If we could do it once, we can do it again, whether it’s climate change, biodiversity loss, or the plastic in our oceans. We once had a hole in the sky — now we have a blueprint for how to mend the planet. And that, in anyone’s book, is a good news story

Our recovering ozone shield could yet be wiped out by unmitigated global warming unless radical action is taken to cut emissions, writes John Gibbons