MALUA BAY, Australia — When the flames swept up from the cove through the gum trees, Neda Cettnic signaled frantically that it was time for her grandchildren to get off the roof.

It was New Year’s Eve, and fires across this vast continent had already scorched tens of thousands of acres. Now the fire was coming for Cettnic’s hillside home.

The three grandchildren, ranging from 8 to 11 years old, had been deployed to clear debris from trees that the government had not allowed the family to cut back in the weeks before fire season. The federal government had also ignored advice to call in advance for foreign reinforcements to help Australian firefighters.

So across the dry valleys and eucalyptus forests of southeastern Australia, preparing for the fires sometimes fell to grandmothers like Cettnic, a retired registered nurse, and her grandchildren, who wondered aloud what had happened to the sun when the sky turned night-black before noon.

“Everything just shriveled with the heat,” recalled Cettnic, her house still largely intact after the flames blew past.

Australia is angry — very angry. Its ire is directed primarily at a government that left citizens like the Cettnics feeling as though they have to fend for themselves during fires that have burned for months. Through the haze of smoke that has blanketed major cities, many Australians are also angry about public policies that largely discount climate change as a problem worth addressing in the near term.

Wildfires that have torched an area larger than Portugal, killed at least 25 people and destroyed hundreds of homes have electrified the politics of climate change here and altered the nation’s long-standing, if largely ineffective, environmental movement. Scientists say that rising temperatures — Australia has measured ­record-breaking heat during its summer — mutated the fire season into something more deadly and devastating than ever before seen.

Prime Minister Scott Morrison is facing a reckoning not only over his government’s preparation and management of the fires, which were doused last week by days of pounding summer rain, but also its larger environmental and energy policy.

The future of the country’s reliance on coal, as its primary export and a key source of its energy, is being challenged more aggressively than ever with the fires and obviously warming climate as a vivid green-screen backdrop.

Reelected prime minister in May, Morrison has called for a federal inquiry into his government’s response to the fires. But he also has indicated he will not curtail his efforts to expand the coal industry, calling it an essential driver of jobs and tax revenue.

“The suggestion that there’s any one emissions reduction policy or climate policy that has contributed directly to any of these fire events is just ridiculous,” Morrison said in a radio interview this month. “And the conflation of those two things, I think, has been very disappointing.”

New tactics for new realities

Helping propel the public criticism is a movement new to Australia known as Extinction Rebellion, which began in the United Kingdom two years ago and operates largely alongside traditional environmental groups.

It is more guerrilla operation than government lobby, an unconnected series of small cells that favor direct public action over long mobilization and information campaigns. Signal, the encrypted messaging app, is the group’s communication mode of choice.

The group has staged large rallies and attention-drawing stunts. At the height of the holiday season, the group built in hurried coordination a Santa’s sleigh in the middle of Sydney’s shopping district, the elves and reindeer “killed” by the coal economy. Such tactics are managing to expand and sharpen Australia’s once-stodgy environmental movement.

“To be a rebel, all we ask is for your email and to come to one talk,” said A.J. Tennant, who left a job as a copywriter for the New South Wales government just before the “Santa action.” The Sydney group’s Instagram account has gone from 1,000 to 35,000 followers in just the past two weeks of fire, protest and civil disobedience.

“People have had a gutful, and the old ways just do not work,” said Larissa Payne, a former high school history and English teacher recently turned full-time activist. “And it’s not just senior citizens, and students and old-school hippies. It’s doctors, dads and their kids, firefighters.”

For years, the environmental movement here was primarily the domain of academics, scientists and young idealists. The pull by Extinction Rebellion and other public-relations-savvy groups to enlist former fire officials, doctors, business leaders and farmers into the national climate conversation has made the government’s criticism of the movement as out-of-touch less plausible than it once was.

“All of the portents were there at the start of this fire season,” said Greg Mullins, who served as chief of the huge New South Wales fire service before retiring after more than four decades in the field. “We tried to warn the government, but we were dismissed as a bunch of activists.”

