"I'd known about it, but I didn't really understand what it would mean for me," the 13-year-old says now.

"My primary school had a bunch of 40-degree days in spring, I thought 'this isn't right' and looked into it. I didn't sleep for a long time. It was the only thing on my mind."

Since then, joining the Canberra arm of the global school strike movement has helped Amelia manage the dread. But this month, as unprecedented bushfires rage across the nation, the reality of life in a changing climate has emerged from the smoke more starkly than ever before.

And, from school children to top scientists, psychologists say more and more people are now suffering from what they call "climate anxiety" or "eco-grief".

"I started having panic attacks again this month," Amelia says. "It's really scary and it's already happening. Our generation doesn't even have a childhood."

A new national survey by Mission Australia has found young Canberrans are the most environmentally-concerned in the country. More than half listed the environment as the most important issue facing Australia - a fivefold increase on 2018 results. But just one in 20 said they felt heard in public affairs.

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Nationally, the environment also rocketed up in teen priorities. In just one year, three times as many young people rated it as of top importance, placing the issue second on the list for the first time in the survey's (now very grown up) 18-year history, just behind mental health.

Research released by Monash University this week found concern about climate change was also up among adult Australians, almost doubling in the past year.

The nation's peak psychological association has even developed resources for climate distress as some in the scientific community speak out against the lingering "taboo" of bringing emotion into the already fraught climate debate.

In 2019, the world is more than one degree warmer than it was before the industrial revolution and scientists warn time is running out to keep it habitable in the face of more extreme weather, disease and ecosystem collapse.

Joelle Gergis, one of the lead Australian authors on the next report by the UN's Intergovernmental Panel on Climate Change (IPCC), has said her own "climate grief" and rage is growing as the most recent models reveal warming is outpacing predictions but emissions reduction targets still fall short of a safe mitigation window.

The ACT's chief scientist Sophie Collins, another lead author on that report, has also shared her fears for the future in recent days as she counts the climate records already broken in her young daughter's short life.

For teens like Maanha Manzur, almost every year of life has ranked among the hottest on record. Maanha and her friends are now seriously reconsidering what career paths to follow, and whether to have kids of their own.

"It's a huge mental weight," she says. "It's there all the time."

Student strikers want policy to keep pace with the science - they are calling for a rapid shift to clean energy, including support to fairly transition workers out of the old emissions-intensive coal and gas industries.

But Prime Minister Scott Morrison has defended Australia's climate record, despite rising national emissions, and warned children against "needless" climate anxiety.

Others have accused "doomsday" climate activists of frightening kids out of classrooms.

Robyn Saunders trains science teachers at the Australian Catholic University and scoffs at concern about missed school time ("what a valuable lesson they are learning in striking"). Instead, she wants educators to be braver when laying out the facts - and the urgency - of global warming.

"It makes some people nervous to teach because it's seen as so political," Dr Saunders says. "But there's ways to do it for different age groups that isn't just the dire warnings, it also shows them they can do something, they have a role here."

In recent months, Dr Saunders has proudly "raised the flag" and joined student strikers herself.

"It's been heart-lifting," she says. "As a society we like to talk about young people being disengaged and living on Netflix - these strikes demonstrate the opposite."

On Thursday, Canberra students will strike one day ahead of their peers around the world - capitalising on the sitting calendar of federal parliament and holding a "climate classroom" rally on its lawns.

Politicians have been invited to join lessons hosted by scientists, while firefighters and some bushfire survivors will talk solutions with students - and make more of those famous signs.

Frantically organising stalls and speakers ahead of the rally, Amelia admits she's still feeling overwhelmed by the scale of the problem. But the last strike on September 20 - which drew record crowds all around the world and Australia - taught her something she couldn't learn in school.

"Before, I felt hopeless, I felt I was the only one who cared," she says. "But so many people came. It gives me hope."

Maanha agrees she's seen a shift lately as climate change takes up more space in news bulletins and speeches.

"Even our teachers are talking about it more," she says.

Fellow strike organiser Lauren O'Daly, 16, says the upcoming sit-in will pay respect to the people and animals caught up in Australia's unfolding bushfire crisis.

"Enough stalling, enough 'thoughts and prayers'," she says. "It's time to act."

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