John Cossham last drove a car the day he passed his test in 1994. He took his last flight in 1997 and never renewed his passport. “I won’t leave the UK again,” he says.

The 53-year-old bearded Yorkshireman has been calculating his carbon footprint since before most members of Extinction Rebellion were born. According to the Resurgence carbon calculator, he emits 2.3 tonnes of carbon a year, less than one quarter of the UK average.

Now – with the threat of global climate collapse on the horizon – it looks like the rest of the world will have to put this distant academic concept into practice. We need to cut down on meat, travel and change the way we power our homes, experts say.

Far from being an off-grid recluse, John lives in a 1930s semi in the middle of York with Gill, his wife of 25 years, and their two teenage children. He says Gill fell for his “great legs” thanks to all the cycling he does. He loves chopping wood and looking after his bike.

From the outside John seems to have quite a conventional domestic set-up. However, his life is peppered with carbon-saving eccentricities.

While most of us jump in a hot shower in the morning, John washes himself with one cup of cold water and a flannel. He uses a compost loo in the garden and will treat himself to a hot shower around four times a year.

The whole household spends £340 annually on the electricity bill with Good Energy and £200 a year on gas. A small fraction of this total bill comes from John who “boycotts” toasters, ovens and hobs, choosing instead to cook his food using a indoor smoke-free woodstove fuelled by scrap wood. He has boiled a kettle only once this year.

“I’m peculiar like that, I feel that it’s more carbon conscious to heat food using waste wood. I don’t mind waiting an extra half an hour for it to heat up. I’ve never been interested in heating things up using an oven,” he says.

John earns a living as a children’s entertainer called Professor Fiddlesticks (John Cossham)

He is a “freegan” and forages for food, finds it in bins or in his garden. He’ll eat dairy but only if he finds it in a bin.

John can’t remember ever having walked into a clothes shop and gets everything second-hand from charity shops. He’s particularly fond of shirts passed down from his late uncle Robert. Every other year he treats himself to a new pair of shoes or sandals.

“I just don’t want to pollute, consume or use stuff. To be green you have to say no to stuff. That’s unfashionable to say because people think you’re denying yourself. I could chat up my next door neighbour’s wife but I don’t. You don’t have to submit to every whim,” he says.

“Our planet is in a perilous state and people are already dying because of climate change. We’re not the pinnacle of evolution. I don’t think we’re any more precious than a slug and we’re going to go extinct soon. It’s not about saving people, it’s about keeping the planet habitable for any organisms which survive the shitstorm we’re throwing at it.”

John loves chopping wood and looking after his bike (John Cossham)

John’s green epiphany came when he was at college in Northampton back in 1984 after being given a “load of psychedelic mushrooms” by a friend. “Having never done them before I decided to take 100. It was an astounding experience, I had an ‘ego death’ and talked to a horse. From this moment on I dropped out of college and became an ardent green campaigner,” he said.

John’s family accept his lifestyle but refuse to use the compost loo. “Most kids just accept their parents,” he notes. John does make some concessions – one of which is eating oven-cooked food if Gill has made it.

When he’s not chopping wood or searching through bins, he earns a living as a children’s entertainer called Professor Fiddlesticks. His show involves riding around on a unicycle while juggling and he only accepts gigs he can reach by train or bicycle. His other job is advising people on how to make compost. Yearly he makes just £6,000 but says that’s plenty: the more money you have the more carbon you emit.

John insists green-living isn’t all about monkish restraint: “There are so many pleasurable things to do which are zero carbon. I have a very fun, happy life.” John is polyamorous and one such luxury is travelling on trains to see his girlfriends who are “all over the country”. He has five at the moment.

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“The UK has so much lovely countryside to explore and interesting towns and villages, and there’s no issues with language, currency or passports. I’m living a great life and showing that you can do it low carbon. It feels right and it’s good and healthy,” he says.

Back in 2008 John won the Oxfam carbon competition for the lowest carbon footprint in the UK. The Act On CO2 government calculator estimated that he emitted just 0.45 tonnes a year. The organisers rang him up because they thought he was mistaken — the person who came second emitted double that.

Carbon calculating is a problematic business. Many calculators focus on an individual’s consumption like diet, and use of electricity and fuel. However, these personal emissions only add up to around half our total footprint.

The other half is from “indirect” emissions that the government spends on our behalf on services like schools and hospitals. The Resurgence carbon calculator takes these into account.

John might be on the extreme side of carbon living but small lifestyle changes can dramatically reduce an individual’s carbon emissions.

Professor Mark Maslin from University College London says that going vegetarian will halve the average person’s carbon emissions from food while going vegan will reduce them by one third.

“Most normal people are just barely coping with being alive and coping with modern day life. What we need is a government that helps them make the right choices by making greener sources of energy cheaper.

“I’m very glad that John has shown it is possible and I think it’s brilliant we have people who have dedicated their life to showing how much you can reduce your emissions,” he said.