New paper "Global climate change, war, and population decline in recent human history"

(Published before print by Zhang et al. in PNAS, vol. 104, no. 49)

A successful example of macroscopic and interdisciplinary approaches to human ecology. Their abstract provides a nice appetizer:

"Although scientists have warned of possible social perils resulting
from climate change, the impacts of long-term climate change on
social unrest and population collapse have not been quantitatively
investigated. In this study, high-resolution paleo-climatic data
have been used to explore at a macroscale the effects of climate
change on the outbreak of war and population decline in the
preindustrial era. We show that long-term fluctuations of war
frequency and population changes followed the cycles of temperature
change. Further analyses show that cooling impeded agricultural
production, which brought about a series of serious social
problems, including price inflation, then successively war outbreak,
famine, and population decline successively. The findings
suggest that worldwide and synchronistic war–peace, population,
and price cycles in recent centuries have been driven mainly by
long-term climate change. The findings also imply that social
mechanisms that might mitigate the impact of climate change were
not significantly effective during the study period. Climate change
may thus have played a more important role and imposed a wider
ranging effect on human civilization than has so far been suggested.
Findings of this research may lend an additional dimension
to the classic concepts of Malthusianism and Darwinism."

Enjoy!
Jordan