Announcement of the 2021 Nobel Prize in Physics

good morning and welcome to the royal swedish academy of sciences and this press conference about the nobel prize in physics it's good to see all of you here today and i would also like to welcome all those who are watching this press conference over the internet or on tv i'm joran hansen i'm the secretary general of the academy and with me today i have two members of the nobel committee for physics on my right hand sanson who is the chairman of the committee and on my left professor john wetlaufer who is also a member of the committee the academy met in session this morning we have taken the decision on the nobel prize in physics we have contacted the laureates and now we're here to tell you about it i will read the announcement first in swedish and then in other languages professor hansen will make some remarks on behalf of the nobel committee and professor wetloffer will present to you the science behind the prize kung leaves academy quantitative analysis the royal swedish academy of sciences has today decided to award the 2021 nobel prize in physics for groundbreaking contributions to our understanding of complex physical systems one half of the prize is awarded jointly to shukuro manabe and klaus husselmann for the physical modeling of earth's climate quantifying variability and reliably predicting global warming the other half goes to giorgio parisi for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales health climatic [Music] and you see the new nobel laureates on the screen above us here are some brief bio data shukuro manabe was born in 1931 in xingu in japan he got his phd from the university of tokyo and he is since many years senior meteorologist at princeton university in the united states klaus hasselman was born in hamburg in germany also in 1931. he got his phd from the georg august universitat in gottingen and he's now at the max planck institute for meteorology in hamburg giorgio parisi was born in 1948 in rome in italy he got his phd at la sapienza universitadi roma in 1970 and he remains at la sapienza as professor with that i'd like to ask to sean thompson to make some remarks on behalf of the nobel committee hans please thank you so many of you might believe that physics is only about simple and ordered phenomena like the earth in its perfectly elliptical orbit around the sun or atoms that are imperfect crystal structures or electric currents that flow predictably from the socket through the lamps or to your refrigerator but physics isn't much more than this one of the basic tasks of physics is to use basic theories of matter to explain complex phenomena and processes like how materials like glass are structured or what is the development of the earth's climate these studies require deep intuition for what structures and what progressions are essential and also mathematical ingenuity in order to develop the models and the theory that describes them things like things at which these years laurades are true masters thank you horns john what lover please tell us more about the science behind the prize floor is yours thank you from a distance complex physical objects can appear simple from atoms to planets taking a closer look always reveals structure we are awash in complexity at every scale that we observe and scientists we ask how much detail is required to explain the observations must we track every water molecule to explain the ocean what length scales are important to understand if we are going to see what phenomenon emerge from such a system one half of this year's prize focuses on the physics of earth's climate that's an old topic in physical sciences it began in 1824 with fourier fourier recognized that the atmosphere of earth is ostensibly transparent to the visible radiation from the sun and yet the earth converts that visible radiation into what he called dark heat the dark energy of fourier's time he surmised that this must interact somehow with the atmosphere to keep earth warm scientists subsequently measured in the laboratory the absorption and emission of what we now call infrared radiation fourier's dark heat and it was to take 70 years before svante arenas took these observations and these measurements and combined them in the first mathematical model of of climate and he predicted that if the concentration of greenhouse gases in the atmosphere increased so too with the temperature of the earth another 70 years two world wars and the computer revolution would pass before shikuru manabe and his colleagues knit together this web of processes including key aspects of the atmosphere's thermodynamics and dynamics and made the first prediction reliable prediction that if you double the carbon dioxide in earth's atmosphere their surface temperature would increase by two degrees celsius and about the same time edward lorenz taught us about chaos that the weather is chaotic it evolves rapidly and becomes unpredictable after about a week could it be that lorenz's chaos was noise to the climate so thought klaus hasselman he made the analogy between the rapidly varying weather and the slowly varying climate and brownian motion from einstein's theory whereby rapid collisions of water molecules with pollen grains displace them slowly over time he then predicted that the weather on time scales of days influences the ocean on the time scale of years he went further with these ideas and he constructed a systematic statistical way to compare measurements observations and models to extract the fingerprints of particular physical processes in the climate system galileo peered into outer space with his telescope giorgio parisi peered into inner space with mathematics and asked questions about apparently banal materials like glass that were deep and impacted many areas of physics we're used to taking a liquid like water and cooling it under normal circumstances it freezes into a periodic well-ordered structure however if we freeze the liquid very rapidly it becomes another body we call it amorphous it has attributes of both solid