These unexplainable mysteries are real-life cliffhangers Have you heard about the strangest unsolved cases of all time? Scientists and detectives can’t quite crack these unexplainable mysteries, which include peculiar disappearances, strange crimes, animals behaving bizarrely and encounters with not-quite-human beings. We dug deep to uncover the latest facts on these real-life riddles. Read on to find out what’s known about these chilling cold cases—and what may remain a secret forever. Get Reader’s Digest’s Read Up newsletter for more interesting facts, humor, cleaning, travel and tech all week long.

laurampriestley/Shutterstock The incident at Dyatlov Pass On Feb. 1, 1959, nine ski-hikers died mysteriously in the mountains of what is now Russia. The night of the incident, the group set up camp on a slope, enjoyed dinner and prepared for sleep—but something went catastrophically wrong. The group never returned. On Feb. 26, searchers found the hikers’ abandoned tent, which had been ripped open from the inside. They also discovered footprints left by the group—some wearing socks, some wearing a single shoe, some barefoot. The prints continued to the edge of a nearby wood, which is where the first two bodies were found, shoeless and wearing only underwear. At first, the scene suggested death by hypothermia. But after medical examiners evaluated the bodies, including the other seven discovered later, hypothermia no longer made sense. In fact, the evidence made no sense at all. One body had signs of a blunt force trauma consistent with a brutal assault. Another had third-degree burns. One victim had been vomiting blood. One was missing a tongue. Some of their clothing was radioactive. Possible explanations included KGB interference, drug overdose, UFOs, gravity anomalies and the Russian version of the Yeti. Recently, a documentary filmmaker presented a different theory—a terrifying but real phenomenon called “infrasound,” in which the wind interacts with the topography to create a barely audible hum that can induce intense nausea, panic, dread, chills, nervousness, raised heart rate and breathing difficulties. The only real consensus is that whatever happened involved an overwhelming and possibly “inhuman force.”

Standard store88/Shutterstock Sickening noises In December 2016, a CIA officer checked in to the American Embassy’s health office in Havana suffering from nausea, headache and dizziness. Days later, two more CIA officers reported similar ailments. By late 2018, the number grew to 26 Americans and 14 Canadian diplomats with roughly the same weird symptoms, ranging from hearing loss to nosebleeds. All the victims said that the symptoms were related to a strange noise they’d heard at their homes or hotel rooms. One noted that the noise was high-pitched. Another described “a beam of sound, pointed into their rooms.” Some said that the noise resembled marbles rolling inside a large funnel. While the cause of these reported brain injuries was still a mystery, the fallout was clear. In October 2017, the Americans removed 60% of their diplomats from Cuba and expelled 15 Cuban diplomats from Washington, D.C. The illnesses confounded medical experts. Doctors at the University of Pennsylvania who examined some of the victims diagnosed concussion-like symptoms but didn’t find signs of concussions. You might be thinking: The Cuban government was up to something, right? The Cubans vehemently denied they were responsible. Many American investigators believed them. Recordings of the sounds only added to the confusion. Two scientists believed the recordings were of lovelorn male crickets. One of the experts, Alex­ander Stubbs of the University of California, Berkeley, said the insects are incredibly loud. “You can hear them from inside a diesel truck going 40 miles an hour on the highway.” Still, scientists had no idea how these sounds could lead to human illness, and they couldn’t explain why other people who lived near the diplomats weren’t affected. Maybe it was just nerves. “Cuba is a high-threat, high-stress post,” a former embassy official told propublica.org. Diplomats are warned that “there will be surveillance. There will be listening devices in your house, probably in your car. For some people, that puts them in a high-stress mentality, in a threat-anticipation mode.” True—but then how to explain what happened in China? In May 2018, an American posted in the consulate in Guangzhou was diagnosed with the very same mystery illness. Ultimately, 15 Americans were evacuated. In 2020, a report from the National Academies of Sciences, Engineering and Medicine concluded that the most probable cause was “radiofrequency energy, a type of radiation that includes microwaves.” Meanwhile, a 2023 intelligence community assessment found that the injuries were likely “tied to previous injuries, stress, environmental concerns and factors such as group psychology, in which illness symptoms reported by one individual in a community can spread serially among its members.” And in 2024, two studies by the National Institutes of Health compared more than 80 affected people with a healthy comparison group. The results, published in the Journal of the American Medical Association, showed “no clinical signs or brain image indications to explain those widely varied symptoms.” Yet attorney Mark Zaid, who represents current and past federal officials and their family members seeking continued medical treatment for Havana syndrome, believes that “the government is knowingly weaponizing the lack of science that exists in this area and intentionally hiding behind the classification wall where much of the evidence that contradicts the results exists.” The mysterious sounds may well be the opening shots in a new kind of cold war.

