Title
The Boring Millions? Vegetation, Atmospheric CO2 , and Climate Revolutions of the Late Miocene
Start Date
5-3-2019 4:00 AM
End Date
5-3-2019 5:00 AM
Access Type
Open Access
Abstract
During the late Miocene (11-5 Ma), global ice volume and deep ocean temperatures appear to be relatively unchanging. These “boring millions” suggest stasis of the climate system with the expectation of only moderate global changes in climate, CO2 and vegetation. However, during this time tropical ecosystems underwent profound changes and surface ocean temperatures declined dramatically. When did these changes occur, what drove them, and what role if any did atmospheric carbon dioxide levels play? I will address these questions through new observations of the onset, pace and geographic extent of vegetation transformations and hydrologic changes reconstructed from molecular biomarkers. I will then examine the role that atmospheric CO2 levels and other factors may have played in these transformations.
Biography
Pratigya Polissar earned a B.A. in Environmental Science from Hampshire College (1995) and an M.Sc. and Ph.D. in Geosciences from the University of Massachusetts (1999, 2005). He joined the Lamont-Doherty Earth Observatory in 2010. His research uses the chemistry of molecular fossils to understand past climates. He currently focuses on reconstructing how Earth’s atmospheric CO2 levels have changed in the geologic past and how those changes shaped our present world, in particular tropical ecosystems and rainfall patterns.
Additional Links
ORCID
0000-0001-5483-1625
The Boring Millions? Vegetation, Atmospheric CO2 , and Climate Revolutions of the Late Miocene
During the late Miocene (11-5 Ma), global ice volume and deep ocean temperatures appear to be relatively unchanging. These “boring millions” suggest stasis of the climate system with the expectation of only moderate global changes in climate, CO2 and vegetation. However, during this time tropical ecosystems underwent profound changes and surface ocean temperatures declined dramatically. When did these changes occur, what drove them, and what role if any did atmospheric carbon dioxide levels play? I will address these questions through new observations of the onset, pace and geographic extent of vegetation transformations and hydrologic changes reconstructed from molecular biomarkers. I will then examine the role that atmospheric CO2 levels and other factors may have played in these transformations.