Geoengineering is a proposed response to anthropogenic global warming (AGW). Conventionally it consists of two strands: Solar Radiation Management (SRM), which is fast-acting, incomplete but inexpensive, and Carbon Dioxide Removal (CDR), which is slower acting, more expensive, and comprehensive. Pairing SRM and CDR offers a contractually complete solution for future emissions if effectively-scaled and coordinated. SRM offsets warming, while CDR takes effect. We suggest coordination using a blockchain, i.e. smart contracts and a distributed ledger. Specifically, we integrate CDR futures with time and volume-matched SRM orders, to address emissions contractually before release. This provides an economically and environmentally proportionate solution to CO2 emissions at the wellhead, with robust contractual transparency, and minimal overhead cost. Our proposal offers a 'polluter pays' implementation of Long & Shepherds SRM 'bridge' concept. This 'polluter geoengineers' approach mandates and verifies emissionslinked payments with minimal friction, delay, or cost. Finally, we compare alternative market designs against this proposal, finding that this proposal offers several advantages. We conclude that blockchain implementation of the 'polluter geoengineers' approach is attractive and feasible for larger wellhead contracts. We also identify a handful of advantages and disadvantages that merit further study.