If the conservative resistance to marriage reform taught the high school students of 2017 not to trust the Liberals, Scott Morrison seems now determined to repeat the lesson for their slightly younger brothers and sisters.

“We do not support our schools being turned into parliaments,” the prime minister explained. “What we want is more learning in schools and less activism in schools.”

“Parliament” derives from the old French word for talk – and the walkouts brought the conversation about climate change into every school.

That was what made them so powerful.

In the past, many mainstream campaigns about climate relied on a top-down approach in which some celebrity or another lectured the great unwashed about the need to replace lightbulbs regularly. That method provided rich material for denialists to exploit – and they duly painted environmental crusaders as finger-waving elitists telling everyday folk what to do.

But you can’t go on strike by yourself (at least, not with any success). To build protests of the scale we saw last week, activists needed to persuade their classmates. Like any manifestation of direct politics, the walkout meant ordinary people talking together: about the climate but also about tactics, strategy, and related issues.

Those face-to-face debates (so rare in contemporary life) gave the students their remarkable confidence.

“We are in a period of abrupt climate breakdown,” says the British civil disobedience group Extinction Rebellion. “We have to start acting like the adults we are. We are children no longer.”

Ironically, it’s the youth showing what that maturity means. Across Australia, students marched for action on what Kevin Rudd called, all those years ago, the “greatest moral challenge of a generation” – and politicians responded with adolescent trolling.

“If they’re really serious,” said Liberal MP Craig Kelly (a member of the House of Representatives’ environment and energy committee, no less), “they should make a commitment – no ice-cream, no hamburgers and no trips to the Gold Coast for schoolies, because of all the emissions from the airplanes.”

Each one of us needs to be involved in the battle for a future

Resources minister Matt Canavan couldn’t content himself with the old sledge about protesters being dole-bludgers but had to explain that the environmentally-minded teenagers needed to learn “to build mines, do geology and how to drill for oil and gas”.

Earlier he’d fired off a tweet in which he mourned the Queensland bushfires – and then welcomed Adani’s coal mine coming one step closer to completion.

Such antics reveal the right as a faction less committed to any coherent ideology than they are to annoying the left, a childish obsession learned from various media provocateurs.

But it’s worth thinking through the comparison with the equal marriage debate.

On that issue, too, an extraordinary gulf grew between a public demanding change and a political class entirely incapable of delivering it.

Back in 2004, John Howard deliberately made same sex marriages illegal – with the full support of Labor.

Thereafter, successive Labor and Coalition governments refused to legislate for equality, with the ALP fully backing the equal love campaign only when its victory became inevitable.

Now, the legalisation of same-sex marriage did not fundamentally alter Australian society, other than by extending a long-overdue democratic right to the previously excluded. But real action on carbon – the kind necessary to limit catastrophic warming – requires major structural changes, social interventions on a scale not seen for generations.

How will a legislature that couldn’t even amend its own law on marriage go about decarbonising the economy?

The honest answer is that it won’t – at least, not without mass pressure.

Think of Labor’s response to last week’s climate walkout.

Bill Shorten might not have abused the protesters. But he didn’t exactly support them either, with his office telling students who wanted to speak with the opposition leader to get back to school.

Even with chants of “Stop Adani” ringing out across the country, Shorten wouldn’t condemn the mine. He merely expressed skepticism that the project would be feasible – and then emphasised that a Labor government wouldn’t shut it down. Indeed, according to the Financial Review, an internal deal has been struck between the Labor factions so as not to make Adani an issue before the election.

That’s despite the levels of carbon pollution already growing so high that, as Robin McKie says, “the world may no longer be hovering at the edge of destruction but has probably staggered beyond a crucial point of no return.”

On the environment, as with marriage, the failure belongs to the political class as a whole.

The politics that’s needed to prevent the climate catastrophe – it doesn’t exist today. We need to change the system, as if we were in crisis, as if there were a war going on.”

That’s Greta Thunberg, the young Swedish woman whose activism inspired the Australian protesters.

It’s a sentiment heard more and more often, as all around the world the scale of the emergency becomes apparent.

In that context, Morrison with his reference to schools becoming parliaments inadvertently hit on something vital. With the planet burning, and our representatives incapable of a serious response, we need to take control ourselves.

That means more grassroots debates; it means, above all, more grassroots action.

Of course the schools should become parliaments – and so too should the universities and the workplaces and the community halls. Each one of us needs to be involved in the battle for a future.

We shouldn’t ask why the students are marching. We should ask why everyone else isn’t.

• Jeff Sparrow is a Guardian Australia columnist