@jeremycherfas Thanks for this link, Jeremy. It is the most usefully informative thing I've ever seen on climate change. It is like things that were written during the dawn of the Internet, not like what is seen more commonly these days.
@Ron Yup. Peter had some very sensible things to say. I do think this time XR went pointlessly too far. I've thought of far more imaginative ways to use the Cambridge college lawns to make the same kind of point.