United States government scientists reported Monday that the Arctic Ocean’s floating ice cover has shriveled to its second-lowest extent since satellite records began in 1979.
Until this month, only once in the last 42 years has Earth’s frozen skull cap covered less than 4 million square kilometers (1.5 million square miles).
The trend line is clear: The extent of sea ice has diminished 14% per decade over that period. The Arctic could see its first ice-free summer as early as 2035, researchers reported in the Nature Climate Change journal last month.
But all that melting ice and snow does not directly boost sea levels any more than melted ice cubes make a glass of water overflow, which gives rise to an awkward question: Who cares?
Granted, this would be bad news for polar bears, which are already on a glide path toward extinction, according to a recent study.
And yes, it would certainly mean a profound shift in the region’s marine ecosystems, from phytoplankton to whales.
But if our bottom-line concern is the impact on humanity, one might legitimately ask, “So what?”
As it turns out, there are several reasons to be worried about the knock-on consequences of dwindling Arctic sea ice.
Perhaps the most basic point to make, scientists say, is that a shrinking ice cap is not just a symptom of global warming but a driver as well.
“Sea ice removal exposes dark ocean, which creates a powerful feedback mechanism,” Marco Tedesco, a geophysicist at Columbia University’s Earth Institute, told Agence France-Presse (AFP).
Freshly fallen snow reflects 80% of the Sun’s radiative force back into space. But when that mirror-like surface is replaced by deep blue water, about the same percentage of Earth-heating energy is absorbed instead.
And we’re not talking about a postage stamp area here: The difference between the average ice cap minimum from 1979 to 1990 and the low point reported today – more than 3 million square kilometers – is twice the size of France, Germany and Spain combined.
The oceans have already soaked up 90% of the excess heat generated by manmade greenhouse gases but at a terrible cost, including altered chemistry, massive marine heat waves and dying coral reefs. And at some point, scientists warn, that liquid heat sponge may simply become saturated.
Altering ocean currents
Earth’s complex climate system includes interlocking ocean currents driven by wind, tides and something called the thermohaline circulation, which is itself powered by changes in temperature (“thermo”) and salt concentration (“haline”).
Even small changes in this Great Ocean Conveyor Belt, which moves between poles and across all three major oceans, can have devastating climate impacts.
Nearly 13,000 years ago, for example, as Earth was transitioning out of an ice age into the interglacial period that allowed our species to thrive, global temperatures abruptly plunged several degrees Celsius. They jumped back up again about 1,000 years later.
Geological evidence suggests a slowdown in the thermohaline circulation caused by a massive and rapid influx of cold freshwater from the Artic region was partly to blame.
“The freshwater from melting sea ice and grounded ice in Greenland perturbs and weakens the Gulf Stream,” part of the conveyor belt flowing in the Atlantic, said Xavier Fettweis, a research associate at the University of Liege in Belgium.
“This is what allows western Europe to have a temperate climate compared to the same latitude in North America,” he said.
The massive ice sheet atop Greenland’s landmass saw a net loss of more than half-a-trillion tons last year, all of it flowing into the sea. Unlike sea ice, which does not increase sea levels when it melts, runoff from Greenland does.
That record amount was due in part to warmer air temperatures, which have risen twice as fast in the Arctic as for the planet as a whole. But it was also caused by a change in weather patterns, notably an increase in sunny summer days.
“Some studies suggest that this increase in anticyclonic conditions in the Arctic in summer results in part from the minimum sea ice extent,” Fettweis told AFP.
Bears on thin ice
The current trajectory of climate change and the advent of ice-free summers – defined by the U.N.’s IPCC climate science panel as under 1 million square kilometers – would indeed starve polar bears into extinction by the century’s end, according to a July study in the journal Nature.
“Human-caused global warming means that polar bears have less and less sea ice to hunt on in the summer months,” Steven Amstrup, lead author of the study and chief scientist of Polar Bears International, told AFP.
“The ultimate trajectory of polar bears with unabated greenhouse gas emissions is disappearance,” he said.
