What will Scotland do when the oil runs out and our gas-guzzling ways are no longer viable?

• David Hamilton's aim is to be able to make cider

"It's a constant fight, isn't it, Rusty?" Hamilton, a tall, genial 38-

year-old, is an officer with Tayside Police. He's the father of a 21-month-old daughter. He's also a transitioner, meaning he is part of a growing movement of people who believe in an urgent need to find new ways to live without oil. Today, that means collecting fruit from the trees in his back garden in Letham, Fife, and juicing it in an apple press which the North Howe Transition Toun – the group to which Hamilton belongs – purchased last year as a community resource.

The press gleams silver in the sun. As Hamilton turns the wheel, the juice flows autumnal and cloudy into a jug. Since this device became available, he has no longer had to buy juice from the supermarket, juice that may have travelled hundreds or thousands of miles, using a great deal of fuel, before ending up on the shelves. "My long-term plan," he grins, "is cider."

It's a small thing, pressing your own apples. But Hamilton has been making a number of small changes – transitions – in his life, and they are adding up. He has installed a wood-burning stove in the lounge and is one of a group of people who have bought an area of woodland from which they intend to gather their own firewood. He has had his cottage thoroughly insulated. He drives halfway to his work then cycles the rest. He plans to learn which wild mushrooms are edible, and how best to prune a fruit tree.

All of these activities are pleasant. It's nice to have a cosy house and fun to eat food you gathered yourself. But Hamilton, by his own admission, is no hippy. "I wouldn't," he says, "go out and hug a tree." His activities are more than mere dalliances. He is beginning to prepare for a future some believe is not too far away, in which the supermarket shelves lie bare and in which communities must learn to feed themselves or starve. "My prediction," says Hamid van Koten, a transitioner who lives nearby, "is that people will start ploughing Kelvingrove Park."

What is transition? A method of making an "elegant descent" from the oil-guzzling world we inhabit now to the post-oil future. The idea is to make that change gradually and without panic. The movement began in October, 2005, when Rob Hopkins, then a lecturer in his thirties, living in Totnes, Devon, began giving talks and showing films around the subjects of peak oil and climate change.

The concept of "peak oil" is crucial to transition, and is what differentiates it from other environmental groups. Peak oil is the point at which the maximum amount of oil that can be produced is being produced. It is a tipping point. From then on, oil will become increasingly scarce and could rapidly become much more expensive.

Transition theory says this will have major consequences for the way we live. Cars will stop running. Planes and lorries will no longer carry food from distant sources to local supermarkets. The national grid will be unreliable if not obsolete. We will be forced to live in a much more localised way – growing our own food, heating our own homes, stitching worn clothes in the absence of Primark. "Reskilling" – the rediscovered ability to make and mend – is a big part of transition. Its adherents tend to be keen on bread-making and seed-sowing. Yet what are presently regarded as rather middle-class hobbies could, in future, be necessary survival skills.

The timescale of when we reach peak oil is ambiguous, but the concept itself is by no means the exclusive dystopian vision of Luddite cranks. Some transitioners say we are already there and cite the current economic downturn, which they see as the start of a bigger slide, as evidence. Optimistic voices within the energy industry and Westminster government estimate we have 40 years till peak oil. The Oil Crunch, a report published in February by an industry taskforce including Scottish And Southern Energy boss Ian Marchant, warned: "Oil shortages, insecurity of supply and price volatility will destabilise economic, political and social activity within five years."

Transition is mushrooming in response to the threats of peak oil and climate change. "It's not really a question of whether all towns and villages in the UK become transition projects," says Hopkins. "It's when."

In just four years, around 200 official transition initiatives have formed in Britain, or been "unleashed" to use the jargon. These include 15 in Scotland, spread over an area from Moray to the Borders and from the Firth of Clyde to the Firth of Tay. There are an additional 40 groups in Scotland working on related projects; for example, Eigg, although not formally linked to the movement, is effectively a transition island, producing most of its electricity needs from renewables and almost halving CO2 emissions since 2008.

