sign in sign up
<<
Home , Freeman Dyson, Nicholas Kemmer

Interview with Interviewer: Masataka Fukugita

Freeman Dyson visited the Kavli IPMU at Kashiwa from 15th to 19th of April, 2014, and at Kamioka from 20th to 22nd. Masataka Fukugita organized a special Q&A session with Freeman Dyson on 17th of April for 4 hours. This document excerpts this session, supplemented by an additional interview on 18th and another Q&A session held at Kamioka on 22nd.

Fukugita: You were an advisor to the King. educated at the William of Wykeham was Winchester College. Would a capable administrator. you tell us about this He founded 6 foundations, legendary college? including New College Dyson: Winchester in Oxford. Students College was founded 650 are allowed to enter years ago by William of Winchester College at Wykeham, a Bishop of age 12 after a tough, very the and competitive competition.

Freeman Dyson was educated as a professor emeritus) for 60 years. from 12 to 17 years of age at He has just passed 90 years of age, Winchester College, a famous but still actively engaged in . elite high school of . He During his long research life he then went to the has worked on an amazing variety department of Cambridge University, of subjects, often two or more where he was supervised by Abram subjects at the same . Starting Samoilovitch Besicovitch. Afterwards with , the subjects he he worked for the , worked on include: while WWII was raging. A year – after the war ended he returned to foundations of quantum eld theory; Cambridge, and gradually switched Statistical mechanics and solid- to theoretical . He then went state physics; to and worked Random matrices; under . He visited the Stability of ; Institute for Advanced Study in 1948, Adaptive optics; where his great for QED was , nuclear completed. Quantum eld theory power as propulsion; we learn today is the formulation Model for the origin of life; thanks to Dyson. His work serves as Time variation of the physical the best example of a mathematical constants; clearing up the mess of physics problem, to create a beautiful theory. He and also some others. was appointed as a professor at Now he is working on game Cornell University in 1951, and then theory, prisoner’s dilemma, besides invited as a professor in the School graviton detection, which was of Mathematics of the Institute for presented in his colloquia on the Advanced Study in Princeton in 1953, 16th of April at Kashiwa and on the where he served as a professor (now 21st at Kamioka.

22 Kavli IPMU News No. 26 June 2014 The exam is for ten or cooling. Education is subjects, including Latin carried on in a very free and Greek. There were style. In the top form we two for mathematics, one were in class only for pure math and the other 7 hours a week. So we applied math. The exam found ample time to learn also includes a modern whatever we wanted. language. My father was a Fukugita: Have you teacher at this college, so decided to be a I was already familiar with from it as a college brat from the time of Winchester the age of 3. The number College? of students is 70, 15 each Dyson: No. I was much year, boys only. This has younger. Mathematics not been changed until was born in me. I loved now. The college is still numbers and very much ourishing the same way enjoyed calculating from as in the old days. I still visit the time I was around it frequently. 3 years old. This is the The graduates are not same as with musicians necessarily academic; some who start playing piano become bankers and some at age 3. It is the same go to government ofces. for mathematics. I knew England is a very class that mathematics was divided society, commercial what I can do best. I was middle class for business already determined to be people and academic a mathematician when I middle class including entered the College at age university and government 12. people, and there is an In the college I found antagonism between “Cours d’Analyse” by them. We, the academic Camille Jordan in the middle class, considered library. It consists of 3 fat ourselves the top students volumes, containing the in the school and looked whole of 19th century down on the others. That mathematics. It is a classic tradition was intact, until work, written around 1900 Margaret Thatcher took and used in École Normale her revenge, putting the in France as a text book. commercial middle class It was a miracle that this rmly in power. book was in the library. We lived in the same building originally built in Masataka Fukugita is professor Interview . at the Kavli IPMU. He served as a the 14th century It has principal investigator at IPMU from thick walls, cool in summer October 2007 to March 2012. He is also a part-time member of School and warm in winter. It is of Natural Science of the Institute comfortable to live there, for Advanced Study in Princeton since 1988. So, he has got along not much need for heating with Freeman Dyson over 25 years.

