Extreme events

Much climate change literature uses the term ‘extreme events’ which covers natural disasters, such as floods and tropical cyclones, and unusual and negative weather events, such as heatwaves.

The BECCA Wiki does not generally use the term extreme event, nor use it as a category of environmental variable. This is because each extreme event is a collection of many environmental variables, for example damaging/destructive wind, extreme rain and storm surge. If these different environmental variables are lumped together under just one term, detailed cause and effect analysis becomes impractical.

To identify the impacts of an extreme event, you need to identify the environmental variables which characterise it, and examine the impact of each of these in turn.

Variables in extreme events

The table below separates each type of extreme event into environmental variables and the key parameters that determine the impacts of these variables on infrastructure.

Extreme event	Environmental variables	Key parameters
Dust storm	Atmospheric physical and chemical properties Airborne particulates Solar radiation Wind Soil quality and health	Sand and soil dust Mean air temperatures Extreme air temperatures Damaging/destructive winds Mean winds
Cyclone Hurricane Severe thunderstorm Lightning storm Storm surge	Sea water Fresh water Atmospheric physical and chemical properties Airborne particulates Wind Lightning Hail Soil quality and health Plant, micro-organism and animal biodiversity Ecosystems	Sea level Storm surge Sea water nutrient level Tidal prism River flow & reservoir volume Fresh water total dissolved solids Fresh water nutrient level Mean air temperature Extreme air temperature Humidity Air pressure Aerosol marine salts Damaging/destructive winds Soil permeability, compressibility and shear strength Soil salinity Plant, micro-organism and animal distribution and life-cycles Ecosystem protection and resilience
Ice storm	Atmospheric physical and chemical properties Wind Hail	Mean temperature Extreme air temperature Damaging/destructive winds Mean winds
Heat wave	Atmospheric physical and chemical properties Airborne particulates Solar radiation Wind Soil quality and health	Mean air temperature Extreme air temperature Humidity Air pressure Total solar radiation
Drought	Fresh water Atmospheric physical and chemical properties Airborne particulates Solar radiation Wind Soil quality and health Plant, micro-organism and animal biodiversity Ecosystems	Sand and soil dust Soil temperature Soil permeability, compressibility and shear strength Soil salinity Soil’s thermal resistance Plant, micro-organism and animal distribution and life-cycles Ecosystem protection and resilience
Flood	Sea water Fresh water Atmospheric physical and chemical properties Airborne particulates Soil quality and health Plant, micro-organism and animal biodiversity Ecosystems	Sea level Storm surge Sea water nutrient levels Tidal prism River flow & reservoir volume Fresh water total dissolved solids Fresh water nutrient level Soil permeability, compressibility and shear strength Soil salinity Plant, micro-organism and animal distribution and life-cycles Ecosystem protection and resilience
Bushfire Grass fire	Atmospheric physical and chemical properties Airborne particulates Wind Lightning Soil quality and health Plant, micro-organism and animal biodiversity Ecosystems	Extreme air temperature Humidity Damaging/destructive winds Plant, micro-organism and animal distribution and life-cycles Ecosystem protection and resilience Rainfall

 

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