They analyzed quantitative data of the El Nino phenomenon/Southern Oscillation (ENSO) from 1950 and 2004 which extend to both tropic and subtropic regions in almost all continents except for Antartica and Europe.
They then found a one-way correlation that 21% of all civil conflicts are strongly associated with these inter-annual climate patterns.
It is easy to imagine how several uprisings could have ignited when the unforgiving weather supports this kind of hotheadedness. Behavior aside, it's an easy recipe for disaster: Prolonged El Nino negatively affects the crop yield and level of drought, which can precipitate into famine and strife.
Efforts in the previous years to correlate civil distress and weather patterns, for example rainfall levels, have been criticized for their weak experimental designs. Now, there is a well-accepted, if controversial, proof that human behavior leading to civil strife can be aggravated by weather temperaments.
|Even Amaya, a fictional babaylan on popular TV, has to beg the heavens for rain.|
image credits: iGMA.tv
Ergo, it is best to please the weather spirits and rain gods just like what our ancestors did. Nothing to lose.
Hsiang, SM, Meng, KC, & Cane, MA. 2011. Civil conflicts are associated with the global climate. Nature 476, 438-441. doi:10.1038/nature10311.
Ottery, C. 2011. El Niño linked to civil conflict in tropical countries. SciDev.net. online article here.