A reversal in Earth's magnetic field 42,000 years ago triggered climate catastrophes and mass extinctions. Can the field flip again?
About 42,000 years ago, Earth's magnetic field broke down temporarily, according to a new study. This lead to environmental cataclysms and mass extinctions, including the demise of the Neanderthals. The dramatic period was a turning point in Earth's history, claim the scientists, full of resplendent auroras, electrical storms, and strong cosmic radiation. These changes were caused by the reversal of the planet's magnetic poles and variations in solar winds.
Amusingly, the researchers behind the international study (which involved scientists from Australia, New Zealand, Switzerland, the U.K., Germany, U.S., Argentina, China, and Russia) called this period the "Adams Transitional Geomagnetic Event' or simply "Adams Event." The Adams they are referring to is the science fiction writer Douglas Adams, who famously wrote in "The Hitchhiker's Guide to the Galaxy" that 42 was the answer to "the Ultimate Question of Life, the Universe, and Everything."
Chris Turney, a professor at UNSW Sydney and co-leader of the study, remarked that their study was the first "to precisely date the timing and environmental impacts of the last magnetic pole switch."
Interestingly, their discovery was aided by ancient New Zealand kauri trees, which have been sitting preserved in sediments for more than 40,000 years.
"Using the ancient trees we could measure, and date, the spike in atmospheric radiocarbon levels caused by the collapse of Earth's magnetic field," said Turney.
What the trees helped the scientists understand were the effects of the magnetic pole switch, which was already known as "The Laschamps Excursion." Using radiocarbon dating to analyze the kauri tree rings, they could gauge how the planet's atmosphere changed.
Paleopocalypse! - Narrated by Stephen Fry.
The study's co-lead Professor Alan Cooper, Honorary Researcher at the South Australian Museum, highlighted the significance of the ancient trees to their work.
"The kauri trees are like the Rosetta Stone, helping us tie together records of environmental change in caves, ice cores and peat bogs around the world," explained Cooper.
Using the trees, the researchers were able to create global climate models that showed how the growth of ice sheets and glaciers across North America, differences in wind belts and tropical systems, and even the extinction of Neanderthals could all be linked to the climate changes brought on by the Adams Event.
"Earth's magnetic field dropped to only 0-6 per cent strength during the Adams Event," pointed out Professor Turney. "We essentially had no magnetic field at all – our cosmic radiation shield was totally gone."
According to the researchers, another fascinating consequence of the Adams Event is that early humans would have been both inspired and terrified by the amazing auroras seen in the sky, brought on by the magnetic field fluctuations. "It must have seemed like the end of days," said Cooper.
He also supposes that the calamities would have forced our ancestors into the caves, leading to the amazing cave art that came about approximately 42,000 years ago.
Could such a magnetic pole reversal happen today? Professor Cooper thinks there are some indications like the weakening of the field by 9 percent over the past 170 years that tells us a reversal may be coming.
"If a similar event happened today, the consequences would be huge for modern society," shared Cooper. "Incoming cosmic radiation would destroy our electric power grids and satellite networks."
Check out the study published in Science.
Rocks from two hundred million years ago show us how everything died and how nothing is new.
- A new study suggests that the mass extinction that gave dinosaurs the evolutionary upper hand was caused by oceanic oxygen deprivation.
- Using ratios of sulfur isotopes, researchers could estimate changes in ocean oxygen levels in ancient seas.
- The authors suggest a similar mechanism as that which can cause dead zones in oceans today caused a mass extinction.
Living on Earth isn't always easy. The fossil record is littered with enough mass extinction events to have once made theories that they occur in cycles seem feasible. The "Big Five" events each killed an average of 75 percent of all species alive at the time, with the largest one wiping more than 90 percent of them. While the question of what caused these events is interesting as a curiosity in and of itself, the problem also takes on an existential one, as most people would like to avoid the same fate as the trilobites.
To that end, a team of researchers based out of the UK, China, and Italy have investigated the causes behind one of the most massive die-offs in history. In a new paper published in Science Advances, they suggest a depletion in oxygen as a cause for the event at the end of the Triassic Era 201.3 million years ago.
