Atmospheric CO2 concentration is expected to increase by 50% near the middle of this century. Indications are strong that rising CO2 effects higher soil organic carbon content in some cases. Glomalin, which accounts for 1/3 of soil carbon, is of particular interest because of its important role in binding soil aggregates and increasing nitrogen use efficiency. The Center for the Study of Carbon Dioxide and Global Change has updated their excellent summary about the CO2 - glomalin relationship. There is a great reference list to dive into.
Image source: USDA-ARS: Glomalin: A Manageable Soil Glue (pdf brochure)