I think that Bianca Nogrady is asking the wrong question in her piece at The Atlantic. Here’s a snippet:
But what happens after the fires have passed through, and Australians return to either their intact homes or smoking ruins, dead cattle, a blackened moonscape where crops once grew? The lucky ones give thanks and get on with their life. The unlucky ones grieve, rage, shake their fist at Fate—and defiantly rebuild on the same ground. The battler spirit triumphs again, but for how long?
As the country suffers through one of its worst droughts on record, and heat waves shatter temperature records not once but twice within the same summer week, some are asking whether Australians can afford to keep returning to the same parched, scorched landscapes that they have occupied not just since the European invasion two and a half centuries ago, but for tens of thousands of years before that. Even before climate change, survival—particularly of agriculture—in some parts of Australia was precarious. Farmers were so often rescued from the very edge of disaster by long-overdue rains that arrived just in time. Now the effects of climate change are making that scenario even less likely, and this bushfire season and drought are but a herald of things to come.
She goes on to consider not just fire but heat and drought.
To my eye “How long will Australia be livable?” is the wrong question. Much better questions are “What is the carrying capacity of the land?”, “What is the cost of adding people beyond that carrying capacity?”, and “Who pays?”.
These are not just questions for Australia but for the United States as well and history can be a guide here. There are parts of the United States that have had substantial populations for millennia—New York City, Boston, and coastal Virginia. St. Louis and its environs was the most highly populated region in North America north of Mexico with a population in the tens or hundreds of thousands. By comparison when the Spanish arrived in the area that would become Los Angeles County, the entire population was in the hundreds.