23 My fellow classmate James It was a very lucky time to but to do two new subjects this was the cause of the Lighthill, who became a be a student. instead: molecular Japanese surrender, and famous mathematician, I was a student of and radio astronomy. so we were told. I recently discovered this book in the Besicovitch, expert on Martin Ryle brought read the book by historian library, and we both read measure theory. He came military radar equipment Hasegawa who claims that and talked about it. from Russia, spoke English and started receiving the real reason for the G.H. Hardy was with a very strong Russian signals from the sky. For surrender of Japan was already an old man in accent. Besicovitch gave radio-astronomy, English not the atomic bombs but Cambridge and the most me problems to work on. I weather doesn’t matter, the invasion of the Soviet famous mathematician liked the Russian language, whether it is cloudy or army from the north. Japan in England. He had been so we spoke in Russian. raining. He immediately could not defend against at Winchester College as We often went for long made great discoveries. Russians from the north a boy 40 years earlier. In walks in Cambridge, and In the molecular biology and Americans from the his autobiography“ Cours while doing so were not group Max Perutz and south. So the Japanese d’Analyse” appears, and allowed to speak English. John Kendrew became generals thought that it I strongly suspect that I was in uenced by the leaders. Both were was better to surrender to it was he who brought Besicovitch style: it is enormously successful and Americans, while keeping this book to Winchester architecture. Besicovitch Cambridge became the Russians out, using the College. I cannot imagine had the ability to build world leader in both the atomic bomb as an excuse anybody else bringing beautiful structures from two subjects introduced by for their dishonorable it. Unfortunately, I never simple components, Bragg. surrender. Now I agree asked him about this. which were used in his After two years at with Hasegawa and wish Fukugita: Then you went mathematical proofs. I Cambridge, I worked that we had not dropped to Cambridge? have used the same style for the Royal Air Force the bomb on . Dyson: In 1941 I came to for my calculations in (1943-1945). It was a The bomb was not as Cambridge. I entered the physics. grim time of the war. I important as we believed. mathematics department. After Rutherford died was a civilian scientist Fukugita: Cambridge Mathematics and in 1937 physics was at a at the headquarters of is the great place for physics were separate low ebb in Cambridge. In RAF Bomber Command, , with departments. Physics was physics, the only professor collecting Newton, Maxwell and then still called Natural was Dirac. Dirac did not about the strategic Dirac. You were following Philosophy. Mathematics interact with anybody. bombing of Germany. in their footsteps. Why is was considered by the Eddington was also there, After the bombing of Cambridge so successful? to be a French he was an astronomer. Germany stopped in April Dyson: The image is disease. We did not count him as a 1945, we still had a huge presented to school It was in the middle of . bomber force. I would children that each country the war. There were very At the time I was there, have own to Okinawa, is good at one special few students in the class. was in in order to bomb Japan thing: music in Germany, The others were ghting charge of the physics from there, but the war painting in France, and in the war. Lectures were department. He succeeded ended in August; so we England it is science. This given by Hardy, John Rutherford. Bragg said: did not need to bomb provokes gifted young E. Littlewood, Abram “Rutherford was the best any more. It was a great children in England to go Samoilovitch Besicovitch, physicist in the world and relief. We did not need to Cambridge and become but students were only I am not: so we should to kill more people. We scientists. The tendency a few. We did not sit in do something else”. It were very grateful to the was enhanced by the class-rooms but sat around was amazing wisdom. He atomic bombs for ending famous Tripos exams in small tables with a few made a quite astonishing the war. At that time Cambridge. students and one teacher. decision, not to do physics everybody thought that Fukugita: What did bring

