Geoscience Reference
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England. There was also a bad year in 1697 and it is estimated that in Finland roughly
a third of the population died.
In 2011 a team of Chinese researchers, led by David Zhang and Harry Lee,
correlated 16 European variables between the 13th and 17th centuries that themselves
are affected by European climate and with northern hemisphere proxy temperatures.
These included tree rings and grain yield as indicators of bioproductivity, agriculture
production from the historic agriculture production index, food supply as suggested
by grain price and the historic wage index, social disturbance, migration, famine
mortality, nutritional status as revealed by average population height, epidemics,
war as quantified by a fatality index, and human population. One hundred and twenty
cross-correlations of these variables were statistically significant (
≥
95%) and of these
116 were highly significant (
99%). The workers used a European temperature series
as another indicator of conditions of harmony or crisis to simulate the 'golden' and
'dark' ages in Europe over the past millennium. They set a temperature-variation limit
equal to
≥
−
σ
σ
means standard deviation) according to the 100-year smoothed
European temperature series as the general crisis threshold. The periods in which
the temperature was lower than
0.1
(
of the long-term
mean represented dark ages and golden ages, respectively. With that threshold, the
dark ages calculated were
−
0.1
σ
or greater than
−
0.1
σ
ad
1212-1381, the Crisis of the Late Middle Ages, and
ad
1568-1665, the General Crisis of the 17th Century. Conversely, the golden ages
were the 10th-12th centuries (the High Middle Ages), the late-14th to early 16th
centuries (the Renaissance) and the late-17th to 18th centuries (the Enlightenment).
This is largely in agreement with time intervals delimited by historians. The mild
cooling in Europe in the late 18th and 19th centuries brought about a rise in consumer
prices, social disturbance, war and migration, but not demographic crisis, because of
social buffers such as cross-continental migration, trade and industrialisation. In the
study, Zhang et al. (2011) all criteria for confirming the causal mechanisms between
climate change and human crisis were met. The alternation of historical golden and
dark ages in Europe and the northern hemisphere, which often has been attributable
to sociopolitical factors was indeed rooted in climate change, even if they were
exacerbated by sociopolitical circumstances. Climate change determined the fate of
agrarian societies via the economy (the ratio between resources and population).
The findings of the Zhang and Lee team have important implications for industrial
and post-industrial societies. They concluded that any natural or social factor that
causes large resource (supply) depletion, such as climate and environmental change,
overpopulation, overconsumption or non-equitable distribution of resources, may
lead to a general crisis.
Let us put the quantitative analysis of Zhang et al. (2011) into some sort of qual-
itative context with what we already knew. As noted, the effect of the harsher Little
Ice Age climate on those already on marginal land was far worse than those on
formerly good lands of the MCA that the Little Ice Age in turn made marginal. Those
already living at high altitudes in mountain pastures were very badly affected. Con-
sequently, Scandinavian, Scottish and Swiss farmers suffered particularly. Problems
were not solely confined to direct climatic impacts. The new Little Ice Age envir-
onmental conditions favoured some crop pathogens. Since snow covered the ground
deep into spring in the mountainous parts of Europe a fungus known as pink snow
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