HR: 16:00h
AN: GC44A-01 INVITED    [Abstracts]
TI: Tipping Points
AU: * Hansen, J
EM: jhansen@giss.nasa.gov
AF: Director, NASA Goddard Institute for Space Studies, 2880 Broadway, New York, 10025,
AU: * Hansen, J
EM: jhansen@giss.nasa.gov
AF: Adjunct Professor, Earth & Environmental Sciences, Columbia University Earth Institute, Columbia University, New York, 10027,
AB: A climate tipping point, at least as I have used the phrase, refers to a situation in which a changing climate forcing has reached a point such that little additional forcing (or global temperature change) is needed to cause large, relatively rapid, climate change. Present examples include potential loss of all Arctic sea ice and instability of the West Antarctic and Greenland ice sheets. Tipping points are characterized by ready feedbacks that amplify the effect of forcings. The notion that these may be runaway feedbacks is a misconception. However, present "unrealized" global warming, due to the climate system's thermal inertia, exacerbates the difficulty of avoiding global warming tipping points. I argue that prompt efforts to slow CO2 emissions and absolutely reduce non-CO2 forcings are both essential if we are to avoid tipping points that would be disastrous for humanity and creation, the planet as civilization knows it.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1620 Climate dynamics (0429, 3309)
DE: 1621 Cryospheric change (0776)
DE: 1626 Global climate models (3337, 4928)
DE: 1641 Sea level change (1222, 1225, 4556)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting