Neil Gaiman spoke at COP26:

We need to reach people’s hearts, not just their minds. Reach the part of their hearts that believes it’s good to plant trees for our grandchildren to sit beneath. Reach hearts to make people want to change, and to react to people and organisations despoiling the planet and the climate in the same way you would react to someone trying to burn down your house, while you are living in it.

So that 200,000 years from now, children can leave handprints in clay, to show us that they were here, and because making handprints and footprints is fun.