Though the concerns of each transition group are the same, there are differences in approach. In Dunbar, 250 local shareholders have bought premises on the high street and plan to run a cooperative bakery. Transitioners in Forres have established a one-acre communal garden – hoaching with chickens – where they grow tatties, tomatoes, beets, beans, sweetcorn and salad. On the Black Isle, they run doors-open days in which locals who own energy-efficient homes invite the public to admire their solar panels.

There are also a further 100 or so towns, villages and even cities that are in the early stages of development. Recently, the movement has even planted its flag in such symbolically powerful locations as Aberdeen and Grangemouth, where the local economies are steeped in the black stuff.

"We've still got a long way to go to get the message across, especially in the north-east where people are so predisposed towards oil," says Corrie Cheyne, transition officer with Aberdeen Forward, an environmental charity.

"It's quite difficult for many of them to be open enough to hear the message because there is a fear factor. Oil has been good to them, but we are starting to see a willingness to engage."

What works in the verdant villages of southern England may not transfer to a culture that is far less bohemian. In most of Scotland, a more pragmatic approach is required. "We have to be aware that this started in Totnes, which is as hippy-dippy as you can get," says Cheyne.

"There's a theory in transition that when people first learn the facts about peak oil and how much trouble we are in, they are going to undergo some sort of emotional crisis. Now, if I go up to an Aberdeenshire farmer and start talking to him about his inner pain about the energy gap, that's really not going to work. We have to be a wee bit more couthy and hard-nosed here. So I might explain to that farmer that if he can get a tractor that runs on bio-diesel, he's going to be laughing when his competitors are left high and dry because oil is unavailable. That level will be understood here."

What's true of Aberdeenshire is surely also true of the Borders. Both are rural areas with a settled way of doing things. Yet Hawick, earlier this year, was the scene of a radical experiment when the town's transition group, A Greener Hawick, launched the Hawick Pound, a local currency that could only be spent in the 40 or so businesses in town signed up to the scheme. The idea is that a community becomes more sustainable and resilient if money remains within the local economy, rather than pouring out of it, typically via the supermarket tills.

The Hawick Pound was a controversial idea that generated strong feelings on both sides of the argument. A Greener Hawick is now working on an even more provocative scheme – building up to 15 wind turbines on publicly owned land to the south-west of the town. This is the sacred landscape used during the town's famous Common Riding ceremony.

Andy Maybury, 50, of A Greener Hawick would like the first turbines to be erected in 2014 to coincide with the town's quincentennial celebrations, meaning that just four years hence we may well see horses and riders galloping past a wind farm. "Wouldn't that be great?" he says. "They're amazing, beautiful machines and to have them as a backdrop for our Common Riding festival, would be wonderful. They would be a wonderful heritage for the future."

The Edinburgh suburb of Portobello was the first place in Scotland to join the transition movement – in 2005 – and has a number of ambitious projects at various stages of development. There is a community orchard, plans for building low-energy housing and for a community farm that would supply at least 400 people with most of their vegetables.

I visit Portobello on its annual car-free day. A young man looks annoyed as he pushes aside a metal barrier that closes off the bottom of Bath Street and struggles to manoeuvre his sports car into its garage. A middle-aged woman sits on a deck chair and plays a jaunty tune on the fiddle, accompanied by a raucous rooftop seagull. Local couples eat ice-cream and discuss whether they should sign up to plant fruit trees in their gardens.

Justin Kenrick, 51, one of the founders of Portobello Transition Town, known as PEDAL, tells me car-free day, though small scale, "is a positive statement of what you hope a town or city can become. A lot of what transition is about is imagining how the future could be different – sketching it in tiny ways, whether that's an orchard, a turbine, a car-free day, and then other people begin to fill in the gaps".

Peter McColl, another member of PEDAL, explains: "We're trying to act as path-breakers – to find ways to live that will be successful when oil prices start to rise." In other words, transition initiatives such as Portobello could act as models, early adopters of a lifestyle the rest of us would eventually follow.

One of the reasons given for the viral spread of transition, which also has initiatives in Europe, Asia and the Americas, including – of all places – Dallas, is that it is easier psychologically to engage with peak oil than climate change. Using less energy seems like something one might actually be able to do, whereas we feel helpless when faced with the idea that the weather is going to kill us.

