Greenpeace turns 40: The story of its beginnings is one of idealism, in-fighting and drama on the high seas

In 1975, a brave young hippie put himself in the firing line of a Russian whaler’s harpoons off the Californian coast. In that moment, Greenpeace was born. Its founders have been fighting causes – and occasionally each other – ever since

The 'Phyllis cormack', an old fishing trawler that has seen better days, slows as it approaches an object somewhere in the lonely Pacific, a few hundred miles off the coast of California. On board, the crew realise they've come across a baby sperm whale, blood staining the sea around its lifeless body.

A young sailor named Paul Watson clambers on the carcass, something he'll later describe as a turning point in his life. He notes how warm it still is; that the whale's eyes remain open. The Phyllis Cormack is just a mile from a nine-strong Russian whaling fleet, led by the lumbering Dalniy Vostok, which has blood gushing from its gunwales as carcasses are butchered on deck.

The graphic footage of all this, shot on 16mm film, may be 40 years old, but it is surprisingly clear and powerful. Some of the crew of the Phyllis Cormack take to inflatable Zodiac motor boats. One, helmed by a thirty-something, long-haired Canadian called Bob Hunter, positions itself between the Vostok and a pod of whales. Suddenly, a Russian harpoon points directly at him. The cameras roll as the Russian gunner fires and a harpoon soars just feet above the Zodiac, impaling one of the whales beyond. As the water turns red, Hunter and the other Zodiacs return to the mothership while the eight surviving whales flee to safety.

What happened that day has been described as the moment that launched the modern environmental movement, as that disparate band of hippies aboard the old fishing boat ended up giving birth to Greenpeace.

In the decades since, there have been fall-outs, lawsuits, and difficult questions about the role of Greenpeace (not to mention a tussle over Brigitte Bardot). But what began with a small group of idealistic individuals intent on fusing the peace movement with the environmental movement evolved into something monumental.

The footage of Hunter's potentially suicidal confrontation with the Russian whaling fleet is also a pivotal moment in How to Change the World, a moving new documentary about the charity's early days, which opens in the UK on Friday. Its director is Jerry Rothwell, a seasoned director who made Deep Water, about British businessman Donald Crowhurst's ill-fated attempt to sail solo around the world.

Eight years ago, Rothwell came across Greenpeace's entire film archive – 1,500 cans of it – at Amsterdam's Institute of Social History. He raised funds, paid Greenpeace a license fee to use the archives, and in return was able to make his film .

How to Change the World begins on Amchitka, one of Alaska's Aleutian Islands. The US had selected the island as a site for underground nuclear weapons testing in the early 1970s, and it was to Amchitka that Hunter, then a columnist for the Vancouver Sun, headed to write about a group of anti-nuclear activists protesting President Richard Nixon's arms policy.

Although he died in 2005, Hunter provides the narration for Rothwell's film: he wrote extensive memoirs, excerpts of which are read by Canadian actor Barry Pepper. "The American Dream was turning into a planetary nightmare," he wrote, "so I buried my college acceptance letter on the steps of my high school and set off to change the world."

While Hunter and his fellow activists awaited Nixon's nuclear detonation, they docked at an Alaskan fishing village near an abandoned whaling station. And it was here, stumbling upon "huge bones thrust out of the moss", that they got the idea for their next campaign. "We are intent on preventing a nuclear holocaust, but for this other race of giant creatures, the holocaust has already come," Hunter wrote.

Because the Canadians had set foot on US soil and hadn't technically cleared customs, they were fined and forced to abandon their inaugural mission. Hunter felt they had failed – but the welcome they received back home would persuade him otherwise. As co-founder Bill Darnell says in the film: "We were treated like heroes."

Struggling with his dual position as journalist and activist, Hunter resigned from his newspaper and reinvented the loosely assembled band of volunteers as the Greenpeace Foundation. With his media background, he realised that there was little point engaging in direct action unless they could relay it all to the public. When Hunter inserted himself between that Russian harpoon and the pod of whales, he noted there were millions of people aboard the boat with him, in the form of TV viewers.

Yet, despite this media savvy, the activists were naive too. The group arrived home from that trip $40,000 in debt – and while Hunter wanted to see Greenpeace offices sprout up everywhere, some in the movement felt it needed a proper organisational structure. As co-founder Paul Spong recalls, "It grew very, very quickly, largely because of the harpoon fired over Bob Hunter. It was so dramatic, it caught people's attention. Suddenly people became involved and wanted to be part of it. And the speed with which that happened caught everybody originally involved by surprise."

There were other challenges. Back in the 1970s, the high seas were thought by some to be no place for a woman, and the captain of the ship wouldn't allow women on board during that first voyage to Amchitka, believing it to be unlucky. But, according to Hunter's wife, Bobbi, a Greenpeace co-founder and the driving force behind the organisation's fundraising and administration in the early days, "Bob was smart enough to realise this was going to be a movement that would involve women. He was a feminist," she tells me from her home in Canada, "and he tried hard to break that mould."

Yet, while the movement was evolving, there was also in-fighting among some original members. Although he supported the decision at first, Hunter backtracked on Paul Watson's plan to disrupt the annual Canadian seal slaughter as it got under way, due to the potential for negative publicity.k

Watson wanted to spray seal pups with green dye, to make clubbing them for their pelts useless. But due to opposition from locals, who claimed it would ruin livelihoods that depended on the trade in seal pelts, Hunter refused. Instead, Hunter and Watson stood in front of a Canadian icebreaker – the mothership of the seal-hunting party – holding hands, forcing it to stop just a few feet away from them, the ice cracking around their feet. Rothwell's film includes striking footage of the pair wearing red anoraks in front of the icebreaker. But Watson felt Hunter had made the wrong decision.

