Interview with Dr John Butler

Armagh Observatory


1. When did you become interested in astronomy?

I was interested in astronomy at school but it was whilst I was studying physics in Edinburgh that I considered taking it up for a career.

2. We are very impressed that you were awarded an MBE in the Queen's Birthday honours for service to science - could you describe the highlights of your career to date?

I am not sure exactly why I got that gong but I suspect it was for involvement in several rather low profile projects at the Observatory in Armagh, possibly including the AstroPark, the Bicentenary Exhibition, the restoration of the historic buildings and instruments or various climate-related projects such as the standardisation of the Observatory’s long meteorological series.

3. The effect of the solar cycle on northern hemisphere winters has received a lot of media attention recently. What's your view on this?

There are quite strong correlations between mean annual temperature and other meteorological data with solar activity that have persisted over several centuries; and indeed millennia, if you include proxy data such as ice-cores and geological data. There are many papers in the literature which show this. The link to colder than average winters, comes mostly through the low solar activity levels (Maunder Minimum) which occurred during the period known as the Little Ice Age.

The difficulty atmospheric physicists have faced is to identify physical mechanisms which can account for the magnitude of the temperature changes that have been observed. The simplest mechanism would be a change in the actual brightness of the Sun associated with solar activity level. In fact, we know from satellite observations that this does occur, and in the right direction, but at far too low a level to account for the temperature changes we have seen. If solar activity is to be a major contributor to global warming, some amplification mechanism must be involved.

In Armagh, about 10-12 years ago, Enric Palle, a research student who worked with me, undertook a study of satellite cloud cover and found evidence that low cloud levels may be influenced by cosmic rays (which in turn are linked to solar activity). This work was done at about the same time as that of the Danish group lead by Henrik Svensmark but it didn’t receive the same degree of publicity. Later papers questioned the accuracy of the satellite cloud data and possible problems associated with the perspective  from which the satellites viewed the clouds. As far as I am aware, these possibilities have never been fully resolved. However, we did point out that changes in clouds at other levels might be involved and this looks increasing likely. The very recently announced results from the “Cloud” project at Cern which involved firing charged particles through a large stainless steel container in which atmospheric conditions were simulated,  appear to lend some support to the contention that cosmic rays influence cloud formation, particularly at higher levels in the atmosphere.

4. What's your view on climate change in general?

There is no doubt that climate change has occurred in the past and no reason not to expect it to continue in the future. The changes have been both regional and global. From geology, and from ice-cores, we know that much larger changes than those we currently experience have taken place in the last few tens of thousands of years. The most recent of these on a geological time-scale are the ice ages which are interrupted  occasionally by interglacials such as the one we presently enjoy.  The alarming thing is that in all probability, some time in the next few millennia, we can expect to return to ice age conditions that will last for about a hundred thousand years. The present interglacial has already lasted for about the average duration of the previous five interglacials. So, whether or not the current concern about global warming is justified, we need to be very concerned about climate change and the more we can understand about it, the better for the future of mankind. Maybe I am a bit optimistic here, but I think its not beyond the realms of possibility that, if we have a sufficient understanding of the mechanisms involved, and the timescales are in our favour, we may just be able to prevent the onset of a future impending ice age.

5. What's your favourite type of weather?

I think I am probably most comfortable in changeable summer weather, as long as it does change at least once a week.

6. What interests have you outside of science?

Archaeology and architecture are two of my interests, though I don’t know a lot about either. Coming from a farming background, I guess I also like growing things, so I spend time in the vegetable garden. At the moment I am trying to grow grapes in the Wicklow Mountains (under glass, of course).


7. Is climate science finally beginning to accept the probable role of solar variability in the Earth’s climate?

This depends very much on who you are talking to, though I think most people would accept that solar variability is involved to a greater or lesser extent. Some people seem to believe that the correctness (i.e. truth) of a scientific theory is decided by the number of people who hold it - a sort of head count of believers. In fact, a scientific theory can only be accepted as valid if its predictions agree with the physical world, which in the case of climate, means fitting the observations. There are many examples in the history of science but I would take the case of Newton’s theory of gravitation. In the mid-19th century, almost all physicists would have accepted Newton’s theory was correct, but a hundred years later, after the explosion of the first nuclear devices and Einstein’s theory of relativity, most physicists would have agreed that Newton’s theory was only an approximation to the truth. It wasn’t the number of believers that decided what was or was not correct, but the agreement of observation and theory. So when I read that 99% of scientists believe that global warming is due to man made greenhouse gases, I wouldn’t accept that as terribly meaningful in terms of what is actually happening. However, I don’t want to give the impression that I think greenhouse gases are not involved, there are plenty of reasons to suggest they are, but its unlikely to be the whole story and maybe not even the most important part of it.


