Afforesting arid land with renewable electricity and desalination to mitigate climate change

Afforestation is one of the most practised carbon dioxide removal methods but is constrained by the availability of suitable land and sufficient water resources. In this research, existing concepts of low-cost renewable electricity (RE) and seawater desalination are built upon to identify the global CO₂ sequestration potential if RE-powered desalination plants were used to irrigate forests on arid land over the period 2030–2100. Results indicate a cumulative CO₂ sequestration potential of 730 GtCO₂ during the period. Global average cost is estimated to be €457 per tCO₂ in 2030 but decrease to €100 per tCO₂ by 2100, driven by the decreasing cost of RE and increasing CO₂ sequestration rates of the forests. Regions closer to the coast with abundant solar resources and cooler climate experience the least costs, with costs as low as €50 per tCO₂ by 2070. The results suggest a key role for afforestation projects irrigated with RE-based desalination within the climate change mitigation portfolio, which is currently based on bioenergy carbon capture and storage, and direct air carbon capture and storage plants.

Upeksha Caldera, Christian Breyer