How to tell what the world was like 201 million years ago using rocks
The mass extinction that ended the Triassic period was a massive die-off that saw somewhere between a quarter and a third of ocean life vanish alongside most large land animals. Plants were not spared a culling either, with perhaps 60 percent of plant species also dying. The event took less than 10,000 years to carry out this morbid work. This remarkable event paved the way for dinosaurs to become the dominant land animal during the Jurassic period, as most of their competition was dead.
Explanations for this event's cause have ranged from gradual climate change, to asteroid impacts, to rampant volcanism. New evidence suggests that ocean anoxia, the depletion of oxygen supplies in the ocean, played a large role.
The researchers examined the levels of two isotopes of sulfur in rocks that would have been on the seafloor during the extinction event from British Columbia, Sicily, and Northern Ireland. The two isotopes, 32S and 34S, can become trapped in limestone and other rocks and exist at different ratios depending on how much oxygen is in the water around them. By examining the changes in the ratio of the two isotopes in rocks formed at the time, we can know what was happening to oxygen levels in the oceans hundreds of millions of years ago.
The scientists noticed "large spikes" in the ratio of 34S to 32S in the samples from all of the locations, indicative of a substantial fall in the amount of oxygen available. These findings can be applied far beyond the sites the rock samples came from, suggesting that oxygen levels fell across large portions of the globe-spanning superocean, known as Panthalassa, that existed alongside Pangea.
And you thought the Dead Zone in the Gulf of Mexico was bad.
This study isn't the only one suggesting Ocean anoxia caused the extinction event. A previous study from 2017 reached a similar conclusion by measuring the trace uranium levels in rocks formed at the time. Similarly to the ratio of sulfur isotopes considered above, the amount of uranium in these rocks varies with the amount of oxygen. That study suggests that the low oxygen levels may have lasted 50,000 years after their initial fall, with a full 250,000 years needed before coral reefs could recover.
In the present day, the researchers hypothesize that this anoxia was connected to significant volcanic activity at the time. By releasing massive amounts of greenhouse gasses, this would have both acidified the oceans by increasing their carbon content and lowered their oxygen levels by raising global temperatures, as warm water holds less oxygen overall. Together, these effects can annihilate marine ecosystems. It is known that major volcanic activity was occurring at the time, lending credence to this hypothesis.
It's a good thing that nothing is causing the oceans to heat up and have lower oxygen levels these days! Oh, wait. Never mind.
If Arctic ice continues to melt at its projected rate, the bears will go extinct due to starvation by the end of the century according to a first-ever projected timeline.
- A new report on climate change by the University of Toronto is projecting that most of the polar bear population could reach extinction in under 100 years due to starvation.
- Polar bears are dependent on sea ice for hunting seals, a primary component of their diet. As temperatures rise and sea ice continues to shrink it has become increasingly challenging for the carnivores to hunt for food.
- The Arctic is likely to have warmed more than double the amount of the global average this year compared to pre-industrial temperatures.
If Arctic ice continues to melt at its projected rate, polar bears will go extinct by the end of the century according to a first-ever projected timeline.
An alarming new report on climate change is projecting that most of the polar bear population could reach extinction in under 100 years.
The University of Toronto published a study in Nature Climate Change last week that put a timeline on the beloved Arctic mammals' crisis for the first time. It's long been known that the ice habitats of polar bears — which most countries classify as an endangered species — have been rapidly melting, but now the "poster animal of climate change" has been given an extermination date by 2100.
Starving into extinction
Polar bears are dependent on sea ice for hunting seals, a primary component of their diet, and aren't exactly built for swimming to catch their prey in the open water. As temperatures rise and sea ice continues to shrink it has become increasingly challenging for the carnivores to hunt for food. The species could be starved out within the next 80 years, save for a few high-Arctic subpopulations.
"Here, we establish the likely nature, timing and order of future demographic impacts by estimating the threshold numbers of days that polar bears can fast before cub recruitment and/or adult survival are impacted and decline rapidly," the authors of the study said.
