Exclusive: In Under the Surface, a special Guardian film, the award-winning writer and environmental campaigner Naomi Klein travels to the Great Barrier Reef with her son, Toma, to see the impact of coral bleaching caused by climate change. In a personal but also universal story, Klein tells how she wants him to bear witness. ‘Just in case, amid the coral that is still alive, he can find something beautiful to connect with, something he can carry with him as he navigates life on a warmer, harsher planet than the one I grew up on. Because climate change is already here – and kids are on the frontlines’

Extra footage supplied by David Hannan

• Naomi Klein: Climate change is intergenerational theft. That’s why my son is part of this story

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• Great Barrier Reef: a catastrophe laid bare

