He's risked his life to make films, been shot at, and his latest film investigates a triple homicide. So is Werner Herzog fascinated by death? No, he tells Steve Rose, he's just not afraid of it

Some years ago, Werner Herzog was on an internal flight somewhere in Colorado and the plane's landing gear wouldn't come down. They would have to make an emergency landing. The runway was covered in foam and flanked by scores of fire engines. "We were ordered to crouch down with our faces on our knees and hold our legs," says Herzog, "and I refused to do it." The stewardess was very upset, the co-pilot came out from the cabin and ordered him to do as he was told. "I said, 'If we perish I want to see what's coming at me, and if we survive, I want to see it as well. I'm not posing a danger to anyone by not being in this shitty, undignified position.'" In the end, the plane landed normally. Herzog was banned from the airline for life but, he laughs, it went bust two years later anyway.Herzog tells this story to illustrate how he'll face anything that's thrown at him, as if that was ever in any doubt. Now approaching his 70th birthday, the German film-maker has assumed legendary status for facing things others wouldn't. He's lived a life packed with intrepid movie shoots, far-flung locations and general high-stakes film-making. He has a biography too dense to summarise. But his tale also confirms the suspicion that he's helplessly drawn to danger and death. Or vice versa.

Herzog's fictional features often entertain notions of civilisation fallen apart – from the mini-revolution in Even Dwarfs Started Small to the semi-abstract deserts of Fata Morgana to the psychotic barbarism of Aguirre, Wrath Of God. His documentaries, too, frequently focus on characters who've come close enough to the final curtain to almost peep behind it. There was Dieter Dengler, the shot-down pilot who nearly starved to death in Laos in Little Dieter Needs To Fly. There was Juliane Koepcke in Wings Of Hope, sole survivor of a plane that crashed into the Peruvian jungle – a plane that Herzog himself was supposed to be on. In Grizzly Man, Herzog even listens on headphones as the movie's subject is mauled to death by the wild bears he so foolishly venerated. Even when he's off duty, danger seems to seek out Herzog – as when he was randomly shot with an air rifle halfway through a television interview, or the time he rescued Joaquin Phoenix from a car crash outside his house. The grim reaper seems to follow him like a groupie.

In his latest documentary, Herzog faces death more squarely than ever. The full title of the film is Into The Abyss: A Tale Of Death, A Tale Of Life, and its subject matter is a grisly triple homicide that's rendered even more tragic by its pointlessness. Herzog covers all bases, talking to the perpetrators (one of whom was subsequently executed), their families, the victims' family, the authorities, and so on. He dispenses with his trademark Bavarian-accented voiceover here, though his gently forthright questioning and nose for everyday surrealism prove remarkably effective. When he asks the prison chaplain, "Please describe an encounter with a squirrel," for example, he gets an emotional outpouring on the beauty of life and the horror of watching another human being die.

Into The Abyss is not overtly about capital punishment. Herzog describes it more as "an American Gothic" – a survey of a Texan landscape of poverty, intoxication, incarceration and death. But he's explicit about his opposition to the death penalty: "I was born when Nazi Germany was still around, and simply because of all the atrocities and the genocide and euthanasia, I just can't be an advocate of capital punishment. There's something fundamentally wrong in my opinion, but I would be the last one to tell the American people how to handle criminal justice."

As well as the documentary, he made another four 50-minute documentaries interviewing other death row inmates. "Not interviewing," he corrects me. "I'm not a journalist; I'm a poet. I had a discourse, an encounter with these people but I never had a list of questions."

What was it that drew him to these "discourses" then? "We do not know how we are going to die and when we are going to die," he replies, "but they know it exactly. They know that in eight days, at 6pm, they will be strapped down, and at 6.01 they'll have 30 seconds for a last statement, then a lethal injection. They know every single protocol. I was fascinated, not so much how do they see death but how they see life. So when you ask me about death, yes, I accept the question, but it always bounces back to how do I see life?"

