The plan, says Adbusters co-founder Kalle Lasn, is to stretch it out and turn it into a Buy Nothing Christmas. He wants us to bypass the tinsel, the tree and the tat and go cold turkey on consumerism for the whole festive period. "We are," he says, "going to try and take back our Christmas season from the commercial forces that have hijacked it."

If you think this sounds like the rantings of a deluded Bolshevik, it's worth noting a few things about Lasn and his cohorts at Adbusters, who have been producing the bi-monthly magazine from their Vancouver office since 1989. Lasn, an Estonia-born, former high-flyer in the advertising industry, now pushing 70, started Adbusters as an antidote to corporate greed, and what he saw as an aggressive pro-consumerist message that was being rammed down our throats. "We felt back then that there was a dark side to consumerism but no one ever talked about it," he says.

Lasn's background in advertising shows. Rather than being a ranting left-wing rag, Adbusters is slick and full of smart graphics and insightful critique. His ideas, so pertinent now in the global financial chaos of today, have always been ahead of their time. And it was he who, in last July's issue of Adbusters, ran a one-page poster which simply read "Occupy Wall Street, September 17th, bring tent".

What happened next sparked one of the most successful protest movements of recent times, one that has gone on to dominate the global news agenda for weeks. That one small page was responsible for hordes of disgruntled people congregating at Wall Street's Zuccotti Park and London's St Paul's Cathedral to express their fury at the world's extreme economic inequality, and many of them are still camping there to this day. And it was responsible for a further thousand or so other Occupy protests that sprung up in solidarity the world over. Lasn, it seems, has chanced upon a formula to harness global support.

"We were inspired by events in Egypt and Tunisia earlier this year," he says, "by that fact that a few smart people using Facebook and Twitter can put out calls and get huge numbers of people on to the streets to give vent to their anger. I always thought I would die a disappointed leftie, but now I have been redeemed. The idea that we, the people, can go into the iconic heart of global capitalism and take it over, and the fact that we can do that from an office staffed with 10 people and then sit back and watch the whole thing catch the imagination of the world – that gives me hope for the future." k

Lasn believes the success of the Occupy movement is down to the fact we have reached an impasse, a kind of critical moment where our future has now become so bleak, people have been driven to act. "We have reached a tipping point," he says. "Our economic system has been run like a global casino and is teetering on the brink of collapse. None of our political leaders seem to know what the hell they are doing any more and there are now seven billion of us facing ecological crisis, too. Young people are looking at a future that doesn't compute. We have reached a moment where, unless we fight for a different kind of future, we're not going to have a future at all."

Lasn saw it all coming back in 1989 when Adbusters started out as a humble newsletter. It was born out of an epiphany Lasn had after seeing an advert on TV for the Canadian forestry industry. "[The advert] was hugely misleading," he says. "They basically said, 'Hey you people of Canada, we are doing a fantastic job of managing your forests, you have nothing to worry about, you will have forests forever.'" Lasn – who left advertising to make documentaries – decided to make his own 30-second advert to tell the other side of the story: the dangers of deforestation. However, when he took his advert to the TV station, they refused, point blank, to sell him airtime.

"That was a devastating moment for me," he says. "In my home country of Estonia you weren't allowed to speak up against the government. Fifty years later, I found myself in the heart of the democratic world suddenly totally unable to speak out because of one company's advertising money.

"It made me realise how all our media and information delivery systems are infiltrated by pro-consumption messages, and that basically every aspect of our lives is controlled to some degree by this consumer machine. Consumption patterns in America have increased by 300 per cent since the Second World War, and the average American now consumes three times more than they did 50 years ago. It was time to rage against the machine."

Adbusters now has a dedicated worldwide circulation of 70,000 (with 20,000 more online readers), and all this has been done without the company ever publishing a single advert. "We have broken all the rules of all the business models," says Lasn, "In this day and age to run a magazine without any advertising sounds moronic." Costs are covered by the slightly higher than usual cover price (£5) as well as donations.

From the beginning, Lasn and his team took a lead from the Situationist movement and, alongside the magazine, pioneered a series of interventions, pranks or "culture jams" as they like to call them. There is Digital Detox Week, for example, a campaign which runs every April and is aimed at challenging our over-reliance on technology. There is also an endlessly expanding gallery of spoof adverts poking fun at our big brands, which kick-started the trend for subverting corporate logos and defacing advertising billboards. (There's a whole gallery devoted to Nike, including one poster featuring a group of sheep which reads "I'm sick of just doing it.")

And there was the fabulously successful launch of the Blackspot sneaker, a fair-trade, environmentally friendly, logo-free shoe sold only through independent retailers; "An experiment in grassroots capitalism and an attempt to demonstrate you can change the way the world does business," says Lasn. Currently, the Blackspot is sold in more than 100 shops worldwide.

And, of course, there is Buy Nothing Day, which is now observed in countries from Sweden to Hong Kong and Japan to France. "When we started it we had all these people saying, 'Buy nothing? You're telling us to buy less? Isn't that bad for the economy? You guys are crazy.' But it had a spark about it right from the start and spread quickly, particularly in the UK and Australia. A lot of people had profound epiphanies when they tried it. Many found that half-way through the day they were like, 'I've got to buy that Mars bar, I've got to buy that cup of coffee.' People really suffered and sweated. It was like giving up an addiction."

Whether we are ready to start trying to kick this addiction remains to be seen. Ways in which Lasn suggests we start trying to get off the consumer treadmill include walking into a shop and asking ourselves, 'What would Jesus buy?', or giving a "gift exemption" card to friends and family – although what my six-year old son would say to that definitely isn't thank-you. And, he says, if it's all too much for our greedy consumerist hearts to contemplate, there are other options to try, such as a Buy Local, Buy Fairer or a Buy Indie Christmas.

Whether or not Lasn successfully manages to harness the support he has mobilised through the Occupy movement remains to be seen. He is optimistic. "This year feels different. Hopefully we will get some of the occupiers to have fun subverting the global commercial system in the month leading up to Christmas. It feels bigger and better than ever before. It feels like there are millions of people around the world all ready to play a cat-and-mouse game with the agents of capitalism."

Finally then, after more than 20 years plugging away with the Adbusters message, Lasn is allowing himself a moment of gratification. "Of course it feels good that after all this time people are finally starting to get it. But there is also a darkness underpinning that good feeling. It sounds apocalyptic, but I have a horrible feeling in the pit of my stomach that the economic pain people are going through is just the beginning. If that's right, then we will really see the young people of the world stand up in a way that is many times bigger than they have up until now. We need to find ways to capture the imagination of the rest of the world. If we can do that then I believe this movement may well pull off some incredible radical transformation that needs to happen to make the future of our planet work."