24 Kavli IPMU News No. 26 June 2014 you from mathematics to but I went to Cornell in a few seconds. How never spoke to us. He physics? and worked under Bethe. was going on never came to seminars, Dyson: We saw the When I came to Cornell in second by second. It was never to lunch. So there news on the day when September 1947, I knew the rst application of was zero communication Hiroshima was bombed: the Columbia experiment to biology, between him and the it did not say‘ Hiroshima nding a 1050 megacycle and since that time biology young members of the was attacked’, but said shift between 2P and 2S evolved fast with the use Institute. I think it was ‘New force of nature states of hydrogen. The of radioactive tracers. mainly his fault, although harnessed’. It meant that old of Oppenheimer said that partly ours. We were new science had emerged. Dirac was wrong. I knew the application of nuclear young and arrogant, and I did not want to use the that Bethe had beautifully physics to biology was we didn’t think we had bomb, but wanted to use explained it. It was exciting. more important than the much to learn from him. knowledge that came It was exactly the right bomb. Fukugita: Have you ever out of the bomb. Nuclear time and the right place Fukugita: How was the talked to Einstein? physics became suddenly for me to be. Richard Institute in Princeton at Dyson: No, never! a fashionable subject, and Feynman was then a that time? He loved children, and it gave a motivation to young professor at Cornell. Dyson: When I came to certainly got along very learn physics. Quantum In early 1948 Princeton, Einstein was well with them. mechanics was still new Oppenheimer received there. I think it was a bad Einstein’s long-term and exciting. General a batch of the new mistake for him to come secretary Helene Dukas relativity was also exciting. Japanese journal, Progress to Princeton. When he was a good, able woman, Many things were going of . He came he had two choices, and a erce protector on in physics. I then started copied it to Bethe and either Caltech or Princeton. of Einstein’s privacy and to study Heitler’s book, Bethe showed it to me. He chose the latter since private affairs. We were “The Quantum Theory of I found the Tomonaga in Caltech he had to teach. friendly with her. After Radiation”. Two years later paper, where Tomonaga In Princeton he did not Einstein’s death she there was a miracle, the had done everything need to teach, so he lost often came to our house. experiment of before we did. We also contact with students. My children adopted at Columbia University knew the work of Hans As a professor in the old her as their substitute measuring the Kramers which appeared German style, he had an grandmother. One rainy levels of hydrogen atoms. a year earlier, as a paper assistant who was his night, a truck came to the I went back to to be presented at the personal slave. In my time, Institute, and took away Cambridge to study 1948 Solvay Conference, Einstein’s last assistant all the Einstein papers physics. explaining the idea of was Bruria Kaufman, that she had collected was my teacher, from renormalisation. who herself is a good and cared for. The papers whom I learned quantum I remember, when I physicist. Kaufman said to were on their way to eld theory. I wanted to visited Berkeley in 1948, me that being Einstein’s the Hebrew University in go to the United States. I was impressed by the assistant looks very good Jerusalem, as Einstein had Geoffrey Taylor, a great chemist Melvin Calvin. He on a resumé but in fact directed in his will. A few hydrodynamics expert used for the rst time a was a boring job. All she days after this, Helene who had worked at Los short-lived carbon radio- had to do was routine passed away. Alamos, immediately isotope to understand calculations. Bohr often came to said that I should go to photosynthesis, how There were many young the Institute. He was Interview Cornell, where Hans Bethe carbon dioxide is absorbed fellows around Einstein, completely different from and the young bright and converted into sugar, doing new science in the Einstein. He was very physicists from Los Alamos by tracing the move adjoining building. Einstein much interested in new were all working. I had of carbon atoms from was never interested in experiments. He came to no idea about Cornell, molecule to molecule what we were doing and our seminars, had lunch

