This report, 'Pacific Climate Change Science Program: Evaluation of severe wind hazard from tropical cyclones', will be delivered to CSIRO to form a subsection of the 'Climate Change in the Pacific' report. The latter will be launched in November 2011 and will constitute one of the main deliverables for the Pacific Climate Change Science Program (PCCSP). The PCCSP is part of the Australian Government's commitment through the International Climate Change Adaptation Initiative (ICCAI) to meet high priority climate change adaptation needs in vulnerable countries in the Asia-Pacific region. This report provides an evaluation of cyclonic wind hazard for the fifteen PCCSP partner countries located in the western Pacific with the one exception of East Timor. The wind hazard is estimated for both the current climate and for the future climate under an A2 emissions scenario. The current climate wind hazard is estimated by applying GA's Tropical Cyclone Risk Model (TCRM) to the historical track record. TCRM is a statistical-parametric model of tropical cyclone behaviour, enabling users to generate synthetic records of tropical cyclones representing many thousands of years of activity. TCRM is then applied to tracks of tropical cyclone-like vortices (TCLVs) detected in downscaled global climate models to determine how the cyclonic wind hazard may change in the future. The results indicated that the wind loading design standard in this region may significantly underestimate the wind hazard for the current climate. For the future climate projections, the analysis suggests that the wind hazard may decrease for countries close to the equator and near the Australian coastline but could increase for countries greater than 20 degrees poleward from the equator.

The Garnaut Climate Change Review is an independent study by Professor Ross Garnaut, commissioned by Australia's State and Territory Governments. The Review is examining the impacts of climate change on the Australian economy, in an effort to recommend medium to long-term policies and policy frameworks to improve the prospects for sustainable prosperity. Geoscience Australia's (GA) outputs for the Garnaut Review consider the economic impacts of tropical cyclones on Queensland, the Northern Territory and Western Australia (severe wind and storm surge impacts) for eight climate change greenhouse gas emission scenarios based on model projections of large-scale environmental factors from the Intergovernmental Panel for Climate Change (IPCC) Fourth Assessment Report simulations. The study focuses on the evaluation of the wind hazard utilising the maximum potential intensity (MPI). This sets a thermodynamic, theoretical upper limit for the distribution of TC intensities obtained by a TC given a vertical temperature and humidity profile and given location. Storm surge impacts in the same States are developed using a simple parameterisation relating changes in TC intensity to changes in storm surge height including the adoption of the IPCC global mid-point sea-level rise predictions. For this study we consider 20 year time slices centred on; 2010, 2030, 2050, 2070, and 2090. For each time-slice and for each region, we produce the spatial return-period 'tropical cyclone wind gust speed' ranging from return-periods of 50 years to 5000 years. Direct losses (infrastructure damage) are calculated for each return-period event. The combined losses (severe wind and storm surge) were regressed to obtain a Probable Maximum Loss (PML) curve for each study region. The average annual cost to the region due to exposure to tropical cyclones across a 5000 year period or Annualised losses are evaluated for each study region. Expressing the annualised loss as a percentage of total reconstruction gives a measure of the intensity of the risk to the studied community that is not so evident in simple dollar values. State annualised loss estimates of direct loss were aggregated from estimates at the SLA (statistical local area) level. The aim of the Garnaut Review is to compare the 'business as usual' scenario (A1FI) with a range of stabilisation scenarios.

Climate change is a challenge facing nations worldwide. The Fifth IPCC Assessment Report (2007) indicated that climate change is inevitable and that nations need to quickly adapt to mitigate its effects on the risks associated with increased tropical cyclone intensity, storm surge inundation, floods and exacerbated spread of disease. Nationally consistent exposure information is required to understand the risks associated with climate change and thereby support decision making on adaptation options. Decision makers can draw on this evidence-base to develop more rational, representative and objective strategies for addressing emerging challenges. Exposure information requires the translation of fundamental data into information and knowledge before it can be put to use for policy, planning and implementation. Communities, businesses, essential services and infrastructure are all exposed to these increased natural hazards. A thorough understanding of exposed infrastructure, building stock and population under current and future climate projections is fundamental to the process of future capacity building. The National Exposure Information System (NEXIS) provides a broad range of information on the exposure profile of any given area at various administrative and disaster sensitive geographic resolutions with Australia-wide coverage. The information is collected, collated and maintained at building level that can subsequently be aggregated geographically. The information recorded in NEXIS covers a wide range of building attributes such as building type, construction type and year built together with information on population demographics and metrics on business activity such as business type, turnover, employee numbers and customer capacity.

