evidence: His 2019 manifesto, Common Sense for the 21st Century(9), was written in his own name but widely hailed as representing the views of Extinction Rebellion and heavily promoted by the organisation’s London HQ. Referencing his claim to ‘one recent scientific opinion’, he warns of 6 to 7 billion people dead as a result of climate change ‘within the next generation or two’. The paper cited as his authority in the footnotes makes no such claim(10). It is purely Hallam’s extrapolation of a 5°C world, given what Common Sense calls ‘the central role of methane in a climate emergency . . . with the system spiralling out of our control and the likelihood of global collapse within a decade or two’. He reiterated the mass dieback claim in a BBC News interview feature, trenchantly insisting: ‘I am talking about the slaughter, death and starvation of 6 billion people this century – that’s what the science predicts.’(11) Climate Feedback, a website more used to taking on deniers than alarmists, invited an expert panel to give their opinions on this prediction. The responses ranged from ‘an illustration of a worst-case scenario’ to ‘wild speculation’. Ken Caldeira, senior scientist at the Carnegie Institution, put it bluntly: ‘I know of no climate model simulation or analysis in the quality peer-reviewed literature that provides any indication’ that there is a substantial probability, above zero, of 6 billion deaths this century.(12)