Global voices in Londonpublished at 15:31
Claire Marshall
Environment correspondent, BBC News
Testimonies from two marchers today have been particularly poignant.
Mickaele Maiava is from Tokelau, a territory of New Zealand, which consists of a collection of coral atolls. Its geography puts it at sea level, and the rise in sea level is rendering the land where Mickaele plants crops useless - it is now poisoned by the salt water.
Wearing a traditional head dress, his hands covered in tattoos, he said his people had been shouting about climate change for years. He feels angry, but now more hopeful that action will finally be taken.
Another woman, dressed in a polar bear suit, was from southern France. Lea had wanted to go the march in Paris - but security concerns meant it was cancelled. She said life has to go on; you can't live in fear.