CNN’s seven-hour climate town hall with the Democratic presidential candidates was the ratings bomb you expected, and no wonder since there was little debate. If it was unwatchable, though, it wasn’t unwatchable enough for some. The Columbia Journalism Review’s “public editor for CNN,” Emily Tamkin, beforehand insisted that moderators should proceed “on the assumption that the climate is in crisis,” and limit themselves to calling for action and faulting inaction.

In other words, make it an exercise in liturgy, not inquiry, as well as a repetition of the most failed experiment in history: trying to bully viewers into accepting predictions of a pending climate disaster.

All this comes as the sixth “assessment report” of the Intergovernmental Panel on Climate Change, still two years off, is likely to offer nothing new on the vexed, contentious 40-year-old stalemate over how much warming actually can be expected from a given amount of CO2.

It comes just days after the shocking suicide of Harvard climate economist Martin Weitzman, rightly praised in obituaries for an insight lacking in the CNN town hall: A climate disaster is far from guaranteed. It’s the low but not insignificant chance of a “fat tail” worst-case disaster that we should worry about. (Mr. Weitzman put the odds at 3% to 10%.)

It comes as Weitzman’s student, collaborator and co-author, Gernot Wagner, tellingly has focused his own attention lately on geoengineering rather than the seemingly lost cause of carbon reduction.