Paleoclimatologists tell a very long history when it comes to explaining the significance of anthropogenic global warming. How far the arc of the geological history explaining Anthropocene warming projects into the future may be quickly seen from the very subtitle of David Archer's The Long Thaw: How Humans are Changing the Next 100,000 Years of Earth's Climate. Human-induced climate change gives rise to large and diverse issues of justice: justice between generations, between small island-nations and the polluting countries, between developed, industrialised nations and the newly industrialising ones, and so on. The scientific problem of climate change emerges from what may be called 'comparative planetary studies' and entails a degree of interplanetary research and thinking. Population is also a problem because both the total size and distribution of humanity matter in how the climate crisis unfolds, particularly with regards to species extinction.