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Issues Water QualityConditionHarvesting and Marine FarmingGlobal Change- Adapting Coastal Settlements to Climate Change
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At a glance 
The issue Decisions are being taken that influence development and investment in areas of the Tasmanian coastline. Some of these areas may be vulnerable to the impacts of climate change, so it is important to minimise the avoidable consequences of climate change. Scientists around the world are generally in agreement that over the last 100 years there have been a number of measurable changes to the planet's climate. These changes will have global consequences for the Earth's inland, coastal, and marine areas (IPCC 2001). The planet's coastal areas are projected to be influenced by a number of climate-related changes, including: a higher sea-level, more frequent and more severe storm events, more frequent and more intense low-pressure systems, changes to short term climatic cycles such as El Nino/La Nina, and an increased number of high rainfall events likely to cause floods. Some of these impacts will be gradual while others will be sudden and extensive following major events, such as storms. The Intergovernmental Panel on Climate Change 3rd Assessment Report of 2001 projected a global average sea-level increase between 1990 and 2100 of between 0.09 and 0.88 metres (IPCC 2001). This is on top of a 0.10 to 0.20 cm sea-level rise last century. In addition, changes to global rainfall patterns, storm patterns, and temperatures are projected. These predictions may not seem significant, but even the smallest increases can result in flooding of low-lying coastal areas, dune erosion and coastal re-alignment. This 'At a glance' section provides an overview of the issue of adapting coastal settlements to climate change. More detailed information and references are available in the Adapting Coastal Settlements to Climate Change Issue Report. An indicator on sea-level change is provided in the Issue Report. The Case Study on Measuring sea-level rise at Port Arthur describes one of the world's earliest benchmarks against which to scientifically measure changes in sea-level. Further information on climate change in general is available in the Atmosphere Chapter. A recommendation is presented on Adapting Coastal Settlements to Climate Change in the report. Favourable news - Decision-making in Tasmania can benefit, if we choose, from the experience of other countries, and climate and sea-level scenarios developed by the International Panel of Climate Change and the CSIRO (such as McInnes et al. 1998).
- Rocky shores occupy about 2,160 km (34%) of the coast in Tasmania and have little risk of recession or flooding over the next century.
- Work is being carried out by the State Emergency Service, in association with local government, to identify emergency risk management requirements for dealing with natural and other hazards. This program provides a useful model in dealing with vulnerability from climate change.
Unfavourable news - Changes can affect existing infrastructure and investment on the Tasmanian coast. Some 975 km (approximately 15%) of the coastline contains low-lying erodible shorelines potentially at risk of recession and flooding. A further 1,147km (18%) contains low-lying shores mainly at risk of increased coastal flooding.
- Overcoming misconceptions about so-called 'one-in-ten year' or 'one-in-fifty year' storm events or scenarios is a challenge. A common perception is that a one-in-fifty year storm occurs once every 50 years (and in 50 years time). This misunderstanding can lead to a false sense of security (Smith 1994). The so called fifty year storm could occur within weeks, in two years, ten years, fifty years, or even in hundreds of years. It also means that there could be a series of storms over a few weeks or months, followed by a period of calm conditions for the following 100 or 200 years.
- Trying to protect sandy coastal environments from rises in sea level can be very expensive and prone to failure if not built to the highest standards. Ad hoc measures can often cause erosion problems elsewhere if not developed as part of an integrated regional works strategy. Such measures can also be visually unattractive.
Uncertain news - The IPCC provides estimates for low-, medium-, and high- sea level rise scenarios, ranging from 0.09 m to 0.88 m by the year 2100 on a global scale (IPCC 2001). There is uncertainty in the predictions, so the scale of potential impacts varies accordingly.
- While there is currently sufficient information to avoid development on the most vulnerable coastal areas in Tasmania-particularly development on foreshore dunes on sandy coastlines-more detailed modelling and collection of high-resolution spatial data are needed to measure shoreline changes over time.
- Valuation data were not available for this SoE Report to provide even general estimates of the present value of the land and structures on vulnerable areas of the Tasmanian coastline. This information would help direct attention to this important public policy issue and, over time, assist in prioritising the four main adaptation strategies for vulnerable areas: abandon, protect, adapt, or retreat (phased withdrawal).
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