There has been much debate on the influence climate change may have on global tropical cyclone activity (Webster et al. 2005, Landsea 2005, Emanuel 2005, Knutson et al. 2001), but the impacts on human settlements is even less clear. Regional differences in projected changes are also apparent, further clouding the issue of identifying changes in hazard and risk. As part of a contribution to the Garnaut Climate Change Review (Garnaut 2008), Geoscience Australia examined the changes in a number of indices of tropical cyclone activity as diagnosed from IPCC AR4 simulations. These results can be used to infer likely changes in tropical cyclone hazard. General circulation models (GCMs) are normally too coarse to accurately resolve peak winds associated with tropical cyclones (Walsh and Ryan 2000). Tropical cyclone-like vortices may be present in the finer resolution models, but these are a poor facsimile of observed tropical cyclones and thus are unsatisfactory predictors of changing tropical cyclone characteristics (Camargo et al. 2007). To gain some understanding of the potential changes in tropical cyclone behaviour under different future climate regimes, we use GCM outputs to examine environmental indices that have been linked to the intensity and frequency of tropical cyclones. Presented at the 13th Australasian Wind Engineering Society (AWES) Workshop 2008

An increase in the frequency and intensity of storms, coastal flooding, and spread of disease as a result of projected climate change and sea-level rise is likely to damage built environments and adversely affect a significant proportion of Australia's population. Understanding the assets at risk from climate change hazards is critical to the formulation of adaptation responses and early action is likely to be the most cost effective approach to managing the risk. Understanding the level of exposure of assets, such as buildings, lifeline utilities and infrastructure, under current and future climate projections is fundamental to this process. The National Exposure Information System (NEXIS) is a significant national capacity building task being undertaken by Geoscience Australia (GA). NEXIS is collecting, collating, managing and providing the exposure information required to assess climate change impacts. It provides residential, business and infrastructure exposure information derived from several fundamental datasets. NEXIS is also expanding to include institutions (such educational, health, emergency, government and community buildings) and lifeline support infrastructure exposure. It provides spatial exposure data in GIS format at a building level and is often provided to clients for an area of interest. It is also designed to predict future exposure for climate change impact analysis. NEXIS is currently sourcing more specific datasets from various data custodians including state and local governments along with private data providers. NEXIS has been utilised in various climate change impact projects undertaken by CSIRO, the Department of Climate Change (DCC), the Department of Environment, Water, Heritage and the Arts (DEWHA), and several universities. Examples of these projects will be outlined during the presentation.

Cyclone Tracy is the only tropical cyclone to have devastated a major Australian population centre. When most adult Australians picture devastation to buildings and infrastructure caused by a cyclone, it is the images of Darwin in the aftermath of Cyclone Tracy that most readily comes to mind. Following the disaster (December 1974), the Australian Government implemented significantly improved building standards aim at reducing the impact of a similar event in future. Here we utilise impact modelling, where we separately assess hazard, exposure and vulnerability for both 1974 and present-day to evaluate the resulting effectiveness of the improved building codes. As often occurs in extreme natural disasters, meteorological instrumentation failed prior to the maximum wind gusts being recorded, so the spatial extent of the peak wind gusts were inferred from models constrained by estimates of the observed maximum peak wind gust. Geoscience Australia has develop models of severe wind risk, covering the Australian continent. One component of this is the tropical cyclone risk model (TCRM), which estimates the winds and impacts associated with tropical cyclones. In this study, we utilise the vulnerability relationships determined in recent years for similar circa 1974 structures and our knowledge of the type and specific location of structures at the time, to make the link between hazard and impact/damage. This spatial damage estimation (site specific values) is compared with the observed (post-event survey) damage in an effort to validate the model.

The OzCoasts web-based database and information system draws together a diverse range of data and information on Australia's coasts and its estuaries. Maps, images, reports and data can be downloaded and there are tools to assist with coastal science, monitoring, management and policy. The content is arranged into seven inter-linked modules: Search Data, Conceptual Models, Coastal Indicators, Habitat Mapping, Natural Resource Management, Landform and Stability Maps and Climate Change. The Climate Change module is the newest feature of the website and was developed in partnership with the Australian Government Department of Climate Change and Energy Efficiency. The module provides information and tools to help communicate the risks of sea-level rise and other potential impacts of climate change on coastal areas. It includes an elevation data and a modelling portal for access to existing and new elevation data and derived products, including sea level inundation maps for Perth to Mandurah, Melbourne, Sydney, Hunter and Central Coast & Brisbane and Gold Coast. The inundation footprints illustrate three sea level rise scenarios: a low (0.5m), medium (0.8m) and high (1.1m) scenario for a 2100 time period, with values based on IPCC projections (B1 and A1FI scenarios) and more recent science. OzCoasts will also soon deliver the Coastal Eutrophication Risk Assessment Tool (CERAT) for the NSW Department of Environment, Climate Change and Water, and the Australian Riverscape Classification Service (AURICL) for the Tropical Rivers and Coastal Knowledge (TRaCK) consortium. CERAT will help identify and prioritise land use planning decisions to protect and preserve the health of NSW estuaries. AURICL has a northern tropical focus, and is a dynamic and flexible system for classifying catchments and their rivers based on the similarity, or dissimilarity, of a wide range of parameters.