The study looked at 13 of the world's 19 subpopulations of polar bears that account for 80 percent of the species' total population. Researchers modeled the energy use of the polar bears to calculate the number of days the bears can fast before their reproductive abilities become impacted. They then mapped that onto the number of estimated iceless days that will be faced in the coming decades, determining that the amount of time the bears would be forced to fast surpassed the amount of time they were capable of fasting. In 20 years from now, some polar bears living in Canada will begin to face reproductive failure and in 40 years a majority of the global population will more than likely be affected.
"The dire predictions in our study result from polar bear's dependence on sea ice and the projected rapid loss of that ice due to human-driven climate change," Marika Holland, co-author of the paper told TIME.
While the scientists noted that moderate cuts in emissions could potentially extend the bears' estimated life-expectancy for a bit, it won't be able to save some species populations from extinction by the end of the century.
"Land-based feeding is unlikely to occur at scales that shift the timelines for recruitment and survival declines by more than a few years, because foods that meet the energy demands of polar bears are largely unavailable on land," the study said, pointing out that some polar bear populations are already feeling the impact.
The melting arctic
Of course, as the International Union for Conservation of Nature has cited, climate change is the main cause of the population's suffering and decline.
According to the World Meteorological Organization, the Arctic is likely to have warmed more than double the amount of the global average this year compared to pre-industrial temperatures. Since the 1970s, satellites have shown sea ice melting by 13 percent per decade. If greenhouse gas emissions stay on their current trajectory, the only polar bears that will be left by the end of the century will likely be those living in the Queen Elizabeth Islands in Canada's Arctic Archipelago.
Keeping tabs on polar bears, the largest land-dwelling carnivore on earth, is how scientists keep their finger on the pulse of the health of Arctic populations at-large. Their loss, as Holland told TIME, "would reverberate throughout the ecosystem."
But the bears won't go down without a fight for their survival. As Arctic temperatures rise, melting the species' normal hunting grounds, the bears may begin to move toward land to find food. For example, in 2019 authorities in Russia's remote arctic region declared a state of emergency as a mob of starving polar bears charged into villages.
Arctic foxes are another species endangered as their habitats and diets are threatened by melting sea ice due to greenhouse gas emissions.Photo by Jonatan Pie on Unsplash
Polar bears have faced extermination in the past. In 1965, scientists were worried that commercial polar bear hunting would cause the species to go extinct. A 1973 worldwide ban on hunting led to a resurgence in bear population, yet the melting sea ice that now threatens the lives of the estimated 26,000 that live on earth today is a much more complex issue to solve. While the species' future looks grim, the study does point out that decreasing fossil fuel burning may reduce Arctic sea ice loss.
If there is a sliver of hope left for the polar bears and other Arctic species endangered by melting Arctic ice, it rests on rapid and radical human action against fossil fuel emissions.
Scientists discovered footprints made by some of the largest creatures ever to walk the Earth.
- Paleontologists published a paper on the discovery of dinosaur footprints on the roof of a French cave.
- The prints are deep underground and were made during the Middle Jurassic period.
- The footprints belonged to titanosaurs, the largest land animals ever.
French scientists found gigantic dinosaur footprints on the roof of the Castelbouc cave the Lozère region of southern France. A new paper outlines the discovery approximately 1640 feet under ground by the paleontologist Jean-David Moreau from the University of Burgundy–Franche-Comté and his colleagues.
The footprints likely belonged to an unknown species of titanosaur and were made 166 to 168 million years ago, in the Middle Jurassic Period. Titanosaurs, a group of long-necked, lizard-like sauropods, could be found all over the world in present day Africa, the Americas, Europe, and Australia. Among titanosaurs were the largest land animals to have ever existed, like the Patagotitan, which stretched 121 feet long and weighed 138,000 pounds.
The titanosaur Alamosaurus.
Credit: Bogdanov, 2006. Creative Commons.
Some of the 38 tracks found in France were as large as 4 feet long. They were likely made by three dinosaurs at the time when the area was on the surface, making up a muddy shoreline along which the giant creatures traveled. Over time, the site was buried by geological processes, with the tracks becoming moldings in the roof of a cave that's half a kilometer underground.
They were spotted as part of a caving expedition in December 2015 by the paper's authors. To find them, the scientists had to go down a narrow labyrinth of crawl spaces that often get flooded. The tracks were in a space about 260 feet long, 66 feet wide and 33 feet high.