and liquid we can understand the difference between these systems in a daily life because we see them in glasses all the time glasses fracture like a solid and yet flow like a liquid we can consider their energies their energy landscapes the periodic solid has a simple landscape a particle in a bowl can only find one place to rest in a glass the landscape is complex and rugged it's not clear where particles will reside they are frustrated giorgio parisi studied a magnetic version of a glass called a spin glass imagine that we can decorate this triangle with magnets they can either have their north poles up north poles down or they can flip between north up and north down however we have the stricture that no two corners can have the same orientation so when we place the third it breaks the stricture it breaks the rule so another one must flip which drives the flipping of another one and so forth forever the system is perpetually frustrating giorgio parisi tamed this frustration this complicated landscape by building a deep physical and mathematical model which was so broad that it has impacted a vast range of fields far beyond spin glasses from how granular materials pack to neuroscience to how we compute to random lasers and to emergent phenomenon far beyond what he envisioned in the seventies when he started this work thank you very much john and it's now time for questions from you ladies and gentlemen uh in the audience and we hope to have one of our nobel laureates with us but i don't know if he is on yet he is okay very good professor parisi are you there yes i'm here very good thank you for being with us we are in the midst of the press conference thank you to you okay you have watched it very good and now we have journalists from sweden and all over the world and i'm sure they would like to ask you some questions who would like to start thomas fonheiner swedish television public service congratulations congratulations professor thank you i'm curious your part of the prize seems a little bit different from the others but there is a connection i'm sure could you describe the connection between your half and the other half well in during my work i have studied the many effects of disorder fluctuations and for example in about 40 years ago i did introduce a new phenomena what is called a stochastic resonance together with benthy sutera and bulbiani that was this was supposed to give a qualitative description of the phenomenal aggregation of big neglectation and given qualitative explanation of the periodic periodicity of qualitative quantitative explanation of the periodicity of 100 000 years so this idea this was not directly related to spin glasses but was part of my study of interplay between fluctuation in physical system thank you thank you david keaton over there and from the associated press uh congratulations uh professor on this uh award uh this award comes just a few weeks before the cop 26 kicks off in the united kingdom do you have a message for world leaders that will be gathering to take decisions on effects ways to limit climate change given the work that you've done and today as a nobel laureate do you have a message for them well i think that it is urgent it's very urgent that we take a real very strong decision and we move a very strong pace because we are in a situation where they we can have a negative positive feedback and that they may accelerate the increase of temperature so it's created for the future generation we have to act now in a very fast way and not release a strong delay thank you we have to act now that was the message from professor parisi more questions yes yes gentleman over there yes daniel igmo express and congratulations mr parisi i would like to ask you thank you if you were expecting this award and how you reacted when you got the news well i was i was very happy i mean sometimes it was also i was not really expecting but they knew that they have some chance and so what i kept the telephone near me but they was expecting that phone call was not respecting the phone callers or everybody was very really very happy i mean they was not expecting but i knew that there was some non-negligible possibility right any more questions yes maria gunter yes uh this is maria gunter from sneta congratulations to your prize you have been working in many different fields in physics what are you working on now well i'm working on for the present moment i want to understand better the physics of glasses there are many questions that are not really understood and also i'm doing some part of the time i'm following the the pandemics okay they try to understand more precisely which is the situation which is a correlation between different events and so on because you see once once at one after events this data big data it is it is very important to follow with different techniques with different viewpoints yes are there more questions david keaton has one more question and then don't be shy the rest of you you have your chance now david keaton thank you david keaton again from associated press uh 2021 saw a great number of um extreme weather events from storms floodings to heat waves in your opinion uh professor how important is it to to truly understand uh weather patterns and how can these this understanding help prevent further catastrophes look there are many many things that we do understand by weather and also for with the threat of the contribution of the other or manabe klaus asthma so this is very important it's clear that there are still some details that we have to understand because we have to understand the role of ocean and so on but what is quite clear that the the effect of climate changing is that the more energy is emitted in the atmosphere and if you have more energy in the atmosphere the chance of extreme event is going to increase very strongly thank you are there any more questions to professor parisi if yes one more question please lady over there uh eliminated on tv four congratulations uh on the price uh yes i wonder when you find these spin glasses