Dr Garth Paltridge, atmospheric scientist

Garth Paltridge (right) was interviewed by Graham Farquhar in 2010.

Garth William Paltridge was born in Brisbane in 1940. He completed a BSc with honours at the University of Queensland (1961) before moving south to Melbourne. Paltridge was awarded an MSc and PhD (1965) from the University of Melbourne. In 1966, Paltridge took up a post-doctoral fellowship at the New Mexico Institute of Mining and Technology in the USA. He changed continents again in 1967 and became a senior science officer at the Radio and Space Research Station in the UK.

Paltridge returned to Australia in 1968 to the CSIRO Division of Meteorological Physics (eventually re-named as the Division of Marine and Atmospheric Research). He began as a research scientist and was promoted over the following eleven years to reach the level of chief research scientist. In 1990 Paltridge became professor and director of the Institute of Antarctic and Southern Ocean Studies at the University of Tasmania (1990-2002). He was then instrumental in setting up one of the first Cooperative Research Centres, the CRC for Antarctica and the Southern Ocean (1991). He was director of the Antarctic CRC until his retirement in 2002. He then became an emeritus professor and honorary research fellow at the University of Tasmania and a visiting fellow at the Australian National University Research School of Biology.

Interviewed by Professor Graham Farquhar in 2010.


Hello. I am Graham Farquhar. I am Vice President and Secretary Biological at the Australian Academy of Science. It is my honour and privilege to be interviewing Professor Garth Paltridge, who is here in Canberra today. He is famous for his work in atmospheric physics and radiation physics, his contributions to agriculture, and his development of the theory of maximum entropy production. I am delighted that he is here. Welcome, Garth.

Raised in the lab

Garth, where were you born?

I was born in Brisbane. I was brought up for the first seven or eight years in Gatton Agricultural College, which was a good place to be brought up in. It is about 50 miles west of Brisbane. My father was an agronomist with CSIRO, would you believe! At that time he was running a fairly small CSIRO research lab on the grounds of the Agricultural College I can remember lots of glasshouses, and pots with plants in them being given different fertiliser treatments. At night-time my father would be there pounding away at a calculating machine. It quite put me off biology. On the other hand, he had a hobby, which was audio amplifiers and the hi-fi of the day. So I can also remember huge electronic amplifiers, loud speakers, huge baffle boards and very loud classical music, which was rather louder than I could put up with. In any event, it did give me something of a feel for classical music.

How long did you stay at Gatton?

Until I was about seven or eight. I am not absolutely sure. After that, my parents moved to Brisbane where my father was a sort of chief of the 'Cunningham Laboratories'. I am not absolutely certain about the name, but they were the predecessors of the CSIRO Division of Tropical Pastures. I can remember that in those days various pooh-bahs from CSIRO in Canberra and Melbourne would come up and occasionally have dinner at our house. I sat on the sidelines and heard a bit about CSIRO. I can remember I used to think it was a terrific organisation. I am not so sure that it is quite so terrific these days, but it was good then.

What about your schooling? Where did you go to school?

I went to various state schools until the year before what was called the 'scholarship year' in Queensland. My father got a job in Ceylon at the Coconut Research Establishment. So I was sent off to boarding school at Brisbane Boys' College and enjoyed myself very much. Particularly as, after a few years, having realised that I was not terribly keen on the politically correct sports of cricket and football, I joined a mob of kids who took to gymnastics. We became quite good at it and became quite respectable in the eyes of the school, so life improved greatly after that. In the present context, the most important thing about the school was the maths teacher, who was a fellow called Pete Laughton. He was a superb teacher and seemed to know the right balance between learning by rote and the understanding of something. It was his teaching that carried me through at least the first couple of years of university mathematics and enabled me to survive (just!) the mathematics of third year.

What is your feeling about rote learning?

Suffice it to say that I don't go along with the current philosophy, which seems to be that you have to understand something before you can learn it. I think, in most things in life, it is exactly the opposite. Particularly multiplication tables and things like that. If you don't 'learn to rote learn', you are missing a lot in life. That is my philosophy and I'm sticking to it!

What did your mother do and did she have any influence on getting you into science?

My mother was one of a family of 12 brothers and sisters and she did not have a formal 'career'. She was the oldest of the 12 kids, so she had to spend a lot of time looking after the family as she grew up. But she was very good at supporting my father in his efforts in science, and put up with an awful lot. He, like many forgetful scientists, could rush away and forget to pick her up for instance, when she was supposed to be taken somewhere to do something. She took all this in her stride.

What did she do in Ceylon – in Sri Lanka as it now called?

I don't know. I'm sorry about that; I really don't know. I presume that she looked after my father and was a hostess for the very many parties that seemed to go on in Ceylon in those days. I went to visit them twice during the three or four years that they were away in Ceylon, and they lived rather well. This was in the days of the old Colombo Plan. My father at that stage was doing research on what sort of pastures it might be possible to grow under coconut trees.

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A very good time at university

What happened subsequently at university?

