Connect with us

Science

The daring plan to save the Arctic ice with glass

Published

 on

The fear that action to combat climate change has been too slow has led some scientists to test unconventional methods to stem the loss of Arctic sea ice.

One of the most important, yet underappreciated, features of the Arctic sea ice is the ability of its blindingly white surfaces to reflect sunlight. For at least as long as our species has existed, the frozen seas at the top of our world have acted as a massive parasol that helps keep the planet cool and its climate stable.

Yet now, much of that ice is rapidly vanishing. Rising temperatures have locked the Arctic in a self-destructive feedback loop: the warmer it gets, the reflective white ice dissolves into darker, blue water, which absorbs more of the Sun’s warmth rather than reflecting it back into space. Warmer water accelerates melting, which means yet more absorption of heat, which drives further melting – and so on in a vicious cycle that is part of the reason why the Arctic is warming around twice as fast as the rest of the planet. This July, ice cover was as low as it had ever been at that time of the year.

As planet-warming greenhouse gas emissions continue to rise, some have been driven to explore desperate measures. One proposal put forward by the California-based non-profit Arctic Ice Project appears as daring as it is bizarre: to scatter a thin layer of reflective glass powder over parts of the Arctic, in an effort to protect it from the Sun’s rays and help ice grow back. “We’re trying to break [that] feedback loop and start rebuilding,” says engineer Leslie Field, an adjunct lecturer at Stanford University and chief technical officer of the organisation.

The melting of the sea ice has impacts far beyond the Arctic and its inhabitants. It will contribute to rising sea levels, and some say it’s already disrupting weather patterns around the globe. If we lose our protective white shield entirely – which some reckon could happen just decades from now – it could have the same warming effect as another 25 years of fossil fuel emissions at current rates, which would mean more intense droughts, flooding and heat waves. By rebuilding sea ice, Field hopes her approach will also restore its ancient function as a planetary air-conditioner and help counteract the effects of global warming. (Read more about how ice loss in the Arctic affects the rest of the world.)

Tiny powder-like beads could increase the reflectivity of Arctic ice, to reflect more of the Sun’s warmth back into space (Credit: Susan Kramer/Arctic Ice Project)

Many scientists frown upon such technological interventions in Earth’s planetary system, known broadly as “geoengineering”, arguing that fiddling with nature might cause further damage. However, “the utter lack of progress on climate mitigation is really opening up a space for all of these [geoengineering] things to be discussed,” says Emily Cox, who studies climate policy and public attitudes towards geoengineering at the University of Cardiff. That said, the urgency does not erase the uncertainty. “What do you do if something goes wrong… especially in the Arctic, which is already a fairly fragile ecosystem?”

Field launched the Arctic Ice Project — formerly known as ICE911 — in 2008, soon after watching the climate change documentary An Inconvenient Truth, which convinced her of the urgency of doing something about the melting sea ice. In particular, it’s the fate of old, thick sea ice that worries her the most – the kind that lasts multiple years. This mature ice, dazzlingly white, has a high albedo, meaning it’s extremely good at reflecting sunlight – much more so than the thinner and darker young ice that forms each polar winter only to melt again during the summer. Yet over the past 33 years, that ice has dwindled by a staggering 95%.

What if, Field asked, she could layer a reflective material on top of the young ice to protect it during the summer months? If it had that extra protection, could it rebuild into sturdy multi-year ice, and kick-start a local process of ice regrowth? She settled on silica – or silicon dioxide – which occurs naturally in most sand and is often used to make glass, as the material of choice. She found a manufacturer that turns it into tiny, brightly reflective beads, each one 65 micrometers in diameter – thinner than a human hair, but too large for them to be inhaled and cause lung problems, Field says. The beads are also hollow inside, so they’ll float on water and continue to reflect away sunlight even if the ice begins to melt.

Over the past decade, she and her team have scattered the silica spheres over several lakes and ponds in Canada and the United States, so far with encouraging results. For instance, in a pond in Minnesota, just a few layers of glass powder made young ice 20% more reflective – enough to delay the melting of the ice. By spring, when the ice in an uncovered area of the pond had completely vanished, there was still nearly a foot of ice in the section treated with the glass beads.

Dark blue water absorbs more of the Sun's rays, accelerating the process of global warming - but bright white ice reflects that radiation away (Credit: Getty Images)

Dark blue water absorbs more of the Sun’s rays, accelerating the process of global warming – but bright white ice reflects that radiation away (Credit: Getty Images)

Field doesn’t want to carpet the Arctic in glass. Instead, she plans on distributing it strategically to protect some particularly fast-melting, vulnerable areas, like the Fram Strait, a thin passage between Greenland and Svalbard. According to results of a climate model she presented last December at the annual meeting of the American Geophysical Union, treating the Fram Strait could lead to large-scale ice regrowth across parts of the Arctic.

