When I first started studying climate change back in the 1980s, I was struck by how difficult it was be for people to understand this issue.

Every country now has its own domestic political debate about how to respond to climate change. This is where the action is.

Apocalypses don't happen very often. They tend to be separated by tens or even hundreds of millions of years.

If you look at the works psychologists have done about individual reports of wellbeing, what happens is that if you're poor, you are not happy. But once you achieve a certain level of material satisfaction then income has very little correlation with people's reported states of happiness, things like climate matter more, things like the culture of the country in which you're raised matter more and so the things really, let's face it, like individual temperament matter more than these things.

The idea that we would raise billions of sentient animals, treat them horribly, pollute our waterways with their waste, compromise the effectiveness of our antibiotics so that they grow faster, and then slaughter them with little regard to their suffering so that we can feed off their corpses, will seem to most people unthinkably cruel and barbarous - sort of in the way that we think of medieval punishments, or Europeans today think of the death penalty.

Attitudes are changing very quickly.

Our traditional systems of decision-making are just not up to preventing changes in fundamental earth systems that are driven by a constant barrage of individually negligible emissions of an invisible, odorless gas, by billions of people all over the world.