Merged Ice-Core Record Graphic | Scripps CO2 Program

Merged Ice-Core Record


Merged ice-core record of the time trend of the concentration of CO2, in ppm, in air extracted from an Antarctic ice core combined with the trend based on direct atmospheric measurements.

Open Black Circles: Antarctic ice core record from Law Dome before 1958 (Macfarling Meure, C. et al., 2006: Law Dome CO2, CH4 and N2O ice core records extended to 2000 years BP. Geophysical Research Letters, 33.) Ice core data are rejected after 1958 which overlap direct measurements.

Closed Black Circles: Seasonally detrended arithmetic average of air measurements from Mauna Loa and the South Pole from the Scripps CO2 program after and including 1958.

Black Curve: Spline function to the direct data and the ice core data using a spline with a stiffness of 0.6.

Data sharing policy

The data and graphics on this website are made freely available, with the understanding that appropriate credit will be given. For applications supporting peer-reviewed scientific publications, coauthorship may sometimes be appropriate. An example would be if an important result or conclusion depends on this product, such as the first account of a previously unreported phenomenon. Ethical usage requires disclosing intentions at early stages of the work in order to avoid duplicating ongoing studies at Scripps. For applications where coauthorship is not needed, which includes all applications outside of the peer-reviewed scientific literature, it is sufficient to acknowledge the Scripps CO2 program as the source. Please direct queries to Ralph Keeling (