I went to university; it must have been from 1957 to 1961. I majored in physics. I very nearly failed the first-year. I was living in St John's College, at the University of Queensland, and it was a great change from the constraints of a boarding school to the lack of constraints in a university college. I had a very good time. I can remember, in the middle of the physics exam at the end of the first year, suddenly realising that I could probably fail this subject, because I hadn't done any work in it. Sometimes I still wake up with dreams about it, sweating about it. If I had failed, it would have been the end of my university career. But I just made it by the skin of my teeth.

I enjoyed university life, but I can't really remember any of the lecturers or even the subjects much. I can remember that one of my pieces of luck was that my father had introduced me at an early age to a thing called the Radio Amateurs Handbook. That was a superb book for teaching you the practicalities of electronics. In those days, if you didn't know any electronics, you didn't get very far in physics. Just the reading of that book when I had been a young teenager made a tremendous difference as to what I could get away with in the university. Incidentally, that little incident where I nearly failed first year was also fortunate because it gave me such a fright that I worked like stink for the rest of the two years. Indeed, I got a high distinction in physics in second year. So things worked out all right in the end.

The other story I remember from my university days had to do with the very first chemistry practical class that I ever had. We were told by the tutors that we were marked not on what we produced in the experiment but how we wrote up what we did, and you had to be terribly honest about writing up what happened. The very first experiment was to produce aspirin, salicylic acid. Mine turned out to be pink, and I gather that aspirin is white, and so they failed me on that day. I learnt then and there that, in order to get on in this world of the university chemistry school and, indeed, the physics school, you made sure that you got the right results in the physics and chemistry practical classes. I did, mostly by rigging the results. That sounds dreadful but, if you rig results, you really have to learn and know more about the subject than if you did the experiments straight. Because you have got to be able to tell a good story and you have to learn to look at an experiment from all sorts of different directions. That is in case the demonstrators caught you out. It was all very good training as to how one ought to be sceptical about real life experiments when one gets out of the classroom and does experiments for real. It was not very honest, but it was good training.

What did you do for your honours year?

The honours year in those days in Queensland was very tough. We had a vast amount of lectures and we also had to do a major practical experiment. I have forgotten what my experiment was. But, after that honours year, leaving Queensland University and going to Melbourne University, I found that its honours year was not very tough at all. I felt sort of cheated.

Electric PhD

In any event, after Queensland University and the honours year there, I went to Adelaide for a job interview with DSTO – that is, with the Defence Science people. On the way, I visited Professor Hopper, who was a Professor of Physics in Melbourne University, and we talked about the possibility of me doing an MSc and a PhD. He had just been reading some journal article on atmospheric electricity and he said to me, 'This looks like a very interesting subject; why don't you have a go at that?' So I started an MSc and a PhD there. I think that that original recommendation of his was the last piece of open advice he ever gave me, although he probably was fairly subtle about his guidance from there on in. Again, I was lucky, I was left alone and could do just about what I liked, as long as it had something to do with atmospheric electricity. While Professor Hopper was a Professor of Physics at the University, specifically he was with the RAAF Academy. So all us research students enjoyed ourselves, flying instruments on balloons and aircraft. We raced around western Victoria searching for balloons that had been tracked on radar, or searching for the packages of the balloons. We really had a good life.

At the time I was also a resident tutor at International House, which was a college of the University of Melbourne. At night I ate at the high table and ate very well. At lunchtime I was usually at Point Cook, the RAAF training base, and I used to eat in the officers' mess, and ate even better there. The net result of all that was that my PhD scholarship, which was pretty miserable in terms of money, was sheer profit. Again, I was very lucky and had that money to spend on good things other than food.

Where did you meet your wife, Kay?

I can't actually remember where I met her but, during the time I was doing the PhD, she used to come out with me on trips looking for balloon packages that had fallen all over the country. She used to help me with punching out Fortran computer cards for the radio valve computer that was at the Melbourne Physics Department at the time. Also I managed to kid her sister into typing my PhD thesis. All of that was very useful!

Do you have any advice for prospective PhD students? Should they take on single or multiple projects?

That's a good question. When I was doing my PhD, there were a few other research students I knew who put all their PhD eggs in the one basket. That is to say, they had one experiment or one instrument that they would spend three years building. They would put it, say, on a rocket at Woomera. If the rocket went up and exploded prematurely, that would be the end of their experiment and, virtually, the end of their PhD. I was slightly luckier in that I had three or four experimental projects running at the one time with instruments to fly on aircraft and balloons. So, if any of those went west, it didn't really matter in the broad scheme of things as far as getting a PhD was concerned. As it happened, I was lucky. I don't think anything was completely disastrous and all those different bits of science came up with the equivalent of a research paper. So it all turned out quite well.

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Flying through thunderstorms

What did you do after your PhD? Did you take a break?