Scientists agree that the beads are well-intentioned, but worry about their potential effects on the Arctic ecosystem. If they float around there indefinitely, “it’s just going to clog up the ocean and mess with the ecosystem,” says Cecilia Bitz, an atmospheric scientist at the University of Washington who specialises in Arctic sea ice.

Field argues that the balls are safe because silica is so abundant in nature – indeed, it routinely washes from weathered rocks via rivers into the sea. And according to some safety testing as part of her 2018 study, the beads, when ingested, cause no ill effects in at least two species – sheepshead minnow fish and northern bobwhite birds.

However, some biologists are concerned about the potential effects on the creatures at the base of the Arctic food chain. Depending on how much light the silica beads reflect, they could block sunlight from photosynthesising plankton, such as diatoms, algae that live under the sea ice and around it. Any change in plankton abundance could cascade up the food web and have unpredictable effects on organisms from fish to seals and polar bears, notes Karina Giesbrecht, an ocean chemist and ecologist at Canada’s University of Victoria who has studied the role of silica in Arctic ecosystems.

On top of that, the silica balls are similar in size to diatoms, which are eaten by zooplankton known as copepods, Giesbrecht notes. If the beads sank into the water column, copepods might consume them thinking they are diatoms, without gaining any nutrition. In the worst case, the copepods could starve, with knock-on effects for other members of the Arctic ecosystem.

So far, Field has been using beads that mostly stay afloat (though some inevitably sink each season), and she is planning to test their impact on plankton ecosystems. If there are any harmful effects, she’ll explore ways of tailoring the beads to make them ecologically safer, she says. One option she is considering is whether to tweak their composition such that they dissolve after a period of time. There are many other questions that her team, which is about to undertake further testing in seawater-filled pools in Alaska, will have to answer to convince the world that the approach is safe and effective.

The young, thin Arctic ice is darker and less reflective than the thick, white, old ice – pushing the Arctic into a feedback cycle of warming (Credit: Martha Henriques)

The young, thin Arctic ice is darker and less reflective than the thick, white, old ice – pushing the Arctic into a feedback cycle of warming (Credit: Martha Henriques)

For one, Mark Serreze, a climate scientist who directs the US National Snow and Ice Data Center at the University of Colorado, Boulder, wonders whether they’ll work as intended. “If you put down the silica beads in an area of fast-moving ocean currents, notably the Fram Strait, they will be quickly dispersed,” rendering them ineffective, he says.

The proposal also raises financial questions, like who would foot the approximately $1-5bn (£800m to £4bn) annual bill for making, shipping, testing and distributing the necessary silica beads in the Fram Strait. It may be an eye-watering figure, but it starts to look small next to the estimated $460bn (£360bn) that the United States incurred in extreme weather and climate disasters between 2017 and 2019 alone, Field notes.

Researchers are exploring the feasibility of other geoengineering approaches to save the melting Arctic, but none come without problems. One, for instance, would entail building millions of wind-powered devices to pump water from the deep to the ice surface in order to build up thicker layers of ice – which is energy-intensive and might not be very effective, Bitz says. She and Serreze view such approaches as stop-gap solutions to climate change, in that they only treat single symptoms – in the case of silica dust, temperatures – while doing nothing about the root cause of it. If Field’s strategy works as intended, “that’s wonderful,” Bitz says, “but I know that not emitting CO2 in the first place will work.”

Field agrees that geoengineering is in no way a replacement for reducing carbon emissions. Rather, she sees it as a chance to buy the time needed for world economies to decarbonise and stave off the worst impacts of climate change. The silica beads, she says, are “the backup plan I hoped we’d never need”.

Source:- BBC News

Source link

Continue Reading

Science

NASA’s OSIRIS-REx grabs rocks from asteroid in historic mission – Al Jazeera English

Published

 on


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.

This mosaic image of asteroid Bennu was composed of 12 PolyCam images collected on December 2, 2018 by the OSIRIS-REx spacecraft from a range of 15 miles (24 km) [NASA/Goddard/University of Arizona/Handout via Reuters]

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.”

‘Exactly perfect’

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.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

New Research Provides Comprehensive Reconstruction of End-Permian Mass Extinction | Paleontology – Sci-News.com

Published

 on


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.

An illustration depicting the onset of the end-Permian mass extinction. Image credit: Dawid Adam Iurino / PaleoFactory, Sapienza University of Rome / Jurikova et al, doi: 10.1038/s41561-020-00646-4.

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

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Haunted houses find ways around COVID 19

Published

 on

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

Source link

Continue Reading

Trending