Carbon Dioxide (CO2), a greenhouse gas, is intricately linked to global warming. The largest store of CO2 is the world’s oceans. How the oceans sequester or release CO2 to or from the atmosphere is important to understand as mankind alters Earth’s climate with the burning of fossil fuels. A new report from researchers at the University of California, Davis offers clues on how that mechanism works by analyzing the shells of plankton fossils.