge implications for the way ice melt is folded into climate models, especially those that deal with the upper 40 to 60 meters of the ocean — the researchers learned glacier ice melts more than twice as fast as ice with no bubbles.
“While we can measure the amount of overall ice loss from Greenland over the last decade and we can see the retreat of each glacier in satellite images, we rely on models to predict ice melt rates,” Pettit said. “The models currently used to predict ice melt at the ice-ocean interface of tidewater glaciers do not account for bubbles in glacier ice.”
Right now, data from NASA attributes about 60% of sea level rise to meltwater from glaciers and ice sheets, the authors note. More accurate characterization of how ice melts will lead to better predictions of how quickly glaciers retreat, which is important because “it’s a lot more difficult for a community to plan for a 10-foot increase in water level than it is for a 1-foot increase,” Wengrove said.
“Those little bubbles may play an outsized role in understanding critical future climate scenarios,” she added.
The Keck Foundation, the National Science Foundation and the National Geographic Society funded the research, which also included Jonathan Nash and Eric Skyllingstad of the OSU College of Earth, Ocean, and Atmospheric Sciences and Rebecca Jackson of Rutgers University.
Gudrun Schmidt, an associate professor of practice in Purdue’s Department of Chemistry, and a team of researchers developed the formulations from zein, a protein found in corn, and tannic acid. A paper about the team’s research was published in the peer-reviewed journal ACS Applied Materials & Interfaces.
The adhesive formulations could be further developed and used in the restoration of coral reefs and have applications in the construction, manufacturing, biomedical, dental, food and cosmetic industries.
Stronger in water
Schmidt and her colleagues conducted underwater adhesive experiments on their formulations, using different surfaces and different waters, including seawater, saline solution, tap water and deionized water.
“Interestingly, the water type does not influence performance a great deal, but the substrate type does,” Schmidt said. “An additional unexpected result was bond strengths increasing over time when exposed to water, contradicting general experiments of working with traditional, petroleum-based glues. Initial adhesion underwater was stronger compared to benchtop adhesion, suggesting that water helps to make the glue stick underwater.”
Protective skin formed on the surface of the adhesives when placed underwater, which kept water from entering the rest of the material immediately.
“But once the skin was in place, it could be broken to induce faster bond formation,” Schmidt said.
The experiments also indicated maximum bonding at about 30 degrees Celsius, then another increase at higher temperatures.
Schmidt said the process to make the adhesive formulations is a short one.
“We can use inexpensive, sustainably sourced, plant-based materials to make gallons of glue within hours,” Schmidt said. “The adhesives are very simple to make in the lab or outdoors, everywhere on the planet.”
The demand for nontoxic formulations
Schmidt said other researchers are formulating adhesives that mimic the glues used by mussels, barnacles, oysters and sandcastle worms to adhere to the seafloor and other wet surfaces. Those best-performing formulations, however, are fully synthetic.
“Lengthy syntheses with the use of harsh chemicals may hold back their future development,” Schmidt said. “Nontoxicity, sustainably sourced materials and minimal environmental impact are increasingly in demand. Consequently, several groups have turned to developing new and remaking old adhesive systems using bioinspired or bio-based chemistry.”
The increased demand of nontoxic materials has led to creating adhesives for biomedical applications. The resulting glues have properties similar to soft tissue. Schmidt said that bio-based adhesives have further applications.
“Once the in vivo and biomedical realm is left behind, there is an entire world of other applications requiring metals, plastics, wood and inorganic substrates that need adhesives to work in the presence of water,” Schmidt said. “Food, oral and cosmetic applications are less restrictive when it comes to purity of starting materials. Food-grade polymers can often be used for making wet adhesives. We also are working on dental applications, trying to make bonds in this wet and challenging environment.”
Coral reef restoration
Schmidt said another particularly intriguing application for the patent-pending Purdue-developed adhesive formulations is the restoration of coral reefs.
“There are several major efforts, worldwide, planting young corals to replace those structures that are already dead,” Schmidt said. “A major hindrance to these efforts is lack of suitable underwater adhesives that work well for this application.”
Schmidt and her research team are working with the Coral Restoration Foundation, sending various formulations to be tested.
“We recently visited the Florida Keys to test a few formulations in bucketsful of ocean water,” Schmidt said. “It is great to see our work outside of the research lab and in the real, wet world.”
The Coral Restoration Foundation constantly searches for the most efficient and effective method of outplanting coral onto reef sites, said Phanor H. Montoya-Maya, coral restoration program manager at CRF.