No. I should point out that in those days you didn't have to worry about hanging around until your PhD had been marked. You just got it bound, sent it off into the system and then off you went. At any rate, two days after I had submitted my PhD, Kay and I got married. We got on a boat from Sydney and went off to the New Mexico Institute of Mining and Technology in the United States. That was a nice way to start a marriage, with three or four weeks on a boat.

What was the boat?

The boat was the Arcadia, one of the old P&O passenger liners. I suppose that leads into the fact that New Mexico Tech was in the middle of the semi-desert at a little half-Mexican town called Socorro. It was marvellous. My supervisor at the time was a fellow who had been with the Manhattan Project. He was there when they let off the first atomic bomb at the Trinity Site, which was only about 30 miles from Socorro. He had stayed on and was concerned primarily with tracking radon and radon daughter products and how they got distributed in the atmosphere. That was the sort of work that I was doing with him. We spent our time flying around in the research aircraft of the US National Centre for Atmospheric Research. Mainly on the top of thunder storms and occasionally, when we made a mistake, in the middle of the thunder storms. Like most of these outdoor activities, they were good fun.

New Mexico Tech at the time was famous for its research in thunderstorms and thunderstorm electricity. There were people like Charlie Moore, Marx Brook and, in particular, a fellow called Stirling Colgate, who was one of the Colgate family. Stirling Colgate was the President of the university. In those days, he might have been President of the university, but this didn't stop him from doing all sorts of research and experimentation, and it was all grandiose stuff. These sorts of guys lived, slept, ate and breathed research. They argued about it all the time and it was just marvellous working with them. The American attitude to research is so much more professional and so much more fun than you strike in most other places.

What was it like flying through these thunderstorms, when you made a mistake and went through them?

The plane goes up and down a lot! I was often sick on those trips, which would completely wipe me out. But one of the guys I mentioned before, Charlie Moore, was absolutely incredible in his ability to be in an aircraft that was going up and down in a thunderstorm and be physically sick one second, then write on a chart recorder the next and then be sick and then write on a chart recorder again. Unbelievable.

Hungry UK scientists

What happened next in your career? What was your next position?

During that year I had been in touch with a fellow called Pasquill, who was quite a famous scientist at the UK Met Office. He suggested that I should come and work with him at the Met Office on another postdoctoral appointment. He arranged for me to be interviewed by a committee of UK bureaucrats who were in the USA at the time, interviewing mainly young English scientists in the hope of attracting them back to England. He arranged for me to be interviewed by that committee, and I explained to them that I had been talking to Pasquill and that we were trying to organise that I should go and work with him. Then, a few weeks after the interview, offers came in from the various research establishments in England that were funding the committee. The funny thing was that the offer in terms of salary for going to work with Pasquill was about 60 percent of the salaries that were being offered by all the other places that wanted research people. I had specifically said that I wasn't really interested in the other places, because I wanted to go to the Met Office. That made me suspect at the time, and I had it confirmed later on, that the English were quite prepared to try to get their scientists cheap.

I finished up actually taking a job in England at the Radio and Space Research Station, which was offering a reasonable salary. I can remember that, within a few weeks of arrival, they sent me down to London to what they called an 'indoctrination course', which was run by various bureaucrats in the Science Research Council of the UK. Not once but twice during those lectures, the lecturers said straight out that it was a good thing to keep scientists hungry because that way they did their best work. They completely forgot that another person and myself in the audience were scientists. I stayed one year, and that was it. I was supposed to be there for three, but I managed to get a job back in CSIRO in Australia.

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Homeward bound for more fun experiments

How did that come about?

I think I had been in correspondence with Dr Priestley, who was chief of the CSIRO Division of Meteorological Physics. He arranged for one of his offsiders to come and interview me in England; I think that's how it went.

How did you travel the second time?

You may remember that Kay and I took the Arcadia to the US. That was on Z-deck because I was paying for it. Coming back from England to Australia, our trip was paid for by CSIRO and they brought their people back first-class on boats such as the Arcadia. We really had a terrific six weeks. It is the best holiday that we ever had. This was in the days before CSIRO and the universities began to fly their new recruits to Australia.

At CSIRO, what division were you in and what did you do?

I went to the Division of Meteorological Physics. Dr Priestley, when I walked into his office, said, 'Perhaps you could work in both atmospheric radiation' – which means looking at things like solar and infrared radiation in the atmosphere – 'and also in agricultural physics,' which was a bit of a specialty of the Division at the time. So that's what I did, although over the years the atmospheric radiation studies became more of a 'purpose' in themselves. I was looking at the radiation 'environment', particularly of clouds and the effect of clouds on how much sunlight gets through to the ground, and what the effect of clouds is on how much infra-red radiation is emitted back to space. It involved a lot of fun experiments with the old CSIRO DC3 research aircraft. We spent lots of happy weeks and months in exotic resort towns up and down the east coast of Australia. 'We' being me and a fellow called Martin Platt, who was in the same group. He and I shared an office for umpteen years. Every morning we would go out in the DC3 and look for clouds over the ocean and make measurements. I keep saying that we enjoyed ourselves, and that was the object of the game.

