A life in writing: Bill McKibben

If William Ernest McKibben had not become a leader of the 21st-century global environmental movement, if he had perhaps been born 150 years ago, he would have made a great vicar. His middle name suits him. After talking to a digital moving picture of him on my computer, via Skype – he in his loft study on the edge of the Green Mountain National Forest in Vermont, with the first snow of the year on the ground outside, me in my loft at home in London – I came away determined to try harder to figure out if I can do more in my own life to help slow the increase in the level of carbon dioxide in the air.

McKibben travels all the time and says his own carbon footprint is "crazily high". But the campaigning organisation he now heads, 350.org, is deliberately organised in such a way that most people campaign and organise as close to home as they can, using computers and telephones to talk to each other. When I suggest there are some things that can't be done so easily or so well electronically (a newspaper interview arguably being one of them), he laughs: "Well, we'd better start figuring out what we can do." By not flying 6,500 miles to Vermont and back to meet him, I have ducked responsibility for 1.5 tonnes of CO₂.

Twenty-one years ago Bill McKibben wrote one of the first books about climate change. The End of Nature set out in detail the facts, as they then were, about the rapidly increasing concentration of greenhouse gases in the atmosphere, and passionately entreated its readers to pay attention. "It is astonishing if you think about it that we knew 30 years ago what we needed to do, and we had much of the technology to do it," he says. "And we just walked away from it. On the list of bad mistakes human beings have made, that's right up there."

Not everyone made the same mistake. With a half-smothered chuckle, he describes how, on a visit to the headquarters of the Chinese solar energy giant Himin Solar earlier this year, he was shown one of the solar panels that Jimmy Carter installed on the White House roof in 1979, and which Ronald Reagan removed soon afterwards. A few weeks ago McKibben drove to Washington DC in a biodiesel-powered van with another of Carter's solar panels, salvaged from its retirement on the roof of a college cafeteria in Maine, to lobby President Obama to bring solar power back to the White House. "They weren't all that keen to see us really. I think they were worried that these solar panels were somehow associated with Jimmy Carter, that they would catch some sort of electoral disease from touching them," he says. "But we kept saying 'no, don't worry, even people who don't know about global warming really like solar panels!' And they called us up three days before this big global work party [the 10/10/10 climate demonstrations], and said 'OK, we're putting them on in the spring'."

For the first 25 years of his career, McKibben was a writer. The son of journalists, and president while at university of the Harvard Crimson newspaper, he carved out a niche as a classy environmental reporter, publishing a book every few years. The Age of Missing Information contrasted the knowledge gleaned from cable TV over 24 hours with a day spent on a mountain. Maybe One tackled the controversial subject of human population – McKibben and his wife, the writer Sue Halpern, have one 17-year-old daughter, Sophie, who is founder-editor of a children's magazine. He wrote about hiking, skiing and genetic engineering, and an anti-consumerist essay about how to spend less than $100 on Christmas.

Full of clearly presented information, McKibben's books were also filled with description and feeling. He left New York, where his first job was writing for the New Yorker's Talk of the Town column, and moved first to the Adirondack mountains in upstate New York, and then to Vermont. He became a nature writer, devoted to finding meaning in landscape: "On the mountain, of course, death surrounds you always. Dead trees, the insects and the birds excavating their guts; dead leaves under your feet beginning to disintegrate with a year of rain and snow; dead bones in the woods."

He looked back at the work of earlier explorers, marvelled at the joy of the American outdoors, "not the dark and forbidding wilderness of European fairytales but a blooming, humming, fertile paradise". The British academic and author Robert Macfarlane recalls the impact of The End of Nature's "astonishing central idea, that the entire globe is post-natural, whether that be a sunset or the Arctic, everything bears our traces. Encountering that idea for the first time was incredibly powerful."

