Role of Seasonality in the Evolution of Climate During the Last 100 Million Years

• Published in: Science
• Main Authors: Crowley, Thomas J., Short, David A., Mengel, John G., North, Gerald R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 1986
• Subjects: Greenland; Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1126/science.231.4738.579; https://www.science.org/doi/pdf/10.1126/science.231.4738.579

A simple climate model has been used to calculate the effect of past changes in the land-sea distribution on the seasonal cycle of temperatures during the last 100 million years. Modeled summer temperatures decreased over Greenland by more than 10°C and over Antarctica by 5° to 8°C. For the last 80 million years, this thermal response is comparable in magnitude to estimated atmospheric carbon dioxide effects. Analysis of paleontological data provides some support for the proposed hypothesis that large changes due to seasonality may have sometimes resulted in an ice-free state due to high summer temperatures rather than year-round warmth. Such "cool" non-glacials may have prevailed for as much as one-third of the last 100 million years.