Atmospheric CO2 has never been higher than 300 parts per million – the geologic record proves that – but what will happen when it reaches 500 parts per million, the level that scientists are predicting in the next 50 years? And if it exceeds that -- or doubles?
Those were the questions geochemist Daniel Schrag, director of the Harvard University Center for the Environment, raised at the Mork Family Department Pings Lecture, held December 9, 2008, on the USC campus. Schrag was introduced to the audience of faculty and students by Katherine Shing, an associate professor in the Mork Department.
Left to right: Mork Family Department Associate Professor Katherine Shing, Harvard University geochemist and keynote speaker Professor Daniel Schrag, and Mork Family Department Chair Theodore Tsotsis.
“The next 150 years are going to look different than anything we’ve ever seen, but we don’t know what it will be,” Schrag said.
Scientists 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, they think it was not significantly higher than this for tens of millions of years, he explained. Geologic records of climate change, 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 general, the uncertainties in our understanding of the climate system are biased towards lack of knowledge about catastrophic events,” Schrag said. “In this context, we have to address a variety of strategies for meeting the world's energy needs with the smallest possible impact on our atmosphere. And we have to consider what strategies we might require if climate change is more dramatic than we expect.”
Schrag, a professor of earth and planetary sciences and environmental science and engineering, studies climate and climate change over the broadest range of Earth's history. He has examined changes in ocean circulation over the last several decades, with particular attention to El Niño and the tropical Pacific; he investigates Pleistocene ice-age cycles over the last million years; he studies the warm climates of the Eocene, 50 million years ago; and, with colleagues from Harvard, helped to develop the Snowball Earth hypothesis, which explains extreme glacial events that occurred more than 600 million years ago.
Currently he is working on the early history of Mars and Earth, trying to understand the environmental conditions around the time of the origin of life. Schrag is also working on new technological approaches to mitigating future climate change, including advanced energy technologies for low-carbon transportation fuel, and carbon sequestration.
Schrag received a B.S. from Yale and a Ph.D. in geology from the University of California at Berkeley, and taught at Princeton before moving to Harvard in 1997. Among his various honors, Schrag was named a MacArthur Fellow in 2000.
Schrag is the second keynote speaker in the USC Mork Family Department of Chemical Engineering and Materials Science Pings Lecture series. The lecture series was established in 2007 to honor the late Cornelius J. Pings, a prominent chemical engineer and former USC provost who served as President of the Association of American Universties from 1993 to 1998..