Simon Reeve: ‘It's entirely appropriate to talk about a climate emergency – it’s akin to the Second World War’

"I'm a city boy at heart but I've been moved to the countryside by my family who all seem to love it," says the married father-of-one. "It's pretty beautiful, we're just a long way from other human beings."

The adventurer - whose latest five-part BBC series finds him trekking 5,000 miles across the United States and beyond - is in Sheffield on Thursday with his show 'An Audience With Simon Reeve', but don't tell him he should move locally to achieve a better balance between urban and rural life.

"Jonathan, the cameraman I work with a lot, is a son of Sheffield and doesn't half go on about it," he says. "But I love him for it, and I know he's right. I'm very well aware of the joys of Sheffield."

Reeve's globetrotting has taken him to around 130 countries, and his broadcasts have an investigative edge.

"I'm not there to film a tourist brochure, that is not my gig at all," he says. "I'm there to learn."

He has previously highlighted the scandal of child labour while exploring tea production in Uganda, was accused of spying by Russia while filming in the breakaway Eastern European state Transnistria, and turns his attention to climate change in The Americas, which is airing on Sunday nights.

The Sheffield audience can expect tales from all these journeys, as well as an insight into Reeve's background, as his early life was not a case of moneyed privilege or an Oxbridge education.

"I didn't get on a plane until I started working," he says. "People always think 'he must be another public schoolboy', but I went to a comprehensive. I walked out of school during my exams, so I managed to leave without any real qualifications. I didn't go to university, I was on the dole and sank very low. I talk about that because it's part of what helps to keep me grounded, I would claim."

His darkest moments came after he left school, when he became deeply depressed and considered suicide.

"I'm quite open about the problems I had," says Reeve, 47. "It's important people recognise you can be doing something positive in life but still be quite a fragile human being. I hope the live show will inspire people, just a tiny bit, to get out there and travel and take a few more chances in life."

Born in Hammersmith, he says his 'gritty' upbringing has permeated his TV work. "It showed me every colour and creed, I was growing up around people from every part of the world, and people in very difficult situations. We're all at risk of the same misfortune."

In the first episode of The Americas, Reeve spent time with drug addicts in Vancouver who, he remembers, were 'going through a living hell'. "For me, that's not such an impossible alternative life."

Most of his work, he says, has the same underlying concept. "I discover - or uncover occasionally - the light and shade of places. The Americas is about as big as it gets. I'm not sure what I do after this, I think I'll have to turn in my passport. It takes me through utter extremes of temperature, climate, geography, wealth, poverty, conflict - it shows everything."

Reeve saw evidence of shrinking glaciers in Alaska and, in Canada, surveyed the Alberta oil sands, a massive industrial project. The human race, he believes, is still in denial about global heating.

"It's quite a hard thing for us as a species to comprehend, that our actions individually and collectively could be changing the very planet on which we live. It's entirely appropriate to talk about a climate emergency. This is akin to the Second World War in seriousness and importance. It requires us to re-order our entire culture and economy to protect the lives we have. Very few politicians are talking in those terms. What we need is some proper leadership, in my humble view."

Reeve is no stranger to delivering dire warnings about the world's fate. In 1998 - three years before the September 11 atrocities - his book The New Jackals predicted that, sooner or later, the terrorist group al-Qaeda would launch an 'apocalyptic' attack on the West.

US President Donald Trump is far from a believer in the climate crisis, but Reeve hasn't devoted much of The Americas to the unpredictable leader. "I wasn't keen to do Trump, Trump, Trump in the United States - there's a lot more to the country than that. There are issues that are bigger and will last longer."

Indeed, he says he found many eco-friendly solutions on his American expedition.

"In Montana there is one of the biggest rewilding schemes on planet Earth. That was an inspiring place to visit, as was climbing a 200ft+ Redwood in coastal California with scientists who are taking samples to propagate millions of the biggest trees that have ever existed."

Another batch of programmes about South America will be screened in 2020. Reeve struggles to reconcile the number of air miles he clocks up with his awareness of aviation's impact on the environment.

"I'm not sure that what I've done is right, but I come down on the side of there being some moral justification for it, on the grounds I'm trying to show people what's going on in the world. You can't do that by staying on our little island or cycling everywhere. On the first leg of The Americas, we were going to places you cannot reach unless you drop out of the sky. We had to do it with planes."

He accepts the travel industry has a harmful effect, but argues: "It has a lot to offer as well in terms of protecting parts of the planet that are at risk of being chopped and logged and fished to death. Tourism does provide an economic incentive to preserve what we all think is special. There are many cases where, if people weren't visiting them, national parks would be turned into palm oil plantations and areas of the sea where more life would be annihilated."

Going from Bangladesh to Burma while making the 2010 series Tropic of Cancer is Reeve's most enduring memory from his travels so far.

"We crossed from Bangladesh, which is very poor and benighted, into India and then into Burma, which was occupied by the military who were harassing and committing human rights abuses against the indigenous Chin people. That didn't just open our eyes, it opened our hearts to the suffering of the people there in a landscape that was completely epic, being led by local guides who were astonishingly brave. The whole experience was overwhelming."

And aside from the serious messages, Reeve will have something else to share on stage in Sheffield.

"I show my pants - some special pants I have to wear on the road," he says, jokingly refusing to elaborate further. "You'll have to come along, I can't give away these top secrets. They're worn in war zones..."

An Audience with Simon Reeve is at Sheffield City Hall on Thursday, October 17. See www.sheffieldcityhall.co.uk for tickets. The Americas with Simon Reeve is on BBC Two on Sundays at 9pm. Viewers can catch up via the iPlayer.