Soil is classified by the U.S. Geological Survey as «the most stable long - term surface reservoir for carbon.» (scientificamerican.com)
Indeed, uptake of CO2 by surface reservoirs has at least kept pace with the rapid growth of emissions [187]. (journals.plos.org)
Rising plumes of relatively warm, but still solid, ice may produce pockets of liquid water tantalizingly close to the satellite's surface, but new research suggests that any such surface reservoirs won't stick around for long, geologically speaking. (sciencemag.org)