Latest news with #GlobalChangeBiology
The Guardian
21 hours ago
- Science
- The Guardian
Antarctic seal numbers falling drastically due to melting sea ice, research shows
Antarctic seal populations are drastically declining as the sea ice melts around them, new research has shown. Researchers from the British Antarctic Survey (BAS) have been monitoring the seal population in the sub-Antarctic since the 1970s, looking in particular at three different seal species in the sub-Antarctic on Signy Island: Weddell seals, Antarctic fur seals and southern elephant seals. Using satellite records from as far back as 1982, the research team compared annual changes in sea ice concentration with seal population counts conducted since 1977. With five decades worth of data spanning a period of long-term warming and temporary cooling between 1998 and 2014, they were able to draw a comprehensive picture of how seal populations react to changing ice conditions, something shorter-term studies would not be able to achieve. The study, published in the scientific journal Global Change Biology, found Weddell seals (leptonychotes weddellii), which rely on stable sea ice to rest, breed and feed, had declined by 54% since 1977. Similarly, Antarctic fur seals (arctocephalus gazella), which breed on land but are affected by food chain shifts, have declined by 47%. The findings challenge previous assumptions that the population in the South Orkneys had stabilised. Southern elephant seals (mirounga leonina), despite sharing similar population trends, presented 'no significant overall long-term decline'. The study serves to emphasise the 'vital importance of long-term ecological monitoring' as well as the interconnectedness between the three species of seal and sea ice conditions. Michael Dunn, lead author of the study, said: 'For once, we're not just predicting how wildlife might respond to shrinking sea ice and environmental shifts, we've had the rare opportunity to confirm it, using solid, long-term data. The emerging picture is deeply concerning.' Sign up to Down to Earth The planet's most important stories. Get all the week's environment news - the good, the bad and the essential after newsletter promotion In light of the BAS's findings, researchers have also raised concerns about how climate breakdown is affecting the Antarctic food web, relied on by all three species.
Newsweek
3 days ago
- Science
- Newsweek
Climate Crisis 'Evil Twin' Is Coming for Marine Life
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. Scientists have warned that the planet crossed the global boundary for ocean acidification around the year 2020, according to a new study. Published in Global Change Biology, the study from Plymouth Marine Laboratory, NOAA and Oregon State University concludes that a key chemical threshold—set to prevent widespread harm to marine life—has already been exceeded. The planetary boundary for ocean acidification is defined as a 20% decline from the pre-industrial aragonite saturation state, a measure of ocean water's ability to support calcifying organisms such as corals and shellfish. March 3 2017, Great Barrier Reef, Cairns Australia. A diver swims over bleached staghorn coral, acropora, during the 2017 coral bleaching event on the Great Barrier Reef. Picture was taken on Pixie Reef. March 3 2017, Great Barrier Reef, Cairns Australia. A diver swims over bleached staghorn coral, acropora, during the 2017 coral bleaching event on the Great Barrier Reef. Picture was taken on Pixie Reef. Photo by Brett Monroe Garner / Getty Images "The original boundary was characterized by two criteria: [First] that the polar regions do not reach undersaturation, and [second] that warm-water coral reefs do not fall below the marginal growth threshold," study author Helen Findlay told Newsweek in an email. "We felt that neither of these things could be really assessed using a surface ocean global average figure without considering natural seasonal and regional variability, and so our study made the reassessment based also on regional changes." Underestimating the Pace Using updated models, the study found that the global average surface ocean had entered the boundary's uncertainty zone by 2020. In deeper layers of the ocean, the findings are even more severe. At depths of 200 meters, 60% of the ocean had surpassed the acidification threshold. Previous planetary boundary assessments, including those as recent as 2023, had judged ocean acidification to be nearing its critical limit but not yet beyond it. The new analysis suggests that the original boundary may have underestimated the pace and reach of acidification. It also reveals that the most affected regions include polar waters and the tropical zones that support the bulk of the world's coral reef systems. 