Dino Osmic/Shutterstock Ghost ship: The Mary Celeste On Dec. 4, 1872, a British American ship called the Mary Celeste was found empty and adrift in the Atlantic. It was seaworthy and had its cargo fully intact, except for a lifeboat, which seemingly had been boarded in an orderly fashion. But why? Like many strange ocean mysteries, we may never know the truth because no one on board was ever heard from again. In November 1872, the Mary Celeste set sail from New York bound for Genoa, Italy. She was manned by Captain Benjamin Briggs and seven crew members and also carried Briggs’s wife and their 2-year-old daughter. The ship had plenty of supplies, including luxuries like a sewing machine and an upright piano. Experts agree that to abandon a seaworthy ship, something extraordinary and alarming must have happened. However, the last entry on the ship’s daily log revealed nothing unusual. And everything inside the ship appeared to be in order. Theories over the years have included mutiny, pirate attack and an assault by a giant octopus or sea monster. In recent years, scientists have proposed the theory that fumes from alcohol on board caused an explosion that, as a result of a scientific anomaly, did not leave behind signs of burning—but was terrifying enough that Briggs ordered everyone into the lifeboat.

csp/Shutterstock Who (and where) is D.B. Cooper? On Nov. 24, 1971, Dan Cooper was a passenger on Northwest Airlines Flight 305, from Portland to Seattle—a 30-minute flight. He was described by passengers and flight attendants as a man in his mid-40s, wearing a dark suit, black tie with a mother-of-pearl tie clip, and a neatly pressed white collared shirt. He took his seat, lit a cigarette and politely ordered a bourbon and soda. Shortly after takeoff, he handed a 23-year-old flight attendant a note that reportedly said: “Miss, I have a bomb and would like you to sit by me.” His demands were for $200,000 (worth $1.5 million today), four parachutes and a fuel truck standing by in Seattle to refuel the plane on arrival. The flight attendant brought the demands to the captain. The airline’s president authorized full cooperation. The other passengers had no idea what was happening; they were told that the landing was delayed due to mechanical difficulties. When the plane landed, an airline employee delivered a cash-filled knapsack and parachutes, and Cooper allowed all passengers and two flight attendants to leave the plane. During refueling, Cooper outlined his plan to the crew: a southeasterly course toward Mexico with one further refueling stop in Nevada. Two hours later, the plane took off. When it landed in Reno, Cooper was no longer on the plane. Cooper (whom the media mistakenly referred to as “D.B. Cooper”) was never seen or heard from again. No parachute was found, and the ransom money was never used. But in 1980, a young boy on vacation with his family near the Columbia River in Oregon found several packets of the ransom money (identifiable by serial number). That surprise discovery led to an intense search of the area for Cooper (or his remains). There was no sign of him. The FBI closed its case in 2016. But that wasn’t the last chapter of this mystery: In 2024, two siblings came forward claiming their father, Richard Floyd McCoy Jr., was actually D.B. Cooper. McCoy Jr., a military-trained parachutist, was convicted for an eerily similar hijacking in April 1972 over Provo, Utah (he was sentenced to 45 years in prison). He died two years later. While he is the most likely suspect, there is still no definitive proof that he pulled off the original heist.

pcruciatti/Shutterstock Living statues From 1917 to 1928, half a million people were afflicted with a ghastly condition that could be part of the plotline of a horror film. The victims—very much alive and conscious—found themselves in inexplicably frozen states, their static bodies prisons for their minds. Encephalitis lethargica (EL), aka “the sleeping sickness,” first appeared in Europe and quickly spread around the world, reaching epidemic levels in North America, Europe and India by 1919. About a third of those stricken with the illness died. Of the survivors, nearly half eventually found themselves unable to physically interact with the world around them, all the while fully aware of their surroundings. Though occasionally capable of limited speech, eye motion and even laughter, they generally appeared as living statues—totally motionless for hours, days, weeks or years. The cause is unknown, but one theory is brain inflammation triggered by a rare strain of streptococcus, the bacteria responsible for many sore throats each year. Science’s best guess is that the bacteria mutated, provoking the immune system to attack the brain, leaving the victim helpless. None of this explains why the illness disappeared only to resurface sporadically, be it in Europe in the 1950s or in China 15 years ago when a 12-year-old girl was hospitalized for five weeks with the disease. Are such occurrences the new normal, or are they signs that EL could be planning something bigger any day? A 2004 analysis of 20 patients with symptoms remarkably similar to EL concluded that whatever ailed them “is still prevalent.” As such, history’s so-called sleeping sickness remains the stuff of nightmares.