I suppose that the radiation work was useful enough, but it was bread and butter sort of research. It was not the sort of research that would lead to setting the world on fire with some great grandiose new theory. Nevertheless, it was good fun and it was useful. It was also very good training in a discipline which is the basis of climate research. It became more and more of an interest to me as the years went past, and perhaps we can talk about that later.

Earth's temperature controlled by clouds

I want to ask you about clouds; you are very famous for your work on clouds. What are they made of, how are they formed and why are they important?

The thing that warms the Earth is the sun shining on it. The amount of sunshine that actually gets to the surface of the Earth and does the heating is determined almost entirely by how much cloud there is between the surface of the Earth and the Sun. Clouds are a very dominant control on how hot the world will be.

If you are in the game of trying to forecast what will happen to the world's climate – will it get warmer or colder – you have to know how to forecast what will happen to the amount and distribution of cloud around the world. In the climate research game at the time, there was no way of calculating the response of cloud or cloud amount to any change in the surface temperature. The reason things are so difficult is that climate models represent the atmosphere only at a series of points on a grid spread over an imaginary atmosphere that is built into the computer program. These grid points are the actual points where the calculations of what will happen in the future are done. So the model knows nothing about the atmosphere between the points. It has to assume that anything between the points will behave more or less the same as is happening at the points.

Clouds in the atmosphere are very much determined by what happens between the points – that is, on the 'small scale'. Bear in mind that the individual virtual points in a computer model of climate may be anything up to 100 kilometres apart. Cloud formation is determined by processes that are much less than 100 kilometres across, they could be 100 metres across. So, if you have a model that can't represent things at that sort of scale, it is not going to be very good at calculating how cloud will change. In essence, the fundamental problem as to why we cannot really guarantee that climate models are working properly is that they cannot reliably represent clouds and cloud behaviour. This was particularly true in the early stages of climate research and things haven't improved all that much over the years.

There is a similar problem with the diffusion of heat into the ocean through small eddies. Do you see any future possibility of using the Maximum Entropy Production principle that you developed for finding ways of dealing with these issues?

It was this sort of worry that was behind the whole idea of looking for such a principle in the first place, as a means of getting around having to describe the actual detail of all the eddies and small processes that are going on in the atmosphere and ocean. Hopefully, if maximum entropy production is a true representation of what's going on, you would hope that the principle could be applied to climate models so as to be able to make some reasonable guess as to what is going on at a sub-grid scale. That is to say, between the points where the calculations are done. So far, that hasn't happened. Largely because the principle applies to the world as a whole and it is very difficult to add a broad-scale principle like Maximum Entropy Production to a huge numerical climate model, which does all its calculations on the small scale. Just the numerical practicalities of how to do it are very difficult.

You said a while ago that clouds determine the energy reaching the Earth's surface, suggesting they determine the Earth's temperature as well. Are you suggesting that carbon dioxide and other greenhouse gases play no role in the Earth's temperature?

No, no, I am not suggesting that. All I am saying is that, if you put lots of carbon dioxide in the Earth's atmosphere there will be an impact on surface temperature. But in order to calculate whether the impact is big or little, you have to be able to calculate the response of cloud amount, cloud type and cloud position to the change of temperature induced by the change in carbon dioxide. Excuse me, let me be specific – if you have a world in which nothing else changes except the carbon dioxide in the atmosphere and you double its amount, given a couple of hundred years for things to settle down, the temperature of the surface of the Earth will probably go up by about one degree. But there is the caveat that 'nothing else happens', and other things certainly will happen. For instance, the cloud cover can change in response to the change in temperature. This may amplify or reduce the initial one degree rise in temperature that we're talking about. At this stage, we simply don't know the answer to the question as to whether the rise due to increasing carbon dioxide will be less than one degree or more than one degree, because there are these things like clouds, which we can't handle yet.

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If we get back to the agricultural physics side of things, that involved a lot of experimentation. I can remember that we ran a three­-year experiment in Rutherglen. This was at the Wine Research Station in Rutherglen in northern Victoria, but they also grew wheat there. We instrumented this field of wheat with all sorts of meteorological machines of one sort or another. I suspect that there were more instruments in the field than wheat plants. Nevertheless, we produced a fair number of results out of the experiment. But, as the years went by, that sort of experimental work in 'agricultural meteorology' became more and more 'theoretical'.

One interesting outcome was that there were two guys in the University of Melbourne, a fellow called John Denholm in the Physics Department and another fellow called David Connor, who was a Professor of Agriculture. David Connor, John Denham and I formed a group called the Consortium for Research in Agricultural Physics and Plant Yield, which, if you are quick, you will realise means 'CRAPPY' for short. We used to meet every couple of weeks in the Clyde Hotel, just outside the university, and we would discuss research of one sort or another. We published several research papers on the evolution of plant growth and other topics of the sort. We actually published one or two papers in the Journal of Theoretical Biology under the name of CRAPPY, at an address called the Clyde Hotel in Lygon Street, Parkville, near the University of Melbourne. You could do that sort of thing in those days and get away with it.

