Scientists have been watching extreme weather events unfold all over the world this summer, seeing the many links between heatwaves, floods, droughts and climate change.
But the scale of some of these events, and just how dramatically they have upended previous records, suggests that the climate is no longer changing in a gradual, predictable way.
Deadly heat waves and other wild weather are putting renewed attention on tipping points — the idea that major shifts to key ecosystems, such as Greenland’s ice sheets or the Amazon rainforest, can cause large, irreversible changes to the planet’s climate balance.
“Tipping points are large-scale changes that could happen abruptly and could be potentially irreversible,” said Owen Gaffney, an analyst at the Stockholm Resilience Centre, a research institute
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He co-authored a 2019 article in the journal Nature that listed nine tipping points around the world that scientists are watching with growing concern. A prime example is the ice-sheets in parts of Antarctica and Greenland. Rather than gradually shrinking as the climate warms, research suggests the sheets could hit points of no return leading to rapid and irreversible ice loss — and a corresponding rise in global sea levels.
In Greenland, models suggest the “ice sheet could be doomed at 1.5 C of warming, which could happen as soon as 2030,” the report said.
In Canada, the trends are worrying. This summer, various parts of British Columbia saw temperature records broken during the heatwave in June, notably the town of Lytton, which set the record for the hottest temperature ever recorded in Canada at 49.6 C — a remarkable 5.2 C increase over Lytton’s previous heat record (which was also a record for B.C.) in 1941.
“The analogy that scientists used to use is that as you warm the climate, it is like loading a pair of dice. And so now when you roll the dice, you get more sixes than you would have before,” said Simon Donner, a professor at the University of British Columbia who studies climate science and public policy.
“But what we’ve been seeing this summer isn’t a six, it’s like a seven or eight, something that wasn’t possible with the old dice.”
A study examining how much of the heatwave on the west coast could be attributed to human-caused climate change by a group of international scientists suggested that one explanation for the high temperatures could be “nonlinear interactions in the climate.”
Rather than gradual increases in temperature extremes, this theory suggests that the present amount of climate change is causing bigger-than-expected increases in extreme heat due to interactions in the climate system that are not fully understood.
And that raises questions about what cities and communities need to do to adapt to a future climate that looks increasingly uncertain.
Tipping points may have been already reached
An international group of climate scientists are now warning that there is “mounting evidence that we are nearing or have already crossed tipping points associated with critical parts of the Earth system.” In a paper published in the journal BioScience on July 28, researchers pointed to the West Antarctic and Greenland ice sheets, warm-water coral reefs, and the Amazon rainforest as climate systems that were possibly nearing or had already reached their tipping point.
The paper tracked 31 key climate variables, such as global emissions and tree cover loss and found that 18 are at all-time records. That includes the three important greenhouse gases, carbon dioxide, methane and nitrous oxide, which reached new records for atmospheric concentrations in both 2020 and 2021.
Given the impacts we are seeing at roughly 1.25 C of global warming, “combined with the many reinforcing feedback loops and potential tipping points, massive-scale climate action is urgently needed,” the paper said.
Paul Ritchie, a mathematician and climate scientist at the University of Exeter in the U.K., researches where those tipping points lie and how far we can overshoot some of them while still being able to recover. Certain changes, such as the loss of ice sheets, have a relatively long timescale, Ritchie said, occurring over many centuries.
“But then there are these other elements… where these can happen over much shorter timescales, maybe years or decades,” he said.
“So pretty much as soon as we go over these particular thresholds, we might instantly know because we have this sudden loss of the Amazon rainforest or the monsoon suddenly stops operating.”
Both events would have devastating consequences. Millions of people rely on the monsoons for agriculture, while the Amazon’s loss could release even more carbon and accelerate global warming.
Adaptation still possible, but Canada not there yet
Canada announced a plan to develop a national adaptation strategy in December 2020. But experts warn the country is not ready for the climate we have now, and needs to move fast to respond to the future.
“The reality is that we should assume that we’re not going to meet that [Paris Agreement] target of 2 C,” said Gordon McBean, a professor at the Western University in London, Ont., of the global deal to reduce carbon emissions to stop the worst impacts of climate change.
McBean was the lead investigator on a report for the federal government earlier this year on building community resilience to climate change.
His report found that while many cities have high level plans to address climate change, others still lack detailed implementation strategies or funding.
“Most actions to build community resilience in Canada are unplanned and take place in recovery following an extreme loss event,” the report said.
As average temperatures rise in linearly fashion, the number of extreme weather events increases more dramatically, McBean said. “An adaptation strategy has to take into account not just future projections of weather, but also future projections of greenhouse gas emissions, and the chance that the rest of the world will not meet its emissions reduction goals.”
Recent heat domes and tornados are examples of the kinds of events that will happen more often in the future, he said.