NASA’s OSIRIS-REx grabs rocks from asteroid in historic mission – Al Jazeera English
A NASA spacecraft touched down on the rugged surface of the Bennu asteroid on Tuesday, grabbing a sample of rocks dating back to the birth of the solar system to bring home.
It was a first for the United States – only Japan has previously secured asteroid samples.
The so-called “Touch-And-Go” manoeuvre was managed by Lockheed Martin Space in Denver, Colorado, where at 6.12pm (22:12 GMT) on Tuesday an announcer said: “Touchdown declared. Sampling is in progress,” and scientists erupted in celebration.
Seconds later, the Lockheed mission operator Estelle Church confirmed the spacecraft had eased away from the space rock after making contact, announcing: “Sample collection is complete and the back-away burn has executed.”
The historic mission was 12 years in the making and rested on a critical 16-second period where the minivan-sized OSIRIS-REx spacecraft extended its 11-foot (3.35-metre) robotic arm towards a flat patch of gravel near Bennu’s north pole and plucked the sample of rocks – NASA’s first handful of pristine asteroid rocks.
The probe will send back images of the sample collection on Wednesday and throughout the week so scientists can examine how much material was retrieved and determine whether the probe will need to make another collection attempt.
Scientists want at least 2 ounces (60 grams) and, ideally, closer to 4 pounds (2 kilogrammes) of Bennu’s black, crumbly, carbon-rich material – thought to contain the building blocks of the solar system. The asteroid is located more than 200 million miles (321.9 million kms) from Earth.
NASA’s science mission chief, Thomas Zurbuchen, likened Bennu to the Rosetta Stone: “Something that’s out there and tells the history of our entire Earth, of the solar system, during the last billions of years.”
If a successful collection is confirmed, the spacecraft will begin its journey back towards Earth, arriving in 2023.
“Everything went just exactly perfect,” Dante Lauretta, OSIRIS-REx principal investigator from the University of Arizona, Tucson, said on a NASA live feed from Lockheed’s mission support building. “We have overcome the amazing challenges that this asteroid has thrown at us, and the spacecraft appears to have operated flawlessly.”
The robotic arm’s collection device, shaped like an oversized shower head, is designed to release pressurised gas to kick up debris.
The spacecraft launched in 2016 from Kennedy Space Center for the journey to Bennu. It has been in orbit around the asteroid for nearly two years preparing for the Touch and Go manoeuvre.
Bennu, which is more than 4.5 billion years old, was selected as a target because scientists believe it is a small fragment of what was once a much larger space rock that broke off during a collision between two asteroids early on in the history of the solar system.
“Asteroids are like time capsules floating in space that can provide a fossil record of the birth of our solar system,” Lori Glaze, NASA’s director of Planetary Science, told Al Jazeera. “They can provide valuable information about how planets, like our own, came to be.”
Thanks to data collected from orbit, the NASA team has determined two key discoveries: first, that between 5 and 10 percent of Bennu’s mass is water, and second, that its surface is littered with carbon-rich molecules. Atomic-level analysis of samples from Bennu could help scientists better understand what role asteroids played in bringing water to the Earth and seeding it with the prebiotic material that provided the building blocks for life.
Studying that material could also help scientists discover whether life exists elsewhere in the solar system, as well.
“If this kind of chemistry is happening in the early solar system, it probably happened in other solar systems as well,” Lauretta, OSIRIS-Rex’s principal investigator, told Al Jazeera in an interview ahead of Tuesday’s breakthrough. “It helps us assess the likelihood of the origin of life occurring throughout the galaxy and, ultimately, throughout the universe.”
Japan expects samples from its second asteroid mission – in the milligramMEs at most – to land in the Australian desert in December.