25 He was in a relaxed state. a normal person. Much We went out to walk nonsense has been written every day and talked a lot about him. He was not an about physics. We called outstandingly strange man. at all the ice-cream places He was an outstandingly along the way, because intelligent man. his doctor had forbidden Fukugita: I think Heisenbeg him to eat ice-cream. He did not come to Princeton? understood all the results Dyson: Heisenberg did from on-going high energy not visit the Institute, but physics, where cosmic he visited Einstein once. ray experiments were It is recorded in the diary the cutting edge at that of Johanna Fantova. She time. I was working on was an Austrian Jew, the convergence of the whose family had been perturbation expansion in acquainted with Einstein quantum electrodynamics. in 1912 while he was Pauli maintained that working at the German it is divergent. I tried to University in Prague. She with us, and talked to early chance to go back to convince him that the became a friend of Einstein young people. He was then Japan. series converges, but he 20 years later in Berlin, working as a diplomat, Fukugita: How was did not agree. After all, we organising his personal representing Denmark ? know now that he was collection of books, sailing at the United Nations in Dyson: Pauli left the correct. I was not unhappy, a boat with him on a lake, New York, campaigning Institute before I came to as I could write a paper and 20 years later again in for international control of Princeton. He was at the on the divergence of the Princeton. In Princeton she nuclear power and nuclear Institute all the time during series, thanking Pauli for took a course to qualify weapons. But he kept up the war. He was close his help. for a job as a librarian, his interest in new physics. to Einstein and enjoyed Fukugita: And, Dirac? following the advice of Tomonaga also came to talking to him. He was, Dyson: Dirac quite often Einstein, and worked at Princeton. I liked him very however, isolated and quite came to Princeton. He the University Library. They much. Unfortunately, he unhappy at the Institute. changed his character, sailed on Carnegie Lake. arrived in the week I left He settled in Switzerland from a silent young man She kept a diary which was Princeton. So I had only after the war, and nally difcult to approach, to recently published. From a short time to talk to got citizenship, which had a talkative, friendly old this diary we can glimpse him. He was an extremely been refused when he man with a big sense of Einstein’s life in Princeton. unselsh person. He lived in Switzerland before humor. Like Einstein, he In it Heisenberg’s and had done much of what the war. He didn’t come stuck to theories of his Bohr’s visits to Einstein Schwinger and Feynman back to Princeton. own preference, the large appear. Neither of them did, ve years earlier, I got to know him in number hypothesis which made a good impression. but he never said so. Switzerland in 1951. Pauli turned out not to work, Heisenberg was still a big Tomonaga felt guilty as he had a big psychological and the negative metric Nazi, dreaming of a greater was not sharing the great problem. Fortunately, it eld theory which I never Germany. Bohr would not hardships his students was one of the rare understood. When he was stop talking until Einstein were suffering in Tokyo. when he was very happy, old, he seemed to have lost was totally exhausted. He felt bad to be in the disobeying the order of his intuitive ability to guess Heisenberg, too, was comfortable environment doctors and his wife. We what is right or wrong. He devoted to his personal of Princeton, so he took an had a very good friendship. became more and more theory, spinor eld theory,

26 Kavli IPMU News No. 26 June 2014 in his late years. He ashes. This was incidentally required his assistant to my rst landing in Japan, work on that. The assistant although I didn’t go out that I knew was Hans-Peter from the airport. Dürr. His career was ruined Fukugita: This reminds me by this work. Heisenberg of the episode of Yutaka did not give up spinor eld Taniyama, who was invited theory until his death. by André Weil to the Fukugita: Have you Institute, but committed got any impressions of suicide before he came Japanese scientists, other to the Institute, and his than Tomonaga, who came ancée followed him. to Princeton? Dyson: André Weil was Dyson: Yukawa came to the most friendly person. Princeton, but he was not He would have cared for doing physics. He came to him if he had come to Princeton as a politician, Princeton. When I visited perhaps as a symbol of Chicago as a young Japanese science. He student, Weil took me out worked for public relations for a long walk of three Fukugita: How about much interested in it, but or as a diplomat and made hours, and talked about contacts with legendary the majority of people a public appearance at the many things. He had a , such as at the Institute were not. United Nations. I saw him a reputation for being erce, , Johann Oppenheimer was not few times but never talked but I never saw him erce. von Neumann, Carl Siegel? interested in it. I was one to him about physics. Maybe he had two sides. Dyson: Shortly after I came of the few who tried to Taro Asano was a young Fukugita: Was there any to Princeton, Hermann keep the project alive after mathematical physicist impact from the work of Weyl and Carl Siegel left von Neumann left. from Tokyo. I had invited Yang and Mills? to Zürich and Germany, The meteorologist Jule him to the Institute. He Dyson: Yang did this work respectively. Siegel Charney came to Princeton had done a beautiful with Mills at Brookhaven in knew me, because I had and ran climate models piece of work on quantum summer. At that time I was strengthened his theorem with von Neumann’s ferromagnets. He was not working on about the approximation computer. When the isolated, he was shy, he physics, but on random of algebraic numbers computer project ended, had no friend to talk to, matrices. I think that Yang’s by rationals. Hermann Charney left. This was a and did not speak much motivation was to make Weyl somehow knew me great opportunity missed. to colleagues. Possibly a of isospin, too, and helped to get The Institute could have the language was a rather than to make gauge me hired as an Institute been the centre of two problem. Towards summer theories a central feature professor. Soon after I new sciences, climate he got depressed and of the universe. Pauli was came to the Institute as a studies and computer disappeared. After the at Princeton at the time. He professor, they had already science, in the same term ended, he drove his was very negative because gone. So I had not much way that Cambridge car at a crazy speed up Yang’s gauge eld was contact with these people. became the centre of Springdale Road, crashed massless. Pauli thought The only one I knew well molecular biology and Interview head-on with a heavy that it had nothing to do was Johann von Neumann radio astronomy under car and killed himself. I with nature and was not who stayed longer. He the leadership of Bragg. I was very sorry for this. I interesting. His opinion was enthusiastically proposed that Charney be escorted his wife, Sachiko, had a big effect on people working on the electronic employed as a professor back to Japan, carrying his including Yang himself. computer project. I was at the Institute, saving the

