Former prime minister Bob Hawke has offered a bleak assessment of global politics, international security and climate change.
Mr Hawke, while launching former Labor foreign minister Gareth Evans' memoir on Wednesday, admitted he could not share his old colleague's incorrigible optimism.
He warned the world was reaching a tipping point amid heightened tensions between the United States and North Korea, rising temperatures, and a string of international terror attacks in recent months.
"For the first time in human history we can either, on the one hand, increase and improve the standard and quality of life for all mankind," he told the National Press Club in Canberra.
"Or B, destroy or vastly diminish life on this planet as we know it, either by global warming or by the use of nuclear weapons."
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Mr Hawke said global stability was in far worse shape than during the Cold War, which included the Cuban missile crisis, when tensions between the Soviet Union and the United States were icy.
"In that situation in the Cold War, neither side wanted to - indeed it feared - their own destruction, while today the terrorists possibly welcome their own death," he said.
"Secondly, in that period, your enemy was identifiable within a defined and unchanged territory."
The damage Islamic State and its cohorts could do with conventional weapons was nothing compared to what they would do if they were to get their hands on nuclear devices.
"And there can be little doubt that is a possibility," Mr Hawke said.
On global warming, Mr Hawke said things were getting worse, with average global temperatures between 0.6 and 0.7 degrees higher than in 1979.
"And to exacerbate matters, you now have a president of the United States whom Gareth has described in these endearing terms as narcissistic, ethically challenged, ignorant and vulgar," he said.
In a lighter moment, Mr Hawke sought to "correct the record" concerning himself, taking issue with Mr Evans arguing he rarely generated any big, new ideas after setting the direction of government.
"This is simply not true," Mr Hawke protested.
"Without in any way being exhaustive," he went on, before launching into a rather exhaustive self defence, including quoting from his own memoir.
