Those who say “I told you so” are rarely welcomed, yet I am going to say it here. Australian scientists warned the country could face a climate change-driven bushfire crisis by 2020. It arrived on schedule.
For several decades, the world’s scientific community has periodically assessed climate science, including the risks of a rapidly changing climate. Australian scientists have made, and continue to make, significant contributions to this global effort.
I am an Earth System scientist, and for 30 years have studied how humans are changing the way our planet functions.
Scientists have, clearly and respectfully, warned about the risks to Australia of a rapidly heating climate – more extreme heat, changes to rainfall patterns, rising seas, increased coastal flooding and more dangerous bushfire conditions. We have also warned about the consequences of these changes for our health and well-being, our society and economy, our natural ecosystems and our unique wildlife.
Many of our scientific warnings over the decades have, regrettably, become reality. About half of the corals on the Great Barrier Reef have been killed by underwater heatwaves. Townsville was last year decimated by massive floods. The southeast agricultural zone has been crippled by intense drought. The residents of western Sydney have sweltered through record-breaking heat. The list could go on.
How serious might future risks actually be? Two critical developments are emerging from the most recent science.
First, we have previously underestimated the immediacy and seriousness of many risks. The most recent assessments of the Intergovernmental Panel on Climate Change show that as science progresses, more damaging impacts are projected to occur at lower increases in temperature. That is, the more we learn about climate change, the riskier it looks.
For Australia, a 3℃ world would likely lead to much harsher fire weather than today, more severe droughts and more intense rainfall events, more prolonged and intense heatwaves, accelerating sea-level rise and coastal flooding, the destruction of the Great Barrier Reef and a large increase in species extinctions and ecosystem degradation. This would be a tough continent to survive on, let alone thrive on.
The city I live in, Canberra, experienced an average seven days per year over 35℃ through the 1981-2010 period. Climate models projected that this extreme heat would more than double to 15 days per year by 2030. Yet in 2019 Canberra experienced 33 days of temperatures over 35℃.
Second, we are learning more about ‘tipping points’, features of the climate system that appear stable but could fundamentally change, often irreversibly, with just a little further human pressure. Think of a kayak: tip it a little bit and it is still stable and remains upright. But tip it just a little more, past a threshold, and you end up underwater.
Features of the climate system likely to have tipping points include Arctic sea ice, the Greenland ice sheet, coral reefs, the Amazon rainforest, Siberian permafrost and Atlantic Ocean circulation.
These tipping points do not act independently of one another. Like a row of dominoes, tipping one could help trigger another, and so on to form a tipping cascade. The ultimate risk is that such a cascade could take the climate system out of human control. The system could move to a “Hothouse Earth” state, irrespective of human actions to stop it.
Hothouse Earth temperatures would be much higher than in the pre-industrial era – perhaps 5–6℃ higher. A Hothouse Earth climate is likely to be uncontrollable and very dangerous, posing severe risks to human health, economies and political stability, especially for the most vulnerable countries. Indeed, Hothouse Earth could threaten the habitability of much of the planet for humans.
Tipping cascades have happened in Earth’s history. And the risk that we could trigger a new cascade is increasing: a recent assessment showed many tipping elements, including the ones listed above, are now moving towards their thresholds.
Now is the perfect time to reflect on what science-based risk assessments and warnings such as these really mean.
Two or three decades ago, the spectre of massive, violent bushfires burning uncontrollably along thousands of kilometres of eastern Australia seemed like the stuff of science fiction.
Now we are faced with more than 10 million hectares of bush burnt (and still burning), 29 people killed, more than 2,000 properties and several villages destroyed, and more than one billion animals sent to a screaming, painful death.
Scientists are warning that the world could face far worse conditions in the coming decades and beyond, if greenhouse gas emissions don’t start a sharp downward trend now.
Perhaps, Australia, it’s time to listen.
Stephen Garnett, Charles Darwin University; Brendan Wintle, University of Melbourne; David Lindenmayer, Australian National University; John Woinarski, Charles Darwin University; Martine Maron, The University of Queensland, and Sarah Legge, Australian National University
That a billion animals may die as a result of this summer’s fires has horrified the world. For many conservation biologists and land managers, however, the unprecedented extent and ferocity of the fires has incinerated much more than koalas and their kin.
The scale of the destruction has challenged what is fundamentally an optimistic worldview held by conservationists: that with sufficient time and money, every species threatened by Australia’s 250 years of colonial transformation cannot just be saved from extinction, but can flourish once again.