Zachary Byer/Shutterstock What is Area 51? Area 51, in southern Nevada, is a U.S. military base. Its very existence was unconfirmed until 2013, when the CIA was obliged to respond to a Freedom of Information Act request from 2005. Based on historical evidence, it appears that Area 51 supports the development and testing of experimental aircraft and weapons. Public satellite images, such as those available on Google Maps, don’t provide insight. Even those with security clearance to visit Area 51 are transported there from Las Vegas via an airline called JANET, which reportedly stands for Joint Air Network for Employee Transportation, on an unmarked plane that turns off its transponder before descending. The intense secrecy surrounding Area 51 has sparked rumors that the government uses it to house crashed UFOs and conduct lab tests on aliens. Other theories about what Area 51 is used for include: research on time travel, research on teleportation, meetings with extraterrestrials, development of a means for weather control and activities related to a shadowy one-world government. Where these Area 51 secrets and theories come from is as much a mystery as Area 51, itself, but one thing is certain: People love a good conspiracy theory. At one point, conspiracy theorists believed the moon landing in 1969 had been faked. Hint: It wasn’t.

Iuliia Timofeeva/Shutterstock Roaming ruins It’s not unusual to find junk in Brazil’s Guanabara Bay, but what Robert Marx unearthed there in 1982 was an unusual kind of foreign matter. In an underwater field the size of three tennis courts located 15 miles from shore lay the remains of some 200 Roman ceramic jars, a few fully intact. According to Marx, a professional treasure hunter, the jars appeared to be twin-handled amphorae that were used to transport goods such as grains and wine in the 3rd century. But how did they get there? The first Euro­peans didn’t reach Brazil until 1500. The Romans, who traded primarily in Mediterranean port cities and the Middle East, had little incentive to invest in ships that could cross oceans. However, they did sail as far as India. Perhaps some untrained navigator lost his way in a storm. Or maybe mutineers steered the ship westward? We may never know, nor are we likely to uncover more evidence. Brazil closed the Bay of Jars to further research in 1983 in an effort to deter looters. Marx claims the government didn’t want the area explored because finding Roman-era artifacts there would mean that, contrary to Brazil’s official history, the Portuguese were not the first Euro­peans to reach the country. And the truth? It’s resting 100 feet under the sea.

Universal History Archive/UIG/REX/Shutterstock What is the Voynich Manuscript? The Voynich Manuscript is a roughly 250-page book written in an entirely unknown language/writing system. It’s been carbon-dated back to the 1400s and includes illustrations of plants that don’t resemble any known species. Named for the Polish book dealer who purchased it in 1912, it is believed to have been intended as a medical text. Its first confirmed owner was Georg Baresch (1585–1662), an alchemist from Prague, who discovered it “taking up space uselessly in his library.” Baresch tried to investigate the manuscript’s origins, to no avail. The manuscript changed hands for centuries until it was purchased by Voynich, who posited that it was authored by Albertus Magnus (an alchemist) or Roger Bacon (an early scientist). However, some believe that Voynich fabricated the manuscript and its history all by himself. Various other hoaxes have been proposed over the years. Of course, that wouldn’t explain the carbon-dating of the paper and ink. Centuries after its first (alleged) discovery, the Voynich Manuscript remains as impenetrable and inexplicable as ever.

Chayatorn Laorattanavech/Shutterstock Do the Pollock sisters prove reincarnation? Roughly 33% of Americans believe in reincarnation. Although scientists tend to pooh-pooh the possibility, every once in a while, an unsolved mystery comes around that is so compelling and otherwise unexplainable that it gives even scientists pause. That is what we have in the story of the Pollack sisters. In 1957, two young English sisters, Joanna Pollock, 11, and Jacqueline Pollock, 6, died in a tragic car accident. One year later, their mother gave birth to twins, Gillian and Jennifer. When the twins were old enough to talk, they began identifying and requesting toys that had belonged to their dead sisters, pointing out landmarks only their dead sisters would have known (such as a school they’d attended), and sometimes panicking upon seeing cars idling (“That car is coming to get us!” they reportedly shrieked on one occasion). After the twins turned 5, these incidents became less frequent, and the girls went on to lead normal lives. Still, the story of the Pollock sisters made its way to Ian Stevenson, MD (1918–2007), a psychiatrist and professor at the University of Virginia who studied reincarnation. After investigating thousands of supposed cases, Dr. Stevenson wrote a book describing 14 of them he believed to have been real, including that of the Pollock sisters.