New Research Provides Comprehensive Reconstruction of End-Permian Mass Extinction | Paleontology – Sci-News.com
The end-Permian mass extinction, also known as the Permian-Triassic extinction event and the Great Dying, is the largest mass extinction event in Earth’s history that peaked about 252.3 million years ago. The catastrophe killed off nearly 96% of all marine species and 70% of terrestrial vertebrate species on the planet over the course of thousands of years. Massive eruptions in a volcanic system called the Siberian Traps are thought to have played an important role, but the causational trigger and its feedbacks are yet to be fully understood. Now, a research team led by Dr. Hana Jurikova from the GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel and the Helmholtz Zentrum Potsdam has assembled a consistent biogeochemical reconstruction of the mechanisms that resulted in the end-Permian extinction.
Dr. Jurikova and her colleagues studied isotopes of the element boron in the calcareous shells of fossil brachiopods and determined the rate of ocean acidification over the Permian-Triassic boundary.
“These are clam-like organisms that have existed on Earth for more than 500 million years,” Dr. Jurikova said.
“We were able to use well-preserved brachiopod fossils from the Southern Alps for our analyses.”
“These shells were deposited at the bottom of the shallow shelf seas of the Tethys Ocean 252 million years ago and recorded the environmental conditions shortly before and at the beginning of extinction.”
Because the ocean pH and atmospheric carbon dioxide are closely coupled, the researchers were able to reconstruct changes in atmospheric carbon dioxide at the onset of the extinction from boron and carbon isotopes.
They then used an innovative geochemical model to study the impact of the carbon dioxide injection on the environment.
“With this technique, we can not only reconstruct the evolution of the atmospheric carbon dioxide concentrations, but also clearly trace it back to volcanic activity,” said co-author Dr. Marcus Gutjahr, a researcher at the GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel.
“The dissolution of methane hydrates, which had been suggested as a potential further cause, is highly unlikely based on our data.”
“Without these new techniques it would be difficult to reconstruct environmental processes more than 250 million years ago in the same level of detail as we have done now,” said co-author Professor Anton Eisenhauer, also from the GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel.
The team’s findings showed that volcanic eruptions in Siberian Traps released immense amounts of carbon dioxide into the atmosphere.
This release lasted several millennia and led to a strong greenhouse effect on the late Permian world, causing extreme warming and acidification of the ocean.
Dramatic changes in chemical weathering on land altered productivity and nutrient cycling in the ocean, and ultimately led to vast de-oxygenation of the ocean.
The resulting multiple environmental stressors combined to wipe out a wide variety of animal and plant groups.
“We are dealing with a cascading catastrophe in which the rise of carbon dioxide in the atmosphere set off a chain of events that successively extinguished almost all life in the seas,” Dr. Jurikova said.
“Ancient volcanic eruptions of this kind are not directly comparable to anthropogenic carbon emissions, and in fact all modern fossil fuel reserves are far too insufficient to release as much carbon dioxide over hundreds of years, let alone thousands of years as was released 252 million years ago.”
“But it is astonishing that humanity’s carbon dioxide emission rate is currently 14 times higher than the annual emission rate at the time that marked the greatest biological catastrophe in Earth’s history.”
The study was published in the journal Nature Geoscience.
H. Jurikova et al. Permian-Triassic mass extinction pulses driven by major marine carbon cycle perturbations. Nat. Geosci, published online October 19, 2020; doi: 10.1038/s41561-020-00646-4
Haunted houses find ways around COVID 19
Psychotic clowns. Axe murderers. Bedrooms possessed by poltergeists.
Many of the frights greeting visitors of horror attractions this Halloween will be familiar, but the thrill-creators behind them say one terrifying experience is squarely off-limits: the terrors of COVID-19.
Before the pandemic shook our lives, haunted houses sometimes dipped into the fears of contagion, splashing themed rooms with signs of a viral outbreak, hazmat suits and contamination warnings.
But with those experiences uncomfortably close to reality this year, horror masters like Shawn Lippert say reminding people of the virus is one line they’re not willing to cross.
“We use the analogy: Treat `COVID’ like the F-word in church,” said the owner of Scarehouse, an industrial-sized indoor haunted house in Windsor, Ont.
“It’s too real and so close to home. It’s almost like when you tell a joke and they say, `Too soon.”’
