One approach to mitigate anthropogenic climate change is carbon capture and storage (see the article by David Kramer, Physics Today, January 2020, page 44). The carbon dioxide from burning fossil fuels is either harvested from the air or gathered from the source. Among the suitably long-term reservoirs for the captured CO2 are geologic formations of porous rock. This two-dimensional top-down view of a recent large-scale 3D numerical simulation of an injection site shows CO2 flow structures. The flows formed cells of about 50 cm for a typical 50-m-deep underground reservoir with pore sizes of 50–400 μm. The red-to-yellow color gradient indicates the variation in CO2 concentration. Carbon dioxide exists as a supercritical fluid at the reservoir’s temperature and pressure. Driven by the density difference between CO2 and the liquid brine found in some permeable rocks, the solution exhibits what’s known as Rayleigh–Darcy convection.
Marco...
