Geological Carbon Storage Is a Scarce, Finite Resource – New IIASA-Led Study Warns

(Bioenergy International) A new IIASA-led study has for the first time mapped safe areas that can practically be used for underground carbon dioxide storage, and estimates that using them all would reduce warming by only 0.7°C. The result is almost ten times lower than previous estimates of around 6°C, which considered the total global potential for geological storage, including in risky zones, where storing carbon could trigger earthquakes and contaminate drinking water supplies.

Carbon dioxide (CO2) storage is widely seen as essential for achieving climate goals, whether by capturing emissions from manufacturing and power plants or removing CO2 from the atmosphere.

Storing carbon deep underground has been presented as an almost limitless solution to the climate crisis.

Carbon storage reality is far more limited

However, a study, presented in a paper entitled “A prudent planetary limit for geologic carbon storage” and published in the scientific journal Nature, shows geological carbon dioxide (CO2) storage is a scarce, finite resource and warns countries must use it in a highly targeted way.

Led by researchers at the International Institute of Applied Systems Analysis (IIASA) in collaboration with an international team of colleagues, the study shows that the reality is far more limited than previously thought.

The team has estimated a “prudent global limit” of around 1,460 billion tonnes of CO2 that can be safely stored in geologic formations – an amount almost ten times smaller than estimates proposed by industry, as risks to people and the environment have not been considered.

According to lead author Dr Matthew Gidden, a senior researcher in the IIASA Energy, Climate, and Environment Program and at the Center for Global Sustainability at the University of Maryland, USA, the study’s findings highlight the need for caution.

The team assessed their suitability for carbon storage by considering risks such as CO2 leaking back into the atmosphere, the possibility of triggering earthquakes during the storage process, contamination of groundwater supplies, and proximity to population centers or protected areas.

Sites that were too close to the surface to store carbon reliably, too far underground, or at ocean depths that make storage too expensive and risky were also ruled out.

When these factors are taken into account, the global storage capacity shrinks dramatically from industry estimates of around 14,000 gigatonnes.

They also caution that removing carbon may not reduce warming in the same way that emitting it causes warming, and that the climate system might not return to its earlier state even if global temperatures are brought back down.

Fossil fuel-producing countries such as the United States, Russia, China, Brazil, and Australia have the most potential safe storage, as disused mines are the most efficient type of geological storage.

The countries with the lowest risks include Saudi Arabia, the Democratic Republic of the Congo, and Kazakhstan, while countries that see large decreases in potential storage space due to high risks include India, Norway, Canada, and countries in the European Union (EU).

About 70 percent of all storage is onshore, with the remaining 30 percent at offshore sites.

Issues of fairness and responsibility

Call for international cooperation and planning

The platform provides country-level visualizations of safe, practical carbon storage potential, helping users understand the tradeoffs and risks involved in different regions.