Increasing cost of natural hazards as climate changes

A special edition of the journal Climatic Change, featuring CRC researchers A/Prof Jason Sharples and Prof Albert van Dijk, documents the historical record and projected change of seven natural hazards in Australia: flood; storms (including wind and hail); coastal extremes; drought; heatwave; bushfire; and frost. The Conversation is also publishing feature articles on each hazard.

The comprehensive study of these hazards in Australia paints a picture of increasing heatwaves and extreme bushfires as this century progresses, but with much more uncertainty about the future of storms and rainfall, said editor of the special edition, A/Prof Seth Westra from the University of Adelaide.

"Temperature-related hazards, particularly heatwaves and bushfires, are increasing, and projections show a high level of agreement that we will continue to see these hazards become more extreme into the 21st century,” A/Prof Westra said.

“Other hazards, particularly those related to storms and rainfall, are more ambiguous. Cyclones are projected to occur less frequently but when they do occur they may well be more intense. In terms of rainfall-induced floods we have conflicting lines of evidence with some analyses pointing to an increase into the future and others pointing to a decrease."

A/Prof Sharples led the bushfire study, reflecting on recently developed understandings of bushfire dynamics, considering historical changes in the occurrence of extreme bushfires and the potential for their increasing frequency in the future under climate change projections. The Conversation is carrying a summary of the paper. The article looks at the most catastrophic bushfire cases and the factors that drive them, beyond the usual hot, dry and gusty weather. There has been an overall increase in the frequency of major bushfires in south eastern Australia since the mid-19th century. In particular, in the past 15 years a major fire event has occurred every five years or less. While some of this increase is due to changes in land use since European colonisation, there is also strong evidence of climate-driven changes.

Prof van Dijk was involved as a co-author in the papers on floods and droughts.

All seven papers in the special edition are available at Springer. The special issue represents a major collaboration of 47 scientists and eleven universities through the Australian Water and Energy Exchange Research Initiative (www.ozewex.org), an Australian research community program.