The nation’s silent, apocalyptic firescapes have left many conservation biologists grieving – for the animals, the species, their optimism, and for some, lifetimes of diligent work.
So many of us are wondering: have lives spent furthering conservation been wasted? Should we give up on conservation work, when destruction can be wrought on the environment at such unprecedented scales?
The answer is, simply, no.
Federal government figures released on Monday showed more than half of the area occupied by about 115 threatened species has been affected by fire. Some of these species will now be at significantly greater threat of extinction. They include the long-footed potoroo, Kangaroo Island’s glossy black-cockatoo and the East Lynne midge orchid.
Some field ecologists lost study populations of species that had been researched and monitored for decades. Anecdotally, the fires have affected the best known population of the northern corroboree frog. Others lost substantial amounts of field equipment such as long-established automatic cameras needed to monitor wildlife responses to fire.
Of course, action is an effective therapy for grief. There is plenty to do: assess the extent of damage, find and nurture the unburned fragments, feed the survivors, and limit further damage to burned but recovering areas of native vegetation.
The official recovery response has been swift. Victoria,
New South Wales and now the Commonwealth have all issued clear statements about what’s happened and how they’re responding. The determination and unity among government agencies, researchers and conservation groups has been remarkable.
However, busyness may just be postponing the grief. Many universities have rightly offered counselling to affected staff – as, presumably, have other institutions. Many researchers are bereft and questioning their chosen vocation.
But as we grieve, we must also remember that decades of conservation work has not been in vain. Some populations and species may indeed have been lost in the recent fires – we shall not know until long after the smoke clears. But the conservation efforts of the past mean fewer species have been lost than would have been the case otherwise.
Take the subspecies of glossy black cockatoos endemic to Kangaroo Island. Up to 80% of the area the cockatoos occupy has been burnt – but some survivors have been sighted.
Decades of work by researchers, conservation managers and the community had reportedly brought the cockatoos’ numbers from about 150 to 400. Without this extraordinary effort,
there would have been no cockatoos to worry about during these fires, no knowledge of how to help survivors and no community of cockatoo lovers to pick up the work again.
Or take the southern corroboree frog. At Melbourne Zoo, a giant black and yellow frog guards the entrance to a facility where the species is being bred for release. This success is the result of decades of research into this highly imperilled species.
The captive colony was established exactly because a catastrophic event could overwhelm the species in the wild. This fire season is the latest in a sequence of existential threats.
This hard-won knowledge of threats is also improving the nature and speed of fire response. For example, there is now far greater awareness of the damage introduced predators can wreak, especially after severe fires when animals are exposed and vulnerable in a burnt landscape. Control of feral cats and foxes will be critical. Effective fox control immediately following fires in 2003 was likely to have been critical in the persistence and then recovery of the endangered Eastern Bristlebird.
Introduced herbivores such as deer and horses will remove food resources for native herbivores, damage fire-sensitive soils, and weeds will take advantage of the cleared ground. Managing these threats at large scale soon after fires have been extinguished will be needed.
The conservation focus of late has, understandably, been on areas burnt. But it is also critical to continue conservation efforts away from the fire zones.
A recent analysis of the 20 species of mammals and birds most likely to become extinct in the next 20 years showed they are scattered across the
country, mostly in places far from those recently burnt.
The bushfires require large-scale urgent action. But we must not withdraw attention and resources from species elsewhere that need saving. If anything, now we know the unprecedented scale of threats such as fire, more conservation funds are required across the board to prepare for similar events.
Biodiversity loss is mounting across the world. If this generation is to pass on its biological inheritance to the next, more conservation science and management is urgently needed.
History does not have to repeat itself. Conservation programs have been severely set back, and people are right to mourn the severe impacts on biodiversity. But they should also take solace that their earlier efforts have not been wasted, and should recommit to the fight for recovery.
In future fire seasons, the emergency response is likely to be better prepared to protect natural assets, as well as life and property. For example, the extraordinary emergency operation to protect the Wollemi pine in NSW could be carried out for multiple species.
Those involved in conservation should lose neither hope nor ambition. We should learn from these fires and ensure that losses are fewer next time.
Stephen Garnett, Professor of Conservation and Sustainable Livelihoods, Charles Darwin University; Brendan Wintle, Professor Conservation Ecology, University of Melbourne; David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University; John Woinarski, Professor (conservation biology), Charles Darwin University; Martine Maron, ARC Future Fellow and Professor of Environmental Management, The University of Queensland, and Sarah Legge, Professor, Australian National University
In this record-breaking bushfire season, notifications from emergency managers have become a familiar feature of Australian life. Terms like “out of control” and “contained” are regularly heard as descriptions of the status of fires, but what do they actually mean?
