Using fossils to help predict the response of ecosystems to climate change

Human activity has direct and indirect effects on the biosphere.  The direct effects are due to immediate disturbance, such as the making of dam, the building of a city, or the clearing of a forest.  The indirect effects can be global (climate change) or local (ecological fragmentation due to growth and infrastructure development).  How can we gauge the response of the biosphere to these types of change?  The only hard data we have is on how ecosystems have responded to past major perturbations.  Using the fossil record, Charles Marshall, Director of the UC Museum of Paleontology, will answer the following questions:  Are we in a 6th mass extinction?  Has the globe experienced climate change with similar rates and magnitudes to those predicted for modern climate change?  What were the biotic responses to these changes?  To what extent can these responses be generalized to the present crisis?  What do we learn about the resilience and recovery potential of different ecosystems?