One afternoon in April 2020, I took an old bamboo rod out of my shed and cut it to a length of 115cm. Stood on the ground, it came about halfway up my chest. I laid it on a scrubby patch of our garden on the island of Aegina, in Greece: one end next to a tough-looking dandelion, the other pointed northwards. Then I dug up the dandelion with a trowel and replanted it at the other end of the stick. A small step for humans, but quite the leap for the dandelion.
This 115cm corresponds to a particular measurement. It is the present average velocity of climate change — how fast the effects of global heating are moving across the surface of the planet — and thus represents the speed we need to move in order for the conditions around us to stay the same. It also implies a direction: the bubble habitats where different forms of life can survive and thrive are moving uphill, and towards the poles.
Local differences in velocity are determined by the shape of the land and of the Earth itself: climate change moves fastest in flooded grasslands, mangrove swamps and deserts; and is slower in mountain uplands and boreal forests. The impact is uneven too: if you live in a desert, you might have a lot of room to move, and a long way to go before you run into obstacles. If you’re already halfway up a mountain, you might soon have nowhere to go.