Future changes in extreme weather and pyroconvection risk factors for Australian wildfires

Abstract

Extreme wildfires have recently caused disastrous impacts in Australia and other regions of the world, including events with strong convective processes in their plumes (i.e., strong pyroconvection). Dangerous wildfire events such as these could potentially be influenced by anthropogenic climate change, however, there are large knowledge gaps on how these events might change in the future. The McArthur Forest Fire Danger Index (FFDI) is used to represent near-surface weather conditions and the Continuous Haines index (CH) is used here to represent lower to mid-tropospheric vertical atmospheric stability and humidity measures relevant to dangerous wildfires and pyroconvective processes. Projected changes in extreme measures of CH and FFDI are examined using a multi-method approach, including an ensemble of global climate models together with two ensembles of regional climate models. The projections show a clear trend towards more dangerous near-surface fire weather conditions for Australia based on the FFDI, as well as increased pyroconvection risk factors for some regions of southern Australia based on the CH. These results have implications for fields such as disaster risk reduction, climate adaptation, ecology, policy and planning, noting that improved knowledge on how climate change can influence extreme wildfires can help reduce future impacts of these events.

The Proximal Drivers of Large Fires: A Pyrogeographic Study

“…The unprecedented burnt area of the 2019-2020 forest fires in eastern Australia, characterised by extreme preceding dryness, are consistent with this (Boer et al, 2020;Nolan et al, 2020). Our results suggest potentially opposing implications of projected increases in the severity of fire weather under climate change (Clarke and Evans, 2019;Dowdy et al, 2019). In forests, increasing fire weather could lead to higher probability of large fires, although this does not factor in potential shifts in seasonality (Miller et al, 2019).…”

Deconstructing Factors Contributing to the 2018 Fire Weather in Queensland, Australia

“…While we have not provided a quantitative extreme event attribution assessment of this event, ours is one of many results that points to increasing fire danger risks in eastern Australia. In Australia, an overall increase in the FFDI has been observed in many regions, particularly for southern and eastern Australia in recent decades (Dowdy 2018), with future projections clearly showing an increase in the FFDI throughout Australia based on a comprehensive set of modeling approaches (Dowdy et al 2019).…”

Adaptive prescribed burning in Australia for the early 21st Century – context, status, challenges

“…How do we make the case, and garner necessary political support for, resourcing the broader implementation of preventative and sustainable fire management in the face of ever-increasing investment in and reliance on expensive suppression activities and assets (e.g. water bombers)especially given the exacerbating realities of diminishing seasonal opportunities for safe and appropriate implementation of prescribed fuel reduction and ecological burning, and deteriorating fire weather conditions generally (Lucas et al 2007;Keelty 2012;Clarke et al 2013;Hughes and Steffen 2014;Hughes and Alexander 2017;Dowdy 2018;McCaw 2018;Dowdy et al 2019;Morgan et al in press)?…”