Climate change is a big problem—literally Earth-sized—and its cause is thought to be humans and our highly industrialized societies. To stave off the coming massive climate shift, scientists are developing many technologies, each with the promise to help reduce humanity’s environmental impact. These technologies include cleaner energies, improved industrial practices, and carbon sequestration strategies, among others. The least famous of these, carbon sequestration, is a method of removing carbon from circulation, and may provide a way to store massive amounts of carbon in the crust of the earth.
Carbon sequestration works by manipulating carbon’s natural flow through the environment. Carbon naturally cycles through organisms, the ocean, earth’s crust, and the atmosphere as a result of natural processes. Researchers studying carbon sequestration propose to artificially tilt the balance of carbon toward the Earth’s crust. This would lead to an accumulation of carbon in rocks- crucially, diverted from the atmosphere where it causes so many problems. So far, efforts at carbon sequestration have seen little success, generally due to expense and safety concerns. But, as a recently completed study in Iceland shows, successful carbon sequestration may be a matter of finding the right rocks.
The study, led by Jureg Matter of The University of Southampton, used carbon dioxide captured from a geothermal power plant outside of Reykjavik, Iceland. The carbon dioxide was mixed with water and injected into a well at a depth of just over a quarter of a mile beneath the surface, just slightly deeper than the Eiffel tower is tall. In this particular section of Earth’s crust, the rocks at this depth are of a type called basalt, and the researchers think this common rock may have a big impact on carbon sequestration.
Basalt is the rock that forms from cooled, hardened lava. The researchers point out that the special properties of basalt may make it unusually reactive with carbon dioxide. Compared to other types of rocks that comprise earth’s crust, basalt is relatively rich in iron, calcium and magnesium. Basalt also dissolves quickly (as rocks go, at least), which releases the aforementioned ions into the well water, in turn allowing them to react with dissolved carbon dioxide.
The resulting chemical reaction is either very slow or very fast, depending on your frame of reference. Over the course of the study’s two years, 98% of the injected carbon dioxide turned into rock through a process called mineralization. From the point of view of a laboratory researcher, this reaction is beyond painfully slow. From a geological standpoint, however, this reaction moved along like Usain Bolt.
Overall, the mineralization process proved much faster than the researchers predicted, which marks carbon sequestration as promising technology requiring further study. This technology, however, is not the only answer to climate change. Though this most recent iteration of carbon sequestration could lead to sweeping improvements in the technology as a whole, capturing carbon remains expensive and unlikely to see widespread adoption. That said, smart deployment of this technology could boost its usefulness. It is potentially a good fit for areas like Iceland, where geothermal energy is plentiful and basalt rock layers are common. Carbon sequestration may yet have a place in the patchwork of energy solutions for climate change, where each solution efficiently utilizes its surroundings to create cleaner energy for all.
The Inner Life of Life 