The paper of which we were most proud was one which established the optimum strategy for maximising the amount of grain growth. If you were a plant trying to grow grain, you should do nothing for the first part of your growth period except grow leaves and then, immediately, you should switch over from growing leaves to growing grain. You would not adopt a strategy of growing leaves and grain at the same time. It all sounds a bit silly but, in fact, it is quite a significant realisation. That is what plants ought to do, if they want to have big productivity.

I read that paper, and it's well known among agronomists and crop physiologists.

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Principle of Maximum Entropy Production

During this time you worked with Platt on a textbook on radiation physics, which became a standard. How did you find time to do that?

That is a good question. I can remember that it took about six months of solid work. There was no difficulty in getting that time from the Division. They accepted that producing a textbook was the sort of thing that research scientists should do at least once in their life. CSIRO treated us very well in those days.

Did that lead you in your thinking about how to predict global cloud cover?

I suppose you are right. At about that time, it must have been in the late 70's or early 80's, one of the central problems of predicting weather and climate was that the models, as I mentioned, were still pretty primitive and had no way of predicting how much cloud there was, or would be, in the sky at any one time. In those days, the models simply had to assume that, no matter what happened, the amount and the distribution of cloud around the world was fixed.

I started thinking about what are called 'extremum principles', which are the last gasp of a scientist when he can't think of anything else to do in order to solve a problem. He starts wondering whether such-and-such a phenomenon will obey some sort of principle of maximising or minimising something. It doesn't sound very scientific, but I simply set up a rough model of the broad distribution of climate around the world. I then went on a random search for any variable representative of that overall model which might have a maximum or a minimum at a distribution of cloud and of surface temperature that looked roughly right.

After a few months I did manage to come up with a variable that looked as if it was at a maximum when the clouds and the surface temperature of the world had a distribution that looked like reality. Then, having got such a variable, I had to figure out what it meant physically. I talked to a thermodynamicist called Kevin Spillane. He thought a bit and said, 'What you're dealing with is the entropy production of the atmosphere-ocean system.' I said, 'What on earth is entropy production?' and he then proceeded to tell me what entropy was all about. It turned out that what I had been maximising was a thing called the 'rate of entropy production'. The idea that a complex system might maximise entropy production became a principle called (not surprisingly!) the 'Principle of Maximum Entropy Production'.

Over the years a fairly long stream of people have investigated the principle and, with a remarkable lack of success, have tried to establish why such a principle should exist. They have tried to apply it to all sorts of other phenomena concerning essentially turbulent media or turbulent processes. It is only in the last few years that it looks as though an explanation of this principle is being worked out theoretically by, among others, Roderick Dewar, who is in your department.

With this principle, which has made your name quite famous, where would you say some problems need to be addressed in the near future?

I think a couple of things are needed to make it fully 'respectable'. The first is for somebody to come up with a problem which can only be solved by the application of the concept of maximum entropy production. Otherwise, there is not much point to it, is there! I suppose the second thing is for somebody to invent a machine which behaves according to the Maximum Entropy Production principle but is simple enough to visualise and to be understood. At the moment people are attempting to apply the principle to turbulent systems. Turbulence is one of those great and complex unsolved problems of physics.

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Involvement with Industry

Somewhere along the line, CSIRO became involved with industry. How did that affect your work?

That was an interesting time in CSIRO. All of a sudden, CSIRO got it into its head that it had to be more relevant to industry, which I suppose is a worthy enough goal. I can't remember when it was exactly, it must have been in the mid 70's. As a consequence, our Division was looking at what might be done in that way. The net result was that we turned my Radiation Group towards the development of instrumentation for getting data from, and analysing the data of, the new polar-orbiting satellites. These were monitoring things to do with weather and Earth's surface characteristics. We spent quite a lot of effort and money on developing a radio dish that would receive the satellites as they passed overhead. As well, we spent lots of effort on instrumentation that could handle the data and produce a product that would be useful.

We involved a local, relatively small electronics firm, with the idea that that firm would get out into the world and market the stuff that we had produced. It was going all right, in principle, until we suddenly woke up to the fact that some of the very big international companies were also in the same game and there was just no way in the world that we could compete. We could have competed, but it would have required vast quantities of money. I suppose that the lesson I learnt – and we learnt – was that, if you really want to go into the sport of international commerce and the making of commercial products, you have to spend a lot of money and a lot of effort. It is no good trying to carry on as one had in the past in CSIRO, for instance, where a lot of the research was based around individuals rather than large teams with given objectives that one had to stick to.

For what it is worth, I think that CSIRO didn't at that time really wake up to the fact. I presume they have now, although I am not absolutely certain. But there is still a tendency, in CSIRO and in the universities in Australia in general, to be very good at defining research programs, where you have lots of different people doing different things within a broad umbrella of a general discipline. What Australian research in general is absolutely hopeless at doing is defining a problem and setting out to solve it, as opposed to doing research under the umbrella of a general program. I have got a bit off the subject here but, for what it's worth, that is my opinion of one of the main problems of Australian research in the past.

