Thursday, February 16, 2012, 4:30PM - 5:30PM
RL-1 room 269
Superimposed on long-term orbital forcing, Greenland ice cores have revealed twenty-five abrupt climate warmings occurring during the last glacial cycle at roughly ~1,500 year intervals. These abrupt climate changes, known as Dansgaard-Oeschger (D-O) events, occurred on time scales proportional to a presidential term, and well within the bounds of a human lifetime.
Abrupt climate changes have had profound impacts on past human civilization, including the collapse of the Akkadian empire in Mesopotamia 4,200 years ago, the Mayan civilization in central America 1,500 years ago, and the Anasazian Indian culture of the American southwest 700 years ago. The same risk exists for our current societies. The Committee on Abrupt Climate Change has stated that human activities could trigger abrupt climate change and that there are serious doubts whether we can mitigate and adapt in the face of near-term fast acting climate events.
Our study will help to inform predictive modeling efforts with high-resolution measurements of past abrupt climate changes using ice cores from Greenland and Antarctica. In particular, we will characterize the speed, timing, magnitude and mechanisms of abrupt climate change, which may tell us where to look for the initial warning signs of abrupt change, and whether they reside in the tropics or poles. Ultimately, accurate modeling seeks to better inform policy makers and governments about the risks of abrupt climate change, and how to mitigate and adapt should a rapid change occur.
This talk will start with an exciting movie from the 2011 field season at the NEEM ice core site in northern Greenland, including documentation of what may be the highest latitude game of croquet ever attempted. I will then discuss some preliminary results from the NGRIP ice core in central Greenland.