Tuesday, October 05, 2021

Trio win physics Nobel for work deciphering chaotic climate

Niklas Pollard and Ludwig Burger and Simon Johnson
Tue, October 5, 2021

In this article:

* 2021 Nobel Prize for Physics goes to three scientists

* Their work improved understanding of changing climate

* World Meteorological Organization hails decision (Adds Manabe, Hasselmann comments, background)



By Niklas Pollard, Ludwig Burger and Simon Johnson

STOCKHOLM, Oct 5 (Reuters) - Japanese-born American Syukuro Manabe, German Klaus Hasselmann and Italian Giorgio Parisi won the 2021 Nobel Prize in Physics on Tuesday for work that helps understand complex physical systems such as Earth's changing climate.

In a decision hailed by the U.N. weather agency as a sign of a consensus forming around man-made global warming, one half of the 10-million Swedish crown ($1.15-million) prize goes in equal parts to Manabe, 90, and Hasselmann, 89, for modelling earth’s climate and reliably predicting global warming.

The other half goes to Parisi for discovering in the early 1980s "hidden rules" behind seemingly random movements and swirls in gases or liquids, which can also be applied to aspects of neuroscience, machine learning and starling flight formations.

"Syukuro Manabe and Klaus Hasselmann laid the foundation of our knowledge of the Earth’s climate and how humanity influences it," the Royal Swedish Academy of Sciences said in a statement. "Giorgio Parisi is rewarded for his revolutionary contributions to the theory of disordered materials and random processes."

Hasselmann, who is at the Max Planck Institute for Meteorology in Hamburg, told Reuters from his home that he did not want to wake up from what he described as a beautiful dream.

"I am retired, you know, and have been a bit lazy lately. I am happy about the honour. The research continues," he said.

The Academy said Manabe, who works at Princeton University in the United States, had laid the foundation in the 1960s for today's understanding of Earth's climate after moving to the United States from Japan to continue his research.

"In the context of the competition of the Cold War era, America in the 1960s was putting a tremendous amount of effort into scientific research," he said in an interview with Japanese broadcaster NHK after learning of his award.

"Being invited to America was my good fortune, rapid development in electronic calculators was also my good fortune, and so with an accumulation of good fortune I am here today."

Hasselmann, the Academy said, had developed models about 10 years later that became instrumental in proving that mankind's carbon dioxide emissions cause rising temperatures in the atmosphere.

Parisi, who dialled into the media briefing announcing the winners, was asked for his message to world leaders due to meet for U.N. climate change talks in Glasgow, Scotland, from Oct. 31.

"I think it is very urgent that we take real and very strong decisions and we move at a very strong pace," said the 73-year-old laureate who works at Sapienza University of Rome.

Scientists have spent decades urging climate change action on an often reluctant society, Hasselmann said in a recording published on the Nobel Prize's website.

"It is just that people are not willing to accept the fact that they have to react now for something that will happen in a few years," he said.

GLOBAL WARMING


Work on climate changes has been recognised by Nobel prizes before.

Former U.S. Vice President Al Gore and the U.N. climate panel received the Peace Prize in 2007 for galvanizing international action against global warming, and William Nordhaus won one half of the 2018 Economics prize for integrating climate change into the Western economic growth model.

Swedish climate activist Greta Thunberg is also seen as a strong contender for this year's Peace Prize, due to be announced from Oslo on Friday.

"Sceptics or deniers of scientific facts ... are not so visible anymore and this climate science message has been heard," World Meteorological Organization Secretary-General Petteri Taalas said of this year's award.

Physics is the second Nobel to be awarded this week after Americans David Julius and Ardem Patapoutian won the prize for medicine
on Monday for the discovery of receptors in the skin that sense temperature and touch.

The Nobel prizes were created in the will of Swedish dynamite inventor and businessman Alfred Nobel and have been awarded since 1901 with only a handful of interruptions, primarily due to the two world wars.

As last year, there will be no banquet in Stockholm because of the COVID-19 pandemic. The laureates will receive their medals and diplomas in their home countries.

The physics prize announcement will be followed in the coming days by the awards for chemistry, literature, peace and economics. ($1 = 8.7290 Swedish crowns)

(Ludwig Burger reported from Frankfurt; Additional reporting by Terje Solsvik in Oslo, Supantha Mukherjee and Anna Ringstrom in Stockholm, Johan Ahlander in Gothenburg, Kirsti Knolle in Berlin, Emma Farge in Geneva, Chizu Nomiyama in New York and Angelo Amante in Rome, Editing by Timothy Heritage and Jon Boyle)

Physics Nobel: deciphering climate disorder to better predict it

Issued on: 05/10/2021 - 
US-Japanese scientist Syukuro Manabe who has been awarded the 2021 Nobel Prize in physics
 KENA BETANCUR AFP/File

Paris (AFP)

The Nobel Prize in Physics has gone to three scientists who sought to predict the long-term evolution of a complex system such as the climate by modelling variables -- weather, human actions -- that create disorder within those systems.

