Thirty years ago Bougainville lost 20,000 people in a brutal civil war that lasted almost a decade.

This week Bougainvilleans will go to the polls to vote on independence from Papua New Guinea, but in a very different mood – one of joy and celebration. Underlying this historic occasion is a resolve by all sides to honour the fallen, but never again return to conflict.

This long journey has been possible because of a peace process that resulted in the signing of the Bougainville Peace Agreement – or BPA – in August 2001 by the leaders of multiple warring Bougainville factions and the government of Papua New Guinea.

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It was founded on three pillars: weapons disposal, autonomy, and a guaranteed but non-binding referendum on independence. At its beating heart has been a mantra of “peace by peaceful means”, born of a unique Melanesian process of reconciliation and consensus making.

Resolving long-standing disputes and independence aspirations without violence is not easy. Conflicts rage around us. Less than half of the world’s peace agreements survive their first five years.

On my own island of Ireland the Good Friday Agreement took 13 years of hard negotiation from ceasefire to political settlement. Even today, 21 years later, the agreement requires constant care and tending.

Facebook Twitter Pinterest Francisca Semoso, women’s candidate for north Bougainville, signs her oaths of allegiance during elections in 2005. Photograph: Lloyd Jones/AAP

Agreements are not only signed pieces of paper. They are the implementation and the new relationships that they set out to define. So on the eve of this referendum, what can the BPA and the “Melanesian Way” that underpins it teach us all about peaceful conflict resolution?

The BPA was built on compromise. Different factions in Bougainville wanted different things to end the conflict. Some wanted immediate independence from Papua New Guinea; others wanted a chance to rebuild Bougainville before an independence vote, while others wished to remain with Papua New Guinea. At the same time the national government wanted a say in the final political outcome. Hence the BPA represents true compromise – all parties gave something, there was no “winner takes all”. This is one critical lesson of successful peace processes.

Voting begins in the referendum on Saturday and provides more than 206,000 Bougainvilleans in a country of nearly nine million people with a democratic chance to have their say about their future through an internationally recognised process. There is a palpable pride that the eyes of the world are watching. I believe the process will be a credible one, free of the fear and intimidation once wrought by weapons of war. The results are expected two weeks after voting closes on 7 December.

Today Bougainville is a changed place. People have moved back from their jungle camps where 60% of the population once fled to during the conflict. Under the direction of a fledgling Autonomous Bougainville Government, and with the support of the national government and the international community, hospitals, schools and airports have been rebuilt. Buka, Buin and Arawa townships are economically active.

Some old suspicions remain – both between PNG and Bougainville, and also within communities. Old wounds are hard to heal. Development and service delivery remain a challenge. People I have met during our consultations and awareness meetings talk about the trauma of the past and the challenge of creating a new life. After a generation of conflict, the pain of the past needs a new purpose.

There is lot to hope for. Bougainville is blessed with natural beauty and resources, and the last 12 months has seen a concerted effort by combatants from all sides to lay down arms and reconcile – between brothers and sisters, between communities, and most recently between Bougainville warlords and the PNG defence force two weeks ago. These symbolic but heartfelt events pave the way for many smaller but just as significant reconciliations within Bougainville. They represent forgiveness and laying the past to rest.

This restoration of friendships and rehabilitation of trust between old enemies is vital for the long road ahead. Once the referendum vote is known in a few weeks, the referendum process will continue. After a 40-day appeals process the two governments will consult and then put the outcome of their deliberations to the national parliament for final decision-making.

As with every step since the ending of the bloodiest conflict of the South Pacific, the journey will continue to need time, patience and an unwavering commitment to peace by peaceful means. It will also need continued support from the international community as the two governments consult, compromise and reach a consensus.

I am encouraged by the resilience of the people of Bougainville and the reinvigorated engagement of the two governments. And I am inspired by their dream of a future built on peace. Regardless of whatever the final political outcome will be for Bougainville, it should be seen as a redefinition of a new relationship between PNG and Bougainville, and a lesson for us all in the Melanesian way of addressing disputes only seen in PNG and Bougainville.

Bertie Ahern is the chair of the Bougainville Referendum Commission and was Taoiseach of Ireland from 1997 to 2008.