Australia’s raging bushfires have already taken a great toll. At least 28 people have died this season, and more than 3,000 houses have been destroyed, displacing thousands of people and decimating communities.
The longest-lasting impact of the conflagration, however, may remain to be seen. We will not know how much environmental damage has been done until burned areas can be surveyed, but the toll on biodiversity is expected to be immense. Using average population density values for native birds, reptiles and terrestrial mammals, I have estimated that more than a billion of these animals have been killed. The estimate is conservative, as it does not include bats or other classes of vertebrate. Chris Reid of the Australian Museum has provided an additional and cautious estimate that more than 240 billion insects have been lost in the fires.
It’s difficult to understand the enormity of such a loss of wildlife, which portends a grim future for ecosystems around the globe. Still, through the smoke remains a glimmer of hope for Earth’s biodiversity — as long as world leaders heed the warnings of Australia’s crisis.
The wildlife death toll tells only part of the story. We will need to ask how species and their habitats fare in the bushfires and to what extent recovery can be expected. The bad news is that many already threatened species live in the burned areas, and some will have lost all or most of their habitats. Between 20 and 100 such species of vertebrate animals and plants are in this parlous situation, as are as many as 700 species of invertebrates. Old-growth rainforests, littoral rainforests and alpine plant communities are also susceptible to high-intensity fires. The collapse of such communities and extinctions of any of their constituent animals will grievously erode biodiversity.
But there is good news, too. Australian ecosystems have co-evolved with fire, and we can expect that key shrub and tree species such as the eucalypts and their allies will recover quickly in many areas. After rain, there will be flushes of grasses and herbs, and wildlife will move in quickly to exploit the fresh, green bounty.
Recovery of rainforest and other fire-susceptible habitats should also occur, though it will take longer, and animals that need resources that regenerate slowly — such as deep leaf litter, logs or tree hollows — will also remain scarce for long periods. Koalas will persist — despite the loss of tens of thousands of individuals, the species as a whole remains secure. And recent surveys show that Australia’s “dinosaur tree,” the unique and endemic Wollemi pine, was saved in its single, secret location by dedicated firefighting efforts.
What can be learned from the unfolding bushfire catastrophe? In Australia, climate modeling by economist Ross Garnaut in 2008 predicted that warming and drying trends in the southern parts of the continent would create conditions that would lead to more intense bushfires. The predictions were correct: Last year, Australia experienced its hottest and driest year since records began, setting the scene for this year’s catastrophic bushfires. There can no longer be any denial of the reality or the impacts of climate change.
Fortunately, the government under Prime Minister Scott Morrison this week pledged 50 million Australian dollars ($34.5 million) for a wildlife and habitat recovery package. Meanwhile, a meeting this week of wildlife experts in Canberra, Australia’s capital, is expected to help guide the recovery process. These are encouraging steps.
Globally, Australia is sometimes seen as a “climate canary” in the coal mine. Given the island continent’s variable climate, general aridity and flammable ecosystems, scientists have long expected the impacts of climate change to be seen earlier and with greater intensity there than elsewhere. Hence, we might ask whether the unprecedented bushfires presage not just a “new normal” for Australia, but signal what is likely to come elsewhere in the world.
The world will monitor how Australia rises to the challenge of climate change. With courage and will, the international community can learn from the bushfire crisis Down Under. Perhaps we may yet be able to change our collective behavior and take swift and concerted action to mitigate the risks and impacts of climate catastrophes globally.
Christopher R. Dickman is a professor of ecology at the University of Sydney.