The Bramble Cay melomys lived on a tiny island near the Great Barrier Reef, foraging for food among sparse vegetation. But this week Australia formally declared the little rodent extinct, making the species the world’s first in what is predicted to be a large number of mammals that will be lost to climate change.
The demise of the melomys was first noted in 2016 by Queensland state government scientists, who concluded sea-level rise and increased frequency and intensity of weather events, including storm surges, had caused dramatic habitat loss and wiped out the species.
A 2008 recovery plan for the melomys never received government funding, which meant no captive breeding plan was put in place.
“This extinction could easily have been prevented, as the precariousness of this species was well known,” said John Woinarski, a conservation biologist at Charles Darwin University who has studied the rodent. “Climate change will almost certainly accelerate the rate of species extinctions.”
A 2015 report by researchers at University of Connecticut predicted 8 per cent of global species would become extinct due to climate change, with Australia, New Zealand and South America cited as the most vulnerable areas. Endemic species with a limited range of habitat were found to be most at risk, as they struggle to cope with temperature changes, sea water inundation and severe weather events.
A separate study of 17,000 bird, coral and amphibian species by the International Union for Conservation of Nature concluded that 6-9 per cent of birds, 11-15 per cent of amphibians and 6-9 per cent of corals were both highly vulnerable to climate change and already threatened with extinction.
Mark Urban, associate professor of biology at the University of Connecticut, and author of the 2015 study, said the fate of the melomys — also known as the mosaic-tailed rat — was a cautionary tale, as many more island species were likely to be washed away by the rising tides of climate change.
He said the number of species lost would depend on many factors but the most important one was how much the earth was allowed to warm by humans.
“Most surprisingly, extinction risk doesn’t just rise linearly with each degree that the earth warms, but accelerates. If we follow our current trajectory, we could lose as many as one in six species,” said Mr Urban.
Global warming poses a risk to animals living in cool climates, with many changing their behaviours in an attempt to adapt. As Arctic ice sheets melt, polar bears are being forced to look for new food sources, often in or near human settlements.
The American pika, a rabbit-like creature that lives in the mountains of the western US, is being forced to move to higher elevations to ensure its warm fur coat does not kill it in hot weather. Scientists warn the species risks running out of higher, cooler ground.
Extreme heat also poses a deadly risk, with the past five years the warmest on record in the modern era, according to Nasa. Half of the coral on the Great Barrier Reef has died since 2016 from bleaching and heat stress, an ecological disaster that threatens the habitat of numerous species, including clownfish and marine turtles.
Australia is a biodiversity hotspot and one of only 17 countries that account for an estimated 70 per cent of the world’s plant and animal species. But its size, remoteness and extreme weather make it vulnerable to climate change-related extinctions, says experts.
“Many flying foxes literally boiled alive when the temperature hit 42.5 degrees in Cairns in November,” says Evan Quartermain of Humane Society International, a charity working with endangered animals.
This week Canberra added the species to its endangered list.
Australia’s eastern states are suffering severe drought that is devastating its largest waterway, the Murray-Darling Basin, which is home to the Murray cod, a freshwater fish listed as critically endangered by the IUCN.
Scientists say the best way to limit the risk of mass extinctions caused by climate change is to cut greenhouse gas emissions, slow the pace of global warming and give species more time to adapt to rising temperatures.
“Many species are already adapting to rising temperatures on their own but this takes time and it’s essential we give them as much as possible,” said Wendy Foden, chair of the IUCN’s species survival commission.
She says protecting habitats can build species’ resilience, noting extinctions are often caused by a variety of factors. More work needs to be done analysing which species are most at risk and implementing conservation strategies to keep them alive, said Ms Foden.
“The danger is that we often can’t tell when a species is at risk due to the extreme weather events,” she said. “We thought the spectacled flying fox was safe until last November.”