Earth’s carbon-climate feedbacks varied in past warming episodes

Records from drill holes in the eastern equatorial Pacific indicate that Earth’s orbital eccentricity played an important role in controlling climate as the planet warmed.

Embedded within the Earth’s long-term cooling trend over the past 65 million years are several climate spikes—swift transitions to “hothouse” conditions—that had profound consequences for life. These spikes could serve as analogues for the future of our warming planet.

The cause of these spikes may in part be due to changes in the atmospheric concentration of carbon dioxide, an important greenhouse gas. But the complex feedbacks between the Earth’s climate and the carbon cycle have been hotly debated, and there is little scientific consensus on this issue. Read more.