“Having different alternatives means different species and habitats can be outplanted with positive results,” Montoya-Maya said. “Science collaborations like this allow us to test and fine-tune methods before mainstream restoration. Field preliminary results are very encouraging, and we’ll continue to provide feedback to Purdue researchers to ensure the final product is consistently successful across multiple restoration goals.”
Schmidt disclosed the adhesive formulations to the Purdue Innovates Office of Technology Commercialization, which has applied for a patent to protect the intellectual property.
Adnan Rajib, a UT Arlington assistant professor in the Department of Civil Engineering, was the lead author on the published study, “Human Alterations of the Global Floodplains.”His doctoral student, Qianjin Zheng, played a significant role in developing the research.
U.S. Environmental Protection Agency (EPA) scientists Charles Lane, Heather Golden and Jay Christensen; Itohaosa Isibor of Texas A&M University-Kingsville; and Kris Johnson of The Nature Conservancy collaborated on the study. The work was funded through NASA and the National Science Foundation.
“The bottom line is that the world is at greater flood risk than what we realized, especially considering what effect human development has had on floodplains,” Rajib said. “In 27 years, between 1992 and 2019, the world has lost a dramatic 600,000 square kilometers of floodplains due to human disturbances, which include infrastructure development, industry and business construction and expansion of agriculture.”
The team used satellite remote sensing data and geospatial analytics in studying 520 major river basins of the world, discovering previously unknown spatial patterns and trends of human floodplain alterations.
“Mapping the world’s floodplains is relatively new. While there is increasing awareness to map floodplains accurately and understand flood risks, an attempt to map human disturbances in those floodplains at a global scale never existed,” said Rajib, who also is the director of the UT Arlington Hydrology and Hydroinformatics Innovation Lab. “It’s been done in smaller regions around the world and certainly in the United States and Europe, but not in data-poor regions of the world.”
The study concludes that wetland habitats are in danger and that one-third of the total global loss of floodplain wetlands occurred in North America. Rajib said the magnitude of risk for floodplains is much larger than what was previously understood. He and the team examined satellite pictures of those floodplain areas taken over the past 27 years.
“We wanted to look at floodplains at the neighborhood level,” Zheng said. “We wanted to see the impact of development on someone who lives adjacent to or near a floodplain. Some of the changes in these pictures are good, like when trees are planted or parks are built. But many of the pictures reveal disturbing outcomes. For instance, we saw a dramatic increase in the development of parking lots or the construction of buildings without adequate stormwater runoff allowances.”
Johnson, a co-author on the paper, said that “worldwide, floodplains are biodiversity hotspots that also provide a wide range of ecosystem services for people. We hope this study sheds light on this critical habitat we’re losing as well as ways in which we can reverse the trend.”
Melanie Sattler, chair and professor of the Department of Civil Engineering, said this study should give planners a vital tool to reduce flood risks for people.
“Rajib’s work can be our lens to help guide future development in order to decrease susceptibility to floods in a changing climate,” Sattler said. “And, in some cases, we hope this study can help us correct mistakes we’ve made through past development decisions.”
Published in Environmental Science & Technology, the study showed that in stormwater runoff during rain approximately 19 out of every 20 microplastics collected were tyre wear particles with anywhere from 2 to 59 particles per litre of water.
“Pollution of our waterways by microplastics is an emerging environmental concern due to their persistence and accumulation in aquatic organisms and ecosystems,” said lead author Dr Shima Ziajahromi, a research fellow at the Australian Rivers Institute.
“Stormwater runoff which contains a mixture of sediment, chemical, organic and physical pollutants, is a critical pathway for microplastics to washed off from urban environments during rain and into local aquatic habitats.
“But to date, our knowledge of the amount of microplastics in urban stormwater, particularly tyre wear particles, is limited, as is the potential strategies we can use to minimise this source.”
Tyre rubber contains up to 2500 chemicals with the contaminants that leach from tyres considered more toxic to bacteria and microalgae than other plastic polymers.
“Due to the analytical challenges in measuring this source of microplastics in stormwater, research to date often lacks information about the actual number of tyre wear particles water samples,” said Dr Ziajahromi.
Quantitative information of this type is crucial to improve our understanding of the amount of tyre wear particles in stormwater, assess the risk to the environment, and to develop management strategies.
