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Causes and consequences of Eastern Australia’s 2019–20 season of mega‐fires: A broader perspective

Author(s): Mark A. Adams, Majid Shadmanroodposhti, Mathias Neumann
Year Published: 2020

Climates—especially seasonal and long‐term droughts—and fuel loads combine to determine risks of wildfires across much of Australia. Here we illustrate how long‐term accumulations of fuel combined with a serious drought to drive the behaviour and extent of recent fires in South‐eastern Australia.

This article is a commentary on Nolan et al. 26, 1039–1041. See also the response to this letter by Bradstock et al. 26, e8–e9.

Nolan et al. (2020) give their perspective of the current fire season in Eastern Australia, yet draw attention solely to fuel moisture as a “key constraint on the occurrence of large wildfires in this region.” Here we provide a broader view.

Mega‐fires were the subject of an international conference held in Tallahassee, Florida in 2011, spawned by increasing awareness that fire suppression was “running out of road.” Jerry Williams, the former National Director of Fire & Aviation Management, United States Forest Service, was the keynote speaker and wrote: “protecting people and sustaining natural resources can no longer rely on suppression capabilities, alone; protection will become more dependent on how we manage the forests where high‐impact mega‐fires incubate” (Williams, 2013). The conference gave rise to discussions about “tipping points,” in particular greatly increased risks to ecosystems not previously threatened by fire, and critical ecosystem functions created by the confluence of changing climates and accumulating fuels (Adams, 2013).

More recently, an international group of authors emphasized that an ever‐increasing focus by governments on fire suppression was a trap, as it allowed fuels to accumulate to levels that would eventually burn at intensities well beyond the capabilities of any fire fighting service, anywhere (Moriera et al., 2020).

Sadly, these predictions have proved correct in Australia. Ultimately, it was only rainfall that extinguished the fires. Speculated extraordinary losses of wildlife will be matched by wholesale changes to plant diversity and abundance across much of the forest estate of New South Wales, Victoria and parts of Queensland and South Australia. Losses of soil carbon are unknown, while after an initial increase, water yield will likely take decades to recover to pre‐fire condition in key catchments (Brookhouse, Farquhar, & Roderick, 2013; Gharun, Turnbull, & Adams, 2013).\p>

We agree with Nolan et al. (2020) that this fire season is unprecedented in some respects. We also note and support the basic premise that the duration and severity of drought in NSW—which has set many records—is a fundamental driver of the extent and severity of these and other fires in Australia. Drought and fire have had clear, long‐term associations in NSW forests, as shown by Figure 1a. (+ more)

Citation: Adams MA, Shadmanroodposhti M, Neumann M. 2020. Causes and consequences of Eastern Australia’s 2019–20 season of mega‐fires: A broader perspective. Global Change Biology 26 (7): 3756-3758. https://doi.org/10.1111/gcb.15125|
Topic(s): Fire Behavior, Extreme Fire Behavior, Case Studies
Ecosystem(s): None
Document Type: Book or Chapter or Journal Article
NRFSN number: 21705
Record updated: Aug 6, 2020