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PaleoClimate

PaleoClimate. Mechanisms for Glacial-Interglacial Oscillations. By Gillian Robbins. Ice Ages. 1. Huronian (2.7-2.3 billion yrs ago) 2. *Snowball Earth (850-630 million yrs ago) 3. Andean Saharan (460-430 million yrs ago) 4. Present Age (40 million yrs ago-Today). Climate Variation.

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PaleoClimate

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  1. PaleoClimate Mechanisms for Glacial-Interglacial Oscillations By Gillian Robbins

  2. Ice Ages 1. Huronian (2.7-2.3 billion yrs ago) 2. *Snowball Earth (850-630 million yrs ago) 3. Andean Saharan (460-430 million yrs ago) 4. Present Age (40 million yrs ago-Today)

  3. Climate Variation

  4. The Milankovitch Debate Oscillation Theories: 1920 Milankovitch Cycles Orbital Forcing VS 1990-94 Imbrie, Ghil, and Saltzman 2000 Gildor and Tziperman Milankovitch is incomplete (at the 100,000 yr time scale)

  5. “Sea-Ice Switch” Mechanism,Model Develop Ocean-atmosphere-sea, ice-land, ice climate system box model Results: • self sustaining oscillations without external, Milankovitch forcing. • The asymmetric sawtooth structure is observed Conclude: • Abrupt sea-ice growth and retreat acts as a switch for glacial-interglacial changes

  6. Switch is On

  7. Switch is Off

  8. Why 100 kyr?

  9. The future of the Holocene? • Global Warming and its impacts • Becoming an ice free environment • Resulted feedbacks in climate system

  10. Ref • Hezi, G., Tziperman, E. (2001) Journal of Geophysical Research106, 9117-9133. • Hezi, G., Tziperman, E. (2003) Philosophical Transactions Royal Society London361, 1935-1944 • Pixar • An unidentified user lecture figure from MIT

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