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The Australian Coastal Zone and Global Change: Research Needs

Australian Academy of Science, Becker House, Canberra. Friday 16 December 1994


Professor Roger McLean: We have had three papers in this last session. These papers are open now for discussion, comment or questions. Any questions please?

Dr Peter Holloway: Perhaps I could ask Greg a question. I realise you have to define a scope and keep things not too broad, but a logical extension would be to incorporate the effect of cyclones on the continental shelf and on offshore structures or reefs, and also relate them closely to some of the aims we have heard of this morning about carbon cycles and so on. I was just wondering whether you would like to comment on excluding that from your project?

Dr Greg Holland: The answer is twofold. Firstly, we are going to be extremely careful about not getting overloaded. Having said that, we are interested in offshore coast structures. I should define 'coast': 'coast' is defined here as 200 kilometres to the ocean side and 100 kilometres inland. So we are interested in offshore structures. You might have noticed on that list, Heron Island, which happens to be a reef with a small island. We are interested in that from a straight scientific viewpoint, but we are also extremely interested because it is one of the really scary scenarios where a lot of people could be killed in a tropical cyclone. So it is a combination there.

From the point of view of the Western Australian continental shelf area, I think the answer would be if we could get people that are interested in helping out, we would be able to do that in as much as we can.

Professor Ann Henderson-Sellers: I have got a couple of questions for Tad Murty. Maybe I will ask the second one first. The second one was: you spoke about tsunamis a lot and just mentioned tropical cyclones once. I wondered whether you could help me understand whether they are essentially the same phenomena when they hit your tide gauges or whether the sort of research that you do to understand the impact of tsunamis is different from that which you would do to understand storm surges associated with meteorological events?

The second question is somewhat loaded. But you did say early on in your presentation that many of the sea-level gauges were there to detect greenhouse-induced sea-level rise. It was my understanding that because of the difficulties of figuring out where the land was, because of changes in land elevation, it was going to be extraordinarily difficult, at least any time before 2030, to be able to detect sea-level rise from that array of tide gauges. I just wondered whether you would like to clarify that.

Professor Tad Murty: Ann, I will answer your second question first on this greenhouse effect and then the distinction between tsunamis and storm surges. Of course, because of lack of time, I could not really go into the details. When these gauges were put in, the idea was to detect the sea-level changes due to the greenhouse effect. There is a geodetic component, of course. You are very correct in saying that. What we really see are any changes in the relative sea levels, not the absolute, so we have to correct for the tectonic movement. In fact there is a geodetic program, not totally satisfactory but getting better. We have some surveys now completed to what we call the first tidal accuracy that is needed and so within the next few months we will be able to digest this information and get some idea of the absolute sea levels. I totally agree, unless we do that really we will never know what is causing what.

Your first question on the coastal effects of tsunamis and surges: there are some similarities, but there are some differences also. In a theoretical sense they are all long-gravity waves but tsunamis travel through the deep ocean, whereas storm surges are simply a coastal phenomena. Storm surges cannot happen in the deep water because there is not enough transfer of energy between the atmospheric system and the water wave; it is not efficient because the water wave is travelling too fast compared with the speed of the weather system.

Having said that, more or less at the land inundation phase the effects are more or less similar except that there is a lot more bottom scouring and erosion associated with the tsunamis generally; there could be exceptions because tsunamis happen on a much larger space scale than storm surges. So, in a general sense, there are lot of similarities but there are some distinctions also.

Professor Roger McLean: Any further questions? If not, then would you please join me in thanking our three speakers for their contributions this afternoon. Ladies and gentlemen, it is a bit difficult for me to conclude this session. I had better have a look at our timetable here and program.

One of the reasons for holding this meeting was simply awareness raising among those dealing with aspects that are of relevance to the Land-Ocean Interaction Program. I am sure that that has happened today, that those of us who are involved in coastal work have learnt a lot and have been exposed to a range of scientific views and also, to a lesser extent, to the two cultures that Bruce Thom opened with this morning.

One of the things that I think that we are lacking from this session is in fact a significant biological or ecological input. Peter Saenger has helped in that regard, but I think on the whole we are physical scientists here rather than biological scientists and perhaps that is an area of deficiency that needs to be made up in terms of the LOICZ Program.