'Now is the time' "In our lifetimes (and by year 2100) we are committed to the ocean acidification that has already taken place," Findlay told Newsweek. "We cannot reverse that in the short term. "Even if we were to stop emitting CO2 today, the ocean would remain at this level of ocean acidification for thousands of years." However, Findlay noted that carbon dioxide removal and fewer emissions could speed the process up. "Our models tell us that this is the decade for decisions," she told Newsweek. "For ocean acidification, the emissions pathways diverge around the year 2030, which means that now is the time to make the choice about how we minimize further damage." How Ocean Acidification Happens Ocean acidification occurs when carbon dioxide from the atmosphere dissolves into the ocean, changing the water's chemistry. This process lowers the pH of seawater and reduces the amount of carbonate ions, which are essential building blocks for many marine creatures. Animals like corals, oysters, clams and some types of plankton need carbonate to build their shells and skeletons. As acidification increases, it becomes harder for these organisms to grow and survive. Findlay added that there has been misreporting that "all shellfish will die in the next 5-10 years". "This is not the case," Findlay said. "Organisms are resilient when they are given the chance, but it is the rate of change that is important, and more likely that some local populations will survive and some may not." Wide-Ranging Negative Effects According to the researchers, habitat degradation has already become evident. The study reports that suitable conditions for tropical coral reefs have shrunk by 43%, and for polar pteropods by up to 61%. Coastal regions vital for shellfish like oysters and mussels are also increasingly at risk. Researchers propose redefining the ocean acidification boundary to a 10% decline from the pre-industrial saturation state to better protect marine biodiversity. 'Stick to the Paris Agreement targets' When Newsweek asked about meaningful ways to combat acidification, Findlay explained, "Stop CO2 emissions! Stick to the Paris Agreement targets. Protect and restore ocean habitats and ecosystems. Minimize damage to the seafloor. "Prevent the addition of nutrients and pollution in the coastal regions that can cause local acidification and therefore add to the overall global problem. Fund and support local communities to protect their local environment in a way that has sustainable benefits to them."
Yahoo
5 days ago
- Science
- Yahoo
'It's a ticking time bomb': Acid levels in Earth's oceans have already breached 'danger zone', study suggests
When you buy through links on our articles, Future and its syndication partners may earn a commission. Earth's oceans are in worse condition than scientists thought, with acidity levels so high that our seas may have entered a "danger zone" five years ago, according to a new study. Humans are inadvertently making the oceans more acidic by releasing carbon dioxide (CO2) through industrial activities such as the burning of fossil fuels. This ocean acidification damages marine ecosystems and threatens human coastal communities that depend on healthy waters for their livelihoods. Previous research suggested that Earth's oceans were approaching a planetary boundary, or "danger zone," for ocean acidification. Now, in a new study published Monday (June 9) in the journal Global Change Biology, researchers have found that the acidification is even more advanced than previously thought and that our oceans may have entered the danger zone in 2020. The researchers concluded that by 2020, the average condition of our global oceans was in an uncertainty range of the ocean acidification boundary, so the safety limit may have already been breached. Conditions also appear to be worsening faster in deeper waters than at the surface, according to the study. "Ocean acidification isn't just an environmental crisis — it's a ticking time bomb for marine ecosystems and coastal economies," Steve Widdicombe, director of science and deputy chief executive at Plymouth Marine Laboratory, a marine research organization involved in the new study, said in a statement. "As our seas increase in acidity, we're witnessing the loss of critical habitats that countless marine species depend on and this, in turn, has major societal and economic implications." Related: Atlantic ocean currents are weakening — and it could make the climate in some regions unrecognizable In 2009, researchers proposed nine planetary boundaries that we must avoid breaching to keep Earth healthy. These boundaries set limits for large-scale processes that affect the stability and resilience of our planet. For example, there are boundaries for dangerous levels of climate change, chemical pollution and ocean acidification, among others. A 2023 study found that we had crossed six of the nine boundaries. The authors of that study didn't think the ocean acidification boundary had been breached at the time, but they noted it was at the margin of its boundary and worsening. Katherine Richardson, a professor at the Globe Institute at the University of Copenhagen in Denmark who led the 2023 study and was not involved in the new study, told