Climate change and wildfires: lessons from Australia’s Blue Mountains

On 26 October 2019 lightning struck the drought-stricken region of Gospers Mountain in the Greater Blue Mountains World Heritage Area of New South Wales, Australia. This ignited a bushfire which ran for three months to burn-out 838,000 hectares (around 80% of the World Heritage Area) and impact an estimated 140 million reptiles, birds and mammals.

This was the largest single fire in Australia’s recorded history; however, it was only one in a devastating fire season. In 2019 and 2020 fires extended from the tropical north of the country to the south. Over 17 million hectares, representing 20% of forests across five states, were burnt. This unprecedented conflagration covered cities with a blanket of smoke for months, even blocking the sun to turn daytime into night upon occasion. In October 2020 an Australian Government inquiry into these horrific wildfires concluded, for the first time, that their scale and intensity was a direct consequence of climate change. In December 2020 the IUCN World Heritage Outlook 3 found that climate change is now the biggest threat to natural World Heritage globally.

The fire’s impact on the tree canopy across the Greater Blue Mountains World Heritage Area. Approximately 80% of the Area was burnt-out which affected an estimated 140 million reptiles, birds and mammals. Photo: Dr Aaron Greenville, BMWHI An Australian Government inquiry into these horrific wildfires concluded, for the first time, that their scale and intensity was a direct consequence of climate change.

As we look at the worldwide picture in 2020, Australia’s experience is part of a pattern of global mega-fires including those that engulfed the western states of the USA, and the huge area of arboreal forest burnt in Siberia. The role of climate change in the formation of these mega-fires and the impact on forest ecosystems and biodiversity is of pressing concern. However, as many of you will be aware, these fires often happen in ecosystems that depend on fires to create diverse habitats. So, what’s the problem?

The problem is one of frequency and intensity. Many of the species of the Australian eucalypt forests require fires for seed pods to open and regeneration to occur. The indigenous peoples of the country had for 60,000 years used ‘fire stick farming’, as it’s been called, to manage the land and to maintain the diverse habitats that supported the plants and animals they depended upon. With the arrival of Europeans in the late 18^th Century and the subsequent appropriation of indigenous peoples’ lands, the use of fire as a tool for managing the landscape rapidly declined. As large areas of bushlands returned to thick scrub, recurrent wildfires became a threat to farms, townships and biodiversity. Now climate change is causing longer, hotter and drier summers, and more extreme and intense weather conditions, which are making these fires more frequent and severe.

So, despite the fire dependence of Australia’s predominant eucalypt forests, more regular fires mean that a number of species are potentially unable to regenerate and replenish their seed beds, such as the Blue Mountains ash (Eucalyptus oreades) and Banksia species. Other eucalypt species that resprout following fires are being stressed by higher temperatures and drought, that in turn make forests more scrubby and vulnerable to intense fires.

There is also the problem of the scale of the fires that we witnessed earlier this year. The rich biodiversity of the Blue Mountains World Heritage Area is a product of its geology: the area is a plateau dissected by massive eroded sandstone canyons which in the past have allowed a mosaic of unique ecosystems to prosper. In one such area can be found the Critically Endangered Wollemi pine (Wollemia nobilis), an extremely ancient tree species that dates back to the Carboniferous period when Australia was connected to the Antarctic continent. A small stand of pines has survived in a protected fire shadow for around 300 million years. It is the last place on Earth where they grow wild, and was only discovered 30 years ago. This year fires threatened this last remaining stand of Wollemi pines, and had it not been for the heroic efforts of National Parks and Wildlife Service fire-fighters, who were helicoptered into the remote site, they would probably have been lost.

All IUCN Members must help limit the rise in climate extremes as a global necessity.

Wollemi pine (Wollemia nobilis) Photo: Wikimedia Commons

Other ancient plant and animal species may face a similar fate in the future as we see a shift to more mega-fires. In the past the norm was for smaller and more localised fires, allowing wildlife to seek refuge in unburnt areas and then return to repopulate the burnt areas as they regenerate. If climate change continues to drive a change to more intense and frequent fires, impacting as much as 80% of the World Heritage Area as has happened this year, we could see a significant decrease in biodiversity and the loss of unique ancient species such as Wollemi pines.

What can be done? All IUCN Members must help limit the rise in climate extremes as a global necessity. However, the existing volume of greenhouse gasses are yet to have their full impact, even if we are able to limit temperature rises to 1.5 or 2 degrees under the Paris Agreement. Given what we are already witnessing with extreme weather conditions producing catastrophic fires in Australia and around the world, we are going to have to become more skilful in limiting their effect.

With this traditional knowledge and the best of science, we may be able to limit the long-term destruction caused by the sort of fires we have seen over the past twelve months.

For those of us working in Australia, this is one of the recommendations of the Government’s Bushfire Inquiry which argues for the use of more sophisticated hazard reduction burning techniques to help prevent lightning-ignited fires spreading and becoming mega-fires. The report also recognises the need to learn from the indigenous culture of Australia’s First Nation peoples, who traditionally used low intensity burning techniques to manage the country’s unique biodiversity, and to prevent the destructive impact of wildfires. I hope that with this traditional knowledge and the best of science, we may be able to limit the long-term destruction caused by the sort of fires we have seen over the past twelve months.

Greater Blue Mountains World Heritage Area, New South Wales, Australia Photo: Wikimedia Commons