Remains of Land Plants (IMAGE) Geological Society of America Caption The remains of land plants can be used to calculate the amount of CO2 in Earth's atmosphere. Credit Photo credit: A. Hope Jahren. Usage Restrictions Photo credit: A. Hope Jahren. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.