Mullins sits on the Climate Council, described as the nation’s leading independent climate change communications organization. His April warning to Morrison’s government came in the form of four letters, each signed by 23 former fire chiefs from every state.

“We were seeking a meeting to relay to the prime minister what we had been seeing and studying,” Mullins said.

The chiefs wrote that the Australian government should begin immediately securing leased firefighting aircraft from the United States, which can take time to deliver, especially with the American West facing its own severe fire seasons. There was no meeting, and the warning was never acted on.

“The government continues to say that it is insensitive to talk about climate change while people are losing their homes,” said Mullins, 60. “But people want to know now, they are the ones asking: ‘Why with more firefighters, more firefighting equipment, better building standards are we seeing what we are seeing now?’”

A clearly warming climate

Last year was the hottest ever recorded in Australia based on average daily temperature readings, scientists say. The country registered 33 days hotter than 95 degrees.

That figure is five times higher than past studies had predicted for the year.

“It was just another indication that the climate is racing far ahead of the models we have been using until now,” said Will Steffen, professor emeritus at the Australian National University in Canberra.

The rising heat is affecting weather patterns here.

Steffen said the warming planet is pushing the tropics farther from the equator, which for Australia means that its winter storms sometimes fail to make landfall on their way to the poles. Drought here is severe, with much of the country under water-use restrictions.

Steffen, a councilor on the Climate Council, and Extinction Rebellion members talk about “tipping points” that have been reached in recent years.

The first harsh signal sounded loudly in 2016 and 2017, when stunned scientists reported a massive bleaching of corals on the Great Barrier Reef, one of the seven natural wonders of the world.

Bleaching occurs with rising water temperatures, among other conditions, which kill off corals. A study published last year in the journal Nature reported a nearly 90 percent collapse in new coral formation on the reef since the bleaching event.

“I believe the same kind of tipping point is happening in our forests this year,” Steffen said. “These forests that are burning are experiencing record-high temperatures and record-low moisture.”

Tweaking King Coal

Dan Bleakley grew up in the small Queensland town of Claremont, not far from what today is the single-most-contested energy project in the country.

The Indian multinational Adani has worked for years to begin mining Queensland’s Galilee Basin, in what would be the largest coal mine in the country. Coal was forecast to be Australia’s most valuable export last year.

The project played a key part in Morrison’s reelection, and local Queensland politicians are generally behind what is known as the Carmichael mine. Adani predicts the project would produce 10 million tons of coal annually, in its initial phase, and create thousands of jobs in Queensland. The company declined a Post request to visit the site.

Adani also needs to build a rail line to the coast to ship its coal for export. The new business would add at least 500 coal-ship passages through the Great Barrier Reef World Heritage Area each year for the project’s six-decade life.

“The coal mine is proposed to open up the biggest coal supply in human history,” said Bleakley, an Extinction Rebellion member who runs a sign business in Melbourne. “And this is coming at a time when our goal must be to begin a rapid transition to a sustainable economy in the very short term.”

Bleakley had never been an activist before the May election, which gave Morrison’s Liberal/National Coalition another term after it looked for weeks as though an environmentally focused coalition of Labor and the Greens might win enough seats to form a government.

In the closing weeks, a mining tycoon named Clive Palmer spent more than $60 million in ads critical of the Labor Party’s economic policies, a move that is now drawing calls for campaign finance reform. “Out of despair and fatigue,” Bleakley said, “I got involved.”

In November, the month the fires began last year, Bleakley carried out a 10-day hunger strike opposing the Carmichael mine project on the steps of the Victoria state Parliament building. At the time, new public opinion polling found that 60 percent of Australians believe the government is not doing enough to address climate change, up by nearly double digits from eight months earlier.

