for National Geographic News
Small, warty, and armed with a poison strong enough to kill crocodiles, the cane toad is generally regarded as a blight on the Australian landscape.
Native to the Americas, the species was introduced to northern Queensland 70 years ago to control sugarcane beetles. The toads failed in that duty but spread across Queensland and into neighboring Northern Territory.
Now the interloper is poised to invade the states of Western Australia and New South Wales (NSW). NSW wildlife authorities fear the amphibianswhich have poisonous backs that kill hungry predatorswill have a devastating impact on native species.
Those fears may be about to be realized. Australia's leading government research body, the Commonwealth Science and Industry Research Organisation (CSIRO), forecasts a rise in average temperatures that will make NSW ideal habitat for the cane toad.
Tony Robinson, head of CSIRO's Wildlife, Pests, and Diseases Program, said climate change is increasing the amount of suitable habitat for the toad.
"With climate change, models have been produced that suggest [the cane toads] might go down as far as Sydney and some areas of Western Australia," Robinson said.
Recent estimates put the pace of the toad's westward march at nearly 17 miles (27 kilometers) a year and slightly slower from north to south.
More southerly cities, such as Melbourne and Adelaide, would likely remain too cold and dry to ever suit the toads, Robinson noted, but Perth could expect cane toads in five years' time.
Sydney could see their arrival in the next 20 years.
Predictions for temperatures in NSW show rises of up to 2 degrees Celsius (3.6 degrees Fahrenheit) by 2030, with longer, warmer summers and more rain along the coast. That's a prescription for the tropical conditions enjoyed by the cane toad.
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