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 why do some people have a hard time believing scientists when they talk about climate change?

A sizeable chunk of that blame pie belongs to the fossil industry, which has deliberately manufactured this distrust of science so it can keep on selling its product (there’s more on this in chapter 3). But the sheer complexity of our changing climate also means it’s difficult to know where to begin if you have basic questions about the science. With this in mind, I’ve tried to explain the science behind three basic facts that come up in the climate conversation:

  • 97% of scientists support the theory of man-made global warming (‘the consensus’)
  • If we want our earth to stay liveable, we can’t emit more than 500 gigatons of CO2 into the atmosphere
    • The CO2 humans have released is causing our earth to warm
  • The maximum ‘safe’ amount of warming we can take is two degrees centigrade

The stories behind these numbers at times reveal the strength of their foundations (the scientific consensus is really quite sturdy indeed), 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 the world could agree on at the time).

The simple truth is that even if – when – we decide to trust climate scientists to give their opinion on climate science, and even when we make that all important Plan for renewable energy, there’s still a huge amount left to be done. We still have to decarbonise the cat.