Mapping sea level rise
Coastal areas will be vulnerable to flooding from sea level rise in different ways, in large part due to the topography, or elevation, of the landscape. Highly accurate mapping of the elevation of the landscape is therefore essential to identify low-lying areas that are potentially at risk of inundation from rising sea levels.
The Australian Government, through the Department of Climate Change and Energy Efficiency and the Cooperative Research Centre for Spatial Information (CRCSI), has invested in high resolution elevation data and imagery to develop tools to help communicate the risks of climate change.
One of the advantages of such large scale mapping is to be able to identify broader patterns of risk. For example, it is now clear that significant risks exist for areas not directly on the coast, but which will be exposed to rising sea levels along river banks and around estuaries, lakes and lagoons.
The nationally consistent approach taken in this mapping helps all governments and decision-makers understand the risks. Adaptation is a complex and long term process, new partnerships will be needed to address the challenge of climate change impacts.
Sea level rise maps
The Australian Government, through the Department of Climate Change and Energy Efficiency, has developed maps of low-lying areas that are more vulnerable to sea level rise for a number of regions.
These maps show low-lying vulnerable areas for a low (0.5m), medium (0.8m) and high (1.1m) sea level rise scenario, for the period around 2100. The maps illustrate the type of flooding event that could be expected to occur at least once a year – and possibly more frequently – by the year 2100, for the three different sea level rise scenarios.
The simple scenarios for sea level rise (relative to 1990) have been developed to cover the range of plausible sea level rise projections and to help understand the potential impacts and risk to society.
The low (0.5m sea level rise), medium (0.8m sea level rise) and high (1.1m sea level rise) scenario shown in the maps are relevant for the 2100 period.
The low scenario (B1): considers sea-level rise in the context of a global agreement which brings about dramatic reductions in global emissions and represents the upper end of the range for sea-level rise by 2100 which is likely to be unavoidable.
The medium scenario (A1FI): Represents the upper end of IPCC’s 4th Assessment Report (AR4) A1FI projections and is in line with recent global emissions and observations of sea-level rise.
The high-end scenario: considers the possible high end risk identified in the AR4 and more specifically in post IPCC AR4 research. This scenario factors in recent publications that explore the impacts of recent warming trends on ice sheet dynamics beyond those already included in the IPCC projections.
The regions covered are:
- Sydney, NSW
- Hunter and Central Coast, NSW
- Melbourne, VIC
- Adelaide, SA
- South East Queensland (including Brisbane and the Gold Coast)
- Perth to south of Mandurah, WA
The maps have been prepared to provide additional information that can help communities understand the potential impacts of sea level rise.
The maps are available online via the OzCoasts website.
Sea level rise visualisation tool
The sea level rise visualisation tool is an interactive, web based tool that displays potential flooding from sea level rise. As a pilot, the sea level rise visualisation tool will be available for government decision-makers to assess functionality and usefulness.
The sea level rise visualisation tool is based on Digital Elevation Models (DEMs) that have been developed from high resolution elevation data (LiDAR elevation data with a vertical accuracy of +/- 10-15cm).
National Elevation Data Framework (NEDF) portal
Digital Elevation Models (DEMs) provide a three dimensional model of the ground surface topography and are critical to assessing risk from inundation in low-lying areas. The creation of a national coastal DEM was the highest priority task identified for the Government’s National coastal risk assessment, released in November 2009.
ANZLIC - the Spatial Information Council has been tasked with coordinating the development of the National Elevation Data Framework (NEDF), to optimise investment and access to existing and future spatial information data collections and ensure this investment is directed to policy and operational needs across national, state and territory and local levels.
The Australian Government has invested in a mid resolution DEM covering the entire coast derived from SPOT High Resolution Stereoscopic Reference3D (SPOT) satellite imagery, which was the best resolution available for the entire coast at the time. State Governments, as well as the Australian Government have made significant investment in high resolution elevation modelling for key urban centres.
The Australian Government has committed to providing access to the generated DEMs for public good purposes. Through the NEDF, and in partnership with the Cooperative Research Centre for Spatial Information and Geoscience Australia, the Government has developed a portal to facilitate access to elevation data and derived products.
The NEDF portal allows users to search, discover, view, licence and take delivery of elevation and related data products. In the longer term it will become a ‘virtual repository’ for elevation data across Australia as part of the ongoing implementation of the NEDF.
The maps are available online via the Geoscience NEDF Portal.