Klemens Seelos

A late Eemian aridity pulse in central Europe during the last glacial inception.

Investigating the processes that led to the end of the last interglacial period is relevant for understanding how our ongoing interglacial will end, which has been a matter of much debate (see, for example, refs 1, 2). A recent ice core from Greenland demonstrates climate cooling from 122,000 years ago driven by orbitally controlled insolation, with glacial inception at 118,000 years ago. Here we present an annually resolved, layer-counted record of varve thickness, quartz grain size and pollen assemblages from a maar lake in the Eifel (Germany), which documents a late Eemian aridity pulse lasting 468 years with dust storms, aridity, bushfire and a decline of thermophilous trees at the time of glacial inception. We interpret the decrease in both precipitation and temperature as an indication of a close link of this extreme climate event to a sudden southward shift of the position of the North Atlantic drift, the ocean current that brings warm surface waters to the northern European region. The late Eemian aridity pulse occurred at a 65° N July insolation of 416 W m-2, close to todays value of 428 W m-2 (ref. 9), and may therefore be relevant for the interpretation of present-day climate variability.

14. Abrupt cooling events at the very end of the last interglacial

Abstract A comparison of a last interglacial annually laminated and varve counted maar lake record from the Eifel/Germany, with a laminated lake sediment record from Northern Germany, shows that high-resolution cores can be correlated across central Europe by dust/loess content, if the resolution of grain-size data is on the order of decades/centuries. Phases of widespread dust dispersal are the same as the cold events in the Greenland ice and North Atlantic sea-surface temperature patterns. The first occurrence of dust in Northern Germany and in the Eifel is during the late Eemian aridity pulse (LEAP, Sirocko et al., 2005) which is called C26 in ocean records (McManus, this volume). This cold and arid event occurred exactly at the time of the last glacial inception at 118 kyr. Vegetation change in Northern Germany and the Eifel is out of phase after the LEAP. A taiga/ tundra vegetation characterizes Northern Germany between the LEAP and C24, whereas at the same time a Carpinus -dominated temperate forest spread in the Eifel region, comparable to the Carpinus -dominated forests in France (Sanchez Goni et al., 2005). A drastic cooling, associated with widespread aridity, came with the C24 cold event, when the vegetation of central Europe changed to a tundra or shrub tundra.