A WORLD-leading scientist has warned Donald Trump may signal the end of the world — and Australia could be first to face the catastrophic consequences.

Michael Mann claims Mr Trump’s relationship to “post-truth” politics and “alternative facts” is much more than just embarrassing for the US and has the potential to destroy civilisation.

Sitting in an office at the University of Sydney Business School ahead of his sold-out talk this week, the Penn State professor says one only has to look at the city’s record January temperatures for proof of how dangerous the President’s attitude is.

“He’s building a wall between himself and the evidence of climate change,” Professor Mann told news.com.au. “He waffles, it’s hard to pin down, he says one thing to one audience then another thing to another audience.

“Some of his quotes firmly deny basic evidence, then there’s a ‘kinder, gentler’ form of denial — ‘there’s some warming, human activity has some role’ — that is still in denial of science. The science is far stronger than that.”

Mr Trump has sent mixed signals over what he may do about the issue, if anything. He called global warming a “hoax” and pledged to reverse Mr Obama’s efforts to curb coal-fired power plant emissions, but also recently met climate activists Al Gore and Leonardo DiCaprio. His daughter and close adviser, Ivanka Trump, has also shown interest in the cause.

Professor Mann says Mr Trump panders to his right-wing supporters and the Republican party’s conservative base, which is regularly lobbied by certain fossil fuel companies. But the 70-year-old’s engagement with the “fake debate” of whether climate change is real is delaying other important questions about nuclear fuel, pricing carbon and renewable energy opportunities, he warned.

The North and South Pacific have both seen one of their strongest cyclones in the past year and a half, with Vanuatu still recovering from Tropical Cyclone Pam. Australia’s ‘Angry Summer’ of 2013, which saw 123 weather records broken over a 90-day period, is yet another example of the impending risk for Prof Mann.

“The Antarctic ice sheet is close to home,” he said. “If we lose the West Antarctic ice sheet, and we are very close to the threshold, we set in motion the destruction of the ice shelf. The ice shelf is ready to collapse. Then we’re talking a 10- to 12-foot [3- to 4-metre] sea level rise, we don’t know how quick.

“We’re talking massive loss of coastal civilisation. That could be catastrophic for Australia and New Zealand.

“That’s a tipping point we’re very close to, if we haven’t already crossed it. Every bit of carbon makes a difference. What is it that will put us over the edge?”

Mr Trump has made it clear he believes in “America First” but the professor of atmospheric science says the nationalism seen in global politics right now is dangerous.

“Trump is maybe signifying a larger nationalist, nativist political wave, like we see with Brexit, that poses a particular kind of threat to activities that require global co-operation,” he said.

“Trump is a threat to a larger global movement. The next election will be a critical decision — do we want global co-operation or a divided world?”

While the President has said he may pull out of the Paris accord on climate change, Prof Mann does believe the world is moving in the right direction and that the billionaire businessman may represent the “last hurrah” for climate change denial. But according to the scientist, that could be enough to push us over the point of no return into global disaster.

“The tide of history can’t be turned,” he said. “Ultimately, fossil fuels will be priced out because of economies of scale. But we’re delaying it a bit — at what cost?

“Even a temporary setback of four years could be enough to make it impossible to meet critical targets.”

Prof Mann, who created the famous ‘hockey stick’ graph showing the recent unprecedented spike in global temperatures, has tough words for Mr Obama too, saying he “made a mistake making healthcare his first fight” and “didn’t have enough political capital left” to turn the tide on signing up to ambitious climate targets.

While the former president ramped up production of renewable energy like solar, he did not go as far as imposing a carbon tax advocated by Democratic candidate Bernie Sanders.

The Republican party remains officially opposed to such action to reduce emissions, but Prof Mann believes three-quarters would quietly accept the science, supported by the majority of experts. “The impact is becoming so real it’s increasingly difficult to deny,” he said.

A group of senior Republican statesmen are pushing for a tax on carbon, saying the evidence has become too compelling to ignore, but are meeting entrenched opposition from within the party.

Former Secretary of State Jim Baker went to the White House on Wednesday to gain Trump administration support for the plan, which would place a tax on oil, natural gas and coal and use the proceeds to pay dividends of an estimated $2000 each year to families.

Mr Baker conceded the group faces long odds for political success. “This makes such good sense from a conservative, limited government, free market, pro-competitive approach, that at the very least we hope they’ll take a look at it,” he said. “But we know we have an uphill slog to get the Republicans interested in this.”

Within hours of their announcement, influential conservative anti-tax crusader Grover Norquist took to Twitter to suggest any proposal that includes a carbon tax is dead on arrival at Capitol Hill.

“Now that the GOP can repeal all the anti-energy, anti-job regs — the Left offers to trade those regs for a carbon tax,” the president of the group Americans for Tax Reform tweeted. “Nice try. No.”

This may be progress, but it does look slow. And any change may come too late to save us.

Professor Mann is in Australia as a guest of the University of Sydney’s Sydney Environmental Institute and the University of Sydney Business School’s Balanced Enterprise Research Network (BERN).

emma.reynolds@news.com.au