Fotosr52/Shutterstock Where are the Sodder children? Unexplainable mysteries involving children are always extra chilling. George and Jennie Sodder of West Virginia were forced to cope with not only the loss of five of their children but also with the mysterious circumstances surrounding that loss. After the Sodders’ home burned to the ground on the night before Christmas in 1945, five of the 10 Sodder children were still alive and accounted for. But what about the other five? They had vanished into thin air. Notice how we don’t say “vanished into smoke”? That’s because there was zero physical evidence of the children in the ruins (virtually impossible from a scientific standpoint). And that wasn’t all that was off about the night’s events. Apparently, George tried to save his children, who he believed were trapped inside, by using a ladder he kept against the side of the house, but the ladder was missing. Also weird, the phone lines to the house were cut. A woman claimed to have seen all five missing children peering from a passing car while the fire was in progress. And a woman at a Charleston hotel said she had seen four of the five missing kids a week after the fire. “The children were accompanied by two women and two men, all of the Italian extraction,” she said in a statement. “I tried to talk to the children in a friendly manner, but the men appeared hostile … and wouldn’t allow it.” The Sodder family theorized that the children had been kidnapped, perhaps in an attempt to extort money, or maybe in retaliation for George’s outspoken criticism of Mussolini and Italy’s fascist government (the Sodders were Italian immigrants). From the 1950s until Jennie Sodder’s death in the late 1980s, the Sodder family maintained a billboard on State Route 16, with pictures of the five vanished children, and offered a reward for information. The last (known) surviving Sodder child, Sylvia, died in 2021 at age 79. Up until the end, she didn’t believe her siblings perished in the fire.

Kumpol Chuansakul/Shutterstock What really happened to young Walter Collins? In 2008, Clint Eastwood’s film Changeling reawakened interest in one of the most bizarre and tragic crime stories of the 1920s. In March 1928, single mom Christine Collins reported her 9-year-old son, Walter, missing from their home in Los Angeles. Five months later, the police brought “Walter” back to Christine, except it wasn’t Walter, and Christine knew it. But the L.A. police dismissed Christine’s concerns, going so far as to accuse her of terrible mothering and having her committed to a mental hospital. The real Walter Collins was never found, and over time, authorities came to believe he was one of the victims of convicted child murderer Gordon Stewart Northcott, who was caught and executed in 1930. Northcott’s mother confessed to killing Walter and was sentenced to life in prison. Walter’s body was never found, so we don’t know for sure what happened, and this case remains one of those baffling unsolved crimes. Nobody ever figured out why the police were so invested in covering up the boy’s disappearance that they brought a different child back to Christine and tried to convince her that it was her missing son.

Elena Elisseeva/Shutterstock The disappearance of Paula Jean Welden Paula Jean Welden, 18, was a sophomore at Bennington College on Dec. 1, 1946, the day she told her roommate, Elizabeth Parker, she was going for a long walk but failed to return. A search focused primarily on Vermont’s Long Trail (a 272-mile trail that cuts through the center of Vermont to the Canadian border), where local witnesses reported having seen her. The trail yielded no clues, though, and soon, what the local newspaper Bennington Banner referred to as “tantalizing and unquestionably strange leads” began to materialize. These included claims by a Massachusetts waitress that she’d served an agitated young woman matching Paula’s description. Upon learning of this lead, Paula’s father disappeared for 36 hours, supposedly to follow this clue. After this strange move, her dad became a prime suspect in Paula’s disappearance. Soon, stories circulated that Paula’s home life was not nearly as idyllic as her parents had told the police. Apparently, Paula had not returned home for Thanksgiving the week prior, and she may have been distraught about a disagreement with her father. For his part, Paula’s father suggested Paula was distraught about a boy and perhaps that guy should have been a suspect. Over the next decade, a local Bennington man twice bragged to friends that he knew where Paula’s body was buried. He was not able to lead the police to a body, though. With no body and no forensic clues, the case grew colder, and the theories grew stranger, including those linked to the paranormal. New England author and occult researcher Joseph Citro came up with the “Bennington Triangle” theory, which explained the disappearance as linked to a special “energy” that attracts outer-space visitors, who could have taken Paula with them back to their world.