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What about sabbaticals? Did CSIRO have sabbaticals in those days?

They weren't called 'sabbaticals'. In my case, I managed to get overseas and have various years away in different circumstances. And I have to say that I had great difficulty in persuading CSIRO to let me go to the various places. Not because it wanted to keep me or anything ridiculous like that, but simply because it didn't approve generally of the sort of thing that I wanted to do for a year or more. They weren't necessarily strictly research jobs or research sabbaticals.

For instance one of them was a year in Geneva at the World Meteorological Organization. I spent the year with the team that was stitching together the bureaucracy of the World Climate Research Programme.

Another was a year in Boulder, Colorado, working with a group that was trying to put together the International Satellite Cloud Climatology Project. I think I mentioned earlier that clouds are a big problem, and one of the things that nobody knew at that time was how much of the world was covered by cloud at any one time. The guesses ranged from 40 percent to 80 percent and nobody knew any better, so a big international satellite program was organised to look at the problem. It was during that year, apropos of nothing, that I was working with some people in NOAA and managed to produce the first published paper on global temperature change over the years. This was from vast amounts of ocean surface data that had been gathered from ships floating around the world.

It must have been in the late 80's that I managed to have a year in Washington DC with a funny crowd called the National Climate Program Office. It was a small group in the US government that was supposed to 'coordinate' – there is a good bureaucratic term – the climate research activities of all the various government departments around the country.

I even managed at one time, it must have been in the early 80's, to have a year with the Australian Institute of Petroleum doing absolutely nothing by way of science. Among other things, I was involved with the oil industry organising itself to be able to look after oil spills from ships and so on. CSIRO really did not like me taking a year off to work with the oil industry. Apparently, the name 'big oil' frightened CSIRO even in those days. But, I had a year with them and it was a great experience, I must say. I like to think that it did what CSIRO said that they wanted to see, namely, that their research staff should get a feel for the problems of industry.

At any rate, despite all the troubles, I managed to get away quite often and get a break from pure research, which is something that, to me, is a good idea. You can't do research 100 percent of the time throughout your life. You need a bit of a break every so often.

You hired people while you were at CSIRO: Graeme Stephens, Denis O'Brien and Martin Platt. Did you treat them the way that you would like to be treated?

You would have to ask them about the treatment I gave them. But I can remember distinctly hiring Denis O'Brien, who turned out to be one of the geniuses of this world – and also Graeme Stephens, who now is a big shot running a climate research institute at JPL in the United States. There were a number of people over the years that I was lucky enough to get hold of. They contributed an enormous amount to the development of the Radiation Group in particular and to the reputation that it got.

Did you give them free rein, or did you give them problems to solve?

I gave them free rein. You do not give geniuses problems to solve, as far as I can see, particularly people like Denis O'Brien.

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Cooperative Research Centre

In 1990, you left CSIRO and went to the University of Tasmania. What did you do there?

The University of Tasmania had just established the Institute of Antarctic and Southern Ocean Studies, which was to be a postgraduate research training ground for Antarctica and the Southern Ocean. This was in 1989 or 1990. I applied for the job as its director and got it. Within a year of that, things expanded enormously because we managed to nail down and 'get' one of the first round of the new Cooperative Research Centres that were established by your friend Ralph Slatyer. I combined the two, the original Institute of Antarctic and Southern Ocean Studies and the new CRC, so that you couldn't tell the difference between them. It became a very successful CRC in that it made a fairly large difference to the reputation of Hobart as a centre for things to do with Oceanography and Antarctic research.

For the first six or seven years of the CRC, it was tremendous fun because it took that time for the bureaucrats in charge of the overall CRC program to get their act together. While they were doing that, we, as a new CRC, did exactly as we liked. And I could deliberately run it in the fashion of the earlier CSIRO divisions. That is to say, let people do what they wanted to do. It was a successful CRC and it still exists today as a CRC-type entity. In the second six­year contract, it wasn't quite so enjoyable because the system of the CRCs had evolved and had become very administration minded. There seemed to be reviews every year and one was always producing documents as to what one had done last week. All in all, I was quite glad to retire in the end, because things were no longer the same as they had been. 'Nostalgia isn't what it used to be,' as they say.

However, the success of that CRC was largely due to the fact that the Chiefs of the partner organisations – the University of Tasmania, the CSIRO Division of Oceanography, the Weather Bureau and the Antarctic Division – were very keen to ensure that the CRC should stand on its own and be successful. All of them were marvellous at helping the CRC along the way. Things have changed as the years have gone by. I don't know, but I suspect that a lot of CRCs in general have become little more than grant-giving bodies that give the money from the CRC back to the partner organisations to do X, Y and Z in the way of research. But, for what it is worth, certainly for that first period of the Antarctic CRC, the partner organisations were just marvellous.

Who were the Chiefs of the partner organisations at that time?