With the climate set to continue to change for years to come, and new information coming out about the dangers of tipping points that could lead to extreme weather that’s unforeseen, adaptation has become more urgent.
McBean said there’s enough information available now to start planning for that uncertain future, and make communities more resilient.
“It’s not saying we failed. It’s saying here’s what we need to do,” he said.
Dark Energy Could Be Responsible for Mysterious Experiment Signals, Researchers Say – Gizmodo
A team of physicists at the University of Cambridge suspects that dark energy may have muddled results from the XENON1T experiment, a series of underground vats of xenon that are being used to search for dark matter.
Dark matter and dark energy are two of the most discussed quandaries of contemporary physics. The two darks are placeholder names for mysterious somethings that seem to be affecting the behavior of the universe and the stuff in it. Dark matter refers to the seemingly invisible mass that only makes itself known through its gravitational effects. Dark energy refers to the as-yet unexplained reason for the universe’s accelerating expansion. Dark matter is thought to make up about 27% of the universe, while dark energy is 68%, according to NASA.
Physicists have some ideas to explain dark matter: axions, WIMPs, SIMPs, and primordial black holes, to name a few. But dark energy is a lot more enigmatic, and now a group of researchers working on XENON1T data says an unexpected excess of activity could be due to that unknown force, rather than any dark matter candidate. The team’s research was published this week in Physical Review D.
The XENON1T experiment, buried below Italy’s Apennine Mountains, is set up to be as far away from any noise as possible. It consists of vats of liquid xenon that will light up if interacted with by a passing particle. As previously reported by Gizmodo, in June 2020 the XENON1T team reported that the project was seeing more interactions than it ought to be under the Standard Model of physics, meaning that it could be detecting theorized subatomic particles like axions—or something could be screwy with the experiment.
“These sorts of excesses are often flukes, but once in a while they can also lead to fundamental discoveries,” said Luca Visinelli, a researcher at Frascati National Laboratories in Italy and a co-author of the study, in a University of Cambridge release. “We explored a model in which this signal could be attributable to dark energy, rather than the dark matter the experiment was originally devised to detect.”
“We first need to know that this wasn’t simply a fluke,” Visinelli added. “If XENON1T actually saw something, you’d expect to see a similar excess again in future experiments, but this time with a much stronger signal.”
Despite constituting so much of the universe, dark energy has not yet been identified. Many models suggest that there may be some fifth force besides the known four known fundamental forces in the universe, one that is hidden until you get to some of the largest-scale phenomena, like the universe’s ever-faster expansion.
Axions shooting out of the Sun seemed a possible explanation for the excess signal, but there were holes in that idea, as it would require a re-think of what we know about stars. “Even our Sun would not agree with the best theoretical models and experiments as well as it does now,” one researcher told Gizmodo last year.
Part of the problem with looking for dark energy are “chameleon particles” (also known as solar axions or solar chameleons), so-called for their theorized ability to vary in mass based on the amount of matter around them. That would make the particles’ mass larger when passing through a dense object like Earth and would make their force on surrounding masses smaller, as New Atlas explained in 2019. The recent research team built a model that uses chameleon screening to probe how dark energy behaves on scales well beyond that of the dense local universe.
“Our chameleon screening shuts down the production of dark energy particles in very dense objects, avoiding the problems faced by solar axions,” said lead author Sunny Vagnozzi, a cosmologist at Cambridge’s Kavli Institute for Cosmology, in a university release. “It also allows us to decouple what happens in the local very dense Universe from what happens on the largest scales, where the density is extremely low.”
The model allowed the team to understand how XENON1T would behave if the dark energy were produced in a magnetically strong region of the Sun. Their calculations indicated that dark energy could be detected with XENON1T.
Since the excess was first discovered, the XENON1T team “tried in any way to destroy it,” as one researcher told The New York Times. The signal’s obstinacy is as perplexing as it is thrilling.
“The authors propose an exciting and interesting possibility to expand the scope of the dark matter detection experiments towards the direct detection of dark energy,” Zara Bagdasarian, a physicist at UC Berkeley who was unaffiliated with the recent paper, told Gizmodo in an email. “The case study of XENON1T excess is definitely not conclusive, and we have to wait for more data from more experiments to test the validity of the solar chameleons idea.”
The next generation of XENON1T, called XENONnT, is slated to have its first experimental runs later this year. Upgrades to the experiment will hopefully seal out any noise and help physicists home in on what exactly is messing with the subterranean detector.
Scientists may have accidentally detected dark energy – CTV News
Dark energy, a mysterious force believed to be causing the universe to expand at an accelerated rate, may have been detected by scientists for the first time.
In a new study, published Wednesday in the journal Physical Review D, the authors suggest certain unexplained results from an experiment designed to detect dark matter could have been caused by dark energy.
