In an airless library in north London, 56 people are trying to help fix not one global crisis but two. There are students and builders, a civil servant, an entrepreneur, a restaurateur, a support worker. There are immigrants and retirees and even a retired immigrant.

This is Britain’s first climate assembly, a randomly selected panel of local people convened by the London borough of Camden to consider what can be done to confront the climate emergency. The jurors have been assembled to listen to briefings, pose questions, assess facts, debate and discuss, and then ultimately recommend action to Camden council. The big question before them is what action the district can take to limit global heating and its impact.

The hope is that the series of deliberations this summer will have a bearing not just on the climate crisis but on the crisis in democracy too. A national climate assembly is planned for Westminster this autumn and Camden is being closely watched for the dos and don’ts of this relatively new form of public engagement.

“I am interested in the idea of citizens assemblies and not just for climate change,” said the local MP Keir Starmer, a Labour frontbencher. “I think they might turn out to be a way to have a different kind of political dialogue to avoid the shouty tribalism of the last few years.”

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Things take a while to get going. The opening session, something of a factfinding exercise, is held on a muggy summer night in the semi-basement rotunda of Swiss Cottage public library. The room swelters, as if to make a point. A woman wafts a fan. Facilitators urge brevity, inquiry, civility. One helpful juror draws a smiley face on a paper cup to keep a restless child amused.

Climate experts such as Prof Mark Maslin, of University College London, set out the indisputable science of the climate emergency. Participants have yellow and red cards to slow him down or stop him if they get lost. (“It’s the first time I’ve ever been red-carded during a presentation,” he says later.)

Not everyone finds it easy. One young woman is on the verge of walking out because progress is slow. For others it’s all a bit fast. And one juror, Neil Chappell, who works in construction, wonders who chose the experts and how they chose the facts. “The people they had talking were good at getting their agenda over but didn’t give us enough information to make informed decisions,” he said.

Facebook Twitter Pinterest Information boards at a citizens’ assembly session. Photograph: Vanessa Berberian

A gulf in knowledge between jurors is exposed when they are invited to pose questions. One wondered: “How many people in Camden die from air pollution each year?”. Another asked: “Can wind farms change the direction of the wind?”

But council officials are enthusiastic about the process and adamant they will act on its recommendations in a new environmental plan to be drawn up for 2020.

Georgia Gould, the council leader, said she hoped the outcome would be “some concrete action that we can take forward as a council. That’s the idea of it being an open process – you are letting go of that control. There has been a complete breakdown in trust in our political system, we need to create new democratic mechanisms to break through that and this is it.”

What is to be done?

After an initial fact-finding phase, the 56 panellists get into the nitty-gritty. What is to be done? What works?

A pair of local trailblazers talk through their own personal carbon “hygiene” measures: an electric car for their horticultural business; rail travel for holidays; meat as a treat, not a staple; double glazing, solar panels, and – perhaps less convincingly – “warm” wallpaper.

They even approach idling cars on the street and tell drivers to switch off their engines. “Most people respond politely,” Stephen Evans tells the audience.

Campaigners and experts lay out the pros and cons of certain measures. Refitting all Camden’s buildings with greener heating such as air source heat pumps and insulation would cost at least £1.3bn. Is that a bargain or a burden? Who would pay?

Facebook Twitter Pinterest Chris Dunham: ‘In the age of austerity it’s a real challenge for councils.’ Photograph: Vanessa Berberian

What about pedestrianising streets, a zero-emissions motoring zone, greening driveways, grasscrete – would that make enough of a difference? And is there any space to plant more trees? (Answer: not really.)

“I think it’s very interesting but I’ve been wondering quite a bit about where it’s going to lead,” said Chris Dunham, the director of Carbon Descent, an eco-consultancy, who spoke as an expert at the sessions. “My concerns are that in the age of austerity it’s a real challenge for councils which don’t have the money or power to do the things that are needed to complete the piece.”

Panel action

Citizens’ assemblies have been rising to prominence since an Irish experiment in 2016 to convene randomly selected laypeople to thrash out the abortion issue broke the deadlock and paved the way for a national referendum in 2018.

Camden has debated social care and its 2025 borough plan. Its climate assembly will be followed by similar exercises in Cambridge, Oxford, Sheffield, Lambeth, Devon and Hertfordshire this autumn, and a national climate assembly is also scheduled to take place. Scotland will debate its future in a citizens assembly.

“In the last six months the interest in the idea has risen exponentially,” said Tim Hughes, who helped to facilitate the Camden exercise. As the director of Involve, a public participation charity, Hughes has worked on a range of assemblies. What makes them work well?

“You want a good range of expertise, time and space for assembly members to reflect and reach recommendations,” he said. “You are not looking for complete consensus because that could be false consensus. You also want a good sense of where people disagree.”

Debate at the six tables in the library rotunda produces plenty of disagreement but participants say it is good-natured. Rupert Cruise, who is originally from Johannesburg and has lived in Camden since 2001, said: “I think it’s fantastic. The only surprise we’ve had is that there are no climate change deniers. There are differing views on where we should focus but it’s done in a respectful tone.”

Some have suggested participation in such assemblies could be made mandatory in the same way that jury service is. Simon Burall, an expert in public participation who also helped to facilitate the Camden assembly, said that may be some way off.

“There is significant distrust in government already, and if you force people to be here and don’t listen to them you will alienate them even further,” he said. “If you tell them they have to come to learn how to be better citizens, they’ll feel patronised.”

Still, the scope for more citizens assemblies on divisive issues seems broad enough. Indeed, a rigorously instituted panel to discuss the pros and cons of leaving the EU might have been useful in the run-up to the 2016 referendum.

Perhaps it might still be useful as a tool to elevate debate, restore the primacy of indisputable fact and return civility and respect to political dialogue.

“For the past few years we have had two or more groups of people talking past each other, whether on Brexit or climate change,” said Starmer. “I’m supportive of the idea.”

This article is part of a series on possible solutions to some of the world’s most stubborn problems. What else should we cover? Email us at theupside@theguardian.com