Underground carbon storage has long been considered a potential solution to combat the effects of climate change by keeping greenhouse gases out of the atmosphere. However, a recent study published in the journal Nature has raised concerns about the feasibility and limitations of this technology.

The study, conducted by researchers from the U.K., Austria, and the U.S., examined a broader range of risk factors than previous assessments of carbon storage potential. Their findings indicate that only about 1,460 billion tonnes of carbon dioxide can be safely stored underground globally, far less than the current projections of around 12,000 billion tonnes. This means that utilizing all available safe storage areas would only reduce global warming by 0.7 degrees Celsius, significantly lower than previous estimates.

Matthew Gidden, the lead author of the study and an associate research professor at the University of Maryland, emphasized the importance of countries being transparent about their plans to use carbon storage to meet their climate goals, considering the limited capacity available.

While interest in carbon storage is increasing as a means to address emissions, challenges remain in demonstrating its efficacy at a large scale. Countries like Canada, the U.S., and Europe have invested heavily in carbon capture and storage projects, but the study suggests that the window of opportunity to implement these technologies effectively is closing rapidly.

Factors Affecting Carbon Storage

Gidden’s research team focused on various risk factors, such as proximity to urban areas, environmentally sensitive habitats, and seismic activity, in their assessment of carbon storage potential. They also set a depth limit of 2.5 kilometres for storage based on current technology capabilities and excluded certain emerging storage methods.

While some experts believe these limitations are justified, others argue that advancements in carbon storage technology may allow for greater depths and alternative storage approaches. For instance, projects exploring carbon storage in basalt rock beneath the ocean floor show promise in transforming CO2 into a solid form, potentially reducing the risk of leaks.

Despite the potential geological capacity for storage, the study underscores the need to demonstrate the practicality and effectiveness of carbon capture and storage on a larger scale to mitigate emissions effectively.

Challenges Ahead

One of the significant challenges highlighted by experts is the financial burden of scaling up carbon storage infrastructure quickly enough to address rising global temperatures. The study suggests that the costs associated with transporting carbon over long distances for storage could be considerable, leading to public opposition and competition for funding with other societal needs.

While the study raises concerns about the limits of carbon storage capacity, it also emphasizes the importance of proving the viability of this technology to offset emissions effectively. As the window for implementing carbon storage narrows, countries and industries must prioritize investments in research and development to demonstrate the feasibility of this critical climate solution.