Dinosaur tracks in the ceiling of Castelbouc Cave in France.
Credit: Jean-David Moreau et al./J. Vertebr. Paleontol.
Speaking to the French science magazine Sciences et Avenir, Jean-David Moreau explained that a caver "who was ahead of me turned to me and with the lamp of his helmet projected a grazing lighting on the ceiling which allowed to bring out the marks."
You can read the paper "Middle Jurassic tracks of sauropod dinosaurs in a deep karst cave in France," published in the Journal of Vertebrate Paleontology.
Australia's beloved and bizarre egg-laying mammal could start vanishing in coming years if current trends continue.
- Platypuses are nocturnal, semiaquatic animals that are endemic to Australia and Tasmania.
- A new study suggests that the species could lose half its population over the next 50 years, due mainly to drought, human development and climate change.
- In 2019, the United Nations reported that some 1 million species of plants and animals are at risk of extinction.
The platypus is at greater risk of extinction than previously thought, suggests a new study published in the February issue of Biological Conservation.
The strange egg-laying, river-dwelling mammal is currently listed as endangered in South Australia, and as "Near Threatened" on the International Union for Conservation of Nature's Red List. But the researchers behind a new analysis of platypus populations say there's strong evidence that platypus populations are declining in Australia and Tasmania, the only two countries where the secretive animals exist in the wild.
The Australia-based researchers wrote:
"[The platypus faces] potentially devastating combination of threats, including water-resource development, land clearing, climate change, and increasingly severe periods of drought."
Lead study author Dr. Gilad Bino, a researcher at the University of New South Wales Centre for Ecosystem Science, called for urgent conservation action and government funding to protect the species.
"There is an urgent need for a national risk assessment for the platypus to assess its conservation status, evaluate risks and impacts, and prioritize management in order to minimize any risk of extinction," Bino told Science Daily.
The study estimated the future decline of platypus populations by considering current rates of climate change, drought, and land and water development. Under this model, the results showed that the platypus population is likely to drop 47 percent over the next 50 years. Drought is expected to be a particularly deadly threat to the species.
Heinrich Harder/Public Domain
Australia has recently suffered some of its worst droughts on record. The researchers suggested that even more extreme droughts are likely to occur in the future, considering that the changing climate will bring even hotter temperatures. Droughts can destroy platypuses' burrows, which the animal usually constructs by digging into the riverbank with its claws. When droughts dry up these hiding spots, platypuses are forced to move into new areas where they risk becoming prey to predators like foxes, dogs, and cats.
Droughts can also increase the likelihood of deadly bushfires. The current bushfire crisis in Australia wasn't mentioned in the recent study, but experts estimate that some 1 billion animals have been killed so far in the fires. As for how many platypuses died:
"The short answer is that we simply don't know," Josh Griffiths, an ecologist with the environmental consulting firm Cesar Australia, told Atlas Obscura in an article published January 24, 2020. "The scale of the fire we've got at the moment is unprecedented. [...] It's one more nail in their coffin."
How to save the platypus
Human development, especially that which involves altering rivers, is another major threat to the platypus. Study co-author Richard Kingsford, director of the UNSW Centre for Ecosystem Science, noted that many platypuses live in areas of Australia currently undergoing development.
"These include dams that stop their movements, agriculture which can destroy their burrows, fishing gear and yabby traps which can drown them and invasive foxes which can kill them," Kingsford told Science Daily.
The researchers offered several suggestions for how to protect the platypus:
- Ban enclosed cray-fish traps
- Prevent land clearing in key areas
- Build "platypus-ways" that provide safe passage from ferals predators
- Citizens can report platypus sightings via the app platypusSpot
In 2019, the United Nations reported that some 1 million species of plants and animals are at risk of extinction, with climate change being a major reason. It's an unprecedented threat to biodiversity, as Patricia Miloslavich, a senior professor in the Department of Environmental Studies at Universidad Simón Bolívar, told CBS News.
"It's true there have been extinctions in the past, that nature has taken its course, it's just that these have been processes that have taken millions of years and nature has had the time to adapt and provide a response," she said. "We are not giving nature a time to provide a response."