Live Science that she was "not at all surprised" by the new findings. "We said it was on the edge in our last assessment and, as atmospheric CO2 concentrations have risen since then, it is hardly surprising that it should be transgressed now," Richardson said in an email. Ocean acidification is mostly caused by the ocean absorbing CO2. The ocean takes up around 30% of CO2 in the atmosphere, so as human activities pump out CO2, they are forcing more of it into the oceans. CO2 dissolves in the ocean, creating carbonic acid and releasing hydrogen ions. Acidity levels are based on the number of hydrogen ions dissolved in water, so as the ocean absorbs more CO2, it becomes more acidic. The hydrogen ions bond with carbonate ions in the ocean to form bicarbonate, which reduces the carbonate available to marine life like corals, clams and plankton. These animals need carbonate for their bones, shells and other natural structures, which they make out of calcium carbonate (CaCO3). Researchers measure aragonite — one of the soluble forms of CaCO3 — to track ocean acidity levels. The ocean acidification boundary would be breached when the oceans see a 20% reduction of aragonite compared with preindustrial levels (estimated ocean acidification for 1750 and 1850). The 2023 study estimated that ocean acidification was at 19%, just below the boundary. The authors of the new study used physical and chemical measurements in the upper ocean and computer models to update and refine previous ocean acidification estimates. They also introduced a margin of error, including uncertainties in both the boundary and the present-day acidification value. RELATED STORIES —Record-breaking piles of sargassum seaweed wash up on Caribbean beaches, with more on the way —The Earth's oceans used to be green — and could one day turn purple, scientists say —There's an acidic zone 13,000 feet beneath the ocean surface — and it's getting bigger With the new data, the researchers found that at the ocean's surface, the global average acidification level is 17.3% (with a 5% margin of uncertainty) less than preindustrial levels. That estimate is lower than the 2023 estimate but well within the new study's wider boundary region (20% but with a 5.3% margin of uncertainty). The newly estimated acidification levels increased at greater depths, though the margin for error also increased below 330 feet (100 meters), according to the study's data. Not all of the ocean is acidifying at the same rate. For example, the researchers determined that about 40% of the water at the surface had crossed the boundary, but that estimate rose to 60% for the waters below, down to about 650 feet (200 m). "Most ocean life doesn't just live at the surface — the waters below are home to many more different types of plants and animals," study lead author Helen Findlay, a biological oceanographer at the Plymouth Marine Laboratory, said in the statement. "Since these deeper waters are changing so much, the impacts of ocean acidification could be far worse than we thought."
Yahoo
09-06-2025
- Science
- Yahoo
‘Ticking time bomb': Ocean acidity crosses vital threshold, study finds
The deep oceans have crossed a crucial boundary that threatens their ability to provide the surface with food and oxygen, a new study finds. Nearly two-thirds of the ocean below 200 meters, or 656 feet, as well as nearly half of that above, have breached 'safe' levels of acidity, according to findings published on Monday in Global Change Biology. The fall in ocean pH is 'a ticking time bomb for marine ecosystems and coastal economies,' Steve Widdicombe, director of science at the United Kingdom's Plymouth Marine Laboratory (PML), said in a statement. The study was funded in part by the National Oceanographic and Atmospheric Administration (NOAA), a federal agency that has been targeted for steep cuts by the Trump White House, in large part because of its role in investigating climate change. Some of the biggest changes in deep water are happening off the coast of western North America, home to extensive crab and salmon fisheries, the study found. The core problem is one scientists have warned about for a long time: the continued global burning of fossil fuels, which releases carbon dioxide — an acid when dissolved in water — is making the seas and oceans more acidic. Or, technically, it's making them less basic, which is to say: Less hospitable to species such as corals and clams that form the foundation of the ocean's ecosystem. 'Most ocean life doesn't just live at the surface — the waters below are home to many more different types of plants and animals,' lead author Helen Findlay of PML. 