Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 5 January 2007:
Vol. 315. no. 5808, p. 14
DOI: 10.1126/science.315.5808.14e
Prev | Table of Contents | Next

This Week in Science

Numerous studies of Cenozoic climate have shown how climate and the carbon cycle are inked, but similar records much farther back in time are rare. Before the start of the current "icehouse," around 35 million years ago (Ma) when large ice sheets began to form in Antarctica, the last period when Earth had sizable volumes of continental ice was during the late Paleozoic (between 265 and 305 Ma). Montañez et al. (p. 87) used a 40-million-year-long record of the stable isotopic compositions of minerals formed in soils, fossil plant matter, and shallow-water brachiopods to explore the relation between continental surface temperatures and the concentration of atmospheric CO2 during this interval when Earth drifted in and out of glaciated and fully deglaciated conditions. Changes in continental ice volume were strongly correlated with shifts in atmospheric partial pressure of CO2, and paleofloral data chronicle the repeated restructuring of paleotropical floral communities that accompanied the inferred climate shifts. These findings suggest that greenhouse gas forcing of climate occurred during remote times in a manner similar to the present era.




To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)