tomasworks/shutterstock The Flannan Isles Lighthouse disappearances In 1900, three keepers of the Flannan Isles Lighthouse off the west coast of Scotland disappeared under the strangest of circumstances. The lighthouse was manned by a three-person team (Thomas Marshall, James Ducat and Donald McArthur), with a fourth man rotating in from shore. On Dec. 26, 1900, the relief keeper arrived to discover the lighthouse keepers gone. The only sign of anything amiss was an overturned chair near the kitchen table. Records at the lighthouse showed that the men were there until the afternoon of Dec. 15, 11 days earlier. But no bodies were ever found. While an official investigation concluded that the men had probably gone out in a boat and got swept out to sea, that hasn’t stopped the endless speculation. Theories range from drownings to abduction by foreign spies to death by a giant sea monster or a ghost ship. Whatever happened back in December 1900 at the Flannan Isles Lighthouse, we may never know.

Fedor Selivanov/Shutterstock The bridge at Overtoun that calls dogs to their maker The Overtoun Bridge—near Dumbarton, Scotland—seems to call dogs to leap to their death. Since the 1950s, some 50 canines have perished, and hundreds more have jumped but survived, reports Slate via its Atlas Obscura blog, with some even returning to leap again onto the rocks 50 feet below. In terms of scientific truth, it is unlikely that dogs are capable of forming an intent to die. Yet something is luring the animals off that bridge, often from the very same spot on dry, sunny days. Many theories have surfaced, including that the bridge is haunted by a ghost. In 2010, the Scottish Society for the Prevention of Cruelty to Animals sent a representative to investigate these unexplainable mysteries. While they decided that most likely a mink or other mammal was marking the area below with an almost irresistible scent, they also admitted that the bridge had a “strange feeling.” Whatever is causing this weird phenomenon, dog owners would be wise to take heed and keep their dogs on leashes.

mkasperek/Shutterstock The Big Grey Man The Big Grey Man is a not-human creature said to haunt the summit and passes of the second-highest peak in Scotland, Ben Macdui. In the native Scottish tongue, the creature is known as Am Fear Liath Mòr. Like the Yeti of the Himalayas and Big Foot (also known as Sasquatch) of the American Pacific Northwest, the Big Grey Man has been seen only by a few eyewitnesses. Those who have spotted the Big Grey Man describe the creature as extremely tall (over 10 feet) and human-like, with short hair, broad shoulders and long arms. Nearly all reported sightings include the sound of gravel crunching beneath footfalls. Scientists haven’t come up with an explanation for these encounters. One theory from psychologists is that the witnesses may have been in a state of physical and mental anguish from exhaustion and/or isolation. For now, the Big Grey Man remains a true mystery, but if you go to Scotland, let us know if you run into the Big Grey Man.

Mike OLeary/Shutterstock The lost colony of Roanoke In 1587, John White led a group from Britain to found an English colony. They settled on Roanoke Island, one of a chain of barrier islands now known as the Outer Banks of North Carolina. White left for more supplies, but on his return three years later, found the colony completely abandoned, with all houses and fortifications dismantled with care. Before he’d left the colony, White had instructed the colonists that if they were taken by force, they were to carve a cross into a nearby tree, but there was no cross. The only clue was the word “Croatoan”—the name of a native tribe allied with the English—carved into a post. White assumed the colonists had moved to Croatoan Island (now known as Hatteras). Future investigations turned up reports that the colonists had been slaughtered by the Powhatan tribe, but there is no archaeological evidence of this. A recent re-examination of the evidence indicates that if a massacre occurred, it was not of the Roanoke colonists but an earlier group of colonists. Other theories suggest the colonists and the Croatoans or other local tribes integrated, but no DNA evidence has positively identified any descendants of the colony.

Irina Sokolovskaya/Shutterstock The Circleville letters In 1976, residents of Circleville, Ohio, began receiving hate mail that has wreaked havoc ever since. The letters, postmarked from Columbus, were invasive and accusatory, highlighting a supposed affair between school bus driver Mary Gillespie and the school superintendent. One letter addressed to Mary’s husband, Ron, threatened his life if he didn’t put a stop to the affair. By 1977, the husband was dead, the result of a suspicious one-car crash that reportedly happened when he was on his way to confront the letter writer. When the sheriff ruled the death an accident, residents began receiving letters accusing the sheriff of a cover-up. The letters continued throughout the 1970s and early 1980s—and even after Ron’s sister’s husband, Paul Freshour, was convicted of writing the letters and attempting to murder Mary via a booby-trap-rigged pistol. But even with Freshour in prison, the letters continued. He even received one himself. In 1994, the letters actually stopped when Freshour was released, and he maintained his innocence until his death in 2012. The true identity of the Circleville letter writer remains unknown. Some still believe it was Freshour, while others point to his ex-wife, Karen Sue. A few think Frehour took the rap to protect his son, Mark, who committed suicide in 2002. Others believe it was Mary all along, and that she used the letters to concoct and support the murder of her own husband.