Also key to the appeal of transition is the fact that it's positive. The post-oil future, as transition sees it, is not the usual climate change nightmare in which starving survivors huddle together on a drowned world. Transition is about hope and vision rather than fear and nostalgia. It is not about damage limitation. It is not about limitation at all. Rather, it is about using the peak oil threat as a catalyst for creating a society better than the one in which we live currently.

"At the moment we are building our whole society on perpetual growth and personal gain and greed," says Carin Schwarz, coordinator of Transition Town Forres. "The ethos is that we work together and with nature. We are talking about something new and at the same time we are talking about something very old. It's a wonderful way of looking at things. Transition is not a protest march, it's a party."

The ability of transitioners to stay positive is remarkable, given their Cassandra-like sense that our present society is basically doomed. Cabbages in Kelvingrove aren't the half of it. Luci Ransome, a 46-year-old community worker, is trying hard to establish transition in Glasgow, especially among impoverished communities in the north and east that would be particularly vulnerable to price rises. As she moves around the city, she sees clearly the futility of the way we live now. "For example, the money that is going into the M74 absolutely doesn't make sense. That's going to be the most fantastic cycle lane in about ten years' time. I mean, who's going to be able to afford to use it?"

The question of what happens in cities is one transition has not yet been able to answer. There is a widely-held belief that Glasgow, Edinburgh, Aberdeen and Dundee will experience large-scale depopulations as those who can afford it move to the countryside, closer to arable land.

That said, there is also an idea that traditional Scottish tenements suit the transition model rather well. Tenants could club together to bulk-buy insulation and solar photovoltaics, and the back courts, once the province of rotund matriarchs hanging out washing, could be used as allotments. How fitting, then, that a transition library I saw in Fife included on its shelves – alongside How To Live Off-Grid and The Revenge of Gaia – Maw Broon's Cookbook. Ambridge, the fictional setting for Radio 4's The Archers, has mulled over becoming a transition village, so why not Glebe Street?

Undoubtedly, it is Scotland's rural communities that are best placed to join the transition movement. A glimpse of one possible future is afforded by the Monimail Tower Project in Fife. Since the early 1980s, the medieval tower and large house have been home to those who wish to live communally and sustainably. At present, there are eight residents. Their heating and hot water are fuelled by wood from the grounds. Much of their diet comes from the flourishing walled garden. Next to the sink is a demijohn of beetroot wine.

"We eat really well," says Louise Durrant, 38, a slender woman with short silver hair who lives there with her partner and two young children. She gestures towards her three-year-old daughter, Ruby. "She's hardly ever ill. She'll go out and just eat things from the garden. A handful of raw broccoli, and cucumber in the other hand. She eats more vegetables out there than she does at the table."

What's striking about Durrant and her family is how content they seem. She had been working in London as a solicitor for the government before deciding her life "wasn't sustainable" and that stress was going to make her ill. "I am so much happier and healthier now," she says, before adding – with a laugh that suggests she doesn't care – "and much poorer."

The happiness factor is important. A core transition belief is that as our work becomes more meaningful – harvesting crops, say, rather than typing in an office – and as we grow closer to those in our small communities, we will be happier than we are now in our high-pressure, high-carbon lives. Transition is very much in the air right now. The idea of community resilience, key to the movement, went mainstream earlier this month with BBC-commissioned research into which areas were best and worst-placed to withstand economic shocks.

Transition is also, arguably, an inspiration for David Cameron's "Big Society" project, intended to see communities take over the running of their own local facilities. Finally, the Deepwater Horizon explosion and spill has been a public relations disaster for the whole idea of oil and will have helped the cause of those who wish to make a case for a life beyond it.

So what next for transition? Already it has made its way from Devon to Scotland and beyond. Where it goes next and what shape it takes is hard to predict. What's clear, though, is the burning passion that transition ignites in those whose activism is fuelled by its message.

"We've waited for so long for the politicians to fix things for us," says Corrie Cheyne from Aberdeen Forward, "and it's not going to work. They don't know what to do. We have to show them. Transition is DIY politics. The beautiful thing is it's a ground-up movement and everyone has a role to play." n

Visit www.transitionscotland.org. The Scottish National Gathering will be at South Hall, Pollock Halls, Edinburgh, on 19 November

• This article was first published in the Scotland on Sunday on September 26, 2010