Climate change to bring more devastating bushfires

Issued by the University of Melbourne

Climate change is likely to see an increase in the larger, more intense bushfires across Australia, a University of Melbourne bushfire expert says.

Dr Kevin Tolhurst, a senior lecturer in fire ecology and management in the University’s Institute of Land and Food Resources (ILFR), says such fires would also have a significant impact on Australia’s water and biodiversity values.

“The current bushfire regime for south east Australia is for a small number of large fires that do significant damage and many smaller fires that do minimal damage. Climate change has the potential to switch this regime to an increased number of the larger more devastating wildfires,” he says.

“To cope with such changes we need to have a fire management strategy that is more adaptable and that takes into account better training, a greater understanding of what we are and could be dealing with, increased community education and more collaboration with the community especially those with local expertise of wildfires and the environment.”

Dr Tolhurst’s research is one of several projects being conducted by the Bushfire Cooperative Research Centre that will be launched by the Federal Minister for Science, the Hon. Peter McGauran, MP.

A fire’s behaviour depends on the nature of the fuel, the weather, the topography and the nature of the fire itself.  Climate change can result in greater sources of ignition through increased lightning, longer periods of dry fuel, production of more biomass to become fuel, hotter, drier and windier weather conditions to drive the fire spread.  The converse is also possible. 

But predicting the impact of fire on the landscape is not a simple sliding scale related to just the effects of fuel, weather and topography. 

For example, in the recent 2003 Alpine fire in Victoria, 558,000 hectares was burnt in major runs on just three days out of the 60 days these fires remained uncontrolled.  This represents half the total area burnt.

“This fire behaviour is common in temperate Australia and shows how important extreme conditions are to the amount of damage a fire inflicts,” says Dr Tolhurst. 

CSIRO projections of future forest productivity indicate that forest biomass may increase by a factor of 25 to 50 percent in SW Western Australia and eastern and southern Australia by the year 2070.  This increased productivity is attributed to increased carbon dioxide levels, 3degree Celcius warmer temperatures and greater summer and autumn rainfall.

“The trend to hotter drier extremes, with the associated increase in forest biomass, is likely to lead to larger more intense fires across the landscape.  It also highlights the need to understand what effects climate change will have on the balance between the two extremes of fire size and abundance,” says Dr Tolhurst.

One problem faced by Tolhurst and colleagues in trying to predict the impact of climate change on wildfire.behaviour is that current climate change models fail to provide a good basis for making predictions about the likely changes to the fire environment. 

“Humidity, moisture content of fuel loads, wind speed profile in the atmosphere and the degree of atmospheric instability are of critical importance to help predict the development and progress of a fire.  Climate change models do not deal with this level of detail,” he says.

“Fire regime scenarios, based on the output of climate change models, for forested lands in southern and eastern Australia will therefore always have a high level of uncertainty.” 

For further information please contact:

Kevin Tolhurst, ILFR on 03 532 14162, 0417 591 485 or email:

Jason Major, Media Unit on 03 8344 0181 or 0421 641 506

Release date

Tue, 09/12/2003