Sovfoto Universal Images Group/REX/Shutterstock The Tunguska event On the morning of June 30, 1908, 830 square miles of forest and an estimated 80 million trees in Siberia, Russia, were flattened by what appeared to be a mysterious explosion. The phenomenon, known as the Tunguska event, has been classified by scientists as the largest “impact event”—which means a recordable impact between two astronomical objects, such as an asteroid and the Earth—in recorded history. Yet no “impact crater” was ever found, making it one of those strange science mysteries no one has solved. Scientists can only surmise what might have happened, which could be that an asteroid exploded over the Earth’s surface and its after-effects caused the destruction in Siberia.

While most oceans around the globe steadily warm, the region south of Greenland has stubbornly cooled, creating a noticeable cold spot. (CREDIT: CC BY-SA 4.0)

For over a century, scientists have noticed something unusual in the North Atlantic Ocean. While most oceans around the globe steadily warm, the region south of Greenland has stubbornly cooled, creating a noticeable cold spot.

After years of debate, researchers from the University of California, Riverside have identified the likely culprit behind this puzzling anomaly—a slowing of the Atlantic Meridional Overturning Circulation, or AMOC.

Understanding the Ocean’s Conveyor Belt

The AMOC acts as a vast underwater conveyor belt, continuously carrying warm, salty surface waters from the tropics northward. As it reaches colder northern regions, the water cools, sinks, and moves back south at deeper depths. This flow plays a crucial role in regulating Earth’s climate, especially across North America and Europe. It influences weather patterns, rainfall, and even marine ecosystems, making its health vital for global climate stability.

Atlantic sea surface temperature trend, 1900-2005 in °C, from the average of six observation datasets. (CREDIT: Kai-Yuan Li/UCR)

Scientists have long suspected the AMOC was slowing down, a theory supported by reconstructions of past climate conditions. But direct measurements of AMOC strength exist only for about two decades. Thus, confirming long-term trends required creative solutions and indirect evidence, leading researchers Wei Liu and Kai-Yuan Li to investigate historical ocean temperature and salinity data.

Cooling and Freshening: Key Indicators

To solve this century-old mystery, Liu and Li examined over 100 years of ocean records. These extensive observations revealed a clear pattern: the cold spot south of Greenland, known as the North Atlantic Warming Hole (NAWH), consistently showed decreasing temperatures and reduced salinity.

The scientists reasoned that a slowdown of the AMOC would mean less warm, salty water traveling northward, resulting in cooler and fresher surface waters exactly where the NAWH appears.

“We found the most likely answer is a weakening AMOC,” explained Liu. The researchers backed this claim by comparing historical data with nearly 100 different climate simulations from international scientific projects like the Coupled Model Intercomparison Project (CMIP).

Their findings, recently published in the journal Communications Earth & Environment, revealed that only climate models predicting a weakened AMOC accurately matched the observed cooling and freshening trends. Models suggesting a stronger circulation, influenced by declining aerosol pollution, consistently failed to replicate the real-world data.

“It’s a very robust correlation,” Li said. “If you look at the observations and compare them with all the simulations, only the weakened-AMOC scenario reproduces the cooling in this one region.”

Atlantic SST and SSS trends in observations and CMIP5/6 models. (CREDIT: Nature: Communications Earth & Environment)

Why Does the AMOC Slow Down?

Identifying that the AMOC is weakening is one piece of the puzzle; understanding why it weakens involves complex interactions between oceanic and atmospheric factors. Historically, the AMOC’s slowdown has been attributed to various causes, including shifts in wind-driven circulation, changes in storm patterns, and variations in the North Atlantic Oscillation—an atmospheric phenomenon influencing weather across the Atlantic.

However, none of these alone sufficiently explained the cooling pattern observed south of Greenland. The study demonstrated that changes in oceanic heat transport—specifically less warm water being carried north—played the most significant role.

Researchers estimated that the AMOC slowed between 1900 and 2005 by about 1 to 3 Sverdrups per century. One Sverdrup equals a million cubic meters of water moving per second, a massive volume capable of significantly altering regional climates.

