The sequence of atmospheric warming across the Earth’s latitudes during the last glacial termination

Ulrich Müller1, Jörg Pross1, Alice Milner2, Ulrich Kotthoff3, Kimon Christanis4
1 Institute of Geosciences, Goethe-University Frankfurt
2 Department of Geography, University College London
3 Geological-Palaeontological Institute, University of Hamburg
4 Department of Geology, University of Patras

V 5.2 in Klima und Umwelt der letzten 130.000 Jahre

18.09.2012, 08:50-09:10, H6

Glacial terminations, key elements in the climate system, are controlled by periodic variations in the Earth’s orbit and arising insolation changes at the top of the atmosphere. However, the sequence of change that leads to a termination remains elusive.

Here we show that the orbitally driven insolation changes resulted in a distinct sequence of atmospheric warming across the high-to-low latitudes of Earth during the last glacial termination, conventionally termed Termination I (TI). The sequence started in the high latitudes with a leading role of the northern hemisphere, continued in the low latitudes of the northern hemisphere, and ended in the low latitudes of the southern hemisphere. In the high latitudes of Earth, the atmospheric warming of TI was consistent with the obliquity controlled increase of integrated summer insolation which occurred symmetric between the hemispheres between 29 and 9 thousand years (kyr) BP. In the low latitudes, the atmospheric temperature change connected to TI was consistent with the precession controlled summer insolation intensity change which is out of phase between the hemispheres.

Since orbitally driven insolation change is a feature persistent over deep time, our work implies that glacial terminations in general are characterised by a specific sequence of atmospheric warming across Earth’s latitudes. The sequence of change will be individual for each termination as much as the phase relation between obliquity and precession varies from termination to termination.

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Letzte Änderung 26.07.2012