We have reached a stage of global warming at which every decision is critical: we don’t know when our last chance will have been. So when, for example, we base the vast part of our climate policy on offset markets and carbon taxes, as we are doing, and proceed to calculate the social cost of carbon to determine an ‘optimal’ carbon tax that ‘efficiently’ manages the ‘trade-offs’ between the costs and benefits of emitting GHGs, we are doing something much more dangerous than is usually acknowledged. A precise calculation of the ‘optimal’ carbon tax is nothing more than a claim that the best way forward is to perch the gargantuan machine of contemporary capitalism as close as possible to the precipice without tipping us all over the edge. That is neither efficient nor optimal. It is a myopic and recklessly arrogant approach to the unknown fate of life on earth.

What we need is a much more honest assessment of what we do not or cannot know, which is, among other important things, where the edge is. We might, in fact, be past it already, treading thin air like Wile E. Coyote before the fall. Today’s politicians don’t like uncertainty: it introduces doubt. Yet we are in desperate need of a politics that looks catastrophic uncertainty square in the face. That would mean taking much bigger and more transformative steps: all but eliminating fossil fuels, for a start, and prioritising democratic institutions over markets. The burden of this effort must fall almost entirely on the richest people and richest parts of the world, because it is they who continue to gamble with everyone else’s fate.