Atlantic temperature and salinity trend differences between AMOC− and AMOC+ . (CREDIT: Nature: Communications Earth & Environment)

Impacts Beyond Ocean Temperatures

A weaker AMOC doesn’t only mean colder ocean temperatures. This cooling directly affects climate patterns and ecosystems on a broader scale.

The NAWH influences the position and strength of the jet stream, a high-altitude wind pattern guiding weather systems across North America and Europe. Changes here can lead to shifts in rainfall patterns, impacting agriculture, water resources, and weather extremes like storms and droughts.

Marine ecosystems face disruptions too. Cooler, fresher waters alter habitats and species distributions, challenging fisheries and biodiversity management.

Atlantic SST and AMOC changes in slab-ocean and fully coupled model experiments. (CREDIT: Nature: Communications Earth & Environment)

Settling the Debate and Looking Forward

The findings from Liu and Li’s research also clarify disagreements among scientists. Previously, some newer climate models predicted a strengthening AMOC due to declining aerosol pollution. However, these newer models consistently failed to reproduce observed historical cooling. Liu and Li’s work confirms that the AMOC weakening better explains the century-long trend, highlighting weaknesses in current aerosol-sensitive models.

“Our results show that only the models with a weakening AMOC get it right,” Liu emphasized. “Many of the recent models are too sensitive to aerosol changes, and less accurate for this region.”

Resolving this mismatch not only improves our understanding of past climate dynamics but also boosts confidence in future climate forecasts, particularly those affecting Europe. With accurate predictions, communities can better prepare for climate impacts like changing rainfall patterns, storm frequency, and ecosystem shifts.

Atlantic SST and zonal-mean ocean temperature changes in GFDL-ESM2M free- and fixed-current simulations. (CREDIT: Nature: Communications Earth & Environment)

A Powerful Approach for Climate Science

Though direct measurements of the AMOC extend only 20 years into the past, Liu and Li demonstrated that historical temperature and salinity data provide reliable indirect evidence. This method allows scientists to reconstruct long-term oceanic trends with confidence, offering a clearer window into past climate changes.

“We don’t have direct observations going back a century, but the temperature and salinity data let us see the past clearly,” said Li. “This work shows the AMOC has been weakening for more than a century, and that trend is likely to continue if greenhouse gases keep rising.”

Looking ahead, if greenhouse gas emissions continue unchecked, the AMOC may weaken further. This could expand the influence of the North Atlantic cold spot, potentially intensifying climate impacts. Liu and Li’s research underscores the importance of historical data analysis in predicting future ocean behavior, providing tools to help society better anticipate and adapt to climate changes.

“The technique we used is a powerful way to understand how the system has changed, and where it is likely headed,” Li concluded. With clearer knowledge, scientists and communities can better manage the impacts of global climate shifts, aiming to safeguard environments and societies worldwide.

Note: The article above provided above by The Brighter Side of News.

Our atmosphere is like one big electrical circuit: Thunderstorms are the batteries that charge it up, and lightning is the current flowing through it. On the ground we see evidence of this circuit when lightning cracks and strikes the ground, or when it lights up deep inside a thundercloud, but high above the clouds lies a secret electrical zoo full of sprites, elves, and jets.

These fantastical terms refer to light displays called transient luminous events or TLEs that occur in Earth’s upper atmosphere during thunderstorms. “TLEs are mysterious, beautiful, and uniquely different from conventional lightning, yet they connect weather, space, and electricity in one dramatic moment. They occur high above the clouds, almost silently, and are invisible to most people—but they reflect powerful processes unfolding deep within thunderstorms,” says Hailiang Huang, a Ph.D. student at the University of Science and Technology of China who studies TLEs.

The very first photographic observations of these events in 1989 captured red flashes streaking across the sky in the blink of an eye. The displays were dubbed red sprites, inspired by characters in Shakespeare’s A Midsummer Night’s Dream, and a medley of other fairytale names followed, as researchers discovered new types of TLEs. Today, scientists are still working to understand these curious phenomena—what causes them, how often they happen, and what they can tell us about Earth’s atmosphere.

A mystery behind Antarctica’s “bleeding waterfalls” has finally been solved as scientists have revealed the secrets behind the bizarre natural phenomena.

Blood Falls, located in the McMurdo Dry Valleys, is named for its red-coloured water which seeps from the ice into the ocean below.