What is the link between the modelling of global warming, which earned Syukuro Manabe and Klaus Hasselmann half the prize, and the work of the third winner, Giorgio Parisi, who focused on the underlying disorder of matter?

All three study complex systems: large-scale climate or the behaviour of certain materials at an infinitely small scale. From the erratic fluctuations within these systems, the three physicists succeeded in teasing out simpler behaviours and reliable predictions.

"We recognised that emerging phenomena sometimes require us to look at all the individual complicated physical mechanisms and knit them together to make a prediction," said Nobel Physics Committee member John Wettlaufer, on hand when the awards were announced in Stockholm on Tuesday.

Climate "is THE complex system par excellence," said Freddy Bouchet, a physicist at France's National Centre for Scientific Research.

A large number of variables, in other words, interact -- atmosphere, oceans, soils, vegetation -- rendering any reliable forecast beyond a few weeks elusive.

But alongside and within this observable chaos there are also clear trends that can be linked to well-identified causes, such as long-term global warming attributable to human activity.

- Hidden rules -


"In climate science, the random and the systematic overlap," said Bouchet. "The mathematical tools developed by Klaus Hasselmann have made it possible to separate the two in order to better understand the evolution of climate."

Being able to tease out patterns in what is random -- the signal in the noise -- is fundamental to understanding the evolution of extreme weather such as heat waves, storms and hurricanes.

The models developed by the Japanese-American Syukuro Manabe have succeeded in cracking the signature code of climate subsystems.

"These are the first models which made it possible to calculate the effect of the increase in carbon dioxide of anthropogenic origin on global warming at the core of contemporary climate models", Bouchet said.

Giorgio Parisi, for his part, made a major contribution to the theory of these complex systems by revealing the hidden rules that govern them.

Co-winner of the 2021 Nobel Prize in Physics, Klaus Hasselmann of Germany 
Daniel Bockwoldt AFP/File

"I started to lay the foundations of this science -- which did not exist at the beginning of the 1980s -- by studying nature through mathematics", the Italian researcher told Corriere della Sera newspaper earlier this year.

It is a science that allows us, for example, to explain the changing form of a cloud of starlings in flight.

Parisi provided the mathematical tools to understand how random processes can play a decisive role in the development of large structures, such as those governing climate.

Today, they are applied in biology, neuroscience and artificial intelligence.

© 2021 AFP

How climate models got so accurate they earned a Nobel Prize

Climate modelers are having a moment.

Kieran Mulvaney 
NAT GEO

© Photograph courtesy NASA This composite image of southern Africa and the surrounding oceans was captured by six orbits of the NASA/NOAA Suomi National Polar-orbiting Partnership spacecraft on April 9, 2015, by the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument. Tropical Cyclone Joalane can be seen over the Indian Ocean. Winds, tides and density differences constantly stir the oceans while phytoplankton continually grow and die. Orbiting radiometers such as VIIRS allows scientists to track this variability over time and contribute to better understanding of ocean processes that are beneficial to human survival on Earth.

Last month, Time Magazine listed two of them—Friederike Otto and Geert Jan van Oldenborg of the World Weather Attribution Project—among the 100 Most Influential People of 2021. Two weeks ago, Katharine Hayhoe of Texas Tech University was a guest on the popular CBS talk show Jimmy Kimmel Live! And on Tuesday, pioneering climate modelers Syukuro Manabe and Klaus Hasselman shared the Nobel Prize for Physics with theoretical physicist Giorgio Parisi—a recognition, said Thors Hans Hansson, chair of the Nobel Committee for Physics, that “our knowledge about the climate rests on a solid scientific foundation, based on a rigorous analysis of observations.”

Climate modelers are experts from earth or planetary science, often with experience in applied physics, mathematics, or computational science, who take physics and chemistry to create equations, feed them into supercomputers, and apply them to simulate the climate of Earth or other planets. Models have long been seen by climate change deniers as the soft underbelly of climate science. Being necessarily predictive, they have been tarred as essentially unverifiable and the result of flawed input producing unreliable results.

A 1990 National Geographic article put it this way: “Critics say that modeling is in its infancy and cannot even replicate details of our current climate. Modelers agree, and note that predictions necessarily fluctuate with each model refinement.”

However, more recent analyses, dating back decades, have found that many of even the earliest models were remarkably accurate in their predictions of global temperature increases. Now, as computing power increases and more and more refinements are added to modeling inputs, modelers are more confident in defending their work. As a result, says Dana Nuccitelli, author of Climatology versus Pseudoscience: Exposing the Failed Predictions of Global Warming Skeptics, “there’s definitely been a shift away from outright climate science denial; because the predictions have turned out to be so accurate, it’s getting harder and harder to deny the science at this point.”