“Our study quantified and characterize microplastics and tyre wear particles in both stormwater runoff and sediment of stormwater drainage systems in Queensland,” said co-author Professor Fred Leusch, who leads the Australian Rivers Institute’s Toxicology Research Program.
“We also assessed the effectiveness of a stormwater treatment device to capture and remove these contaminants from stormwater and evaluated the role of a constructed stormwater wetland for capturing microplastics in the sediment, removing it from stormwater runoff.
“The device is a bag made of 0.2 millimetre mesh which can be retrofitted to stormwater drains. Although originally designed to capture gross pollutants, sediment, litter and oil and grease, it significantly reduced microplastics from raw runoff, with up to 88% less microplastics in treated water which had passed through the device.”
Sediment samples collected from the inlet and outlet of a constructed stormwater wetland contained between 1450 to 4740 particles in every kilogram of sediment, with more microplastics in the sediment at the inlet than the outlet, indicating the wetland’s ability to remove them from stormwater.
“Microplastics that enter constructed wetlands for stormwater drainage systems settle in the sediment and form a biofilm, leading to their accumulation over time, removing them from stormwater runoff,” said Dr Ziajahromi.
“Urban stormwater runoff typically requires treatment for the removal of suspended solids and nutrients such as nitrogen and phosphorus in many jurisdictions in Australia, with some also requiring the removal of gross pollutants. However, regulations are lagging behind when it comes to microplastics and tyre wear particles.”
“Our findings show that both constructed wetlands and the stormwater capture device are strategies that could be potentially used to prevent or at least decrease the amount of microplastics tyre wear particles being transported from stormwater into our waterways.”
Singapore is planning to expand a pilot project that boosts the ocean’s capacity to absorb carbon dioxide emissions, using one of several emerging technologies that supporters hope can play a decisive role in the global battle against climate change.
As scientists call for more research into ocean carbon dioxide removal (OCDR), Singapore’s Public Utilities Board (PUB) has built a plant that uses electricity to extract CO2 from seawater, allowing it to absorb more greenhouse gas from the atmosphere when it is pumped back out into the ocean.
The project, built at a desalination facility on Singapore’s western coast, extracts 100 kilograms of CO2 a day using technology designed by U.S. firm Equatic, founded by scientists at the University of California, Los Angeles (UCLA).
At the plant, seawater is run through an electrolyser, which converts dissolved CO2 into calcium carbonate and produces hydrogen.
PUB is aiming to secure funds by the end of the year to build a demonstration plant with a daily capacity of 10 tons, and will look at expanding further, said Gurdev Singh, a PUB general manager who leads the project.
“We have shown that the technology works, but the key now is to optimise the technology at scale,” he said.
The Intergovernmental Panel on Climate Change (IPCC) has said the removal of CO2 in the atmosphere will be as important as cutting emissions when it comes to curbing temperature rises.
But while OCDR has been described by one environmental group as an “unsung hero” in the fight against global warming, it remains unclear whether the new technologies are feasible when deployed at scale.
Equatic founder Gaurav Sant stressed the commercial potential.
“What makes this a resilient commercial opportunity is that you can essentially have the same equipment to give you two products: carbon credits and hydrogen,” he said.
It could also profit by selling calcium carbonate to the local building industry, he added.
The project is one of several pilot OCDR ventures around the world. Some rely on bringing nutrient-rich deep-sea water to the surface to stimulate seaweed growth, while others aim to reduce ocean acidification levels and thereby boost CO2 uptake.
Some experts warn that the potential ecological impact of these technologies is still unknown. On Tuesday, more than 200 scientists said in an open letter that OCDR research should be prioritised not only to maximise its potential, but also head off potential risks.
Sir David King, head of the Climate Crisis Advisory Group and one of the letter’s signatories, said he favoured nature-based approaches, and was sceptical about the efficacy of energy-intensive OCDR technologies like the Equatic venture, which will cost a lot to pump water in and out of the plant.
But billions of tons of CO2 need to be removed from the atmosphere, and more investment in OCDR research was needed urgently, he said.
“What is needed today is to shorten the experimental timeline, and that really demands much more funding,” he said.
“If somebody came up with a few billion dollars, I believe we would accelerate these programmes to the level that is really needed.”
Rutgers-led research found that marine heat waves — prolonged periods of unusually warm ocean temperatures — haven’t had a lasting effect on the fish communities that feed most of the world.
The finding is in stark contrast to the devastating effects seen on other marine ecosystems cataloged by scientists after similar periods of warming, including widespread coral bleaching and harmful algal blooms.
