Increased atmospheric carbon dioxide is bad for the planet and for human health, leading scientists and engineers alike to search for ways to capture this pollutant in a process known as carbon sequestration.
But new research has shown that putting C02 from cars and coal use out of sight might not really solve the problem.
According to Stanford geophysicist Mark Zoback, storing carbon dioxide underground could trigger small earthquakes that might breach the storage system, allowing the gas back into the atmosphere (Stanford).
Carbon sequestration is the placement of CO2 into a repository in such a way that it will remain permanently sequestered. Efforts are focused on two categories of repositories: geologic formations and terrestrial ecosystems (NETL).
Even though the saline aquifers that make the best storage areas for carbon emissions are deep within the earth, they are made of dense, well-cemented sedimentary rock, with low permeability. This means that filling them with large amounts of pressure may trigger earthquake activity.
“It is not the shaking an earthquake causes at the surface that creates the hazard in this instance, it is what it does at depth,” Zoback told Stanford Univeristy News. “It may not take a very big earthquake to damage the seal of an underground reservoir that has been pumped full of carbon dioxide.”
Although it’s unlikely the earthquakes would be big enough to be a safety concern, allowing the carbon to seep back into the atmosphere would render the very costly and complex process of sequestration futile.
Stanford University News reports that “there are two sequestration projects already under way, in Norway and Algeria, and so far they appear to be working as planned. But Zoback said 3,400 such projects would be needed worldwide by midcentury to deal with the volume of carbon dioxide that we will be generating.”
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