“Despite both components being invisible, we know a lot more about dark matter, since its existence was suggested as early as the 1920s, while dark energy wasn’t discovered until 1998,” Sunny Vagnozzi, of the University of Cambridge’s Kavli Institute for Cosmology, said in a story posted by the university. “Large-scale experiments like XENON1T have been designed to directly detect dark matter, by searching for signs of dark matter ‘hitting’ ordinary matter, but dark energy is even more elusive.”
Nearly everything we can see and interact with, from bacteria to entire galaxies, is considered ordinary matter and energy, and makes up about five per cent of our universe, according to scientists. The rest is made up of dark matter (27 per cent), an invisible attractive force that holds the cosmos together, and dark energy (68 per cent), a repulsive force considered to be responsible for the accelerating expansion of the universe.
The XENON research project is a collaboration of 160 scientists from around the world who have come together to perform a series of experiments aimed at detecting dark matter particles. These experiments involve the use of ultra-pure liquid xenon, a colourless, dense, odourless noble gas found in trace amounts in Earth’s atmosphere.
Experiments are performed at the Gran Sasso National Laboratory, the largest underground laboratory in the world, located approximately 1.4 kilometres beneath the Gran Sasso mountains in central Italy, about 120 kilometres northeast of Rome.
The XENON1T experiment was the latest phase of the project. About a year ago, it detected an unexpected signal, or excess, over the expected background profile.
“These sorts of excesses are often flukes, but once in a while they can also lead to fundamental discoveries,” Luca Visinelli, researcher at Frascati National Laboratories in Italy, said. “We explored a model in which this signal could be attributable to dark energy, rather than the dark matter the experiment was originally devised to detect.”
The researchers created a physical model that used a type of screening mechanism known as chameleon screening to show that dark energy particles produced in the Sun’s strong magnetic fields could explain the XENON1T signal.
“It was really surprising that this excess could in principle have been caused by dark energy rather than dark matter,” Vagnozzi said. “When things click together like that, it’s really special.”
A discovery such as this would mean that experiments designed to detect dark matter, including those performed during the XENON project, could also be used to detect dark energy. But further research is required to confirm these findings.
“We first need to know that this wasn’t simply a fluke,” Visinelli said. “If XENON1T actually saw something, you’d expect to see a similar excess again in future experiments, but this time with a much stronger signal.”
'Happy' SpaceX tourist crew spend first day whizzing around Earth – Phys.org
SpaceX’s all-civilian Inspiration4 crew spent their first day in orbit conducting scientific research and talking to children at a pediatric cancer hospital, after blasting off on their pioneering mission from Cape Canaveral the night before.
St Jude tweeted its patients got to speak with the four American space tourists, “asking the questions we all want to know like ‘are there cows on the Moon?'”
Billionaire Jared Isaacman, who chartered the flight, is trying to raise $200 million for the research facility.
Inspiration4 is the first orbital spaceflight with only private citizens aboard.
Earlier, Elon Musk’s company tweeted that the four were “healthy” and “happy,” had completed their first round of scientific research, and enjoyed a couple of meals.
Musk himself tweeted that he had personally spoken with the crew and “all is well.”
By now, they should have also been able to gaze out from the Dragon ship’s cupola—the largest space window ever built, which has been fitted onto the vessel for the first time in place of its usual docking mechanism.
Most humans in space
The Inspiration4 mission also brings the total number of humans currently in space to 14—a new record. In 2009, there were 13 people on the International Space Station (ISS).
There are currently seven people aboard the ISS, including two Russian cosmonauts, and three Chinese astronauts on spaceship Shenzhou-12, which is bound home after its crew spent 90 days at the Tiangong space station.
Isaacman, physician assistant Hayley Arceneaux, geoscientist Sian Proctor and aerospace data engineer Chris Sembroski are whizzing around the planet at an altitude that at times reaches 590 kilometers (367 miles).
That is deeper in space than the ISS, which orbits at 420 kilometers (260 miles), and the furthest any humans have ventured since a 2009 maintenance mission for the Hubble telescope.
Their ship is moving at about 17,500 mph (28,000 kph) and each day they will experience about 15 sunrises and sunsets.
Their high speed means they are experiencing time slightly slower than people on the surface, because of a phenomenon called “relative velocity time dilation.”
Apart from fundraising for charity, the mission aims to study the biological effects of deep space on the astronauts’ bodies.
“Missions like Inspiration4 help advance spaceflight to enable ultimately anyone to go to orbit & beyond,” added Musk in a tweet.
The space adventure bookends a summer marked by the battle of the billionaires Richard Branson and Jeff Bezos to reach the final frontier.
But these flights only offered a few minutes of weightlessness—rather than the three full days of orbit the Inspiration4 crew will experience, before splashing down off the coast of Florida on Saturday.
© 2021 AFP
‘Happy’ SpaceX tourist crew spend first day whizzing around Earth (2021, September 17)
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