Interactions between climate change, fire regimes and biodiversity in Australia: A preliminary assessment

An assessment of the potential impacts of climate change on fire regimes in Australia, and the consequences of these changed fire regimes for Australia's biodiversity was commissioned by the Australian Government to help increase our understanding of the complex interactions between climate change, fire regimes and biodiversity for future fire management. The report synthesises understanding of the drivers of fire regimes in Australia, identifies changes to fire regimes projected from climate change and identifies the broad implications of these changes for biodiversity. 'Fire regime' is defined as the history of fire events at a point in the landscape. The report finds that fire weather will become more severe in many regions, particularly southern Australia, and that the interactions between biodiversity and fire regimes are complex. It develops a national framework to assess the likely impacts of climate change on fire regimes and biodiversity for different bioregions, using a case study approach. Climate change may affect fire regimes across the Australian landscape through changes to temperature, rainfall, humidity, wind, and the amount of carbon dioxide in the atmosphere. • Modeled climate projections show that much of southern Australia may become warmer and drier. This modeling suggests that, by 2020, extreme fire danger days in south-eastern Australia may occur 5 to 65 per cent more often than at present. • For example, modeling of climate change impacts on the fire regimes of Australian Capital Territory (ACT) landscapes predicts that a 2oC increase in mean annual temperature would increase fire intensity by 25%, increase the area burnt, and halve the mean interval between fires in the ACT. • Climate change is expected to have greater effects on fire regimes in regions where fire weather factors like temperature and wind strength determine fire occurrence and fire intensity. These are regions such as the temperate forests of the south-east and south-west of Australia. Climate change is expected to have less effect on fire regimes in places where fuel levels or ignition sources determine fire occurrence and intensity, such as northern tropical savannas. • Managing fire regimes to reduce risk to property, people and biodiversity under climate change will be increasingly challenging