CSIRO was Dr Angus McEwan, who is a Fellow of the Academy; the Bureau of Meteorology was Dr John Zillman, who is a Fellow of both Academies; and Rex Moncur, who was the Director of the Antarctic Division. Alec Lazenby was the Vice Chancellor of the University at the time.

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Respectable scepticism: The Climate Caper

Garth, what are you doing now? I know that you're still publishing.

Apart from returning to have a good time, I am still 'pretending' to do some research with various people. One is in Canberra and one is in Washington DC. It is mainly research on various climate issues and, at the moment, on how water vapour in the atmosphere is responding to any change of global temperature due to global warming. But, to be more general, what I am enjoying being involved with most is an attempt to ensure that scepticism is at least respectable in the context of what has become the politically correct beliefs concerning climate change and global warming.

I am one of those people who believe that the problem of global warming has most likely been completely oversold. There is no question that there is such a thing as global warming, but whether or not it is a problem and whether or not it will be disastrous is a completely open question. I like to get involved with things which at least maintain the belief that it is okay to be sceptical about such politically correct subjects. It is a dangerous occupation. You can lose friends this way, I can tell you. But, it keeps me off the streets. Last year I produced a book called The Climate Caper, which was intended as a reasonably sceptical view of the overselling of climate change.

Garth, with your credentials in radiation physics, the physics that underlies the whole global climate change/greenhouse effect discussion, why is it that sceptical people seem to be older? And are tending to be at odds with younger scientists in this area?

That is a tremendous question and I don't know the answer to it. I would say that probably one of the most worrying things about the whole climate change debate – if we'll be gentlemanly enough to call it a debate – is that normally it is the younger people who are liable to be sceptical about accepted wisdom, and that is the way it should be. But, with regard to climate change, which is now the accepted wisdom, it is the younger people who are pushing the idea and it is the older people who are sceptical, particularly the retired older scientists. The unretired older scientists who are sceptical about climate change cannot afford, in the present climate of public opinion, to be seen as obviously sceptical about the story. It can be dangerous to one's career to get that sort of reputation. I suppose that one of the reasons the younger generation are not sceptical about global warming is that they are also the people who worry about the future of the world. They feel that there is a problem that they ought to be worried about, and you can't blame them.

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Two kinds of research: problem solving vs following your nose

Garth, you said that at CSIRO you liked to follow your own nose and, paradoxically, you also said that, if CSIRO were to solve problems, it would need a lot of money and people to work on the problems that they were given. How do you reconcile those two views?

The short answer is that I can't reconcile them. Except to say that, if you are an organisation – let's say some mythical organisation called CSIRO – that wants to get involved in 'immediately useful research', first of all it has to be prepared to put money into solving problems as opposed to generating programs. As said earlier, Australians are not very good at defining the problems. And when I say 'put money into it', they have to put big money into it. You can't run such a program or such a type of research, if you are going to allow scientists simply to follow their nose. So I suppose that this mythical organisation of CSIRO is going to have divide itself very obviously into Divisions which are either one or the other: you are either a Division which is out there to make money or to make money for the country, or you are a Division which is 'interested', for want of a better word, in basic research. They have to make that division of roles quite clear to whomever they are going to employ. I don't think you can mix the two.

Would you like to have spent some time in a division making money for the country?

Yes, I think so. Provided that it wasn't my whole career, yes. This is another thing which I think Australian scientific organisations, CSIRO and the universities in particular, might seriously think about. To have the facility for those scientists who want to spend some time as an industrial researcher, as opposed to a basic researcher, to go and work for three, four or five years in an industry which is doing some research for itself. And then be able to come back, or 'sneak back' if you like, into the basic research that they used to do. Things may have changed since my time, but certainly that was not really possible at the time that I was working for CSIRO. You could get short times away or you could just leave and go into industry, without any guarantee that you could come back. Scientists in general are pretty timorous people and they don't like burning their boats and going off into industry without knowing that perhaps there is an avenue to come back to basic research if they don't like the applied stuff.

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Life outside Radiation Physics

What about the other side, Garth? You have always been involved with creative writing along with your research. Would you have liked to have had more time or time off to do other creative things?

No, that is not a thought that has ever occurred to me in my life. But there may be lots of people who would like to have time off to do something 'cultural'. When I retired seven or eight years ago, I did actually go mad and decide to learn to play the piano. So I have spent, with remarkably little success, the last seven or eight years trying to learn to play the piano, and it is enjoyable.

Garth, your father was an agronomist and you too have dallied in biological problems. I always thought it was a shame that we couldn't have attracted you into biology. What would need to have happened to have attracted you into biology?

Despite my great difficulties with mathematics – certainly complex mathematics which I try to avoid if I can – the bottom line is that I am a great believer in the fact that to be a really successful biologist, you have to know and be able to use a fair bit of mathematics. One of the great differences that I have noticed between biological sciences in Australia and biological sciences in the US is that most US biologists of any note are also mathematicians. In Australia, very few biological scientists – present company excepted – know anything at all about mathematics. Therefore, in many ways, they are terribly restricted in the sort of original research that they can dabble in. And there is the danger that biological science done by such people can boil down to nothing more than cataloguing or stamp collecting, unless they are terribly good.

