By the Deep Sky Subsurface Team

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A recent study published in Nature claims underground carbon storage is far less plentiful than original estimates. That conclusion misreads the science and the opportunity, putting our global climate change mitigation efforts at risk.

Planetary storage space isn’t too small. Rather, it’s finite, valuable and complicated. One should think of it like high grade infrastructure, more like oil reserves or freshwater than something limitless. That doesn’t make it trivial, but rather, it reinforces its role as critical infrastructure.

The study’s restrictions on where and how we store CO₂ are far more conservative than engineering reality. There’s no technical reason we can’t inject CO₂ under cities or protected areas. Oklahoma City, for example, has produced oil from reservoirs beneath urban neighborhoods since the 1930s. Alberta is already storing CO₂ in deep formations, and oil and gas routinely operate at deeper than seven kilometers. Depth and proximity shouldn’t be considered barriers. Instead, we should view them as engineering challenges that we know how to solve.

In the US, the Department of Energy’s Carbon Storage Atlas V estimates saline formations alone can store 2,100 to 20,000 billion metric tons of CO₂. That’s before counting depleted reservoirs or emerging methods like mineralization. Canada alone offers nearly 400 gigatonnes (Gt) of prospective onshore sedimentary storage, located mostly in Saskatchewan, Alberta, and Manitoba, according to Clean Prosperity. Globally, the capacity is even greater, especially when mineralization is considered. A study published in ScienceDirect estimates that globally, there are between 8,000 and 55,000 gigatonnes (Gt) of practically accessible geologic storage capacity for carbon dioxide.

When discussing carbon storage, it’s critical to also include mineralization, which is a game-changing storage mechanism. The amount of CO₂ that can be stored using mineralization scales with the amount of available magnesium + iron + calcium in the crust, not pore space. That’s an enormous amount, far more than enough to dispose of all the CO₂ that humans have ever emitted. The technology to access and permanently capture CO₂ through mineralization exists today and the process has already been demonstrated with world class projects like Carbfix in Iceland.  Storage is hardly a mystery, as the report suggests.

Unfortunately, the study inaccurately represents the vast storage opportunity. Even with its overly restrictive parameters, trimming global warming by 0.7°C is the equivalent of 40 years’ worth of emissions. A 40-year cleanup certainly sounds impactful to us. Despite research indicating that we can actually store 10 times that amount, should it be a reason not to do it? The study seems to indicate so.

Overall, the study falls victim to subjectivity. For instance, its own sensitivity analysis shows that by slightly reducing buffer zones around cities and adjusting depth limits, storage estimates nearly double.

The real bottlenecks aren’t rocks; they’re permitting timelines, pipeline build-out, and community trust. When we invest in infrastructure and engagement, storage works. Projects like Quest and Sleipner prove it.

However, there’s one argument in the paper that Deep Sky does agree with: CO₂ storage alone is not enough to solve all of climate change. Widespread emissions reductions and nature-based solutions such as reforestation and restoration of coastal and marine ecosystems are critical pathways to hit net-zero. It shouldn’t be considered an either/or, but rather an “all hands on deck” approach.

So, based on available research, instead of 1,460 Gt of CO₂ storage as the prudent level of storage capacity, Deep Sky – and much of the carbon removal scientific community – estimates that the global storage capacity is at least 20x that amount, and significantly higher when we add in depleted oil and gas reservoirs or mineralization.

Let’s focus on solutions rather than challenges, and get back to work.

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