Historical and Future Changes in Tropical Cyclones and their Impacts in the Australian Region

Currently, an average 6.5 tropical cyclones and lows make landfall in Australia per year with an average four fatalities and more than US $1.62B damages[1]. These numbers are dominated by a small number of highly impactful events. For the Southern Hemisphere in general, and the Australian region in particular, current knowledge about how TC behavior will change in the future is highly uncertain. In particular, knowledge about how the spatial structure of winds and rainfall will change is unknown (IPCC, 2021). Yet, it is the spatial distribution of the winds and rain that results in infrastructure damage, flooding and mudslides.

In this study, historical trends and potential future changes are quantified for Australian region tropical cyclones simulated under their current climate conditions and then again using perturbed conditions under the SSP2-4.5 and SSP3-7.0 climate change scenarios from a Coupled Model Intercomparison Project Phase 6 (CMIP6) ensemble mean. Historical and future changes in intensity, size, wind field structure and rain in the Australian region by the end of the 21^st century will be discussed.

[1] Averages are calculated for the 11-year period 2011/12 – 2021/22. Dollar value for damages is only recorded for major events listed as disasters. Minor damage such as flooded houses are usually not included in disaster databases. Dollars have been converted to a 2023 USD equivalent for proper comparison.