27 computer programme, but Nobody paid attention to students and was very I remember a talk about my efforts failed miserably. it. generous to them. He gave “ abby sheaves”. Oppenheimer did not Einstein never believed Feynman full credit for Somebody asked what show any interest. in black holes. He not only work on problems that he are abby sheaves. The The computer project didn’t believe in them, but had suggested. He was an chairman, André Weil, said went brie y to Princeton also wrote a paper claiming extreme patriot, very right “that is already a classical University before it was that black holes could not wing, a 150% American, terminology and we do dropped a year or so after exist. Oppenheimer, too, politically opposite to not need to explain it”. I von Neumann left. Twenty never revisited this subject. Oppenheimer. Wheeler never understood what it years later, computer He refused to talk about was a big protagonist of was. I got to understand science was centred at black holes, even after black holes. This might bre bundles, but I MIT and IBM, and climate candidate black holes were possibly be the reason why have not gone beyond science was centred in discovered in the sky. I Oppenheimer did not like that. Pure mathematics UCLA and in Norway. I feel tried to talk about it with to talk about black holes. had somehow become sorry for this. The dropping him and to explain to him Oppenheimer disliked extremely abstract. It of the Institute computer why it is interesting, but talking to him. Both Zwicky did not seem to me to project probably delayed he always changed the and Wheeler deserve a be a fruitful way to go. the growth of the two new subject. I did not know better recognition. I preferred to stay with sciences by twenty years. why. The father and the Fukugita: What is the applied mathematics. Fukugita: How about grandfather of the black biggest surprise you There seems to be no Oppenheimer? hole did not like their son. experienced in your barrier between string Dyson: Robert I would mention two research life? theory and mathematics. Oppenheimer was a important people of genius Dyson: The discovery of They understand each complicated character. that Oppenheimer failed weak vector bosons. I other. There is a big With Hartland Snyder, to recognise. One is Fritz had not taken the theory barrier between string he did his most Zwicky, who had many of Weinberg and Salam theory and the rest of important scientic work wonderful new ideas. He seriously, and I had a physics. A new trend is understanding black holes. was an astronomer who personal theory of weak good contact between They showed that every discovered dark matter interactions. So the computer scientists and massive object, with zero and the two main types of discovery of the vector mathematicians. We now internal pressure, will enter supernova, and predicted bosons was a surprise to have two professors in the a state of permanent free neutron . He is now me. The discovery was so School of Mathematics fall, as a consequence of recognised, but had never beautiful that it made me working on computer Einstein’s equations. They been recognised while he happy to be proved wrong. science. One of them is predicted the existence was alive. Oppenheimer Fukugita: What do you Voevodsky. He is working of black holes in any never spoke to him while think of the relation on the mathematical logic universe obeying Einstein’s both were at Caltech. between mathematics and of computability. equations. You don’t need Einstein visited Caltech, physics as a mathematical Fukugita: How do you any new physics. Just but he wasn’t interested physicist? think about the Einstein’s theory is good in him, and never spoke Dyson: The real gap was status of physics? What do enough. It is a wonderful to him. I have never met between pure mathematics you want to encourage? paper. This work appeared Zwicky. The other is John and applied mathematics. Dyson: Physics has slowed in the 1 September 1939 Wheeler. He is also poorly Pure mathematicians down. 60 years ago, issue of Physical Review. recognised. Oppenheimer were talking a different experiments were done in The paper appeared at disliked him strongly. language. Bourbaki 6 months and they were a bad time, on the day Unlike Zwicky, he was was fashionable pure explained in 6 weeks. Now that Hitler invaded Poland not a difcult person. He mathematics, and I was experiments take 20 years. and started World War II. had a large number of not very interested in it. Except for high energy