and how they fluctuate is it a little bit like um artificial intelli intelligence i mean there are so many different ways in which they can form so i wonder if you can shed some light on that how will you sort of get into the clue of this well the point is that the point is that the glasses system like glasses are very familiar in nature and also the problem also complex object object is that we normally see but we don't recognize as complex so one has to make one from one side some kind of generality is some kind that some specialized issue it was a particular object that you want to study great there we got some light through the spin glass one more question yes from lund a gorgeous students newspaper in lund university please thank you so much and congratulations on the prize as a student magazine we're wondering how will you celebrate this prize how do i celebrate well i really had not the time to think about because also with copy the restriction we cannot have a very big celebration but i think that they should do something but i'm not really decided professor parisi when you can travel again i'm sure the students in london will throw a great party for you yes we will oh yes i believe so thank you we're glad to have you any more questions to professor parisi if not thank you very much professor parisi for being with us at the press conference and congratulations again to your nobel prize okay thank you so much goodbye bye bye and now are there any questions to the panel please do you want me to ask in swedish or english we can continue in english okay as being said these are quite different prices what is the link between them so it is a divided price we should say that first it is two pieces to this price but there is also as you saw it was an overreaching you know description of the price which which indicates that although these are two parts two different prices it's divided into two it's not one price but there is the common theme that has to do with this order that has to do with fluctuation that has to do with how disorder and fluctuations together if you understand it properly can give rise to something that we can understand and something that we can predict we can predict what is happening with the climate in the future if we know how to encode the chaotic weather as professor wetlaufer told you about and in the spin glasses although it's a very complicated system it's a hidden structure that you can discover if you analyze it in the correct way and the correct way to analyze it was exactly what professor parisi discovered any more questions if there yes london again thank you so with this prize are the committing hoping to send a message to world leaders about the gravity of the climate crisis well the world leader that hasn't gotten the message yet i'm not sure that they will get it because we are saying it but it's a physics prize and what we are saying is that the modeling of climate is solidly based in physical theory and well-known physics yeah you could say that the the notion of global warming is resting on solid science that's a message john you want to add [Music] i'll just emphasize that we have recognized here i think as you may have seen in the presentation the real core of how climate has been understood and modeled from sort of its inception and so our message is that we believe in physics and that we're recognizing that emergent phenomenon sometimes require you to look at all the individual complicated physical mechanisms and knit them together to make a prediction and to back to the question here the overarching theme really does wed these uh two approaches um giorgio parisi's work looks at the underlying disorder and fluctuations and predicts emergent behavior and the link between his work and shukuro manabe's work is the recognition by klaus hasselman that fluctuations are key for predictability and so we do not understand predictability unless we understand variability and that that's a key here thank you so much more questions if there are no more questions to the panel we close this part of the press conference and now there will be opportunities for interviews with experts for those of you who have requested such thank you very much for your interest and perhaps we'll meet again tomorrow thanks yes yes you're not going to do this [Music] my thank you professor john wetloffer could you summarize what this year's nobel prize is about yes the overarching theme is what we could think about as an umbrella of complex physical systems of course when we look out in nature there are plenty of complex physical systems but what emerged from the committee's work was the duality between the study of earth's climate which is complex on scales from millimeters to the size of the planet and giorgio parisi's work on the other hand which actually does come come back to climate as he as he mentioned uh in the press conference but he's building from the disorder and fluctuations of complex systems at their microscopic constituents and predicting the behavior whereas the work of shukuro manabe is taking the components of individual processes and knitting them together to predict the behavior of a complex physical system and klaus hosselmann sees both the value of the microscopic understanding and the implication of the macroscopic climate problem and so i i think that's a summary even though we've divided the prize between the climate part um and the disorder part there really are um linked and how would you explain this price to a child like 10 years old right so i would focus on the process of the greenhouse effect the hardest part to understand about why is it that if you put more carbon dioxide or water vapor into the atmosphere the planet warms is that everything is invisible and we don't see infrared radiation but we can think about the way in which the atmosphere interacts with infrared radiation just like when you're driving down the road in a car and your headlights on a clear night go as far as you can see them whereas if there's fog you see that the fog is absorbing