Earth’s CO2 Geological Storage Could Max Out By 2200

A study published in Nature and led by scientists at the International Institute for Applied Systems Analysis announces that Earth’s low-risk geological CO₂ storage capacity is much smaller than previously estimated and could be exhausted as early as 2200.

• Main finding and key figures: The study estimates a practical low-risk storage capacity of 1,460 GtCO₂ (down from a physical reserve of 11,800 GtCO₂ and previous literature estimates of 10,000–40,000 GtCO₂). It states that using the 1,460 GtCO₂ solely for atmospheric removal would reverse global warming by only 0.7 °C. The paper warns that stored CO₂ escaping to the surface could form carbonic acid in groundwater, potentially dissolving metal-containing minerals and releasing toxic metals.
• Background, current capacity and required scale-up: The article notes current carbon capture and storage (CCS) technologies remove 49 million tonnes CO₂ per year, with 416 million tonnes per year planned, while meeting the Paris goal would require 8.7 GtCO₂ per year by mid-century (a 175-fold increase over three decades). Co-author Joeri Rogelj (Imperial College London) is quoted on the insufficiency of geological storage to return warming to 2 °C.