28 Kavli IPMU News No. 26 June 2014 physics, there is still a lot Fukugita: How about several important results. I know some people to do. Small scale science ? It is always ready to detect who switched from string is still ourishing. Particle Dyson: I have a critical something unexpected. theory to genomics. 95% physics is a special case. view of LHC. Every event I strongly support this of genomes are not . Even in particle physics, a is complicated with an experiment and its We do not understand small experiment, such as enormous background upgrade. They may wait for what these non-coding the measurement of the of uninteresting . a long time, but they have parts of genomes are electric dipole moment of Software must be written a good chance to discover doing. The discovery the electron by Gabrielse specically to pick out something unexpected. of Human Accelerated at Harvard, is an example what is looked for. You In general, experimental- Regions of genomes, on the frontier and has a can discover only what you ists ought to be prepared where signicant changes chance to nd something expected. Every discovery for something unexpected are seen between chimps new. is predictable. The LHC to happen. This is also true and humans, could Progress in astronomy cannot make unexpected for theorists. They should motivate the start of a is great. Twenty years discoveries. The accelerator not stick to one thing, new science. We must be ago, we knew only a tiny still uses radio-frequency but should think about exible and ready to move part of the Universe, only acceleration, with the a variety of subjects. If into new sciences as they out to redshift 0.2. Now electric voltage per unit they get bored with one emerge. this horizon has been length the same as it was subject, they should break When I was young, enormously extended. half a century earlier. out into other subjects. I carried out hard We can see and explore Ordinary lasers have I have been doing it this calculations competitively. the Universe all the way electric elds 1000 times way throughout my long I was not concerned with back to the Big Bang. higher. The use of laser research life. philosophical questions. Astronomy can do a lot elds for acceleration is beautiful. For me, philosophy was a of important science with must be studied. Bigger One day it may turn out to branch of literature, not a small instruments, both on accelerators using the have something to do with branch of science. Science the ground and in space. same acceleration principle nature. String theory is was a collection of tools Kepler is a small satellite, are not a good way to go. now close to mathematics, that I used for solving but enormously successful. There are several ways but the gap between string problems. When I got older, The BICEP2 microwave we can go for particle theory and the rest of I wrote books and articles anisotropy experiment physics. Underground physics is very wide. String for magazines, rather than at the South Pole is not detectors have a good theory does not have doing competitive science. expensive and is equally future. They can detect enough good problems for So my work has changed successful. Politics focuses everything that happens. ten thousand people to with age. attention on big science, Two countries, Japan work on. I am not worried and big science also gets and Canada, with good about string theory in itself, too much attention from scientists and not too but I am concerned with the media. I want to much money, lead the their narrow training of encourage studies in as world in the use of students. This makes them wide a eld as possible. underground detectors. unemployable for jobs Especially in astronomy, Their projects are more other than string theory. there are so many cost-effective than the Changing people’s careers things to explore. Zwicky projects in America and every ve years would Interview emphasized the advantage Europe, which invested a help to solve this problem. of single-purpose large amount of money in Particle physics is not easy instruments. Kepler is a accelerators. Kamiokande to escape from. Escape beautiful example. We can is a very good experiment from other branches of still nd others. that has already brought science is easier.

