The archbishop of Polynesia, right reverend Winston Halapua, says the areas that he walked and fished as a boy with his father, seeking food for the family, on the island of Pangaimotu in Tonga, have now gone.
He says for some in Polynesia the truth is as plain as writing on the wall.
Land and livelihoods are drowning and others refuse to see it.
The bishops say climate change is undermining the stability of nations and the effects are being felt acutely in the Pacific.