A staggering 1.8 million hectares burned in ‘high-severity’ fires during Australia’s Black Summer


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Ross Bradstock, University of Wollongong; Hamish Clarke, University of Wollongong; Luke Collins, La Trobe University; Michael Clarke, La Trobe University; Rachael Helene Nolan, Western Sydney University, and Trent Penman, The University of MelbourneIn the aftermath of Australia’s devastating Black Summer fires, research has begun to clarify the role of climate change.

We already know climate change contributed to the record-breaking drought and fire weather conditions, leading to the bushfires’ unprecedented range across Australia.

Our new research looks at whether bushfires are becoming more “severe” (an indicator of how intensely the vegetation burned) as a result of climate change.

Our findings were unexpected, as we learned the proportion of high-severity fires generally hasn’t increased in recent decades. However, the sheer breadth of the Black Summer fires meant an unprecedented 1.8 million hectares across southeast Australia were exposed to high-severity fires. This has dire consequences for the people and wildlife who call the forests home.

What is fire severity?

Two measurements in fire science are pertinent to our research: fire severity and fire intensity.

Fire severity refers to how high the flames and the plume of hot air reach, as measured by the resulting damage to vegetation (vertical profile of scorch and consumption of leaves and twigs). Fire intensity refers to the energy released from the fire — how hot and destructive the flames are.

Scientists can estimate severity using using satellite imagery, by contrasting differences in the cover and condition of vegetation before and after fires.

In forests, “high-severity” fires occur when the crowns of dominant trees are fully burnt or scorched. High-severity fires are lethal to tree-dwelling mammals in forests, such as possums, gliders and koalas. They also pose a big risk to nearby homes and buildings.

“Low-severity” fires, on the other hand, may be confined to the leaf litter and ground cover plants beneath the forest canopy, and can even leave entirely unburnt patches in forests.

Are high severity fires becoming more common?

To determine if high-severity bushfires are becoming more common, we looked at satellite data for bushfires from 1988 to 2020. The data covered more than 130,000 square kilometres of forest, woodland and shrubland ecosystems in southeast Australia.

If fires were becoming more intense in recent decades, we would have expected the proportion of vegetation subjected to high-severity fire to have increased.

Instead, we found the average proportion of high-severity wildfire remained constant in dry forest — the dominant vegetation across this region. There was, however, evidence of an increase in the average proportion of high-severity fire in wet forests and rainforests, along with woodlands.




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5 remarkable stories of flora and fauna in the aftermath of Australia’s horror bushfire season


Nonetheless, the main conclusion was clear: across the bulk of the study area, the average proportion of high-severity fires has not changed in recent decades, despite an increase in the area burned during the Black Summer bushfires.

Why the Black Summer bushfires were exceptional

While the proportion of high-severity fires hasn’t changed, the enormous range of the 2019-2020 bushfires meant 44% of the total area burned by high-severity fire since 1988 occurred in that one summer alone.

This means 1.8 million hectares of the forest and woodland regions of southeastern Australia — an enormous proportion — was exposed to intense and severe fire. In this regard, the Black Summer bushfires were exceptional.

As Australians remember all too clearly, this had a devastating effect on the environment. An estimated three billion animals were killed or displaced, vulnerable rainforests burned and 3,000 homes were destroyed.

A firefighter runs through a burning forest
Firestorms could become more common under a changing climate.
AAP Image/Dean Lewins

The 2019-20 fire season also involved a record number of “firestorms”, particularly during the latter part of the season in January and early February. This occurs when fires create their own weather.

These fires can burn at exceptional intensity. And research from 2019 indicates such firestorms could become more common under climate change.

This means we can’t rule out a future change in the proportion of bushfires that burn at the highest levels of intensity and severity.

Ecosystems in jeopardy

The results of our study underline one of the likely consequences of future climate change.

The sheer scale of the area burned in the 2019-20 fire season exceeded not only historical records for forested ecosystems of southern Australia, but also outstripped projections for the late 21st century under strong scenarios of climate change.




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As bushfires become larger in the future, the area exposed to intense and severe fires is likely to increase commensurately. As a result, the future of our wetter forest types, which have not evolved to cope with frequent and severe fires, is in jeopardy.

So, as the area exposed to intense fires is likely to increase in the future, we’ll see major challenges to the long-term viability of our forested ecosystems, the services they provide and the people who reside in and around them.The Conversation

Ross Bradstock, Emeritus professor, University of Wollongong; Hamish Clarke, Research Fellow, University of Wollongong; Luke Collins, Research scientist, La Trobe University; Michael Clarke, Emeritus professor, La Trobe University; Rachael Helene Nolan, Postdoctoral research fellow, Western Sydney University, and Trent Penman, Professor, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

If 80% of Australians care about climate action, why don’t they vote like it?