Lippert said that’s one of several rules he’s introduced at his haunt in order to keep people feeling safe and heath authorities satisfied. Ticketholders arrive at staggered times, and everyone is required to wear a mask.
Creepy objects that once brushed against visitors have been removed, and the giant airbags that evoke the feeling of claustrophobia have been stowed away to decrease the potential spread of germs.
Lippert describes those as small changes in a challenging year.
Many haunt operators were jittery about moving ahead with their usual Halloween festivities, considering health authorities could shut down the houses without much notice if the region experiences a surge in local cases. That would leave a brutal dent in their investments.
“If we can keep our doors open for the full run at this point, that would be a success for us,” Lippert said.
Several Toronto haunted houses decided the risk was too high. Casa Loma’s Legends of Horror and 28-year pillar Screemers at Exhibition Place were among the operators who decided to sit this year out, even before the city introduced tighter restrictions that would’ve closed them anyway.
Some organizers have used the pandemic to imagine ways to scare the living daylights out of people from a distance — often from the safety of their own vehicles.
The Pickering Museum Village put a historic spin on its spooky experience with a drive-thru tour that urged visitors to creep their cars along a roadway checkered with old houses, as ghost stories played on their FM radios.
Others have gone online with virtual group parties for kids or, for those of legal drinking age, what’s being sold as Canada’s first Virtual Halloween Cocktail Crawl.
Mentalist Jaymes White decided to embrace the digital world this year for his annual Halloween seances. His new Zoom experience, called Evoke, invites a small circle of friends to channel a spirit through video chat. He admits the idea goes against the traditions of a seance, where people usually hold hands around a table, but he’s confident the spirits will still be ready to unsettle his guests.
“They don’t care that we have a pandemic,” he said.
Paul Magnuson, one of the leaders at Calgary artist collective Big Art, will take over a downtown self-serve car wash for three days for a drive-in of the dead later this month.
Scare Wash is described as a trip to hell and back that begins when a wash attendee’s seemingly normal car rinse spirals into a nightmare.
Magnuson came up with the idea when it was clear plans for his usual neighbourhood spectacle wouldn’t be possible in the pandemic.
“Last year I turned my garage into a Dexter killer room where we did performances all night. In previous years I’ve had an interactive cemetery,” he said.
“I’m not going to let COVID take this holiday.”
Robby Lavoie felt a similar conviction for keeping Terror Train on track this year at the National Ontario Railroad Museum and Heritage Centre. The annual Halloween event draws thousands of people to Capreol, Ont., part of Greater Sudbury, and provides the museum with a healthy dose of revenue.
Lavoie said he drew inspiration from videos he saw of a Japanese zombie drive-in haunted house over the summer. He knew there was a way to tone down the gore and make the idea a bit more Canadian.
After speaking with museum organizers, Lavoie secured the board’s approval for “Inferno 6077,” an immersive drive-in horror experience inside the garage of the fire hall.
Pulling from his own knowledge of working in live theatre and movies, Lavoie began thinking on a grand scale. He hired a local writer who penned a story about townsfolk who seek revenge on an old man, and built rolling set pieces for the spectacle, which reaches its peak when the space is engulfed in flames, an illusion created with lights and projections.
“We’re putting you almost in an interactive movie, and it all came together within a month,” he said.
“I see myself doing this again next year, even if there isn’t COVID.”
Kathrine Petch understands the urge to keep Halloween on the calendar. As the general manager of Deadmonton Haunted House in Edmonton, she’s laid down strict COVID-19 precautions for their Area 51-themed haunt.
“The absolute, pure excitement of the customers is contagious to us,” she said.
“As long as we can pay the bills and have some money left over to make a different haunted house next year, I think we’ll be pretty happy.”
Petch said keeping Deadmonton open during the pandemic was important to everyone who runs the show.
“One of our biggest goals was to provide people with some kind of escape from all the crappiness that is 2020,” she said.
“And when they reach the end of our haunted house, at least they know the scares are done.”
Source: – CityNews Toronto
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