EurekAlert! AAAS
10-Apr-2008
Pennsylvania State University
Contact: A’ndrea Elyse Messer
aem1@psu.edu
814-865-9481
Absence of clouds caused pre-human supergreenhouse periods
In a world without human-produced pollution, biological productivity
controls cloud formation and may be the lever that caused
supergreenhouse episodes during the Cetaceous and Eocene, according
to Penn State paleoclimatologists.
“Our motivation was the inability of climate models to reproduce the
climate of the supergreenhouse episodes of the Cetaceous and Eocene
adequately,” said Lee R. Kump, professor of geosciences. “People have
tried increasing carbon dioxide in the models to explain the warming,
but there are limits to the amounts that can be added because the
existing proxies for carbon dioxide do not show such large amounts.”