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SUMMARY:Earth System Dynamics and Mass Extinctions - Daniel H. Rothman (Lo
 renz Center\, MIT)
DTSTART:20161122T130000Z
DTEND:20161122T140000Z
UID:TALK69243@talks.cam.ac.uk
CONTACT:Julius Bier Kirkegaard
DESCRIPTION:The five great mass extinctions of the geologic past are each 
 associated with significant perturbations of Earth’s carbon cycle. But m
 any past environmental events are not associated with mass extinction. Wha
 t makes them different?  By transforming geochemical signals to physical v
 ariables\, we find that mass extinctions are associated with rates of envi
 ronmental change that exceed a limit imposed by mass conservation in a nor
 mal carbon cycle.  We suggest that external perturbations of the carbon cy
 cle\, such as extensive volcanism\, can excite responses that breach this 
 threshold.  We conclude with brief remarks on the relevance of these findi
 ngs to modern environmental change and a potential sixth extinction.
LOCATION:MR11\, Centre for Mathematical Sciences\, Wilberforce Road\, Camb
 ridge
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