Friday, December 22, 2006

Earth’s Climatic Heartbeat

The Heartbeat of the Oligocene Climate System. 2006. H. Pälike et al. Science 314: 1894 – 1898.
An international team of researchers drilled down five km below Pacific Ocean sea level to uncover secrets of the Earth’s ancient climate.
From the press release:

Analysis of the carbonate shells of these foraminifera microfossils that are between 23 million to 34 million years-old, has revealed that the Earth's climate and the formation and recession of glaciation events in the Earth's history have corresponded with variations in the earth's natural orbital patterns and carbon cycles.

The authors also show how simple models of the global carbon cycle, coupled to orbital controls of global temperature and biological activity, are able to reproduce the important changes observed after the world entered an "ice-house" state about 34 million years ago.

In the early half of the 20th century, Serbian physicist Milutin Milankovitch first proposed that cyclical variations in the Earth-Sun geometry can alter the Earth's climate and these changes can be discovered in the Earth's geological archives, which is exactly what this research team, consisting of members from the United Kingdom, the U.S. and Canada, has done.