Coupling of CO 2 and Ice Sheet Stability Over Major Climate Transitions of the Last 20 Million Years

• DOI: 10.1126/science.1178296
• Publication Date: 2009-10-09T02:08:01Z
• Authors: Aradhna K. Tripati; Christopher D. Ro...; Robert A. Eagle
• Keywords: 550; 13. Climate action; 15. Life on land; 01 natural sciences; 0105 earth and related environmental sciences

CO 2 and Miocene Climate Change

Atmospheric carbon dioxide is a powerful greenhouse gas believed to be one of the most important determinants of climate. Ice cores provide a detailed and direct record of CO 2 concentrations over the past 800,000 years, but not earlier.

Tripati et al.

(p. 1394 , published online 8 October) report B/Ca measurements of planktonic foraminifera, from which they can infer atmospheric CO 2 concentrations, for the past 20 million years. The concentration of atmospheric CO 2 was similar to preindustrial values for the past 10 millions years, but between 15 and 20 million years ago, during the warm lower Miocene epoch, CO 2 was more abundant, and major climate transitions toward cooler conditions occurred when CO 2 decreased substantially.