Patti, the power of poetry and the potency of youth

"They stand for all of us, certainly every young person," says Smith. "They are the sacrificial lambs to a new generation, but they are inspiring people globally. A youthful catalyst is the purest and most beautiful one. It's so difficult to see these girls in prison but what they're sparking is exciting. They are our young, and the young always have to stand against the Goliaths of the world."

This is classic Smith: idealistic, compassionate, confrontational, engaged. At the age of 65 her belief in the power of poetry, rock 'n' roll and the potency of the young remains unswerving. She has a reputation for being a bit prickly but today, enjoying a rare day off from a "gruelling but fun" European tour which brings her to Glasgow tonight, she is warm, graceful and generous. Yet almost four decades after her landmark 1975 debut Horses, Smith still seems happiest positioning herself as an outsider. "We're a strange band," she says of The Patti Smith Group, two of whom have been her musical allies since the mid-70s. "I have a very strong name, but in some ways we're still struggling. We don't have a sense of being giant stars or anything – we're just ourselves. I'm not career orientated, I'm work orientated. That's the thing for me. Doing good work."

Smith's new album Banga, her 12th, certainly fulfils that brief. Named after Pontius Pilate's dog in Bulgakov's Master and Margarita, it's typically expansive. There are crisp radio rock anthems, gentle girl-group laments and long, rambling centre-pieces about wanting "to die on the back of adventure". Quintessential Smith, in other words, but fresh and vibrant. "I like this record very much," she says. "It's not very contemporary, but I never know where my records fit. I didn't know where Horses fit and I don't know where Banga fits. I do know that we do the best we can and the songs are translating live. They really meld well with our back catalogue. In concert we're doing a lot of songs from Horses and a lot of songs from Banga, and it's almost seamless."

At the heart of Fuji-san, Constantine's Dream and her cover of Neil Young's After the Goldrush lies a dire warning about the state of the planet, a problem she describes as "beyond politics, religion and class. It's the one global issue in which every human being could participate in a large or small way and it would only profit all of us. Sometimes you have to be provocative to make people aware of respecting mother nature. That's why I chose St Francis as the focal point of Constantine's Dream, because his central gift was his love and unity with nature."

Is she more or less hopeful these days about the state of humanity? "I like life. I have children so of course I want to feel more hopeful. I'm not a pessimistic person, but I get disturbed by things around the world: kids walking in sewage, cholera everywhere, with no one to help them. That haunts me, but I pin my faith on new generations. On the young."

The author of several fairly esoteric books of poetry, Smith recently enjoyed a huge mainstream triumph with Just Kids, a touching memoir about her friendship with the artist Robert Mapplethorpe which was, she laughs, "far more successful than any record I ever did". It's an elegy not just to Mapplethorpe but also to youth, innocence and New York. Smith's music is full of similar evocations of loss: she has often paid tribute to departed musicians, from Jim Morrison and Jimi Hendrix in her earlier work to Kurt Cobain and, on Banga, Amy Winehouse, memorialised on the tender This is the Girl.

"It's part of my nature," she says. "My first poem was an elegy to Charlie Parker. My father loved him. He sent it to a newspaper and they published it when I was 15, so the first public thing I did was an elegy. I never dreamed then that I would have to write elegies to my best friend, my husband, my brother, my pianist, my parents – it never occurred to me that I would suffer so much loss in my life, but somehow being able to transfigure it into my work has been helpful to me, and hopefully helpful to others."

She will, she says, end her days writing books. She is working on a detective story and hopes to write more about her childhood and making music, although she rules out a conventional autobiography. "I don't have a hugely controversial life," she says. "I've never had a lifestyle that's going to keep people riveted in terms of its treacherous ups and downs, but I've seen a lot and I've known a lot of wondrous people."

While she remains "effective", however, she feels she has a responsibility to tour rather than stay at home and write. Smith describes performing as an ageless thing – "I feel healthier and stronger now than I did when I was younger" – and has remained on good terms with the majority of her back catalogue. "People say, aren't you tired of singing Because the Night or Gloria? But people love them and want to hear them, and their enthusiasm for a song makes it fresh every night. If I can't re-inhabit it or feel an authentic energy I just drop the song." Having lost her husband, former MC5 guitarist Fred "Sonic" Smith, to heart failure in 1994, she rarely sings Frederick these days "because it sometimes makes me sad. I start thinking of my late husband in the middle of the concert rather than focusing. So there are certain songs I'll stay away from for a reason like that, but in general I have enthusiasm for all of them."

As a child of the 60s, Smith has often appeared evangelical about the potential for art to energise the wider culture. Has the early promise of rock 'n' roll been fulfilled? "When I was young I thought promises were fulfilled. It doesn't work like that. Civilisation is like the sea, it comes in and out, it doesn't progress to a summit. I'm old enough to have seen the whole history of rock 'n' roll unfurl. It evolved so beautifully through the 60s to embrace spiritual ideas, political ideas and the sexual revolution, with our renaissance artists at the helm. We all thought we could change the world because it made such an impact. I started making music in the 70s to play my part in evolving our cultural voice, but there are always setbacks and steps back – that's how life turns out. It comes in waves. I believe a new wave will come."

Banga is out now. The Patti Smith Group play O2 ABC, Glasgow, tonight.