The sixth mass extinction isn't just killing off some of Australia's iconic species; it's a major threat to humanity's future on this planet.
Growing up, going koala spotting down the Great Ocean Road on Victoria’s south coast was a perfectly fun afternoon activity.
Seeing those lumps of fur curled up in the crook of a tree, occasionally moving at an idle pace to reach for leaves, brought great joy. Competitions with family for who could spot the most koalas took up many hours on long drives.
Later, as a teenager, that same drive down long windy roads found nothing but a graveyard of eucalyptus. The majestic trees blackened, it was near impossible to spy those iconic furry lumps.
Koalas are a major source of cultural pride in Australia but the native species is sliding closer to extinction.
They are not the only species under threat as we live during what is being labelled the sixth mass extinction. Sadly, we can’t blame this one on a meteorite hurtling from the sky, or a rapid ice age. This one falls on our shoulders.
More than 99 per cent of all species that have lived on Earth are now extinct. This mainly occurred during the last five mass extinctions caused by various geological disturbances – think severe volcanic activity, changes in oceanic chemistry or asteroid impacts.
Each event saw the extinction of between 75-90 per cent of all species, taking the Earth millions of years to return biodiversity to pre-extinction levels.
However, human activity is the root cause of this current extinction event.
“Biodiversity as a word has only been around since the late 1980s, and the idea that humans are driving mass extinctions is even more recent,” Dr Ben Scheele, a research fellow and lecturer at The Australian National University, says. As an expert in quantifying risks to declining and endangered species, he argues the situation “keeps getting worse and worse and worse”.
The elimination of a species doesn’t happen in isolation. Species are connected in ecosystems, where the extinction of one can cause a cascade effect. Across whole regions, biodiversity is collapsing, just like throwing a stone in a pond, causing an ever-growing ripple.
The evidence now indicates the current extinction event is linked to human activity. Scheele explains that “at the global scale, habitat loss, fragmentation, and over-exploitation are all factors”. However closer to home, “invasive species are also a really big issue in Australia”.
The rate of extinction means we are losing species that are “part of our cultural identity,” Scheele explains.
“One of our most iconic species, the koala, is big for tourism, which also brings a direct economic impact.”
Thanks to a deadly concoction of habitat destruction, bushfires and road accidents, the Australian Government has declared the koala as ‘vulnerable’. Other research suggests the status should be upgraded to ‘critically endangered’.
Meanwhile, the Australian Koala Foundation is arguing the species is ‘functionally extinct’, as the population decline means it can no longer play a significant role in the ecosystem.
It’s not just the koalas that are clinging on for dear life. Current extinction rates have reached 1,000 times greater than the natural background rate as indicated by the fossil record. This means that in only 100 years, we could lose half of the remaining species on Earth.
“It’s an impoverished world that we live in if all those kinds of species are lost,” Scheele says. “Fundamentally, there is just this wonder of life on Earth, and then we’ve just come along and smashed everything.”
Conservation also has a knock-on effect for the ecosystem services we rely on.
Biodiverse ecosystems supply us with fresh water, agricultural pest and disease control, and pollination for crops. When a species dies out, ecosystem services are depleted. Humanity relies heavily on biodiversity for both health and well-being.
“If you protect an area, that then protects the services it supplies, such as filtering high-quality drinking water for us,” Scheele says.
It isn’t all doom and gloom. Scheele argues there are “beacons of light, such as the improved sustainability in a lot of farming practices”.
“Social changes are also beginning to take hold, including recognition of where food comes from driven by consumers. It all makes a difference,” he says.
There is an urgency to take global action to save humanity’s life-support systems. Not only are we at risk of losing that, but the beauty of biodiversity we take for granted.
The sixth mass extinction is already under way; we need to understand and address it. Otherwise, the joys of koala spotting will never be experienced by the kids of the next generation.
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