The phenomenon was first documented by geologist Thomas Griffith Taylor in 1911, and its striking appearance against Antarctica’s pristine white landscape has puzzled researchers ever since. The mystery extended beyond the water’s unusual colour.

WIKIMEDIA COMMONS | Blood Falls is named for its red-coloured water which seeps from the ice into the ocean below

With temperatures averaging nearly -19C in the region, scientists were equally baffled by how the water remained liquid rather than freezing solid in such extreme conditions. Researchers from the University of Alaska Fairbanks made a breakthrough in 2003, finally solving the decades-old mystery. The team, which included National Geographic explorer Erin C Pettit, employed radio-echo technology to investigate the phenomenon. Researchers revealed that the flowing water contains extraordinarily high salt levels – double those found in the surrounding seawater. MORE BREAKTHROUGHS AT THE POLES: Scientists working in -35C dig out world’s oldest ice in Antarctica

Scientists issue warning over melting Antarctic ice…but not for the reason you think

Scientists discover evidence of ‘city-sized’ icebergs just off British coast

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This elevated salt content lowers the water’s freezing point, explaining why it remains liquid despite the frigid Antarctic temperatures. High iron concentrations were also found in the water – and when this iron-rich water comes into contact with air, it oxidises, creating the distinctive red, orange and brown colouration that gives Blood Falls its name. The salt concentration effectively acts as antifreeze, preventing the water from solidifying even in Antarctica’s harsh climate. The iron content transforms the water’s appearance through a simple chemical reaction. As the iron-laden water emerges from beneath the glacier and meets oxygen in the air, oxidation occurs instantly, producing the blood-like hues. Scientists traced the water’s origins back 1.5 million years. LATEST SCIENCE HEADLINES FROM GB NEWS: Nasa issues new odds of ‘city killer’ asteroid striking the Moon following fresh observations

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Nature’s way of cooling off ocean waters in the wake of tropical cyclones is losing its effectiveness as the planet overheats. The shorter lifespans of these cold wakes mean future storms face less inhibition as water temperatures bounce back faster.

What’s happening?

According to New Scientist, a team of researchers raised a serious concern tied to less effective “cold wakes.” The combination of cloud cover, evaporative cooling, and the stirring up of ocean waters in the wake of tropical cyclones can cool the ocean’s surface, inhibiting the growth of subsequent storms.

Research from the Atlantic Oceanographic and Meteorological Laboratory and Pacific Northwest National Laboratory revealed in a recent study that these cold wakes aren’t lasting as long as they used to. The water temperature in these massive pools of relatively cool water is bouncing back more quickly.

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It is just underway, and there is already a growing list of concerns about this year’s Atlantic hurricane season. A couple of weeks before the start of the season, the Federal Emergency Management Agency disclosed that it’s stepping away from its broader framework for disaster relief operations. Also, the National Oceanic and Atmospheric Administration issued its forecast for an above-normal season for tropical activity in the Atlantic basin.

Combined with the news about cold wakes, the potential for serious issues seems high.

“We think in the future cyclones might get stronger due to a general increase in sea surface temperature,” associate professor Shuai Wang of the University of Delaware told New Scientist. “If the recovery time of the cold wake decreases, that can definitely be a secondary effect. This shortening of cold wake recovery time can give a second boost to hurricane intensity.”

Why are shorter-lived cold wakes important?

Tropical cyclones draw their energy primarily from warm ocean water. The scientists’ study, published in Nature, noted that cold wakes are recovering faster because of weakening North Atlantic trade winds, which can limit the ocean’s ability to cool through the evaporation process. Background ocean warming is occurring, too, as the world warms. This study suggests that we can’t rely on cold wakes as much to act as a natural buffer and prevent future tropical cyclones from forming.

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NOAA’s forecast cited warmer than average ocean temperatures as one of the reasons to expect above-normal tropical cyclone activity this year. Nonprofit Climate Central’s analysis of last year’s season found that the overheating planet supercharged all 11 hurricanes in the Atlantic basin.

What’s being done about rising ocean temperatures?

Curbing carbon pollution from dirty energy sources — the burning of which has a steroid-like effect that is fueling more frequent and severe extreme weather — can help cool our planet’s oceans. Engineers are finding ways to transform old dirty energy projects into clean energy production. Recently, engineers announced that they are on track to field-test new technology that could unlock a more affordable power source.

Becoming an advocate in the fight to protect the future of the planet requires exploring critical climate issues and sharing the information with family and friends. Supporting pro-climate action candidates and taking local action are other important ways you can help make a difference.

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