Quantitative Analysis of Climate Change and Human Crises in History - Space-Time Integration in Geography and GIScience - page 248

Fig. 14.5 Climate change and the golden and dark ages in Europe in AD 1000-1900. The
European temperature anomaly series ( ) has been smoothed by 100-year Butterworth low-pass
filter. Horizontal dotted line represents the threshold in defining crisis periods (i.e., tempera-
ture 0.1 ). The periods in which temperature 0.1 stand for golden ages, while the periods

in which temperature 0.1 stand for dark ages

millennium 25 (Fig. 14.5 )(Zhangetal. 2011a ). The periods in which temperature
was lower than 0.1 were AD 1212-1381 (corresponding to the Crisis of Late
Middle Ages) and AD 1568-1665 (corresponding to the General Crisis of the
Seventeenth Century), whereas the periods in which temperature was higher than
0.1 were the tenth to twelfth centuries (corresponding to the High Middle
Ages), the late-fourteenth to early sixteenth centuries (corresponding to the
Renaissance), and the late-seventeenth to eighteenth centuries (corresponding to
the Enlightenment). Basically, the alternation of the above warm (> 0.1 )and
cold (< 0.1 ) phases coincided with the alternation of “golden” and “dark” ages
as defined by historians (Lyon et al. 1969 ; Roberts 1996 ). The Age of Revolution in
the early nineteenth century (one of the darker ages) is an exceptional case, as the
temperature during the time was higher than 0.1 . Nevertheless, when compared
with the other so-called dark ages, the socio-political impact brought by the Age

the temperature change in Europe over time. It was done by normalizing each of the above
series and then taking their arithmetical average. The above two temperature reconstructions were
derived from different proxies and reconstructed by different methods. In order to combine the
two reconstructions together, each of them was normalized to homogenize the original variability
of all series. It should be noted that this transformation cannot preserve the numerical values of
temperature variation, but will provide the relative amplitude of temperature change. Then, the
two normalized series were arithmetically averaged and then smoothed by 100-year Butterworth
low-pass filter to generate the Europe temperature composite.
25 According to Lyon et al. ( 1969 ) and Roberts ( 1996 ), the delineation of golden and darks ages
in Europe over the last millennium is as follows: Golden ages - High Middle Ages (eleventh to
thirteenth centuries), Renaissance (fifteenth to mid-sixteenth centuries), and Enlightenment (mid-
seventeenth to late eighteenth centuries). Dark ages - Crisis of Late Middle Ages (fourteenth
century), General Crisis of the Seventeenth Century (mid-sixteenth to mid-seventeenth centuries),
and the Age of Revolution (late eighteenth to mid-nineteenth centuries).