Seismic sites: The dots on this map represent seismicity activity during March 2011, according to the United States Geological Survey. Red dots stand for seismicity induced by the creation of water reservoirs.
The authors of a paper published today in the Proceedings of the National Academy of Sciences say that large-scale carbon capture and storage (CCS) is unlikely to work because it would trigger earthquakes that could free the trapped greenhouse gas from the ground.
The paper is a blow to hopes that sequestration could become a big part of future climate strategy. The lead author of the paper is Stanford researcher Mark Zoback, a well-respected expert on the seismic risks of oil and gas production. Steven Gorelick, a Stanford hydrologist, is coauthor with Zoback.
Only last week, the International Energy Agency said that CCS will need to contribute over a fifth of the emissions reductions needed by 2050 to ensure an 80 percent chance of limiting the long-term average global temperature increase to 2 °C.
The oil and gas industry already uses techniques that are similar to CCS during resource extraction and wastewater disposal, and these processes are known to induce small earthquakes. Wastewater injection has been blamed for recent earthquakes in Arkansas, in Ohio, and near the border of Colorado and New Mexico.
Zoback says the risks associated with such quakes can be managed through careful site selection, but large-scale CCS could be more problematic. “You have to be far more restrictive” when choosing a carbon dioxide repository, he explains, since the task is to “keep a buoyant fluid in place for hundreds to thousands of years.”
The paper comes just a few days after a report on the earthquake risks posed by various energy technologies, including oil and gas extraction, wastewater disposal, geothermal power, and CCS, was published by the National Research Council. That report said that “CCS may have the potential for significant seismic risk” and added that “insufficient information exists to understand this potential.”
Zoback and Gorelick’s paper notes that if CCS is to significantly affect atmospheric greenhouse-gas accumulation, it must be able to contain about 3.5 billion tons of carbon dioxide per year worldwide—an amount similar in volume to the nearly 30 billion barrels of oil the world produces annually.