There’s a lot of unspoken trust in our lives. We trust that the engineers who made our microwave didn’t make it blow up if we accidentally hit the nine button; we trust that the wing of our airplane is precisely the right shape to get us back on the ground. Science is a fundamental part of our lives; so, when scientists talk about climate change, why do some people have a hard time believing them?

A sizeable chunk of that blame pie belongs to the fossil industry, which has deliberately manufactured a distrust of science so it can keep on selling its product (there’s more on this in chapter 3). But it’s also due to the sheer complexity of the issue; if I want to look up how airplanes work, I can find relatively simple diagrams of air flow over wings, or shiny cutaway drawings of an engine. But if you’re curious why we can’t emit more than 500 gigatons of CO2 if we want our earth to stay liveable, or how we know that 97% of scientists support the theory of man-made global warming (‘the consensus’), you’ll have to dig into some pretty dry texts.

These numbers, and others that are routinely used to justify why we should be changing the way we live, are not without their controversy. The 97% figure in particular is routinely attacked by deniers, and it’s a good tactic – after all, if the scientists who study climate disagree on the problem, how are the rest of us supposed to figure out the truth?

The stories behind these numbers at times reveal the strength of their foundations (the consensus among scientists is about the same as for evolution), while others show how arbitrary decisions must be made to get governments on board (keeping warming below 2C is not a particularly safe target, but it was the only number we could agree on at the time).