It's 1982, and I’m ten years old. A geography lesson in my final year of primary school. We’ve just found out how old the earth is, and we’re compressing those four and a half billion years of planetary history into a single day. A giant timeline stretches round all four walls of the classroom, with a metre for each hour of the twenty-four hours of that day. We draw Earth's history onto the timeline, starting with the planet forming, at midnight. Until three in the morning, or just over a billion years in real time, meteors bombard Earth. At four am, life begins, but we have to wait another fourteen hours – until six in the evening – for sexual reproduction.

Things speed up after that. The last metre or two of the timeline is crammed with excitement. By ten o’clock at night, the vast swamps that will become our reserves of oil, coal and gas are laid down. Dinosaurs appear at eleven o’clock. Then, just under a minute and a half before midnight, the first humans appear, though not yet our own species, Homo sapiens. All of our history as a species – cave dwellers, the Romans, the Industrial Revolution, and of course our own lives – is crammed into the final few seconds before midnight.

It is a dizzying realization for a ten-year-old. I wonder what the earth looked like for all those years, before it was shaped by plant and animal life. Those dinosaurs are suddenly near relatives. My life, my species even, seems an insignificant speck upon a vast, old planet.

I remember this lesson many years later, when I start thinking about climate change. Because it's really only in the last twelve thousand years or so, a fraction of a second on that timeline, that civilization as we know it emerged. The development of agriculture allowed people to group together in villages, towns and cities, leading to larger, more complex societies, forerunners to our own interconnected world.