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The Australian Coastal Zone and Global Change: Research Needs

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

Intergovernmental Panel on Climate Change (IPCC): coastal zones and small islands: an update - continued

I do not want to go into any detail at all about the critique of the vulnerability assessments, but I can say that Australia had a very active role in them and the more recent moves towards a common framework for looking at coastal management strategies, rather than having a somewhat deterministic common methodology.

I want now to briefly go on to one of the outcomes of this particular exercise, the development of the Second Assessment Reports (SAR) which is due for completion by the end of 1995. This IPCC report is to be produced five years after the 1990 exercise. In this case, coastal zones and small islands have been separated from the oceans chapter in Working Group Two, which is concerned with impacts, adaptations and adjustments. The outline of the chapter as it stands now is on Overhead 6.

Overhead 6

IPCC WGII Second Assessment Report

Chapter II.A.8: Coastal Zones and Small Islands

Draft List of Contents

As at 1/12/94

8.1 Introduction (Bijlsma)

8.2 Functions & Values (Klein/McLean)

8.3 Components of Climate Change of concern to Coastal Zones and Small Islands (Warrick/Kulshresthan)

8.4 Biogeophysical Effects (McLean)

8.5 Socio-Economic & Cultural Impacts (Turner.Nicholls)

8.6 Response Strategies (Bijlsma/Niets)

8.7 Research & Monitoring Needs (Nurse & others)

I just want to draw your attention to two parts of this chapter: 8.3 and 8.4. Part 8.3, in fact, derives a great deal from the assessment of Working Group One. This is Richard Warrick's work on sea-level rise projections.

One of the things that I should draw your attention to in this chapter are, the sea-level rise scenarios for the future. These indicate a slight reduction in the mean values, but only a slight reduction. It is mainly at the extremes where a substantial reduction takes place.

Now, one of the points that Dick Warrick makes in his paper is indicated by this chart (Overhead 7) which shows that there has, in terms of the mean, only been a slight reduction over the last several years - from 1986 down to 1993 calculations.

OH 7: estimates of future sea-level rise made over the last seven years

Overhead 7

So that Warrick is in fact making a somewhat contradictory statement to some who say there has been a radical reduction in predictions of global sea-level rise. He uses Overhead 7 to demonstrate that perhaps this is not the case.

The second point that he makes in this chapter is that the sea-level rise estimates, as indicated here are, in fact, still two to four times higher than the historic or recent rates of rise. A third point, and one that I think many of us have been wanting for a long time, has been the start in getting some idea about regional variations in global sea level change. I hope that does not sound contradictory. We are also trying to include other factors such as changes in the permanent or semi-permanent location of pressure belts, changes in wind strength and direction on a semi-permanent basis, as well as higher magnitude, low-frequency events.

OH 8: regional differences

Overhead 8

Just to look at the illustration (Overhead 8) on the regional differences in the predictions: this is the first time I have seen something that is a departure from the global situation, a departure from the means, and results are given as plus or minus 50 centimetres from the mean figure. These are encouraging results even if they are quite crude and the patterns should not be taken literally.

Finally, I want to say something about the biogeophysical effects; the section that I am having most to do with. I have been amazed that, in reviewing progress since the 1990 Assessment, that there has been a very remarkable improvement in our understanding of the effects of climate change and sea level-rise in the coastal zones and small islands. I think this has come through three groups of studies (Overhead 9): the retrospective geomorphological stratigraphic studies looking at the last major rises in sea level, both from the low in maximum glacial times to what has been going on more recently in the late phases or the middle phases of the Holocene, and using these as analogues for future sea-level rise. Second, there has been consideration of contemporary trends in shoreline change, on time scales of years to decades and both linear and non-linear projections emerge from these.

Overhead 9


Progress since 1990 Assessment

Improved understanding of effects of CC and SLR on coastal zones and small islands

3 groups of approaches

Finally, there have been several modelling studies, some of which have been deterministic simulation models of both coastal morphological and ecological systems, at a variety of time scales and at a variety of spatial scales, working from two-dimensional studies such as those ones that Peter Cowell, who is in this room, and others are doing - to three-dimensional studies taking whole deltas for modelling and dealing with changes in sea level and, particularly, sediment inputs up to the delta systems.

