Thursday August 23, 2012 10 :30 a.m.-12:00 noon Building 50 Auditorium

1. Thursday August 23, 2012 10:30 a.m.-12:00 noon Building 50 Auditorium Lawrence Berkeley National Laboratory Hosted by: Margaret Torn, CSD, ESD, LBNL Current Uncertainties in Global Vegetation Mortality and Climate Feedbacks Nathan G. McDowell, Ph.D. Earth and Evironmental Sciences Division Atmospheric and Environmental Dynamics Group Los Alamos National Laboratory, Los Alamos, NM 87545 Nate McDowell has been a staff scientist in the Earth and Environmental Sciences Division at Los Alamos National Laboratory since 2004. He received his B.Sc. in Biology at the University of Michigan in 1994, his M.Sc. in Forest Ecology at the University of Idaho in 1998, and his Ph.D. in Tree Physiology at Oregon State University in 2002. He was awarded a Director’s Postdoctoral Fellowship at LANL in 2003. McDowell studies the interdependency of plant and ecosystem water and carbon cycles and their response to climate and disturbance. His approach is focused on mechanistic hypothesis testing, utilizing a wide variety of approaches including theory, observation, experimentation, and modeling. He has published approximately 65 papers since 2000 and has raised ~$20M in grant funding during his tenure at LANL. He was awarded both LANL’s and DOE’s Distinguished Mentor Award for advising undergraduates in 2008 and 2010, respectively, DOE’s Early-Career Award in 2010, and testified before Congress regarding DOE’s climate change research in 2009. Distinguished Scientist Seminar Series Earth Sciences Division Lawrence Berkeley National Laboratory MS90R1116 1 Cyclotron Rd. Berkeley, CA 94720 Contact: shefty@lbl.gov Phone: 510.486.6455 Fax: 510.486.5686 Web: http://esd.lbl.gov/newsandevents/dsss Abstract There is a growing body of evidence suggesting that vegetation mortality during drought or periods of high temperatures is rising across the globe. Research regarding the mechanisms of vegetation mortality has grown dramatically in the last five years, as has research on the consequences of mortality on climate forcing. This new research has also stimulated valuable debate regarding how universal or variable mortality mechanisms may be globally, and how much feedback there is upon climate. Resolving these questions is essential for improving global climate models due to the inherent land-climate feedbacks. I will review the evidence for the variety of hypothesized mechanisms of death and the subsequent potential climate forcing. I will conclude by outlining a vision towards resolving these scientific questions, with the ultimate goals of improving our understanding and modeling of climate-terrestrial impacts and feedbacks.