International Assessments of the Vulnerability of the Coastal Zone to Climate Change, Including an Australian Perspective
Prepared by
Pamela A. Abuodha and Colin D. Woodroffe
School of Earth and Environmental Sciences, University of Wollongong
for the
Australian Greenhouse Office , Department of the Environment and Heritage, September 2006
Download PDF
Documents are available for downloading as PDF files. (PDF help).
If you are unable to access these documents, please contact us to organise a suitable alternative format.
Executive Summary
This review examines what global coastal vulnerability assessments say about Australia, and considers global, and in some cases national, assessments of vulnerability to climate change to evaluate the implications for the Australian coast, or to assess the applicability of particular approaches and methods to Australia.
Climate change vulnerability assessment aims at assisting policymakers in adequately responding to the challenge of climate change by investigating how projected changes in the Earth's climate may affect natural systems and human activities. Generally studies consider, exposure or susceptibility of natural coastal systems, the effect on socio-economic systems (“impact assessment”), and/or how human actions may reduce adverse effects of climate change on those systems or activities (“adaptation assessment”, a measure of adaptive capacity). The framework for a climate change vulnerability assessment depends on the system under consideration, stressors, responses (effects), and actions (adaptation). It is important that each assessment is undertaken at the relevant spatial and temporal scales, and the results are often appropriate only at those scales.
The reports and literature reviewed contain relatively little information directly on the Australian coast, but a range of techniques that have been adopted overseas is discussed. It is clear that there is no “off-the-shelf” methodology appropriate for the entire Australian coast, but several methods could be adapted for use in Australia. The unique nature of the Australian coast, however, and the innovative nature of several approaches adopted within Australia, suggests that it would be prudent to consider modifying techniques applied elsewhere or developing new tools to assess the vulnerability of the Australian coast to climate change.
Development and application of the IPCC Common Methodology (CM) in the 1990s represented a milestone in the development of international coastal vulnerability assessments. CM has been a foundation on which the majority of subsequent overseas methodologies have been based. In Australia, the National Coastal Vulnerability Assessment Case Studies Project (NCVACSP) was undertaken during 1994-95, comprising 9 case studies (one study in each state, with two in each of Victoria and the Northern Territory) and several deficiencies with the CM approach were identified. The 9 site-specific case studies have not been upgraded to a national level survey in Australia.
The following are the key points to arise from this review.
- The scale of data that international comparisons such as the Global Vulnerability Assessment (GVA) or Dynamic Interactive Vulnerability Assessment (DIVA) use concerning Australia is generally inadequate for assessment of vulnerability within Australia, or between different parts of the Australian coast.
- The majority of overseas assessments of the impact of climate change on coastal environments have concentrated on sea-level rise. There is an increasing recognition, but little assessment, of a series of other climate change drivers, such as changes in sea surface temperatures, precipitation and runoff, wave climate, storm intensity and frequency, and ocean acidification, and the impacts they may have on coasts.
- Vulnerability is defined on the basis of a system’s exposure and sensitivity to climate change, moderated by its adaptive capacity. Modelling these components is better developed in relation to natural systems than it is for socio-economic systems. Despite natural (autonomous) and planned adaptation, it is important to recognise that there will be residual impacts, particularly associated with extreme events. There has been relatively little consideration of the impact of storms and how this may change as a result of climate change.
- The Australian coast is unique; it contains a particularly diverse range of ecosystems and types of human use. Several factors mean that much of the Australian coast appears less vulnerable than highly developed coasts in Europe or North America. In particular, the Australian continent is stable, remote from former ice sheets, and hence subject to only gradual rates of sea-level rise. In addition, little of the coast requires protection today (much is uninhabited), and coastal settlements and infrastructure are generally not too close to the sea.
- Despite this, assessments by the Intergovernmental Panel on Climate Change (IPCC) identify that Australian coastal systems are threatened by climate change, and as a disproportionate percentage of the population lives along the coast, climate impacts on coasts will be amongst those environmental issues of most concern to Australia over the 21st century.
- Little detail about vulnerability of the Australian coast is contained in assessments by the Millennium Ecosystem Assessment, handbooks such as that prepared by UNEP, or databases such as that compiled for a global typology by LOICZ. These generally concentrate on assessment techniques that can be adopted by developing countries.
- Most methodologies for assessing relative global vulnerability of coasts to climate change, such as CM and DIVA, adopt metrics, such as the number of people at risk, the area of land lost, and protection costs or costs of adaptation. These monetary and non-monetary metrics are rarely the measures most suited to evaluating the Australian coast because, compared to coasts in Europe, the Australian coast is sparsely populated and little of the coast requires protection.
- In terms of a vulnerability assessment framework, review of international approaches has not identified a more appropriate methodology for characterising climate drivers than the matrix and template adopted by Engineers Australia (NCCOE, 2004, see Appendix 3).
- Low-lying areas of the Australian coast, particularly wetlands, estuaries and reefs (coral reefs have not been examined in detail in this review) appear the most vulnerable, and there is urgent need for a more systematic integration of highresolution topographic/bathymetric datasets with tidal and storm surge extreme water levels.
- Indices of vulnerability, developed overseas, based on a few metrics (such as relief, rock types, landform, relative sea-level change, shoreline displacement, tidal range and maximum wave height), have not been applied in Australia. To develop an index for use in Australia, research is needed to identify the best set of parameters and to test their validity in an Australian context. This approach would be most appropriate at regional scale enabling prioritisation of those regions most at risk around Australia, but would need customising for Australian conditions (natural and socio-economic) and data availability.
- Most overseas modelling approaches have been based on the Bruun rule, which estimates sandy shoreline retreat in response to sea-level rise. The method has been criticised, overseas and within Australia, and Australian researchers are contributing to the international methodological debates concerning modifications to the techniques available. Both DIVA and CoastClim (a coastal module of Simulator of Climate Change Risks and Adaptation Initiatives [SimClim]) offer modelling capability that requires further testing, modification and validation in the Australian context. There appears to be considerable potential for integration of these open coast modelling techniques with developments that are already occurring, especially in south-eastern Australia.
- Climate change impacts on wetlands and estuaries are less clear. International approaches are primarily appropriate at global scales and cannot easily be adapted to address issues at the regional or local scale that is more relevant for Australian wetlands or estuaries.
- Few of the techniques available from global studies, since the CM, have been tested in the Australian context. Most would require further development and customisation, probably with new sets of data, but their adaptation (especially DIVA and CoastClim) should be considered in conjunction with further focus on methods developed within Australia.