“There is an emerging sense that the oceans do have some resilience, and while they are changing in response to climate change, we don’t see evidence that marine heat waves are wiping out fisheries,” said Alexa Fredston, the lead author of the study who conducted the research as a postdoctoral associate in the Global Change Research Group, part of the Department of Ecology, Evolution and Natural Resources in the Rutgers School of Environmental and Biological Sciences (SEBS.)
The study, published in Nature, assessed effects on commercially important fish such as flounder, pollock and rockfish based on data extracted from long-running scientific trawl surveys — conducted by towing a net along the seafloor — of continental shelf ecosystems in North America and Europe between 1993 and 2019. The analysis included 248 marine heat waves with extreme sea bottom temperatures during this period. The researchers were surprised to find that marine heat waves in general don’t show major adverse effects on regional fish communities.
Although declines in biomass did occur after some marine heat waves, the researchers said these cases were the exception, not the rule. Overall, they found that the effects of marine heat waves aren’t distinguishable from the natural variability in these ecosystems.
“The oceans are highly variable, and fish populations vary quite a lot,” said Fredston, now an assistant professor of ocean sciences at University of California, Santa Cruz. “Marine heat waves can drive local change, but there have been hundreds of marine heat waves with no lasting impacts.”
In addition to assessing the impact on the total quantity of organisms in a given area, known as biomass, the researchers examined whether marine heat waves were causing changes in the variety of fish species composing fish communities. For example, evidence might show the loss of species associated with cold water and an increase in species associated with warm water, a phenomenon known as tropicalization.
The findings suggest fish may be able to find safe havens by moving to areas with cooler water during marine heat waves, which the researchers defined as periods of more than five days with extreme sea bottom temperatures for that region and season.
The data included some notable examples of marine heat waves that did have profound impacts, such as the 2014-2016 marine heat wave in the Northeast Pacific known as “the Blob,” one of the largest on record.
While “the Blob” led to a 22 percent loss of biomass in the Gulf of Alaska, a 2012 marine heat wave in the Northwest Atlantic led to a 70 percent biomass gain. The authors also noted that these weren’t large changes compared to natural variability in biomass, and similar effects weren’t seen after most other marine heat waves.
“We found that these negative impacts are unpredictable and that other heat waves had no strong impacts,” said Malin Pinsky, an associate professor in the Department of Ecology, Evolution and Natural Resources and director of the Global Change Research Group at SEBS and a co-author of the study. “This means that each heat wave that hits is like rolling the dice: Will it be a bad one or not? We don’t know until it happens.”
A new University of Michigan-led study finds that farmers in India have adapted to warming temperatures by intensifying the withdrawal of groundwater used for irrigation. If the trend continues, the rate of groundwater loss could triple by 2080, further threatening India’s food and water security.
Reduced water availability in India due to groundwater depletion and climate change could threaten the livelihoods of more than one-third of the country’s 1.4 billion residents and has global implications. India recently overtook China to become the world’s most populous nation and is the second-largest global producer of common cereal grains including rice and wheat.
“We find that farmers are already increasing irrigation use in response to warming temperatures, an adaptation strategy that has not been accounted for in previous projections of groundwater depletion in India,” said study senior author Meha Jain, assistant professor at U-M’s School for Environment and Sustainability. “This is of concern, given that India is the world’s largest consumer of groundwater and is a critical resource for the regional and global food supply.”
The lead author is Nishan Bhattarai of the Department of Geography and Environmental Sustainability at the University of Oklahoma, formerly a postdoctoral researcher in Jain’s U-M lab.
The study, scheduled for online publication Sept. 1 in the journal Science Advances, analyzed historical data on groundwater levels, climate and crop water stress to look for recent changes in withdrawal rates due to warming. The researchers also used temperature and precipitation projections from 10 climate models to estimate future rates of groundwater loss across India.
Previous studies have focused on the individual effects of climate change and groundwater depletion on crop production in India. Those studies did not account for farmer decision-making, including how farmers may adapt to changing climate through changes in irrigation decisions.
The new study takes into account the fact that warmer temperatures may increase water demand from stressed crops, which in turn may lead to increased irrigation by farmers.
“Using our model estimates, we project that under a business-as-usual scenario, warming temperatures may triple groundwater depletion rates in the future and expand groundwater depletion hotspots to include south and central India,” Bhattarai said.
“Without policies and interventions to conserve groundwater, we find that warming temperatures will likely amplify India’s already existing groundwater depletion problem, further challenging India’s food and water security in the face of climate change.”
