I have lost count of the times I have spoken to public audiences about “ecological conversion” since the promulgation of Pope Francis’ encyclical letter on the environment, Laudato si’. My focus is always on the urgency of personal ecological conversion: that, in Francis’ words, we should “never think the little things don’t matter”.

In the face of a multifactorial global catastrophe, this stress on individual agency is important; otherwise, despondency and hopelessness set in. But staring out of the train window at the Northumbrian coast on a rainy autumn afternoon recently, as I travelled up to Edinburgh to speak on Laudato si’ once more, I realised glumly that the time had come to change the message. In the week in September that had seen the largest climate strikes and protests in history, 15 months before the end of 2020, when carbon emissions must start to flatten out if the rise in global temperatures is to be below 1.5C, it dawned on me that allowing the conversation to stay at the level of merely personal changes of habit and lifestyle is now irresponsible.