The report presents a framework for assessng in quantitative terms the cost of the weather related hazards of severe wind, flood inundation, storm surge, bushfire and hail. It has been developed with reference to the risk assessment approaches used by the insurance and catastrophic loss modelling industry. For each hazard the specific data inputs to each component of the impacts framework are summarised as a list of implementation needs. Finally, the report identifies areas where impact models are immature or not readily available in the public domain.

Beach ridges at Keppel Bay, central Queensland, Australia, preserve a record of sediment accumulation from the historical period back to middle Holocene times. The ridges comprise fine, well-sorted, feldspar-rich quartz sand that was eroded from the Fitzroy River catchment, deposited in Keppel Bay during floods of the Fitzroy River, and reworked onshore into beach and foredune deposits by the prevailing currents, waves and wind. These floods have an average recurrence interval of at least 7 yr and are induced by the passage of cyclones onshore into the large Fitzroy catchment. The youngest series of beach ridges sit sub-parallel to the modern beach and comprise six accretional units, each unit formed by a set of ridges and delineated by prominent swales. Optically stimulated luminescence (OSL) ages of beach ridges in these units indicate they were deposited in periods of rapid progradation approximately 1500, 1000, 450 and 230 yr BP, when there was an enhanced supply of sediment to the beach from the Fitzroy River via Keppel Bay. Estimates of the mass of sediment stored in the beach-ridge strandplain show that it represents a significant sediment store, potentially trapping the equivalent of 79% of the estimated long-term (100 yr) average annual bedload of the Fitzroy River that is deposited in Keppel Bay. There has been a reduction in the rate of sediment accumulation in the strandplain since around 1000 yr BP, which is consistent with other coastal records in eastern Australia of a relatively wetter phase of climate in the late Holocene compared to the present. The youngest beach ridges (OSL ages < 100 yr BP) are tall relict foredunes that reflect a low rate of sediment accumulation. These ridges have a distinctive trace-element composition produced by a greater contribution from catchment areas with basaltic soils. The change in catchment provenance has likely been a consequence of erosion that followed clearing of native vegetation in these areas. Our findings demonstrate the important insights that beach-ridge deposits proximal to a river sediment source can provide into processes of sediment accumulation and the response to variations in climate in tropical coastal sedimentary systems.

Full Version - shows orthographic and fly-through sequence for each of 5 scenarios with a combined max. inundation outline fly-through at end. Description. - Tropical Cyclone Alby passed close to the southwest corner of West Australia on April 4th 1978. Large waves and a storm surge generated by the northerly winds caused substantial coastal erosion along the Lower West coast particularly in the Geographe Bay area. Low-lying areas at Bunbury and Busselton were flooded, forcing the evacuation of many homes including the Bunbury Nursing Home. An approximate 1.1 m storm surge at Busselton caused the tide to peak at 2.5 m about 1 m above the highest astronomical tide. The Busselton Jetty was severely damaged. At Fremantle the surge was about 0.6 m causing a high tide of 1.8 m, about 0.5 m above the highest astronomical tide. [From BOM - http://www.bom.gov.au/weather/wa/cyclone/about/perth/alby.shtml - Retrieved 21/01/2010] This movie displays the results of a number of simulated storm surge events caused by an equivalent storm to Tropical Cyclone Alby on the current built terrain of Mandurah, and projected 2100 coastline with 0.5, 0.8 and 1.1m rises in sea level. Scenario A TC Alby equivalent at current sea level Scenario B Worst case TC Alby equivalent with current sea level Scenario C Worst case TC Alby equivalent in 2100 with 0.5m sea level rise Scenario D Worst case TC Alby equivalent in 2100 with 0.8m sea level rise Scenario E Worst case TC Alby equivalent in 2100 with 1.1m sea level rise