I first met Nbani Friday Barilule when I was standing in Parliament Square at a recent protest by Christian Climate Action. He bounded up to us, with a wide smile and outstretched arms, saying "these are my people". Friday has a joy in his being that is contagious. A Christian from the Niger Delter in Nigeria - this was his first time in London and he was here at a climate protest, to represent his local people at the gates of power, the Houses of Parliament.

A while later, Friday spoke passionately from the main stage, with thousands of eyes on him: "The people united, can never be defeated" the crowd chanted along with him. And this was why Friday had travelled so far. A friend of his had paid for him to come to the UK, because he was determined that the voices of his community, would be amongst those pushing for climate justice.

The Niger Delta is an area of great biodiversity. Historically, it has sustained agriculture and fishing, which many of the 31 million people situated there rely on for their livelihoods. However, Nigeria is an area which is highly susceptible to climate change and over the years the Niger Delta has been devastated by fossil fuel company operations - causing it to now be one of the top ten most polluted places on Earth. There are around 500 oil fields in the Niger Delta and 131 gas flaring sites, from fossil fuel companies, such as Shell, Exxon Mobil and Chevron. Nigeria has recorded 4919 oil spills within six years.

The only time that Friday's smile slips in when he is explaining the devastating impact of these oil spills on local people: "The systematic failure of oil companies and the Nigerian government to clean up has left hundreds of thousands of Ogoni people facing serious health risks, struggling to access safe drinking water and unable to earn a living. Communities have had to be relocated, there has been a loss of our ancestral homes, pollution of fresh water, loss of forest and agricultural land."

The extent of the health risks facing Ogoni communities can be seen by the fact that they are forced to consume water with high levels of benzene that is about 900 times above World Health Organisation (WHO) acceptable levels.

Friday is the Executive Director of Lekeh Development Foundation, a grassroots advocacy organization of ecological defenders. His bravery is evident when he speaks. In the UK, if we take a stand against fossil fuel companies we can be arrested, but our lives are not in danger. It's a different story in Nigeria.

"When the police are called, you don't say anything," said Friday, "you know that they can kill you. The opposition of local communities to oil industry operations has been brutally repressed by police forces, resulting in bloodshed and hundreds of deaths".

But Friday continues to speak publicly about how fossil fuel companies are running his land. When I look into his eyes I'm reminded of how far away my life is from his. The Christ I follow stood up to the oppressive powers of his time, even though he knew it would result in his execution. I have never been put in a situation where I have to choose between fighting for justice and my own life - but Friday has to do that daily.

Friday is currently organising a three-day Niger Delta Climate Change Conference located in the Nigel Delta on the 10th to 12th of July this year. The conference will bring together different groups - experts and researchers, but also activists, frontline communities and marginalized communities affected by fossil fuel projects in Ogoni and the Niger Delta region. The conference will include a field visit to polluted sites in the area.

Despite the joy that Friday exudes, you can tell the sense of responsibility that he holds. He is determined to amplify the voices of his community around the world, to make the changes they need. He is determined that there will no more fossil fuel projects anywhere in Nigeria and that fossil fuel companies should be forced to clean up the mess they have made in his country.

The truth is that Friday doesn't hold the responsibility for his community alone. We all hold it. As Christians, we are called to care for our brothers and sisters in Christ, wherever they are in this world – As 1 Corinthians says, when one part of the body of Christ suffers, all of it suffers with it.

So let's stand together and amplify the voices of the communities of the Niger Delta. Let's cry out like it is our own water turned toxic, our own families killed, our own communities destroyed. Because "the people united will never be defeated".

Holly-Anna Petersen is a founding member of Christian Climate Action, a non-violent prayer and protest group. She has been taking action on the climate crisis for over a decade.