the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Mid-Holocene regional reorganization of climate variability
K. W. Wirtz
K. Bernhardt
G. Lohmann
C. Lemmen
Abstract. We integrate 130 globally distributed proxy time series to refine the understanding of climate variability during the Holocene. Cyclic anomalies and temporal trends in periodicity from the Lower to the Upper Holocene are extracted by combining Lomb-Scargle Fourier-transformed spectra with bootstrapping. Results were cross-checked by counting events in the time series. Main outcomes are: First, the propensity of the climate system to fluctuations is a region specific property. Many records of adjacent sites reveal a similar change in variability although they belong to different proxy types (e.g., δ18O, lithic composition). Secondly, at most sites, irreversible change occured in the Mid-Holocene. We suggest that altered ocean circulation together with slightly modified coupling intensity between regional climate subsystems around the 5.5 kyr BP event (termination of the African Humid Period) were responsible for the shift. Fluctuations especially intensified along a pan-American corridor. This may have led to an unequal crisis probability for early human civilizations in the Old and New World. Our study did not produce evidence for millennial scale cyclicity in some solar activity proxies for the Upper Holocene, nor for a privileged role of the prominent 250, 550, 900 and 1450 yr cycles. This lack of global periodicities corroborates the regional character of climate variability.
K. W. Wirtz et al.


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RC S85: 'Review Wirtz et al', Anonymous Referee #2, 04 Mar 2009
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AC S109: 'Reply to Interactive comment by Ref2', Kai Wirtz, 11 Mar 2009
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AC S109: 'Reply to Interactive comment by Ref2', Kai Wirtz, 11 Mar 2009
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RC S142: 'Review', Anonymous Referee #1, 26 Mar 2009
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AC S211: 'Robustness of the methodology', Kai Wirtz, 17 Apr 2009
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AC S211: 'Robustness of the methodology', Kai Wirtz, 17 Apr 2009
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EC S145: 'editor's comment', Valérie Masson-Delmotte, 26 Mar 2009


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RC S85: 'Review Wirtz et al', Anonymous Referee #2, 04 Mar 2009
-
AC S109: 'Reply to Interactive comment by Ref2', Kai Wirtz, 11 Mar 2009
-
AC S109: 'Reply to Interactive comment by Ref2', Kai Wirtz, 11 Mar 2009
-
RC S142: 'Review', Anonymous Referee #1, 26 Mar 2009
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AC S211: 'Robustness of the methodology', Kai Wirtz, 17 Apr 2009
-
AC S211: 'Robustness of the methodology', Kai Wirtz, 17 Apr 2009
-
EC S145: 'editor's comment', Valérie Masson-Delmotte, 26 Mar 2009
K. W. Wirtz et al.
K. W. Wirtz et al.
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Cited
3 citations as recorded by crossref.
- Holocene land-cover reconstructions for studies on land cover-climate feedbacks M. Gaillard et al. 10.5194/cp-6-483-2010
- Indicator pollen taxa of human-induced and natural vegetation in Northern China M. Li et al. 10.1177/0959683614566219
- Lacustrine responses to middle and late Holocene anthropogenic activities in the northern tropical Andes M. Vélez et al. 10.1007/s10933-020-00152-y