Previous studies found that climate change could decrease the yield of staple Indian crops by up to 20% by mid-century. At the same time, the country’s groundwater is being depleted at an alarming rate, primarily because of water withdrawal for irrigation.
For the newly published study, the researchers developed a dataset that contains groundwater depths from thousands of wells across India, high-resolution satellite observations that measured crop water stress, and temperature and precipitation records.
Most climate models call for increased temperature, increased monsoon (June through September) precipitation and decreased winter precipitation in India over the coming decades. The U-M-led research team found that warming temperatures coupled with declining winter precipitation more than offset added groundwater recharge from increased monsoon precipitation, resulting in accelerated groundwater declines.
Across various climate-change scenarios, their estimates of groundwater-level declines between 2041 and 2080 were more than three times current depletion rates, on average.
In addition to Jain and Bhattarai, authors of the Science Advances study are David Lobell of Stanford University, Balwinder Singh of the International Maize and Wheat Improvement Center in India and the Department of Primary Industries and Regional Development in Western Australia, Ram Fishman of Tel Aviv University, William Kustas of the U.S. Department of Agriculture and Yadu Pokhrel of Michigan State University.
New research by an international team of scientists explains what’s behind a stalled trend in Arctic Ocean sea ice loss since 2007. The findings indicate that stronger declines in sea ice will occur when an atmospheric feature known as the Arctic dipole reverses itself in its recurring cycle.
The many environmental responses to the Arctic dipole are described in a paper published online today in the journal Science. This analysis helps explain how North Atlantic water influences Arctic Ocean climate. Scientists call it Atlantification.
The research is led by professor Igor Polyakov of the University of Alaska Fairbanks College of Natural Science and Mathematics. He is also affiliated with the International Arctic Research Center at UAF.
Co-authors include Andrey V. Pnyushkov, research assistant professor at the International Arctic Research Center; Uma S. Bhatt, atmospheric sciences professor at the UAF Geophysical Institute and UAF College of Natural Science and Mathematics; and researchers from Massachusetts, Washington state, Norway, and Germany.
“This is a multidisciplinary view on what’s going on in the Arctic and beyond,” Polyakov said of the new research. “Our analysis covered the atmosphere, ocean, ice, changing continents and changing biology in response to climate change.”
A wealth of data, including direct instrumental observations, reanalysis products and satellite information going back several decades, shows that the Arctic dipole alternates in an approximately 15-year cycle and that the system is probably at the end of the present regime.
In the Arctic dipole’s present “positive” regime, which scientists say has been in place since 2007, high pressure is centered over the Canadian sector of the Arctic and produces clockwise winds. Low pressure is centered over the Siberian Arctic and features counterclockwise winds.
This wind pattern drives upper ocean currents, with year-round effects on regional air temperatures, atmosphere-ice-ocean heat exchanges, sea-ice drift and exports, and ecological consequences.
The authors write that, “Water exchanges between the Nordic seas and the Arctic Ocean are critically important for the state of the Arctic climate system” and that sea ice decline is “a true indicator of climate change.”
In analyzing oceanic responses to the wind pattern since 2007, the researchers found decreased flow from the Atlantic Ocean into the Arctic Ocean through the Fram Strait east of Greenland, along with increased Atlantic flow into the Barents Sea, located north of Norway and western Russia.
The new research refers to these alternating changes in the Fram Strait and the Barents Sea as a “switchgear mechanism” caused by the Arctic dipole regimes.
The researchers also found that counterclockwise winds from the low-pressure region under the current positive Arctic dipole regime drive freshwater from Siberian rivers into the Canadian sector of the Arctic Ocean.
This westward movement of freshwater from 2007 to 2021 helped slow the overall loss of sea ice in the Arctic compared to 1992 through 2006. The freshwater layer’s depth increased, making it too thick and stable to mix with the heavier saltwater below. The thick layer of freshwater prevents the warmer saltwater from melting sea ice from the bottom.
The authors write that the switchgear mechanism regulating inflows of sub-Arctic waters has “profound” impacts on marine life. It can lead to potentially more suitable living conditions for sub-Arctic boreal species near the eastern part of the Eurasian Basin, relative to its western part.
“We are beyond the peak of the currently positive Arctic dipole regime, and at any moment it could switch back again,” Polyakov said. “This could have significant climatological repercussions, including a potentially faster pace of sea-ice loss across the entire Arctic and sub-Arctic climate systems.”