Environmental activism was always something that interested McKibben: his first book included a discussion of the radical ideas and direct action campaigns of Earth First! and other conservationists in the western US. But he was a writer: he and Halpern built their home on land once owned by the poet Robert Frost, whose own summer cabin is nearby, "so there's some good writing karma, and lots of trees".

"I think my assumption when I was 27 was that explaining rationally all the trouble we're in would be sufficient, and that politicians and whoever would act. I'm older now and I think I've come to understand a little more clearly that we're going to need to build some power if we're going to mount a serious challenge," he says.

So in 1997, as well as publishing two books, McKibben launched Step It Up, with the help of students at Middlebury College where he is scholar in residence, and organised rallies urging Congress to cut carbon emissions. Step It Up morphed into 350.org, named to fix in people's minds the 350 parts of CO₂ per million in the atmosphere that scientists believe is safe. Currently there are 388ppm, and some previous forecasts suggested 450ppm might be OK. But in 2007 the Nasa climate scientist James Hansen revised this figure down to 350, and 350.org set about trying to persuade the world to believe him. It is this work that currently takes up most of McKibben's time. Now he is off to Cancún in Mexico for the current round of UN climate talks, though he is not expecting a breakthrough.

Reviewing McKibben's latest book Eaarth: Making a Life on a Tough New Planet (out this year but yet to find a publisher in the UK), the climate economist Nicholas Stern argued that it was too pessimistic, that science and technology offer more solutions to these man-made problems than McKibben and his ilk will allow and that we must, above all for the sake of the developing world, hold on to the possibility of a new form of economic growth that does not rely on carbon.

McKibben says he has "stopped trying to figure out whether I'm optimistic or pessimistic – I get up in the morning and do my work as hard as I can". Tim Flannery calls him "the most effective environmental activist of our age", and Mark Lynas, who last month on Channel 4 attacked environmentalists for being too negative about nuclear energy and genetic engineering, describes himself as a "huge fan".

McKibben had a happy childhood in suburban Massachusetts, with his parents and a younger brother who is now a primary school teacher. His father's roots were in the mountainous Pacific north-west, and the family spent "treasured times" holidaying each year in a rustic cabin without electricity on Mount Rainier. "Many environmentalists had some sort of experience in the outdoors when they were young, and the most important thing about it is the feeling of being small in relation to the large, beautiful world around you – it's the opposite message from the consumer society which tells you constantly that you're very big and very important." He laughs. "It's a more consoling idea to be a small part of something very large."

But it was not until his 20s, when he wrote an article about where everything in his apartment came from – "olives, gas lines, water lines" – and began reading the Kentucky farmer-essayist Wendell Berry, followed by the first scientific reports on climate change, that he became interested in environmental politics. He recalls the day his father, a reporter who prided himself on his objectivity, was arrested. The family lived in Lexington, where the battle for American independence had begun, "and because it was such a symbolic, historic place, the Vietnam Veterans Against the War wanted to camp out on Lexington Green. The police told them they couldn't and so hundreds of townspeople joined them and were arrested, and my father was among them. It wasn't a huge deal in some ways, but I've never forgotten it, this reminder that there are times when you need to act outside your comfort zone to make things happen."

These days McKibben is outside his comfort zone most of the time. "Writers," he says, "almost by definition are people who aren't so good at communicating in other ways. What I would like to do is spend my time in this small study, writing." Instead, he spends most of his life travelling, although Eaarth looks forward to a time when this will no longer be necessary. If and when we finally get the message that we must stop jetting about and instead settle down in one place, get to know our neighbours and grow more of our own food, McKibben suggests the internet will save us from parochialism, insularity and boredom.

