As each one of your incandescent light bulbs burns out, you change it to a compact fluorescent. You’ve promised yourself that you’ll never again buy water in a plastic bottle, and you dutifully refill your aluminum canteen from the tap. When you travel, you always buy carbon offsets. On a personal level, you feel you’ve taken every small step that you can to help stop global warming.
Then a plain, everyday rock–yes, just a rock—upstages you.
Peridotite is the most common rock found in the Earth’s mantle, the layer just below the crust. Every continent, except perhaps Antarctica, contains substantial amounts of it. And in some places on our planet, such as in the nation of Oman, it lies right on the surface. What makes peridotite so special is that it could “cure” global warming.
Sucking Up CO2
During fieldwork in Oman’s desert, two scientists from Columbia University’s Lamont-Doherty Earth Observatory in New York (geologist Professor Peter Kelemen and geochemist Dr. Juerg Matter) found that exposed peridotite reacts with the global-warming carbon dioxide in the air, absorbing up to 100,000 tons of the greenhouse gas each year and transforming it into a solid mineral (such as limestone or marble). They estimate that the exposed peridotite in Oman alone could “sequester” four billion tons of atmospheric carbon dioxide a year, or one-seventh of the 30 billion tons the world emits annually.
Furthermore, Kelemen and Matter say that simple and relatively inexpensive drilling into the peridotite deposits and then injecting them with heated water enriched with pressurized CO2 captured from power plants could speed up the process of locking the carbon dioxide in the rocks by 100,000 times or more.
Once set in motion, the carbon-capturing process would start building upon itself. The reaction would naturally generate heat, in turn that heat would hasten the reaction, fracturing large volumes of rock. The newly fractured rocks would then be exposed to reactions with still more CO2-rich solution. Since the farther down you drill, the higher the temperature gets, heat generated by the Earth itself also would help. Kelemen and Matter propose that such a chain of events would need little energy input to sustain itself after it was first jump-started.
But Are We the Ones Being Sucked In?
A recent U. S. Geological Survey study reported that our country’s East and West Coasts contain enough peridotite-like rock to soak up more than 500 years’ worth of future U.S. carbon emissions. And Dr. Matter has been working on a separate project in Iceland involving volcanic basalt. He thinks that rock also shows promise for sponging up CO2 in the atmosphere.
Could rocks such as peridotite and basalt, after all, be the magic “cure” to the global warming crisis that we’ve been looking for? And if the solution lies in something as simple as rocks—and our past sins and trespasses on the environment can be quickly reversed—will we naturally slide back into our old, comfortable global-warming habits, such as gas-guzzling cars and deforestation? Or should we keep trying to live lightly as players within the planet’s carbon cycle, from one burned-out light bulb to the next?
Depending on just ONE THING to fix the problem of rapid climate change and take care of everything for us could wind up being a big mistake. As every traveler knows, a journey to anywhere is made up of several small steps.
Here’s to finding your true places and natural habitats,