He points to the fact that one of the convicts in Into The Abyss somehow impregnated a sympathetic helper who fell in love with him, despite being behind bars. "A few months after filming, a baby boy was born and I do believe that this child will be outside this vicious circle of violence and drugs and crime and imprisonment. So it's not just about death, it's also about the intensity of life."

But did proximity to their own death change these people? As an example, he cites one of the inmates who was granted a reprieve 23 minutes before his execution was due. The 40-mile drive to the execution chamber was the first time he'd been outside in 17 years. "He describes his last trip. He sees trees, cows in the field, an abandoned gas station, and he says: 'It was like Israel. It was like the holy land.' And that alerted me. After our discourse I instantly grabbed my camera and I drove the same route. I was looking out, where's the holy land? And it's a godforsaken rural area of Texas, yet all of a sudden everything looks like the holy land."

When I suggest that Herzog himself has come closer to death than most people, he denies it. "There is always this kind of distant echo as If I were endangering everyone and always dragging them into near-death experiences. That's all baloney," he says. "My proof is that in more than 60 films not a single actor ever got hurt. Not one."

Not even you? "Sometimes, yes, but that doesn't count."

Michael Perry in Into The Abyss. Photograph: Allstar

The myth of Herzog is something he can't control, he says. Any more than he can stop people imitating his accent on YouTube or pretending to be him on Facebook. Those tales about getting shot or rescuing Joaquin Phoenix take on a life of their own. "Completely insignificant incidents about me appear everywhere. Nothing you ever try to do will ever take them away."

Herzog wouldn't even classify himself as adventurous: "I'm a very professional man. I'm not out for the experience of adventure. The last thing that would be on my agenda is to have experience of myself and my boundaries." He puts a disdainful emphasis on the final word. "I'm really not into that business. It's abominable. There's a simple attitude: when there is a clear vision and there is a great story I would do it and I would accept certain risks."

Can he think of the time he was closest to death?

"There were … quite a few," he says, and pauses for a long time, raising his hooded eyes to the ceiling.

Is he thinking about the inflight near-miss he described earlier? "No, that was just an arabesque," he laughs. Is he thinking of the bomb that nearly destroyed his home in Munich when he was just a baby? Or the time he almost got frostbite in his toes from sleeping in his car in New York while his leg was in plaster? Or the visit to a volcano that was about to explode to make a documentary? Who knows?

"It's of no significance," he decides. "Everyone has come close, sometimes very close. It has no significance on how I conduct my life. I'm simply not afraid. It's not in my dictionary of behaviour."

As for what happens after death, Herzog went through what he describes as "an intensive religious phase" in his teens, but he's no longer a believer. "Frankly speaking, I couldn't care less," he says. "And it doesn't make me nervous." Having said that, his prognosis for the future of humanity is not optimistic. "By the way," he continues, "when you look at human life on this planet, we are not sustainable. Trilobites died out, dinosaurs died out. Life on our planet has been a constant series of cataclysmic events, and we are more suitable for extinction than a trilobite or a reptile. So we will vanish. There's no doubt in my heart."

Doesn't he feel a need to help save the world?

"Saving the world is a very suspicious concept," he replies. "I'm as responsible as it gets in my situation. I drive my car less than 10% of what I used to drive 20 years ago. I'm not into consumerism. But when it comes to the end of the human race, there are certain suspects. Microbes can come and wipe us out. It can happen fast. Avian virus or mad cow disease, you name it. Microbes are really after us. Or a cataclysmic volcanic eruption which would darken the skies for 10 years – that's gonna be real trouble. Or a meteorite hitting us, or something man-made. I don't believe we'll see a nuclear holocaust but there are quite a few scenarios out there."

What about a good-old fashioned breakdown of society? "You mean anarchy and cannibalism? Yes but there would be survivors. Maybe 10% would survive, enough to replenish the species. I'm talking about total extinction. We are not sustainable."

Isn't that a bit nihilistic?

"Martin Luther was asked, what would you do if tomorrow the world would come to an end, and he said, 'I would plant an apple tree today.' This is a real good answer. I would start shooting a movie."

Into The Abyss is out on DVD and Blu-ray on 30 Apr