Does he get depressed about climate change, thinking about these terrifying scenarios in which much of the earth becomes virtually uninhabitable in just a couple of decades, when he is reaching retirement age and his only daughter will be in her 30s? In the past he has admitted wondering where he could store a year's supply of food, or whether he should buy a gun. "I do my best to avoid . . ." he says, tailing off into silence. "Look, I have one advantage," he picks up. "I've been thinking about this stuff for 21 years now, so in a sense I got a lot of my angst out of the way early on, and like anything else if you work with something long enough, at some level you come to deal with it. When I wrote The End of Nature, before I was an activist of any kind, that was a very dark moment . . . But when I get discouraged, I have one good resource I can turn to, which is the Flickr account for 350.org. We have about 30,000 photographs now from these rallies around the world, and simply going and seeing how many people are deeply engaged in this fight and how creatively, that always cheers me up."

Some of his earlier work was deeply personal, as when he wrote of the decision not to have more children and about his father's last illness, but in Eaarth McKibben announces his determination to be "relentlessly practical". Where previous books bubbled over with revulsion at the prospect of a world made over in man's image by genetic engineering, today McKibben is determined to keep the focus on carbon. He believes a huge investment in renewable energy is the only way out of our predicament: he is convinced nuclear energy is too expensive.

"We're losing at the moment in this climate fight. The reason we're losing is that by and large we've failed to build a movement, and it's going to take a movement to counter the raw power of the fossil fuel industry. At least in America the fact that it's the most profitable industry we have has been enough to give it outsize political influence. They're winning and winning easily."

Since Obama's climate legislation failed to get through a Democrat-controlled Congress, the election of a few climate change-denying Tea Party candidates last month does not feel like the end of the world. "We're in trouble, it's going to be a difficult century," McKibben says. "The question is whether it's going to be an impossible one. In 25 years we'll know whether we took the steps to keep things from getting absolutely out of control." How quickly the ice will melt remains the great unknown, but McKibben believes flooding caused by changes in hydrological cycles is the most immediate danger.

But if the literary and philosophical investigations of McKibben's previous self have to some extent been left behind with his reincarnation as a political organiser, the imaginative aspect of climate change still preoccupies him. From the outset he perceived that part of the difficulty with global warming is that human beings, brought up with the idea that the planet is billions of years old, do not really accept that it can be quickly and easily spoiled. His first book began with a discussion of time, and argued that the mounting evidence that humans had altered the weather was of profound existential significance.

His most recent project, a collaboration with artists and activists around the world, tried to reflect something of this alienation from reality: in the run-up to the Cancún talks, thousands of people gathered in locations around the world and formed themselves into designs – an elephant in India, a bird in LA, King Canute on Brighton beach, overseen by Radiohead's Thom Yorke – and were photographed from above. As well as reaching out to the artistic community, which he feels has not been sufficiently engaged by environmentalism, he hopes these "beautiful and fun" images will help us to see the world differently, "to remind ourselves of where we are, of how gradual and delicate and beautiful this all is".

When he is not travelling around the world and networking via social media – he says most of 350.org's work would not have been possible even a few years ago, so much do they rely on new technology – McKibben is a Methodist Sunday school teacher. He met his wife, whom he married in 1988, while running a homeless shelter in the basement of his church in New York, and he wrote a book about the environmental message of the Book of Job. He sees faith communities around the world as essential allies in this new "crusade", and while to secular people his way of thinking about the stewardship of God's creation may seem quaint, his deep sense of responsibility lends an urgency that is, if you accept the basic facts of global warming, hard to resist.

The fight against climate change is "as morally compulsory as the battles for civil rights or against totalitarianism", he wrote in a recent edition of The End of Nature. The book goes on to quote one of Martin Luther King's favourite hymns: "Once to Every Man and Nation, comes the moment to decide, / In the strife of truth with falsehood, for the good or evil side. / Some great cause, God's new messiah, offering each the bloom or blight, / And the choice goes by forever, 'twixt the darkness and the light."

This is a preview from tomorrow's Guardian Review. Also in tomorrow's Guardian Review, an exclusive short story by Booker prize-winning novelist Hilary Mantel, plus Annie Proulx, Adam Foulds, David Mitchell and much more ...