December 2007 BAGS Meeting:
Understanding Natural Climate Variability: The Key to climate Change
Caspar M. Ammann
National Center for Atmospheric Research
Paleoclimatology
Thursday, December 13, 2007
Please join us
for lunch in the Chevron cafeteria. Remember
to request a visitors badge!
Abstract:
By mid-September 2007, sea-ice coverage of the Arctic Ocean reached the
smallest extent since record keeping began. This is just the latest in
an ever-increasing number of signals that the climate is changing and
that the globe is warming up. But how can we be so sure that this
recent trend is man-made and not just an artifact from a too short
instrumental record? Couldn't other factors, such as internal
variability or changes in solar activity be responsible for what is
happening right now? Just how do current and possible future
anthropogenic signals actually measure up against the range of natural
variations? Clean separation of anthropogenic from natural climate
change is not always easy. However, process studies as well as the
time-perspective gained from past climates allow for a better
understanding of the ongoing change, and the respective roles of
natural and human contributions can be assessed.
This presentation will focus on the available data that strongly
supports the argument for human-induced climate change, and where
climate science is currently heading to improve projections of relevant
issues. Results of high-resolution climate reconstructions, as well as
state-of-the-art climate models, indicate that natural forcing factors
have dominated climate before the 20th century. Increased emissions of
greenhouse gases are, however, responsible for the current rapid
warming. If emissions are not reduced in the near future, then the
Earth's climate system will undoubtedly experience drastic changes that
far exceed the range of what civilizations have experienced. But
simulations also show that strong reductions of emissions can keep
climate changes in check.
Biography: Caspar Ammann [PDF]
Education
- Ph.D., Geosciences, University of Massachusetts, Amherst, 2002.
- M.S. (equiv), Geography, Geology and Mineralogy, University of Bern, Switzerland, 1996.
- B.S. (equiv), Gynasium Köniz, Bern, Switzerland, 1987.
Experience
- Oct. 2006-present, Scientist II, Climate Change Research, Climate and Global Dynamics Division,
National Center for Atmospheric Research, Boulder, Colorado.
- 2003-2006, Scientist I, Climate Change Research, Climate and Global Dynamics Division, National
Center for Atmospheric Research, Boulder, Colorado.
- 2002-2003, Postdoctoral Fellow, Advanced Study Program, National Center for Atmospheric Research, Boulder, Colorado.
- 1997-2001, Research Assistant, Department of Geosciences, University of Massachusetts, Amherst,
Massachusetts.
- 1999-2001, Visiting Graduate Student, Climate and Global Dynamics Division, National Center for
Atmospheric Research, Boulder, Colorado.
- 1991-1996, Programmer, Population Dynamics, Federal Office of Statistics, Bern, Switzerland.
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