But researchers are now quantifying the causal relationship between
extreme climate and human conflict. Whether their focus is on
small-scale interpersonal aggression or large-scale political
instability, low-income or high-income societies, the year 10,000 B.C.
or the present day, the overall conclusion is the same: episodes of
extreme climate make people more violent toward one another.
In a paper published this month in the journal Science, we assembled 60
of the best studies on this topic from fields as diverse as archaeology,
criminology, economics, geography, history, political science and
psychology. Typically, these were studies that compared, in a given
population, levels of violence during periods of normal climate with
levels of violence during periods of extreme climate. We then combined
the results from those studies that concerned modern data in a
“meta-analysis,” a powerful statistical procedure that allowed us to
compare and aggregate findings across the individual studies.
As Hurricane Sandy makes landfall on Monday, meteorologists predict a
powerful storm that will cause power outages for millions, a storm
surge creating massive inland and coastal flooding, and sustained winds
that are threat for those living in urban and more rural areas across
the northeast.