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Titel |
The origin of the European "Medieval Warm Period" |
VerfasserIn |
H. Goosse, O. Arzel, J. Luterbacher, M. E. Mann, H. Renssen, N. Riedwyl, A. Timmermann, E. Xoplaki, H. Wanner |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1814-9324
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Digitales Dokument |
URL |
Erschienen |
In: Climate of the Past ; 2, no. 2 ; Nr. 2, no. 2 (2006-09-19), S.99-113 |
Datensatznummer |
250000497
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Publikation (Nr.) |
copernicus.org/cp-2-99-2006.pdf |
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Zusammenfassung |
Proxy records and results of a three dimensional climate model show that European
summer temperatures roughly a millennium ago were comparable to those of the last
25 years of the 20th century, supporting the existence of a summer "Medieval Warm
Period" in Europe. Those two relatively mild periods were separated by a rather cold
era, often referred to as the "Little Ice Age". Our modelling results suggest that
the warm summer conditions during the early second millennium compared to the climate
background state of the 13th–18th century are due to a large extent to the long term
cooling induced by changes in land-use in Europe. During the last 200 years, the effect
of increasing greenhouse gas concentrations, which was partly levelled off by that of
sulphate aerosols, has dominated the climate history over Europe in summer. This induces
a clear warming during the last 200 years, allowing summer temperature during the last
25 years to reach back the values simulated for the early second millennium. Volcanic
and solar forcing plays a weaker role in this comparison between the last 25 years of
the 20th century and the early second millennium. Our hypothesis appears consistent
with proxy records but modelling results have to be weighted against the existing uncertainties
in the external forcing factors, in particular related to land-use changes, and against
the uncertainty of the regional climate sensitivity. Evidence for winter is more equivocal
than for summer. The forced response in the model displays a clear temperature maximum at
the end of the 20th century. However, the uncertainties are too large to state that this period
is the warmest of the past millennium in Europe during winter. |
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