I wonder if anyone would like to comment any further about the value of today's meeting and, if Patrick is available, whether in fact he may like to say something about what he feels this day has resulted in as far as the standing committee is concerned. Would you like to say something now, Patrick, about the value to you as Chair of the Scientific Standing Committee?

Dr Patrick Holligan: I do not really have anything to say except that it has been a very interesting day for me. I suspect, like all countries, in looking at a project like this you are going to need to bring some of the elements together, to take it a bit beyond where each of you as individuals is working at the moment. That is something we are finding everywhere, both to get the cross-linkages right, but also to get the dimensions of the project right. I think in Australia, because your country is so big, that second problem is much less difficult for you than if you sit in a country like Belgium or Holland where this project office is situated.

Having said that, I do think that I have heard some excellent things today. I am sure you have got plenty to build upon, and I am sure there is plenty to build upon that is not represented here, like the biologists that you have stated.

I see, for instance, the problems of coupling terrestrial processes with marine coastal processes, with ocean processes, is something that has been relatively well talked about at this meeting. That to me is a very positive sign. I know in other countries this is proving very difficult, in part because the scientific communities are not in touch, and in part because the funding sources actually prevent them working together.

The only thing that I really want to say, apart from that, is just to remind you that we do have this focus four, and if you think you have got problems about under-representation of biologists, you have got far greater problems about non-representations of sociologists and economists here, I suspect.

So, I do not want to talk about it, but simply to remind you that it is here because this is the element of the program from which we expect to generate a lot of resources for new work. In a sense, the areas of science we have talked about are ongoing, and we will be going back to what Gerry Morvell was telling us about how we are going to approach the future of this: is it no change if there is an add-on value and so on? But I think in this area we are beginning to see, through international organisations and through organisations like the European Community where I work, people willing to look at this area in much greater detail than they have in the past.

Those are the sorts of elements that are there and you are going to see very simple models being looked at as to how to relate these - to recognise that there are feedbacks, to recognise that when you go through natural systems and socioeconomic systems these are themselves changing, so the feedbacks themselves are constantly being modified. These are quite difficult things to model, one suspects, or even to gain a dynamic understanding of. Of course, in looking at those things in relation to coastal management, these are the sorts of issues that are in the background.

So, do not forget this area of work because in some way or another it is going to happen. I suspect it is going to be very painful. We have already experienced some of that in language problems, in trying to find the sort of people to talk to. I suspect it may provide the rationale for what you may want to do as natural scientists, as well as for new work in this area that you might yourselves want to get involved in. So, can I just leave it like that.

Professor Roger McLean: Thanks very much, Patrick. Are there any questions that anyone would like to address or any comments that anyone would like to make?

Dr Robert Burne: I have learned that Dr Neil Hamilton, who is my colleague from the CSIRO Division of Wildlife and Ecology, unfortunately had a car accident so could not be here today. I was speaking to him yesterday and he was particularly interested in bringing up today the significance of his research on the coastal and marine information system of CSIRO - he has a display outside here - in relating the various data sets derived from physical, chemical and biological distributions in the coastline to exactly this focus of focus four: the economic and social impacts of global change on coastal systems.

There are particular interests in his group in looking at the impacts of population growth, changes in agricultural practice and so on, and relating this to coastal data sets.

I just wanted to bring the meeting's attention to the valuable work that Neil Hamilton is doing. It is just unfortunate that he could not be here today to present it at greater length himself.

Professor Roger McLean: I wonder if I could follow that up with a question to you, Bob? What particular areas of research or monitoring should Australia take some leadership role in the coastal zone programs? I think Peter Saenger gave us some idea that perhaps mangroves and mangrove environments would be one. I think Peter Craig gave us an indication of ocean currents and continental shelf interactions. But I wonder whether in fact GIS and remote sensing - interacting in a social and economic sense - as well as that question that was raised earlier about a global taxonomy of a coastal classification, may also be significant. Would you like to comment about the status of that GIS remote sensing, research and classification research as far as Australia is concerned?

