
Image caption
Deep ocean temperatures were generally high throughout the Paleocene and Eocene, with a particularly warm spike at the boundary between the two geological epochs around 56 million years ago. Temperatures in the distant past are inferred from proxies (oxygen isotope ratios from fossil foraminifera). "Q" stands of Quaternary. Graph by Hunter Allen and Michon Scott, using data from the NOAA National Climatic Data Center, courtesy of Carrie Morrill.