According to Bobbi Hunter, in 1976 the organisation wanted to pull off another whale campaign, hiring a much larger ship called the James Bay. "We had a crew of 40 and went to Hawaii to confront the Russians," she recalls. Little did Bobbi know when the ship set sail that she would become the first woman in the organisation to stand in front of a harpoon – just as her husband had done the year before. "We didn't know what was going to happen. In the end they didn't shoot, but they could have. It was a hugely scary moment, but because Bob was beside me, I felt I'd be safe."

During a second trip to protest the seal cull, Watson had to be airlifted to hospital from the ice floes, after handcuffing himself to the cable that transferred the seal pelts from the snowpack to the ship, causing him to break his arm, damage his back, and fall into the icy water.

It was another media coup, but it also led, indirectly, to Watson falling out with Patrick Moore, another of the protestors aboard the Phyllis Cormack. When Watson returned home, he was greeted by Brigitte Bardot, who would lend some star power to Greenpeace – but was also the cause of more tension. In 1977, Watson revisited Newfoundland, taking Bardot. "Pat Moore had become vice-president and invited himself along," he tells me. "At one point, he wanted to get in the helicopter with [Bardot] and I refused to let him. I needed photographers in there, so he told me: 'I'm in the helicopter or when I'm president you're out the door.'"

Hunter relinquished the reins three months later, Moore became president, and Watson was voted off the board of Greenpeace. Watson went off to start Sea Shepherd, a marine conservation organisation that would enjoy considerable success after a long-running TV series followed its exploits chasing down the Japanese whaling fleet.

For his part, Moore says Watson was a "loose cannon on deck" and not a team player. It was during Moore's presidency that Greenpeace sought to more strictly control the use of its name, culminating in an agreement to establish Greenpeace International in 1979 as the umbrella organisation. Moore tells me that if he hadn't led that effort, there would be no Greenpeace today – "it would have fallen into a million pieces" – but some of the original founders were left frustrated.

Paul Spong, a cetologist known for his pioneering work with orca whales, and campaign director for Greenpeace's first anti-whaling campaign, wanted the founders to retain control. But possibly because they did not, Spong says, the organisation went on to achieve much greater things. "We attempted to keep our hands on the reins for a while, but obviously that didn't work and I'm thankful for that, because in the end Greenpeace became a force in the world."

Spong says the issues have changed in the intervening years. "Way back when I was involved with whaling, it was vital, it was something I was deeply concerned about, but in a sense it was a niche issue. In terms of scale, there are other things that are ultimately threatening for the future of our planet. And today Greenpeace is out there in front, leading that effort in so many ways."

Currently, the organisation operates on an annual budget of around £58m and has offices in more than 40 countries, co-ordinated out of a central office in Amsterdam. But some of the early founders feel the organisation lost its way in the 1990s and early 2000s; that it was focused more on lobbying, and had become, in Paul Watson's words, "mainstream".

"They were politically correct, afraid to take risks," he says. "But in the past year or so, things have changed. They've been taking risks again. I've seen positive changes."

What sort of risks? In 2013, 22 members of Greenpeace's Arctic Sunrise vessel were detained for two months on charges of piracy by Russian authorities after they attempted to stop the oil tanker Mikhail Ulyanov from entering the port of Rotterdam. Last year, Dutch police boarded the Rainbow Warrior, Greenpeace's flagship, arresting 44 activists after they tried to prevent a Russian tanker unloading Arctic oil. And this past July, a group of its activists abseiled off a bridge in Oregon to block an icebreaker involved in Arctic drilling from leaving port.

In a remarkable turn of events, Moore has become a considerable thorn in Greenpeace's side. He left the organisation in 1986 and is now pro- nuclear energy ("I think we made a mistake confusing nuclear energy with nuclear weapons," he tells me), is sceptical that global warming is man-made, and diverges notably from Greenpeace on issues such as genetically modified food. Moore has said in the past that he felt Greenpeace "abandoned science and logic in favour of emotion and sensationalism".

Moore tells me: "They have the best PR and communications advisors money can buy. They aren't the slightest bit interested in science. We started trying to save humans from nuclear war but the 'peace' got dropped. All they care about is green, and 'green' has become some kind of fantasy; a purely marketing term with no scientific definition."

But, as Paul Watson says, "Although I disagree with Pat, he's still a co-founder. You can't take that away from him just because you disagree with him." (Greenpeace, for its part, vehemently rebuts that Moore was a "co-founder", and much else that Moore contends.)

Forty years on from when her father started the movement, Emily Hunter, Bob and Bobbi's daughter and an activist in her own right, has taken up a post with Greenpeace. "Ten years ago, I wouldn't have done that," she tells me. "But I've seen a transition in the past four or five years. There are new powerful leaders such as Kumi Naidoo [who became the new international executive director of the organisation after spending decades fighting apartheid in his native South Africa] and Annie Leonard, head of Greenpeace USA. It's going back to its roots of people empowerment and direct action."

As for the film, Emily says it's long overdue. "I'm not sure why it took so long, but I always knew it would have an audience. It's about ordinary, humble, flawed individuals doing extraordinary things. And my dad? He'd be over the moon. He'd have a tear in his eye and be waving a revolutionary fist in the air." 1

'How to Change the World' (15) is released on Wednesday