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UP: Fachverband Umweltphysik

UP 15: Bodenkunde und Kryosphäre

UP 15.3: Vortrag

Freitag, 27. März 2015, 10:30–10:45, G/gHS

Glacial-interglacial variability change: a view beyond ice cores — •Kira Rehfeld¹, Sze Ling Ho¹, Thomas Münch^1,2, and Thomas Laepple¹ — ¹Helmholtz Junior Research Group ECUS, Alfred-Wegener-Institut für Polar und Meeresforschung, Potsdam, Germany — ²Department of Physics, Universität Potsdam, Germany

The last glacial period was characterized by a highly variable climate, including abrupt changes such as Heinrich- and Dansgaard-Oeschger events. By contrast, the warm Holocene time period was relatively stable. This variability change is often discussed based on data from polar ice cores, particularly from Greenland. Here, we contrast the polar ice core based variability change with the variability change as recorded by a global compilation of marine and terrestrial proxy records.
Accounting for uneven sampling in time and space, we develop an understanding of proxy signal-to-noise ratios which allows insight into proxy-specific biases concerning the recording of climate variability. Our results suggest that the oxygen isotopic composition of Greenland ice cores may not have reliably recorded Holocene temperature variability.
Globally, we find climate at the glacial maximum five times more variable than during the Holocene. This variability is expressed in particular by the polar ice cores: We find a stronger polar amplification of climate variability during the Glacial than during the warm Holocene. Our results indicate that the view of an extremely variable Glacial contrasting with a quiet Holocene may underestimate the actual variability of the present warm Interglacial.