'Since these deeper waters are changing so much, the impacts of ocean acidification could be far worse than we thought.' As of five years ago, Findlay's study noted, the oceans may have crossed a critical threshold in which oceanic levels of calcium carbonate — the main ingredient in limestones, and also the shells of those animals — fell to more than 20 percent below pre-industrial levels. If true, that shift would mean the Earth has passed seven out of nine of the critical 'planetary boundaries' needed to maintain its ecosystem, as the Potsdam Institute for Climate Impact Research found last year. That shift, Widdicombe of the Marine Lab said, means 'we're witnessing the loss of critical habitats that countless marine species depend on.' 'From the coral reefs that support tourism to the shellfish industries that sustain coastal communities,' he added, 'we're gambling with both biodiversity and billions in economic value every day that action is delayed.' The further implications are even more serious. The reasons for the ocean's rise in acid, or fall in base, is that its waters have absorbed about one-third of all the carbon dioxide released by surface burning of coal, oil and gas. But the more carbon dioxide it absorbs, the lower its ability to absorb more — meaning faster warming on the surface. Making that dynamic even more dramatic, seas and oceans have also absorbed 90 percent of the global heating that the Earth's surface would have otherwise experienced, according to NASA. In addition to absorbing heat and carbon dioxide, the ocean also provides 50 percent of the Earth's oxygen — which comes from the very marine ecosystems that warming and acidification are threatening. Ecosystem loss and fossil fuel burning mean that levels of oxygen below the surface are decreasing, as, more slowly, is oxygen above the surface. —Updated at 12:37 p.m. EDT Copyright 2025 Nexstar Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
The Hill
09-06-2025
- Science
- The Hill
Ocean acidity crosses vital threshold, study finds
The deep oceans have crossed a crucial boundary that threatens their ability to provide the surface with food and oxygen, a new study finds. Nearly two-thirds of the ocean below 200 meters, or 656 feet, as well as nearly half of that above, have breached 'safe' levels of acidity, according to findings published on Monday in Global Change Biology. The fall in ocean pH is 'a ticking time bomb for marine ecosystems and coastal economies,' Steve Widdicombe, director of science at the United Kingdom's Plymouth Marine Laboratory (PML), said in a statement. The study was funded in part by the National Oceanographic and Atmospheric Association (NOAA), a federal agency that has been targeted for steep cuts by the Trump White House, in large part because of its role in investigating climate change. Some of the biggest changes in deep water are happening off the coast of western North America, home to extensive crab and salmon fisheries, the study found. The core problem is one scientists have warned about for a long time: the continued global burning of fossil fuels, which releases carbon dioxide — an acid when dissolved in water — is making the seas and oceans more acidic. Or, technically, it's making them less basic, which is to say: Less hospitable to species such as corals and clams that form the foundation of the ocean's ecosystem. 'Most ocean life doesn't just live at the surface — the waters below are home to many more different types of plants and animals,' lead author Helen Findlay of PML. 'Since these deeper waters are changing so much, the impacts of ocean acidification could be far worse than we thought.' As of five years ago, Findlay's study noted, the oceans may have crossed a critical threshold in which oceanic levels of calcium carbonate — the main ingredient in limestones, and also the shells of those animals — fell to more than 20 percent below pre-industrial levels. If true, that shift would mean the Earth has passed seven out of nine of the critical 'planetary boundaries' needed to maintain its ecosystem, as the Potsdam Institute for Climate Impact Research found last year. That shift, Widdicombe of the Marine Lab said, means 'we're witnessing the loss of critical habitats that countless marine species depend on.' 'From the coral reefs that support tourism to the shellfish industries that sustain coastal communities,' he added, 'we're gambling with both biodiversity and billions in economic value every day that action is delayed.' The further implications are even more serious. The reasons for the ocean's rise in acid, or fall in base, is that its waters have absorbed about one-third of all the carbon dioxide released by surface burning of coal, oil and gas. But the more carbon dioxide it absorbs, the lower its ability to absorb more — meaning faster warming on the surface. Making that dynamic even more dramatic, seas and oceans have also absorbed 90 percent of the global heating that the Earth's surface would have otherwise experienced, according to NASA. In addition to absorbing heat and carbon dioxide, the ocean also provides 50 percent of the Earth's oxygen — which comes from the very marine ecosystems that warming and acidification are threatening. Ecosystem loss and fossil fuel burning mean that levels of oxygen below the surface are decreasing, as, more slowly, is oxygen above the surface.
