The value of coastal wetlands for storm protection in Australia

Cyclones cause significant damage, particularly to coastal areas. In the 50 years between 1967 and 2016, 54 cyclones struck Australia with total damages of approximately AUD 3 billion. Wetlands diminish cyclone impacts by absorbing storm surges and slowing winds. We examine the effects of wetlands on cyclone damage by creating a Bayesian regression model for storm damage as a function of wind speed, economic development in the storm swath, and the area of wetlands in the coastal plain in the storm swath using data from all 54 storms. Our results show that wind speed has a strong positive effect on cyclone damage and that wetland area has a strong negative effect. We estimate a total of AUD 29.6 billion of damage was averted during the 54 storms because of the presence of wetlands with a median of AUD 236 million per storm. This equates to an average of AUD 4203 per year per hectare of wetland, consistent with previous studies. Our results suggest that preserving wetlands is a cost-effective way to minimize cyclone damage while providing numerous other valuable ecosystem services. We estimate that maintaining at least 1.5% of coastal area as wetlands maximizes the averted damage.