Dr Robert Burne: I am not really in a position to give a complete overview of this but I could make some comments. Others at this meeting were involved in February in a meeting in Sydney looking at the biophysical regionalisation of the Australian seas. The impetus for this came from the IUCN requirement for representative marine and protected areas for various countries of the world. In order to this we have to have an inventory of exactly what particular areas are in existence in the Australian coast and coastal marine area. This brought a very vigorous discussion of how one regionalises, how one divides up the coastal and marine province. Arising from that there has been some considerable discussions involving groups of us in the area to try and use GIS and to try and use standard methods of categorising things like coastal geoscience, communities' ecological ecosystems and other parameters to bring about this sort of regionalisation.

The same sorts of approaches are being used to look at change in the coastal zone. We have a history in Australia of aerial photography that goes back to about 1950 and there has been remote sensing of one form or another since about 1970. There is an increasing interest in using this sequential series of snapshots of the environment to look at rates of change in the coastal zone. To do this, certainly in Australia, it is becoming more and more important that the various groups form consortia to focus on particular elements, either biophysical regionalisation or change in the coastal zone. In an attempt to facilitate this coordination there are groups such as ERIN, the Environmental Resources Information Network, set up within DEST, to act as intermediaries, people capable of processing large amounts of information to assist in this type of work. That is about all I would like to say.

Professor Roger McLean: Good, thanks Bob.

Professor Ann Henderson-Sellers: Today I am going to switch hats and back up Patrick's comment about LOICZ's focus four because I also agree that not only do we need to take into account the physical processes that WCRP would encompass, but also the Human Dimensions Program which is the third leg of the still very wobbly stool that is researching into global change.

In doing that I would like to do two things: first of all to compliment Neville Smith, who actually, though he did not land a question, did encompass all of the aspects, at least in the context of the Global Ocean Observing System and looked at human factors as well; and also to comment that Greg Holland's talk was almost exclusively about focus four in LOICZ and that it is motivated very strongly by the need in Australia to understand the current impacts of tropical cyclones and the associated bad weather and storm surges and potential future impacts.

In that context in the Climatic Impacts Centre in Macquarie we are also involved in a joint research project with the Bureau of Meteorology looking at something which again is topical in the sense of funding fatigue in many nations for many aspects of our normal day-to-day life, and that is looking at the benefits of meteorological service provision, just present-day meteorological service provision. Greg Holland actually quoted a figure for the cost of the tropical cyclone warning system at present in Australia, but the benefits are very much greater than that and the very much greater factor, we do not know exactly yet, but it is potentially of the order of somewhere between 20:1 and 100:1.

So, it is extraordinarily important to have these sorts of things in place in terms of social impact. In Australia a very important factor is tourism; the tourist industry in all of the northern areas of Australia where tropical cyclones are a factor is very, very sensitive. It turns out that if there is a tropical cyclone essentially anywhere in the Australian region then very many people appear to cancel holidays. So, we get into this rather extraordinary situation where if there is the potential of a tropical cyclone somewhere near Darwin then many of the tourist agencies would like the Bureau of Meteorology to say, 'But Cairns and Townsville are having really nice weather and there isn't a chance of a tropical cyclone there'.

So, we have to try and have people understand much better what the processes are and what the likelihoods are and what level of guarantee there is associated with forecasting and the disaster prevention services that are in place. So I absolutely agree with you, Patrick. I think focus four of LOICZ is very important. It is certainly important in Australia, and I think at least a couple of the talks in this last session back that up.

Professor Roger McLean: If I could just comment on that, Ann. Through the IPCC work, and through the coastal zones and small islands work, where there is a socioeconomic appraisal going on, one of the major problems that we have had in that part of the chapter has been that our two economists have taken the extreme extremes as being the things that they are working with. They are not only wanting to take a one-metre rise in water level to the year 2050, but they, as economists, say, 'Well, let's really make sure about this and we will take a 2-metre rise in water level over this time'. Increased storminess as well is added to our socioeconomic forecasts, and things get completely out of hand. In other words, the building blocks of the science and our communication with the socioeconomic assessment people has not been good so far, it seems to me, and that that obviously is an area that we have to do a lot more work on; of course that was what Bruce was talking about earlier today.

Are there any further comments? If not, thank you very much indeed for your attendance.