the visible light and it's that which is important for the greenhouse effect in the infrared it's just an analogy but the light is absorbed and some of it bounces back to you that's a little bit like what's happening in the greenhouse effect that has taken from 1824 until 1967 to really understand quantitatively the work of giorgio parisi looks inside of glass you can see through glass and yet when it was made it was flowing it was hot and flowing like a liquid when it's on the window it's solid so why is that and the reason that is is that it's made of both components in a different way than normal solids are and everything is a complex system so right as opposed to having all your atoms in a row this doesn't happen in a glass there's a little chunk over here that looks like a solid and this sort of looks like a liquid and this looks like a solid almost like you really spilled something and it just sort of found itself organized on the floor and coming back to climate what is actually the difference the main difference between weather phenomena and climate right so crudely the first thing you could say is that the climate is the average of the weather we know that we can't predict the weather beyond seven ten to ten days something like that so then how can we predict the climate well the weather doesn't except for extreme cases like tornadoes the weather doesn't explode you know it rains then it stops raining sun comes out the weather is chaotic but it's it's bounded it doesn't blow up and the climate is taking big steps through the weather and so it sees some average uh on the big steps that it takes and we know you know it's very predictable that on average the temperature in stockholm in december is i don't know minus 10 um maybe not minus seven yeah um and in the summer you know a high temperature would be 30 degrees and and so we know how the weather behaves on these every month and the question is as we put more things into the atmosphere like greenhouse gases how does climate change how does that periodicity change so what is the major obstacle actually to make climate predictions right so people used to think it was just bigger and bigger and bigger computers and and so one direction there is to build bigger and bigger and bigger computers which people have done it gives you more and more realism but it's not clear that that will actually solve the problem because we cannot track the smaller scales in the climate and so the impediment is how do we numerically and mathematically resolve the small scales and yet still march the climate on in these broad steps and that's a very very contemporary area of research and klaus husselman's thinking actually has driven that so how come the nobel prize is awarded this year in climate you mean well there's um there's a problem with trying to understand the physics of climate as opposed to a laboratory experiment in a laboratory experiment you go in on monday morning and you do your experiments today and you have your results today or tomorrow our observations are till right the second and then to the next second to the next second so we only know the future by making predictions and so we want to recognize the veracity of basic physical arguments and models in trying to predict the future how however uncertain that is we need to embrace the prediction and its uncertainty and that's what happened now that's you know so we could have said well why this today and why not you know last year um well there's a lot of things to choose from and and it seems reasonable now given that the principal architects of this have been doing their work since the the 60s and that it makes sense to recognize this with such a prize at this time so let's come back to the nobel laureates this year did you talk to them what did they say so um we called them right before the press conference and we had trouble getting a hold of giorgio parisi and then he finally answered and he was very excited and he also recognized we described to him the prize he also very clearly recognized the importance of the other part of the prize which i thought was um typical of him of his in insightfulness because he's worked across so many different areas and then um we spoke to klaus husselman and then we spoke to shukuru manabe and klaus hosselman was dumbfounded and he knows shakur manabe but not giorgio parisi and he was very very pleased as anyone would be and i would say shukura manabe was to use a american english term gobsmacked he was he said but i'm just a climatologist um and and i think that's the point is that we explained to him our rationale and that he really did construct the models from which all future climate models were built and i think that scaffolding is essential for the improvement of predictions of climate my last question would be what makes you excited about this year's prize well first of all um what makes me most excited is that the physics is exciting you know um and so we learned an enormous amount um from our own research on the committee and from the the international community so in a very selfish way digging very deep into the history and all of the science that led up to their discoveries that are being awarded um is just uh liberating you know so for me as an academic i've learned an enormous amount that i didn't know before a lot of detail and so that's a selfish perspective the unselfish perspective perhaps is that i i think this sends a message and that there are these areas of physical science that really are important and you would think that they were also not connected but they are on a fundamental way they're connected and i think that shows not just the world but the scientific community how these things are into interwoven um and i think it gives other people license to do new things and i think that this holds up a light for for other people going forward thank you john wetloffer it's a pleasure to talk to you thank you very much you

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Length: 45min 9sec (2709 seconds)

Published: Tue Oct 05 2021