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Rebecca Colvin, Australian National University and Frank Jotzo, Australian National UniversityPoll after poll suggests a large majority of Australians cares about climate change. Yet in recent federal elections, this hasn’t translated into wins for parties with stronger policy platforms on climate change.

So what determines someone’s climate change attitude, and how does it translate into voting?

In research published today, we studied 2,033 Australian voters’ attitudes across the political spectrum in the context of the 2019 federal election. And we found over 80% said they think it’s important Australia reduce greenhouse gas emissions. This includes close to 70% of conservative voters (those voting for Coalition parties).

However, digging deeper reveals nuance to these attitudes. While most Australians support climate action, stark differences emerge along political party preferences in terms of how important voters think it is.

Our research suggests the question about social support for climate action in Australia is no longer: “does climate change matter to enough Australians?”. Instead, the critical question may well be: “does climate change matter enough to Australians to shift climate politics?”.

Why the ‘climate election’ didn’t pan out

We conducted our survey in July 2019, two months after the Coalition won the federal election. Its victory came as a surprise to many, as the election was sometimes billed the “climate election”, implying climate change was a bellwether issue.

The climate policies of the two major parties were night and day, with the Labor Party campaigning on ambitious mitigation targets and the incumbent Coalition maintaining the status quo of very limited climate policy.

So what were the voters thinking?

We found about half of Australian voters (52%) said climate change was important when deciding their vote in the 2019 Australian federal election. However, climate was the most important issue for only 14% of voters.

Even among those who said they felt it was extremely important for Australia to reduce greenhouse gas emissions, most (58%) said climate change was important, but not the most important issue, when deciding their vote.




Read more:
Australia’s major parties’ climate policies side-by-side


Climate change was stated as the most important issue for 21% of Labor voters and 39% of Greens voters, but for less than 5% of Liberal Party, National Party, and Queensland LNP voters.

This pattern was reversed for those who didn’t take climate change policy into account in their vote: 26% of Liberal, 21% of National, and 31% of Queensland LNP voters did not consider climate change when deciding their vote. Under 15% of Labor and Greens voters did the same.

And when we looked at how much voters cared about climate action, the differences become more potent. Three quarters (73%) of progressive voters (those voting for the ALP or the Greens) see Australian action to reduce emissions as “extremely important”. Only one quarter (26%) of conservative voters say the same thing.



Who’s more willing to make sacrifices for the climate?

Our research also explored the extent voters were willing to accept a personal cost to support climate action. We asked about their willingness to accept a significant or small personal cost, but didn’t specify what we meant by small or significant, because a small cost to one person may be a significant cost to another.

Most voters (72%) said they’d be willing to incur some personal cost in return for emissions reductions. Across the political spectrum, the proportion of voters willing to accept a small personal cost is relatively similar: 60% of progressive voters, 55% of conservative voters.



Major differences emerge when it comes to “significant personal cost”.

While 26% of progressive voters are willing to incur a significant personal cost, only 5% of conservative voters feel similarly. At the other end of the spectrum, 40% of conservative voters are unwilling to incur any personal cost, but only 14% of progressive voters feel the same.

Support for strong climate policies may depend on whether the policies will, or are perceived to, personally impact voters. Given political leaders’ stances influence public support for climate policies (as 2018 research showed), our research highlights an opportunity for conservative political leaders to clarify their position on climate change.



Interestingly, age was a consistent predictor of responses. Younger people were more likely than older people to consider it important that Australia reduce greenhouse gas emissions. Younger people were more willing to incur a personal cost to support climate action, and to consider climate change when deciding their vote.

In fact, we found an Australian voter from the Baby Boomer generation is half as likely as a voter from Generation Z to consider it important to reduce greenhouse gas emissions.

Divisive politics have a limited shelf life

If future young people cared just as much about climate change as today’s young people, and if existing cohorts don’t change their views as they age, then the percentage of Australian voters who consider greenhouse gas emissions to be “extremely important” is likely to increase from 52% in our 2019 data, to 56% by 2030. By 2050, this figure could rise to 65%.



These projections are purely on the basis of more climate-aware cohorts coming into voting age and replacing older voters. It doesn’t consider any future changes in attitudes within cohorts (which may also make a big difference).

The key implication is simple. If Australian political leaders pursued stronger climate action, they could rest assured most of the voting population will broadly support them, along with most of their own voter base — regardless of which party is in power.

This will become only more pronounced with gradual generational change, and likely changes in attitudes within age groups. In any case, it’s clear divisive politics that result in climate delay have a limited shelf life.




Read more:
Nearly 80% of Australians affected in some way by the bushfires, new survey shows


The Conversation


Rebecca Colvin, Senior lecturer, Crawford School of Public Policy, Australian National University and Frank Jotzo, Director, Centre for Climate and Energy Policy, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.