View source for Ancient Perspectives on Future Climate

{{2007 Public Lectures}}


'''Ulam Memorial Lecture Series'''

'''Daniel Schrag''' is Director of the Laboratory for Geochemical Oceanography at Harvard University. A 2000 MacArthur Fellow, Schrag studies the history of oceans and climate using analytical chemistry and modeling. His projects cover the widest range of time scales. Currently, he is using corals from the Pacific to study El Niño and modern ocean circulation, deep-sea sediments to study the last ice age (20,000 years ago), and ancient sediments to study the Neoproterozoic Snowball Earth. 


Discussant:  '''Doug Erwin''', Curator of Permian Gastropods, National Museum of Natural History and Professor, Santa Fe Institute 


The increase in atmospheric CO2 due to burning coal, oil and gas represents an unprecedented and uncontrolled experiment on the planet Earth.  We know from air bubbles trapped in ice cores that CO2 has never been higher than 300 parts per million in the last 650,000 years, and from indirect measurements, we think it was not significantly higher than this for tens of millions of years.  Exactly how the rise in CO2 will affect the Earth over the next few centuries remains uncertain.   Geologic records of climate change over earth history, as well as observations of neighboring planets, provide a variety of important lessons that can guide us in evaluating the risks of future climate change.  In the first lecture, the paleoclimate history of Mars and Venus will be discussed in the context of the Earth in exploring what regulates Earth’s climate, and how might have it been in different in the past, before modern forms of multicellular animals evolved.  In the second lecture, the extremes of hot and cold climates on Earth will be explored, including the warm climates of the Eocene, the ice ages of the Pleistocene, and the Neoproterozoic Snowball Earth.  In the final lecture, the question of future climate change will be addressed directly.  The level of risk will be assessed, and possible steps to prevent harmful effects will be discussed.