A large saltwater crocodile captured in Australia. Photo: AFP
A large saltwater crocodile captured in Australia. Photo: AFP

Killer crocodiles are descending on island resorts off Australia and koalas are hiking to new habitats in search of food as climate change creates a wave of species migration on the world’s hottest and driest continent.

About 50% of Australia’s animal species have already been wiped out in the past decade due to rising temperatures and water shortages, and the survivors are being drawn to cooler climates in the south. Scientists have warned that at least 200 more species are at risk of being decimated.

“Land-based species are moving polewards by an average of 17 kilometers per decade, and marine species by 72 kilometers per decade,” said Professor Gretta Pecl of the University of Tasmania, who led a global study last year on biodiversity redistribution impacts under climate change.

The report, published in Science magazine, said human society “has yet to appreciate the implications of unprecedented species redistribution for life on Earth, including for human lives.” It said there would be winners and losers, “reshaping the pattern of human well-being between regions and different sectors and potentially leading to substantial conflict.”

Australia has more to lose than other continents, as the changes will be more extreme and it has fewer options for migration. The Commonwealth Scientific and Industrial Research Organization, a government research agency, has forecast temperatures will climb four to five degrees Celsius by 2090, almost twice the global rate. The international target is a two degree rise.

Global studies by the World Wildlife Fund for Nature suggest that a 3.2% rise in temperatures would put 78% of amphibians, 67% of mammals, 60% of plants, 55% of reptiles and 47% of birds at risk of extinction if they fail to disperse. More birds and mammals would survive if they did switch habitats, but ratios for other affected species would remain the same.

In Australia, the warming of temperate regions in the south is allowing tropical animals to migrate to new habitats and forcing mammals with less resistance into cooler coastal and alpine areas. Most of Australia’s snow cover is likely to vanish within two to three decades, putting these species at severe risk.

Tropical fish have been found 1,000 kilometers south of their usual range and saltwater crocodiles are turning up 250 kilometers below their traditional habitat in Queensland and the Northern Territory. Crocodiles have been trapped on the Mary River, just 100 kilometers from holiday resorts on the Sunshine Coast.

Darwin-based crocodile expert Adam Britton said after a sighting last year that over-population of northern river systems was also a factor in the migration. The hunting of crocodiles has been banned since the 1970s.

“Eventually you can’t get any more crocodiles, particularly dominant males, in the one place. It’s a bit like a movie theatre where everyone wants to sit in the back rows but once they are full you have to move; and crocodiles are resilient, they will adapt if they have to,” he said.

Bathers have been stung by Irukandji jellyfish on beaches at Fraser Island and Mooloolaba, which are on the same Queensland coastal strip. Like the crocodiles, they could migrate as far south as the iconic Gold Coast.

Rock wallabies, possums, turtles, frogs, lizards, parrots, robins, butterflies, tree kangaroos and some snakes are among species at risk of extinction. Many koalas, possums and gliders are relocating to new habitats to find food as eucalytpus leaves dry out and lose their moisture and nutrients.

Environmentalists say it is not too late to soften the impact of climate change by altering public policies — especially Australia’s reliance on fossil fuels for power generation. Switching to alternative fuels could limit the temperature rise to three degrees, but politicians are mostly unsympathetic.

State and federal governments are considering a national plan that will prioritize coal as the main fuel source in Australia’s energy mix and make it even harder to achieve targets to reduce greenhouse gases by 2030.

“If it goes ahead, [this] will lock us into decades of more coal pollution and sabotage clean energy development,” said Gavan McFadzean of the Australian Conservation Foundation. “This will mean even more damage to our climate and more heatwaves, firestorms and droughts.”

The heat is on for Australia’s threatened native wildlife.