You have two children; do they have any connection with science?

My son, who is married and has three children now, is in the music game and, among other things, records the music of groups who want their music recorded for sale. My daughter lives in Melbourne with her husband and she works for Leighton Holdings in some reasonably minor position, I gather. They seem to have turned out quite well, I have to admit, quite reasonable individuals.

That's a credit to your wife, Kay, Garth.


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You were involved in setting up the World Climate Research Programme, the WCRP, and later you were involved when the Intergovernmental Panel on Climate Change was being set up. What did people at the time expect that the IPCC would do or produce?

That is actually a difficult question to answer because obviously, as far as the IPCC was concerned, the different countries had entirely different views of what it should achieve. I suppose that it was best summed up for me by a comment made by an American friend of mine, who had just been to one of these interminable international conferences on climate change. He reported the outcome of that meeting as basically the underdeveloped countries saying to the audience that the world had been taking money and resources out of the third world countries for the last 500 years. It was therefore time to redress the balance so 'give us all your money.' That was on the one side. On the other side there were a fair number of countries who simply regarded it as a mechanism for getting more money for climate research. What it actually turned out to be seems to be an amalgam of those two extremes and with just about every shade in between. It's all a bit strange.

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Work of the team

Your work with Martin Platt, Graeme Stephens, Denis O'Brien and others at CSIRO … what was the Division was called then?

Initially, when I joined it, it was called the Division of Meteorological Physics, but that was a bit of a mouthful. So over the years, I don't know exactly when, it was changed to the Division of Atmospheric Physics. Then it became the Division of Atmospheric Research and finally the Division of Marine and Atmospheric Research. I'm sure there was lots of heart-searching about each of the changes, but they happened.

What areas of research in atmospheric physics would you regard as being the most important work of your team?

As far as the team is concerned, Martin Platt evolved a technique for using laser radars based on the ground to detect cirrus cloud and also, in fact, to describe the clouds in some detail. Cirrus cloud is very high cloud, made of ice crystals and generally at a height that research aircraft find difficult to get to. At that time not much was known about them, and they are very important in the scheme of things. Martin's development of the laser radar technique was one of the highlights for the group.

The general radiation work from aircraft that he, I and a few others were involved in concerned issues, which sound a bit esoteric, but which we really need to know something about. For instance, how much of the solar radiation gets absorbed by a cloud? A cloud is a white sort of object and it reflects solar radiation back to space and so removes it from heating the surface. But one of the important processes is that water vapour and water drops can absorb solar radiation. That is to say, the cloud or the air around the cloud will heat up because it is absorbing energy. At the time there was virtually no experimental data on just how much solar radiation clouds absorbed. So a lot of our work was concerned with flying above clouds and under clouds, measuring the difference in solar radiation and trying to calculate how much energy they absorbed. Indeed, at that time there was no real information on how much solar radiation was absorbed by the water vapour in general in the atmosphere. We did a lot of work on that particular problem so as to be able to calculate, if there is such and such an amount of water vapour in a particular depth of atmosphere, how much solar energy would be absorbed in that layer?

When those layers absorb energy, does that heat the surface of the Earth at all?

Yes, in a roundabout way. If you are talking about the surface of the Earth, yes. It removes immediate solar radiation from heating the surface of the Earth because it is absorbed in the atmosphere. But there are processes by which that energy or that heat, if you like, is transmitted or brought to the surface and contributes to the heating of the surface.

What did Graeme Stephens and Dennis O'Brien do?

Denis O'Brien is an applied mathematician, who was brought up on a chicken farm, would you believe, and was therefore also a very practical guy. Among other things, because he was so bright and helpful, he was the fellow to whom everybody else in the Division would come if they had some insoluble problem to do with physics. They would come to him and he would say, 'Leave it with me overnight,' and the next morning he would come back with the solution. So he became very popular. He got involved in what was actually the first effort in Australia to develop a new satellite instrument. The idea was to monitor from a satellite how much carbon dioxide there is in the atmosphere. He is now actually in the US, still in the same game because the Americans are now building such an instrument. The Japanese have also built one. The first American instrument was built only two years ago, was put on a rocket and fell into the ocean. So that was the end of that, and they have had to start again. But, in a way, his impact on satellite remote sensing in general has been quite significant.

Graeme Stephens developed some marvellous new 'practical-theoretical' approaches, which everybody could use for calculating – in models – things like the heating of clouds, and the heating of water vapour.

Garth, it has been an honour and a privilege to interview somebody who has made the contributions that you have. I have admired your work. As I said before, the first work that I knew being in agriculture and then, more recently, I got to know your work on radiation physics and climate change. It has been a pleasure and a privilege. Thank you very much for accepting the invitation to be interviewed.

Thank you for having me and putting up with me. Thank you.

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