Buildings, beaches and, tragically, lives have been lost in wild weather that hit the eastern seaboard over the past week. The storm and its trail of destruction is a graphic reminder of the dramatic impact that the combination of storms (e.g. east coast lows), sea-level rise, extreme sea levels and waves has on the natural and built coastal environment.
In a changing climate, it’s a scenario that is likely to play out more frequently in the future, so it is critical that we understand the changes in sea level, extreme sea levels (storm surges) and waves, and their combined influence on processes at the coast. This understanding will allow us to make policy, planning and development decisions that will minimise the economic, environmental and human cost of coastal hazards.
What we’re doing
A three-year project being led by CSIRO’s Dr Kathleen McInnes aims to reduce the uncertainty that surrounds both past and future changes sea level, storm surges and waves, and better understand their combined impact.
Our research will improve our knowledge of past climate-driven changes in coastal hazards. For the first time, we’ll provide time series of sea level, storm surges and waves for the Australian coastline and use these time series to understand the combined effect of these hazards on our coasts.
We’ll build on this improved understanding of past changes to develop projections of future changes and the subsequent sensitivity of coastal landforms to higher sea level and changes in storminess.
Specifically, we will:
- Develop estimates of historical sea-level changes using satellite altimeter data from 1993 to present. These estimates will have a greater focus on regional and coastal sea level and its variability than current estimates.
- Use satellite gravity data to improve estimates of contributions over the past decade of polar ice sheets, mountain glaciers and changes in terrestrial water storage to global and regional sea-level changes.
- Extend historical tide gauge records through digitisation of marigrams (printed records of tide levels) at a number of Australian tide gauge locations to the late 19th century.
- Estimate extreme wave conditions, sea-level events and factors contributing to these changes from the latter 20th century onwards (the period that instrumental records are available).
- Compile indices that characterise national coastal extremes, and for the first time providing national projections of waves and coastal extremes, as well as updating projections of regional sea-level rise for the 21st century (and potentially into the 22nd century).
- Estimate coastal hotspots for erosion in Victoria based on analysis of climate models and geomorphological surveys.
More resilient coasts
The datasets we develop will provide coastal councils, state planning and conservation groups, federal government, and the public with the critical information they need to support national coastal planning, protection of the coastal environment and investment and development decisions.
The overall project outcome will be a better informed and aware coastal population, an improved knowledge base from which to improve coastal planning and management by councils, state planning and conservation authorities and coastal developers, and appropriate responses to environmental and social developments. Together these will result in more resilient management of Australia’s coastal assets.