Cenozoic CO2 from marine proxies

Atmospheric CO2 has been reconstructed over the last 66 million years from two marine proxies: the boron isotope composition of foraminifera and the carbon isotope composition of alkenones. Data have been compiled from the literature and CO2 estimates have been updated in a consistent framework following the latest approaches. Separate spreadsheets containing CO2 estimates from each proxy are provided, as well as a summary spreadsheet containing data from both proxies.