We may have 10 times less carbon storage capacity than we thought

Storing carbon dioxide underground is seen as a way to mitigate climate change, but the world could run out of safe storage space within 200 years if we keep on burning fossil fuels

By Madeleine Cuff

3 September 2025

A geothermal power plant in Iceland where carbon dioxide has been injected underground for long-term storage

Sigrg/CarbFix

The world may run out of storage space for captured carbon dioxide within the next two centuries, according to new research that suggests the planet’s practical capacity for holding CO2 underground is far less than we thought.

Storing captured carbon dioxide in underground reservoirs has been touted by governments and industry as a way to reach net zero without eradicating fossil fuel use.

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The planet’s capacity for storing this CO2 was thought to be vast, with industry estimates putting global geological storage capacity at around 14,000 gigatonnes of CO2. “Until today, the storage capacity was, to all intents and purposes, considered limitless,” says Joeri Rogelj at Imperial College London, UK.

But together with colleagues, Rogelj has conducted further analysis of storage reserves and found the usable volume of storage space may be far smaller. The team analysed stable geological formations, excluding areas affected by risk factors such as proximity to large cities, environmentally sensitive landscapes or regions vulnerable to earthquakes. Once those risk factors are taken into account, they conclude that just 1460 gigatonnes of geological storage capacity is available globally.

“From a position where we have practically unlimited storage potential, now the CO2 storage potential that we can prudently rely on becomes a precious resource,” says Rogelj. “We have reduced the practical potential that we think one should assume for CO2 storage by a factor of 10.”