Industrial civilisation is close to breaching a seventh planetary boundary, and may already have crossed it, according to scientists who have compiled the latest report on the state of the world’s life-support systems. They say ocean acidification is close to critical threshold, posing a threat to marine ecosystems and global liveability. Ian Sample speaks to Prof Helen Findlay, a biological oceanographer at the Plymouth Marine Laboratory, to find out why the oceans have reached this state, and whether there is anything we can do to reverse the damage.. Help support our independent journalism at theguardian.com/sciencepod