Geochronology/Medieval Warm Period

The Medieval Warm Period (MWP) dates from around 1150 (950 AD) to 750 (1250 AD) b2k.

Global temperature reconstructions are for the past 2,000 years.
The figure shows the number of samples in time for the Central European oak chronology. Credit: Stand.
The center of the graph shows the time axis of conventionally dated historical events. Upper and lower coordinates show reconstructed time tables. The black triangles mark the phantom years. Credit: Hans-Ulrich Niemitz.

"A proof-of-concept self-calibrating chronology [based upon the Irish Oak chronology] clearly demonstrates that third order polynomials provide a series of statistical calibration curves that highlight lacunae in the samples."[1]

As indicated in the figures, the data used in the plots comes from radiocarbon dating of Irish Oaks.[2]

Gaps occur near the 720s (1280 b2k), 1070s (930 b2k), 1370s (630 b2k), 1670s (330 b2k), 1800s AD (200 b2k) during the rising Δ14C values.

"The number of suitable samples of wood, which connect Antiquity and the Middle Ages is very small [shown in the first figure on the left]. But only a great number of samples would give certainty against error. For the period about 380 AD we have only 3, for the period about 720 AD only 4 suitable samples of wood (Hollstein 1980,11); usually 50 samples serve for dating."[3]

"The center of the graph [in the second image on the left] shows the time axis of conventionally dated historical events. Upper and lower coordinates show reconstructed time tables. The black triangles mark the phantom years."[3]

"In Frankfurt am Main archaeological excavations did not find any layer for the period between 650 and 910 AD."[3]

"Specialists now do not favor the terms “Little Ice Age” and “Medieval Warming Period” since the climatic manifestations of the underlying phenomenon of these [Rapid Climate Change] RCC events can differ greatly from one region of the world to another and the connotations of climate homogeneity within those periods can be misleading."[4]

"When the “Medieval Warming Period” began and ended is defined very differently by scientists and historians, who analyze the diverse data with different methods and chronological smoothing scales and techniques. Furthermore, while historians’ professional background makes them extremely sensitive to chronological precision on the yearly, if not finer, scales, climate scientists often work in thousands, hundreds of thousands, or even millions of years and hence may sometimes seem rather more casual toward a historical time scale."[4]


  1. Each century from 3000 to 500 b2k has been demonstrated to exist by radiocarbon dating or dendrochronology of an artifact.

See also



  1. Gunnar Heinsohn (8 September 2014). A Carbon-14 Chronology. Malaga Bay. Retrieved 2014-10-25. 
  2. Gordon W. Pearson and Florence Qua (1993). "High-Precision 14C Measurement of Irish Oaks to Show the Natural 14C Variations from AD 1840-5000 BC: A Correction". Radiocarbon 35 (1): -24. Retrieved 2014-10-25. 
  3. 3.0 3.1 3.2 Hans-Ulrich Niemitz (3 April 2000). Did the Early Middle Ages Really Exist?. Cambridge, UK: Cambridge University. Retrieved 2014-10-26. 
  4. 4.0 4.1 Michael McCormick, Paul Edward Dutton, and Paul A. Mayewski (October 2007). "Volcanoes and the Climate Forcing of Carolingian Europe, a.d. 750–950". Speculum A Journal of Medieval Studies 82 (4): 865-895. Retrieved 2017-10-22. 

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