These terms vary slightly between Australian states and territory, but as similar firefighting strategies are used Australia-wide, the meanings are comparable.
The status of a fire is a description of the stage of the firefighting effort, not the nature of the fire or its likelihood of being a threat. This means that to understand what actions to take when an active fire is nearby, it’s important to follow the advice of your local fire and emergency information sources.
A fire described as “going” or “out of control” is one where parts of its perimeter are burning and have the potential to spread into unburnt areas.
The perimeter is the focus as it is where unburnt fine fuels (consisting of the litter on the forest floor, shrubs and bark) are being ignited and burning rapidly. The flames of these subside quickly, so the majority of a fire’s interior consists of blackened area where only heavy fuels such as logs and branches continue to burn.
A fire will be given the status “going” when it is first detected or reported to emergency authorities. The status may also be used for fires that were controlled and subsequently breakaway (escape control).
“Going” fires will typically be the subject of concentrated firefighting effort to prevent growth and minimise the impacts to things of value (i.e. lives, property, infrastructure and ecosystem services). However the term is inclusive of all fires that are able to spread, so encompasses everything from shrubs burning under a tree hit by lighting to intense firestorms.
A “contained” fire is one with a complete containment line around its perimeter. “Being controlled” will have a complete or near-complete containment line. Containment lines (also called control lines or firelines) are the main way to stop bushfires spreading.
While our images of firefighters involve hoses spraying water against the flames, water is, in fact, inefficient because of the vast amounts needed to douse the large amounts of burning vegetation and the difficulty of maintaining supply in rugged terrain.
Instead, to stop fires spreading, firefighters create containment lines where all fuels are removed in bands adjacent to the fire’s perimeter. This prevents the fire reaching unburnt vegetation, starving the flames of new material to burn.
So how are containment lines created? Typically, with heavy machinery (often bulldozers), which scrape away all burnable material around the edge of the fire so nothing but mineral soil remains. In rugged terrain, this may be done by hand, by specialist crews using tools such as rakehoes and chainsaws.
Where there are existing areas of low fuel in the landscape, such as roads, bodies of water or previously burnt areas, firefighters may also include these as part of their containment strategy.
The containment line is built next to the burning fire edge, so the more intense or erratic a fire is, the more difficult and dangerous it is for crews to work.
It’s not safe to construct a line where fires are spreading rapidly, producing many embers, behaving erratically, have deep flames or are exhibiting firestorm-type behaviours (where the fire is so intense it can generate extreme winds and even lightning).
At such times firefighters will either move to parts of the fire where behaviour is less intense (typically where the wind is pushing the flames away from unburnt fuel), apply indirect firefighting methods such as backburning (burning areas in front of the advancing fire) or retreat and focus on protecting life and property.
The exceptionally hot, dry and windy conditions of the 2019/20 fire season have resulted in many rapidly expanding bushfires that have overwhelmed the capacity of firefighters to build containment lines.
As a fire is being contained, crews will be assigned to patrol the already constructed parts of the line to prevent escapes. The burning-out of unburnt fuels within the containment lines may be done to reduce the chance this ignites and causes issues at a future date.
A fire that’s “under control” has a full containment line around it, and there has been a degree of consolidation so fire escaping outside the lines is unlikely.
This consolidation is called “mopping up” or “blacking out”, and consists of crews working along the edge of the fire to extinguish or stabilise any burning material in the fire area within a set distance of the line.
Fire elevates the risk of trees falling, so at this stage there may also be work to identify and treat dangerous trees.
After line consolidation is complete, routine patrols to prevent escapes will continue for days to weeks until the fire is deemed safe.
The final status applied to bushfires is “safe”. This is where deemed that no sources of ignition within containment lines have the potential to cause escapes.
Once a fire is declared safe, it’s assumed no longer necessary to maintain patrols and the fire can be left alone.
After the fire season it’s common for management agencies to rehabilitate the containment lines, to restore the site to its prior condition to protect biodiversity values and water quality.
The status of a fire can change – even fires thought to be safe occasionally break away when hot and windy weather returns. Regardless of whether there are known fires in your area, it is important to have a bushfire survival plan and to pay attention to the advice of your local fire and emergency information sources