Another thing that emerges from the work that IPCC is putting together for this chapter on coral reefs, on sedimentary coasts, on deltaic coasts, on sandy barriers and dune systems, coral atolls, et cetera, is, firstly, that the coast does not remain passive as the sea rises over it. Obviously the coast is quite dynamic. One of the things that has hamstrung work in the recent times - or going back to the first work on the impact of sea-level rise - has been this ridiculous idea that there would be a simple adjustment, where you raise water level by the equivalent of the global sea-level rise and translate the land-sea boundary, on a topographic map, to a new position, without taking into account any dynamic component. Unfortunately, we still get those simplified inundation models being presented, particularly when seeking funding or publicity.

Secondly, coasts are affected by relative sea-level rise - or change, of which the global sea level is just one component. Thirdly, there are different responses dependent on local conditions. Fourthly, the relative roles of average or incremental sea-level change, against high-magnitude, low-frequency events, becomes critical of our analysis. That is something that we need to do far more research on and I hope it is something that the LOICZ project will tackle.

Other significant things to come from these studies are that virtually all coasts have been subject to, or are subject to, direct or indirect human impact and effects. And, in compiling the Biogeophysical Effects part of the chapter, it is interesting to find that critical in the analysis is the role of sediment supply and biological production in determining how a shoreline or a coral atoll or island will respond to sea-level change.

Finally, what is the IPCC process? The IPCC process, as our chairman indicated, has peer-review components and, as far as our Working Group Two is concerned that progress is on-going with government reviews coming up (Overhead 10).

OH 10: working group diagram

Overhead 10

Government review follows a scientific peer-review process which some people in this room have contributed to. The process continues, ultimately to December. Let me just identify one major problem that IPCC Working Groups Two and Three have. We are getting our primary assessments in terms of the science from Working Group One and yet, as you will see from these time lines, Working Group One is still in an early phase of the process. So we are having to make decisions based on projections that may not be 100% correct.

The last section of our report deals with research and monitoring and that is a section we hope Patrick Holligan speak. In conclusion, I do want to draw your attention to several areas of future work - integrated coastal zone management being one. Secondly, we need to develop a global coastal topology that in fact is related to climate change and sea-level rise. We also need to do far more research on integrating the three types of data that I mentioned earlier with regard to the biogeophysical effects (Overhead 9).

Lastly, in the Sydney papers - and in last week's Canberra Times and also on radio and television in Australia - was something that quite disturbed me. It relates to a headline in the newspaper and comments by the Prime Minister of Tuvalu which has these opening words:

The inhabitants of a tiny Pacific island threatened by rising sea levels, fear they will have to man the canoes before the rest of the world wakes up to their plight.

This quote is of course about sea-level rise. There is also comment to the effect that several islands have disappeared and that sea erosion is occurring rapidly. And another about how nice it would be for Australia and New Zealand to receive some people from these islands before they have to take to their canoes. This is quite disturbing for me, having worked in Tuvalu since 1973 and seeing these headlines initially in the late 1980s appearing again in 1994. The question and comment that Bruce Thom made about two cultures coming together is one that is most appropriate here because, it seems to me, that in this illustration there are linkages made between climate change and sea-level rise and coastal erosion and population migration and the economy and so on. Some of those linkages, in fact, may not be direct ones but may be quite independent of one another. But, in spite of the incredible progress we have made in understanding sea-level impacts, we still have a remarkably long way to go in communicating that science effectively and with empathy to people like the Prime Minister of Tuvalu. Thank you.

Professor Graham Farquhar: Thanks very much, Roger. Well, we will break for morning tea now. If we could be back here at 11 o'clock for session two, for which the Chair will be Professor Thom. Thank you very much.

Professor Bruce Thom: In this session we will hear more about the international programs, particularly LOICZ and the responsibilities that exist there on the international side, coming out of the Scientific Steering Committee. We will have a half-hour presentation from Patrick Holligan, who has chaired this scientific steering committee. Then we will hear from Stephan Kempe on the operational plan, and then we will have a presentation from John Parslow in relationship to carbon fluxes and continental margins. At the completion of that we then will have time for questions and discussions. So I think we will run the three presentations together, one after each other, and then we will have discussion. So it is a great to introduce to you Patrick Holligan. I have already mentioned my association with Patrick over the past few years on the IGBP. Patrick, I will turn the microphone over to you.