The idea behind the Icelandic company Carbfix is simple: pack water full of carbon dioxide (literally carbonate it, like a SodaStream) and inject it deep underground into Iceland’s porous basaltic rock. Minerals in the rock dissolve in the water, where they react with the CO2 to become calcium carbonates. The carbon effectively becomes rock, which it will remain, for all intents and purposes, permanently. Or at least thousands and thousands of years. It is as long-term as carbon sequestration gets.The idea dates back to 2006, but pilot injections didn’t begin until 2013 and it wasn’t until 2016 that a study published in Science confirmed that 95 percent of the CO2 in the water was mineralizing within two years — far faster than most had assumed possible. Since it started, Carbfix has sequestered almost 100,000 metric tons of CO2 at its original site, but that is just a drop in the bucket compared to what it believes is possible. It has plans to make Iceland a major international carbon-burial hub and to replicate its technology in other geographies, maybe even in the shallow ocean. When I visited the Carbfix operation in October and saw it in action, I was extremely intrigued and had a million more questions, so last week I got in touch with Ólafur Teitur Guðnason, Carbfix’s head of communications, to talk about where the company gets the CO2 it buries, where it plans to get it in the future, whether burial can work in other kinds of rocks and geographies, and exactly how much carbon Iceland can store. Get full access to Volts at www.volts.wtf/subscribe