Geophysikalisches Kolloquium: Toward a unified theory of Quaternary climate dynamics

Dr. Ganopolski, A.

Potsdam Institute for Climate Impact Research

The aim of my talk is to discuss current status in understanding of climate dynamics of the recent geological epoch. Numerous paleoclimate records obtained in recent decades indicate that climate was much more unstable during ice age as compared to climates of previous warm epochs. The largest portion of climate variability occurred on the orbital (from 20 to 100 thousand years) and millennial time scales. A comprehensive and generally accepted theory explaining this pronounced climate variability is still absent. In my talk I will discuss firstly the most important aspects of glacial climate variability and the stages of pronounced regime changes which occurred during last 3 million years, namely, the onset of large-scale glaciation in the Northern Hemisphere, transition from the dominant 40,000 years cyclicity to 100,000 years cyclicity about one million years ago, a strong asymmetry of the recent glacial cycles, and abrupt climate changes associated with Dansgaard-Oeschger and Heinrich events. I will then try to explain this peculiar behavior of the climate system in terms of crossing a number of the thresholds which activated different types of intrinsic instability of the climate system. I will then present a number of simulations with an Earth system model of intermediate complexity ranging from millennial to million years time scales which support proposed mechanism of glacial climate instability.

Datum

19.06.2008

Uhrzeit

15:15 Uhr

Ort

Geomatikum H4
Lecture hall H4 (ground floor), University of Hamburg, Bundesstr. 55, Hamburg

ReferentIn

Andrey Ganopolski, Potsdam Institute for

Chair


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