OCCASIONALLY, just occasionally, there are weeks full of silver linings. The one that saw Britain’s first nationwide schools “climate” strikes was definitely one of them.

When Greta Thunberg began her lone climate protest outside the Swedish Parliament last August she was not to know that within six months there would be 70,000 pupils a week, across 270 towns and cities worldwide, who would be joining her. Their message was simple: “Wake up! There’s a climate emergency.” If you had followed the week’s debates in Britain’s Parliament you wouldn’t have guessed.

Politicians had been given plenty of notice that pupils would be walking out of lessons, demanding recognition of the looming climate crisis. But barely a mention of the climate protests emerged within Westminster.

It didn’t seem to matter whether Rome (or California, or South Australia) was burning, Brexit continued to fill the parliamentary corridors: 52 per cent of voters have become a binding obligation, whereas 98 per cent of climate scientists remain a matter of opinion. No wonder the kids are saying politicians are unfit to lead – because we aren’t. And as Thunberg bravely told world leaders, “When adults behave like children, children must step up and behave like adults.”

What is both humbling and inspiring is that this generation grasps that, in a crisis, it is the fundamentals that matter, not the details. As I stepped out of my daughter’s secondary school with her that morning, I realised that those joining her will still be in their twenties when the first “12 year” milestone of climate physics is reached. This will be when the shit hits the fan.

If we haven’t cut current global CO2 emissions in half by then all bets are off for what follows. This is the climate emergency that the kids are challenging us, first to acknowledge and then to act upon.

On current form, by the end of that decade, Davos will have merely built a Trump wall around itself, COP meetings will still be copping out, and the British Parliament will still be debating Brexit. What passes for politics has become completely disconnected from the climate emergency. A moment that calls out for systems change is lucky to get more than loose change.

Look back across the last year and ask yourself when Labour and the Conservatives went head-to-head over the climate emergency. When did it dominate Prime Minister’s Question Time? When did it even figure? No wonder the kids are losing patience. It has been left to Extinction Rebellion, and now schoolchildren, to lead the way.

Dozens of local authorities are trying to do their bit — passing local Climate Emergency resolutions, despite lacking the powers to follow them through. If localities have any sense they will start to bring the kids into the conversation.

Acknowledging a “climate emergency” is the starting point. But don’t expect young people to arrive with the answers. It is enough that they bring the questions. It is what follows that will turn everything upside down. As things stand, no political party has grasped the scale of what this involves.

Rosa Luxemburg predicted that in this century we would face a choice between socialism and barbarism. Even she didn’t see that it would be ecological genocide rather than class divides that would drive the choice. Capitalism has been consuming itself (and us) to death. Growth theories — based around ever expanding production, consumption and waste — will run out of species, soil, minerals, air and space to support them. Student placards calling for “system change, not climate change” nail the issue in one.

What the kids grasp — and most of the left still don’t — is that the “system change” needed involves a race into “circular economics”. It is the only route into radical CO2 cuts, environmental security and a more inclusive politics.

Out of the conversations driven by our children will step tomorrow’s giants; those who will abandon a current politics that lives in thrall of growth delusions, carbon intensive production and limitless consumption.

Just before the students took to the streets I had a delicious sample of what tomorrow’s alternatives might involve. Staff from the office of Alexandria Ocasio-Cortez were in Britain to share some of the lessons of how their Green New Deal (GND) is shaking US politics to its core. It is anything but incrementalist.

The GND builds upon the original Roosevelt plan which grabbed the US economy by the scruff of the neck, dumped the Gold Standard (ruling out austerity politics) and turned huge sectors of industry into producing completely different goods.

Like Roosevelt, today’s Green New Dealers are offering unlimited reconstruction finance. But this time round, what Ocasio-Cortez and the Justice Democrats team insist is that everything must be “Green.”

At its core, their campaign begins not by arguing about the voting age, but about how you get rid of crap politicians? Justice Democrats have been targeting the most conservative (corporately compliant) Democrats, and planning to replace them; actively promoting more radical voices who know how little time climate physics actually gives us.

Some Democrat incumbents are trying to reposition themselves as GND supporters. But acceptance comes with a price. No-one receiving support from fossil fuel industries, commodity speculators, or environmentally destructive industries gets to join the GND. Corporate donations must be returned, sponsorships declined. No-one is going to avoid the climate crisis without breaking their dependency on its causes.

Cutting carbon emissions by 50 per cent within a decade requires upheavals, including immediate shifts in public subsidies from dirty to clean, and throwing support into “smart” systems that consume less rather than more. We must cut our carbon footprint of consumption. Throw-away cultures, from clothing to plastics, must themselves be thrown away. Localised food and product markets will take precedence over globalised ones. We must tax-favour repair, reuse and recycling over primary production; constructing markets that put back into ecosystems far more than they take out.

We don’t (yet) have to panic but we do have to disrupt and transform. This is what young people are shouting into our ears. It is what the GND is trying to turn from a negative to a positive.

At its core, tomorrow’s Green New Deal will have to break the corporate grip on global economics.

This is the space in which locality, democracy and accountability will meet climate security. And it is here that Labour faces its most difficult dilemmas.

Labour’s leaders — Jeremy Corbyn, John McDonnell and Rebecca Long Bailey — grasp how little time we have. Those surrounding them may not. The Labour leadership know that their “3 Ds” — decarbonisation, decentralisation and democratisation — hold the key to taking the public with them. But around the leaders, delay and dither hold greater sway.

Shadow ministers, wanting to push more radical change, have found their ideas buried in corridor caution. References to a climate emergency get discouraged. Radical disengagement from fossil fuels never quite makes the shift from long-term promises to short-term guarantees.

Maybe Rebecca Long Bailey’s launch of Labour’s “Green Transformation” conversation will change all that. Maybe it will open up the spaces that student climate strikers are calling for. Maybe it will push system change to the front of the political agenda. At the moment, the jury is still out.

Long before last year’s Labour conference shadow minister Alan Whitehead came up with a brilliant idea. Why not produce a book on “local energy” to map out options for radical change?

Independent contributors were invited to outline plans of how Labour might race into this space. It was to form a backcloth to Jeremy Corbyn’s “400,000 Green jobs” conference speech.

In the event, the book was ready but the politics was not. Caught up in corridor confusions between old style nationalisation and radical decentralisation, the book was left to tread water.

After adding a “balancing” chapter on nationalisation, the book is ready to run again. The trouble is that those wedded to yesterday’s economics would still prefer Labour to avoid addressing the system change that our kids and the planet demand.

In existential terms, this is not a negotiation, it is a choice. Labour will have to embrace wholesale change or miss the last opportunity to do so. Thunberg didn’t mince her words in telling politicians they were “shitting on her future.” If Labour ducks this one we should not complain when our kids denounce us in similar terms.

Alan Simpson is currently the shadow chancellor’s adviser on sustainable economics. He was Labour MP for Nottingham South from 1992-2010.