Overview

• The Nature paper led by IIASA estimates about 1,460 GtCO₂ of practical, low‑risk geological storage after excluding shallow or ultra‑deep sites, seismic zones, protected areas, and locations near populations.
• Even full use of that prudent capacity would at most reverse roughly 0.7°C of warming, and the authors warn stores could be effectively exhausted by around 2200 if used to offset ongoing fossil emissions.
• Current deployment is tiny compared with modeled needs, with about 49 million tonnes stored annually and 416 million tonnes planned versus roughly 8.7 GtCO₂ per year in some mid‑century scenarios.
• Experts differ on the estimate’s conservatism, with some saying careful pressure management could raise safe capacity and others arguing real‑world political and economic barriers could lower it further.
• The findings elevate prioritization for hard‑to‑decarbonize sectors and are spurring interest in mineralization pathways, including CarbFix’s EU‑permitted onshore basalt storage in Iceland and the PERBAS expedition now assessing offshore basalt potential off Norway.