Then Bleakley glued himself to the Melbourne lobby window of the German industrial electronics giant Siemens, one of only three companies in Australia capable of building the coal rail line needed at Carmichael and the only one that has yet to declare it will not participate.

The head of Australia’s Green party, Richard Di Natale, has warned Siemens that it is risking its reputation by potentially participating in a project he called a “carbon bomb.”

Similar protests have taken place in Siemens offices around the world since Bleakley’s escapade made YouTube. In solidarity, one man glued himself to the lobby window of the Siemens headquarters in Munich.

Bleakley and other Extinction Rebellion members say they are heading into an “autumn rebellion,” a steady stream of provocative public acts drawing attention to the Carmichael mine project and Morrison’s environmental record, using the fires as fresh evidence.

For 2020, the Climate Change Performance Index, prepared each year by a group of international environmental think tanks, ranked Australia the worst of 57 countries for its national and international climate policies.

“We don’t have a choice,” said Bleakley, 37. “This world is going through some tipping points, and we have no time to waste.”

The local and the global

Jane Morton was among the founders of Australia’s Extinction Rebellion movement, propelled by the 2016 news of the Great Barrier Reef bleaching that had taken much of the country by alarm.

Extinction Rebellion formed about two years later. She called it “initially a grass-roots movement running alongside the big environmental movements.” But the more direct-action strategy — and a rethinking of the traditional electoral politics approach — has set the less-established groups apart.

“It was really only the grass-roots groups holding the flag,” said Morton, an environmental activist and writer who lives in Melbourne, “and we were having a hard time holding it.”

What Morton has pioneered is a strategy of local focus, which plays somewhat below the radar of Extinction Rebellion’s larger, more public acts.

It was an approach she saw executed during Australia’s debate over creating a national disability insurance benefit — a lawmaker-by-lawmaker lobbying effort that started in the backbenches of parliament and moved slowly with momentum to the leadership, not the other way around.

Morton is applying those lessons to winning local district councils, which have the ability to declare local climate emergencies that serve as a goad to the federal government. She said that in 2016, the council in Darebin, a Melbourne suburb of more than 150,000 people, became the first local council in the world to declare a climate emergency.

For Extinction Rebellion’s overall message, Morton said it was important “to say that what we are facing is a human security emergency — that food and water supplies are at risk, that this is a threat to all life on Earth.”

“And let me tell you, it’s been hard to make a catchy phrase out of ‘You are all going to die,’ ” Morton said. The name they came up with — Extinction Rebellion — is meant, she said, to state the problem and offer the solution.

Through the national parks

The road is empty, only the occasional army convoy or firetruck rumbling by. It is usually a major route south from Sydney. Now it is a gray thread running through a burn scar the size of a small state.

The forests here are charred. But thousands of resilient gum trees still stand, their thin, branchless trunks blackened to pitch. Kangaroo and ostrich crossing signs line the road. Many kangaroo corpses line the road — evidence, perhaps, of frantic evacuations carried out in the midst of busy firefighting work.

Smoke sits heavy in the wide valleys, spare of brush and only slightly rolling, a Tolkien backdrop when the sun is obscured by smoke. Two wild horses lie burned amid muddy tufts of ground, apparently having died in the flames as they scrambled to climb a small hill and reach the firmer road. Their lips burned back to show teeth in a gruesome, sad rictus.

You can drive for hours — in nearly any direction southeast of Sydney — and never leave the burn scar.

“I don’t know what else they could do,” said Scott Hillam, a wheat farmer and volunteer firefighter who worked against the flames in the town of Tumbarumba.

The immediate danger past, there is a sense of unease about the future.

“What we’re fighting against now is a whole lot of things,” he said.

Hillam brought his family here to Malua Bay, which had been evacuated just two weeks earlier, for a small summer vacation after the fires. In the clear emerald waves, his four children played, one with the inevitable shark-fin floaty strapped to his back.

Another scampered out of the foamy water, smiling, and ran across a tide line defined thickly by curves of black ash against the white sand.