© Illustration by Niklas Elmehed, Nobel Prize Outreach Nobel Prize winners Syukuro Manabe, Klaus Hasselmann and Giorgio Parisi

That 1990 article quoted Manabe—generally considered the father of modern climate modeling—as saying that, in some early models, “all sorts of crazy things happened … sea ice covered the tropical oceans, for example.” But in a seminal 1970 paper, the first to make a specific projection of future warming, Manabe argued that global temperatures would increase by 0.57 degrees Celsius (1.03 degrees Fahrenheit) between 1970 and 2000. The actual recorded warming was a remarkably close 0.54°C (0.97°F).

A 2019 paper by Zeke Hausfather of the University of California, Berkeley, Henri Drake, and Tristan Abbott of the Massachusetts Institute of Technology, and Gavin Schmidt of the NASA Goddard Institute for Space Studies analyzed 17 models dating back to the 1970s and found that 14 accurately predicted the relationship between global temperatures as greenhouse gases increased. (The estimates of two were too high, and one was too low.) That’s because the fundamental physics have always been sound, says Dana Nuccitelli, research coordinator at Citizens’ Climate Lobby and author of Climatology versus Pseudoscience: Exposing the Failed Predictions of Global Warming Skeptics.

“We’ve understood for decades the basic science that if you introduce a certain amount of carbon dioxide into the atmosphere we would get a certain amount of warming,” he says. “These predictions in the 1970s were remarkably accurate, but they were also using quite simplified climate models, in part because of our level of understanding of climate systems but also because of computation limitations at the time. It’s certainly true that climate models have come a long way.”
The more things change…

In the realm of climate modeling, “What hasn’t changed over the years is the overall assessment of just how much the world would warm as we increased CO2,” says Hayhoe, who is also Chief Scientist for the Nature Conservancy and author of Saving Us: A Climate Scientist’s Case for Hope and Healing in a Divided World. “What has changed is our understanding at smaller and smaller spatial and temporal scales. Our understanding of feedbacks in the climate system, our understanding of, for example, just how sensitive the Arctic really is.”

As that understanding has increased, she says, so it has allowed the development of what she refers to as “the cutting edge of climate science today”—individual event attribution, the specialty for which Otto and van Oldenberg were recognized in Time, which for the first time is able to draw strong links between climate change and specific weather events, such as heat waves in the western United States or the amount of rain deposited by Hurricane Harvey.

“We couldn’t do that without models,” Hayhoe says, “because we need the models to simulate a world without people. And we have to compare an Earth with no people to the Earth we’re living on with humans and carbon emissions. And when we compare those two Earths, we can see how human-induced climate change has altered the duration, the intensity, and even the damages associated with a specific event.”

In Hayhoe’s case, the actual act of modeling involves “looking at thousands of lines of code, and it’s so intense that I often do it at night, when people aren’t emailing and the lights are off and I can focus on this bright screen in a dark room. Then I blink and it’s suddenly four-thirty in the morning.”

Much of the work, she says, requires trying to find things that are wrong in the models, to ensure they reflect reality. “If it doesn’t quite match up, we have to look harder because there’s something we didn’t quite understand.”

Whereas such discrepancies can be flaws in the models, they can sometimes reflect errors in observations. For example, a series of studies in 2005 found that satellite data which appeared to show no warming in the lower atmosphere, or troposphere, and which were used to cast doubt on global warming models, were themselves flawed. The models, supported by data from weather balloons, were right all along.

The irony, says Michael Mann, Distinguished Professor of Atmospheric Science at Penn State University and author most recently of The New Climate War, is that “climate scientists were dismissed as alarmists for the predictions that we made, but the predictions, if anything, turned out to be overly conservative and we’re seeing even greater impacts than we expected to see.”

The apparent looming collapse of the system that drives Atlantic Ocean currents is, he says, one such example. “It is something that we anticipated could happen, but it is not only happening, it is happening sooner than we expected, he notes.” Manabe, he points out, was one of those to first raise the possibility decades ago. “It just underscores that what’s happening in climate science is the worst thing that can actually happen to a climate modeler: to see your worst predictions come true.”

Modelers do acknowledge that the science isn’t perfect; even now, uncertainties remain, and not just one kind.

“Do we have all the physical processes in the model? And if we have them in there, are they correctly represented or not?” asks Hayhoe rhetorically. “Then there’s a second source of uncertainty called parametric uncertainty." Additionally, she says, some processes take place on such small scales—for example, among cloud particles—that they cannot be measured directly but must be inferred. Obviously that adds some uncertainty.” However, the greatest uncertainty, she says, lies not with the physics, but with our own collective behavior, and how much we are prepared to allow global levels of greenhouse gases to rise.

“If we didn’t know that carbon emissions produced all these impacts on us, that it isn’t just a curiosity of global temperature increase but is also our food, our water, our health, our homes, then we wouldn’t act,” Hayhoe says.

“That’s why I do what I do, and that’s why models are so important, because they show what’s happening right now that we’re responsible for, and what’s going to be happening in the future. I’m looking forward to the day when we can just use climate models to simply understand this incredible planet, but right now, these models are telling us, ‘Now is the time to act!’ And if we don’t, the consequences will be serious and dangerous.”





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