29 it is absorbing carbon simple. sun and the climate. This dioxide. If more carbon Carbon dioxide is totally absent in the dioxide is in the air, the causes warming of the climate models. The sun process is more efcient climate. This is a serious was active for the last 50 and evaporates less water, concern. Unfortunately, years, and less active in encouraging growth. the United Nations set the last 5 years. Strong The effect of carbon up the committee IPCC global warming lasted for dioxide is substantial for for studying climate. 50 years, but seems to biology. There is a 30% They have written into have stopped for the last

increase of CO2 in the the denition of the ten years. This is a clear Climate? It takes much atmosphere compared programme that they observational hint, but it is too long to explain. In with the amount a should look at effects not included in the climate short, I am skeptical hundred years ago, and of human activity on models. about prevailing anxieties it caused an increase in the climate, but are not The world average about climate. Oak Ridge vegetation, wild forest and supposed to look at temperature is a National Laboratory also food crops roughly non-human effects. The misleading concept. It is had a very good climate half as great, namely 15% programme is highly unclear what it means. programme, started increase of biomass due to biased from the beginning, The most intense warming

50 years ago, before it 30% increase of CO2. This and this is what I am happens in very cold became fashionable. is not well known to the ghting against: I am not places, mostly at high The director was Alvin public. simply opposing what they latitudes. There are a lot of Weinberg. He insisted that For climate, carbon are doing. The scientists unknowns in the model. we must understand the dioxide is the easy part working for the United It is also not clear if real world. I worked with of the problem. There Nations are allowed only local warming is bad. In him for some years. There is a huge complicated to look at human causes some arctic areas, local were a lot of biologists, feedback and recycling of . people are happy with who were concerned with of carbon dioxide, but it Climate is a difcult the warming. They had a soils, trees, vegetation, can be measured and is problem. Particularly, very hard life in the past, microbes and all kinds fairly well understood. clouds are crucial but relying on shing in a of ecology. In addition Water vapour is much poorly treated. The horrible climate. Warming there were physicists who more difcult. It is more resolution is poor in has made their life easier. wanted to understand abundant and the simulations. One takes There are always winners climate. So, it was a well greenhouse effect is averages over 100 km in and losers when the balanced programme. larger. Evaporation of global climate models, climate changes. For carbon dioxide in carbon dioxide from the while actual clouds require I am skeptical whether the atmosphere, half of ocean is a minor effect. a resolution of at most 1 models give good pictures the effects are concerned Evaporation of water from km vertically and 10 km of reality. The real world is with climate and half with the ocean is much larger horizontally. What the much more complicated. ecology. Carbon dioxide is and dominates the effect models do is not to model My conclusion is that I

a powerful fertiliser. It can of CO2. Water vapour is clouds but to represent do not believe the ofcial be a substitute for water. strongly absorbing, but average cloudiness in a predictions of climate for The limitation is that it is also has a tendency to region by fudge factors. the next 100 years. The only a small fraction of condense into clouds. The present state of models are good tools for the air, while the fraction This is why the problem is understanding of climate understanding climate but of water vapour is usually difcult. Vegetation is also is poor. I don’t trust the bad tools for predicting larger. Suppose we open a a huge source of water models. climate. They are good for pore in a leaf and get one vapour, and so is coupled I also mention that understanding because carbon dioxide molecule to the circulation of water. there was the little ice they allow us to see the to go in through the Evaporation of water is age in the 17th century, effect of changing one pore. While the pore is crucial to the nal effect. when the sun went to factor at a time. They are open, about 100 water That is why it is so hard sleep for 70 years. The bad for predicting because molecules come out. So to calculate. If you only world suffered from a cold they leave out a large the leaf is evaporating have to deal with carbon climate. There is a strong number of factors that water much faster than dioxide, the problem is correlation between the might be important.

30 Kavli IPMU News No. 26 June 2014