8. What is your favourite film genre and why? What attracts you to that particular genre?

I must admit I have rather old-fashioned preferences in films. I like films that tell stories about ordinary people who lead rather uneventful lives. I don’t like violent films and if they do include warfare, I prefer them to be anti-war. There are some very interesting films of this genre out there from many countries, most notably France, but also China, Iran and Afghanistan.

9. You have supervised the restoration of Armagh Observatory’s main historic telescopes. How well do these 19th Century instruments perform compared to their modern counterparts?

There is no comparison in the quality of old  scientific instruments and their modern equivalents - the modern ones are far superior. The main reason to restore the older instruments is to show how scientists developed their understanding of the universe - they are the physical link between us and the work done by past generations.

10. If you could do it all over again would you still have been an astronomer?

I was very lucky to be able to enjoy a lifetime in scientific research and particularly in astronomy at a time when there has been such a surge in activity through the space programme. However, other scientific disciplines have also made major strides in recent decades and I would have been equally content to have been involved in those.

11. Do you have a favourite constellation?

I guess I would have to chose the southern constellation of Doradus as it contains the nearby galaxy I spent so much time studying in my early years, the Large Magellanic Cloud.  Over 15 months in 1965/6 I regularly scanned the stars and nebulae in this galaxy with what at that time was one of the largest telescopes in the Southern Hemisphere, the 60-inch Rockefeller Telescope at Boyden Observatory,  near Bloemfontein. The amazing variety of objects in that galaxy and the sense of discovery one got when peering through the eyepiece of that telescope, alone in a dome in the African bush, is something I can never forget. Unfortunately, young astronomers seldom get that sort of experience now as telescopes are set automatically and so they don’t have to find their way manually through the constellations.

12. How would you best describe the climate of Armagh? Have you observed any peculiarities of weather patterns and events that you would consider unique to the county/city?

I think weather conditions in Armagh are fairly typical of Ireland, at least for a region reasonably distant from mountains and the Atlantic. What’s particularly interesting is the longevity of the series, some of which began in 1795. This makes it possible to see decadal cycles in climate that would otherwise not show up so clearly. The cycles in relative humidity which I have been working on recently are most remarkable and seem to connect quite clearly with the potato famines of the 19th century and oscillations in the oceans.

13. We have had some spectacular views of Noctilucent Clouds in Ireland this year so far. It has been suggested that Noctilucent clouds are a relatively recent phenomena and may be partly enhanced by human activity and pollution. Do you think this is the case? Or does extra-terrestrial influences have an influence on their development?

As far as I know, the reasons for the appearance of Noctilucent Clouds are still uncertain. They are known to have been prevalent after the eruption of Krakatau, when they were first described in the scientific literature, but its possible that Thomas Romney Robinson saw them earlier and described them to colleagues. In some plots they appear to follow the solar cycle, which is not entirely surprising considering they are situated about 80km high where the influence of solar ultraviolet and corpuscular radiation is strong. Some astronomers, including Mark Bailey in Armagh, believe their occurrence might be linked to meteoric dust falling into the atmosphere from interplanetary space. Its possible that anthropogenic material would be involved and that pollution has contributed to their greater prevalence in recent years.

14. Is it possible, do you think, that the increased urban spread in recent years has an influence on temperature readings in nearby rural locations? and that this may, in part, explain the trend in temperature readings over the last 30 years or so?

It looks fairly certain that there are strong urban effects on temperature in some regions, particularly where there are large expanses of hard surface and relatively little wind. Its something we have to be continually aware of when comparing old records with those of recent years. However, when Alan Coughlin made a study of urban effects at Armagh, he was not able to find any. It seems that the local environment, say within a few hundred metres, is very important for these effects, and if the ground cover/vegetation is maintained in an area of this size around the station, the urban effects are minimal - at least that was the conclusion of his study.  However, its easy to see how small differences of the order of several tenths of a degree could occur and when averaged over many sites, with the effects all going in the same direction,  the net result would be systematic shift upwards.

15. You are to be banished to remote island for 1 year for stealing a loaf of bread, but the judge in his/her kindness has allowed you to bring one piece of music with you to keep you entertained. What would that one music track be? and why?

A difficult one and one that would probably change in a couple of weeks. At the moment, I would take Andy McGann and Paul Brady’s CD recorded many years ago. The fiddle playing is superb and Paul’s accompaniment equally brilliant. The main reason would be to have something to aspire to on the  fiddle that was washed up beside me (hopefully).


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