The large climate oscillations, such as El Niño or the Indian Ocean Dipole, could play a much more significant role in armed conflicts than previously estimated. This is revealed by a study conducted by researchers from Rice University (United States), published in the journal Proceedings of the National Academy of Sciences on Monday, May 11th. Over several years, this team of eight scientists compiled a unique dataset, documenting over 500 onsets of civil conflicts and wars that occurred between 1950 and 2023, to understand if certain climatic phenomena increased the risks of escalation and violence.
“We wanted to understand if the risk of armed conflict is linked to these climatic variations and if the risk of local conflict is proportional to the influence of these variations on the local climate,” explains Tyler Bagwell, one of the authors. With this approach, he and his colleagues mainly aimed to identify the regions of the world where weather disruptions make societies more fragile and more exposed to political or social tensions.
Their research focused on two climatic phenomena. The first is El Niño – Southern Oscillation (ENSO), whose impacts are felt beyond the South Pacific, and the second is the Indian Ocean Dipole (IOD), less publicized but highly influential around East Africa and Southeast Asia. “The extreme phases of ENSO and IOD are each associated with distinct local climate impacts, often opposing,” notes Tyler Bagwell.
While some regions become drier, others receive more rain. “By exploiting these differential impacts, we then established statistical correlations between the location and date of armed conflicts, the El Niño or La Niña phase of ENSO, and the dry or wet impacts experienced by the concerned societies,” continues the scientist.
The study notably shows that violence increases in regions affected by drought during El Niño. “The global risk of armed conflict is higher during El Niño than during La Niña,” observe the scientists. Conversely, in regions where “the climate’s enfant terrible” brings rain, the authors found “no credible link” to an increase in conflicts.
This conclusion reinforces the idea that water scarcity, agricultural losses, and pressure on food resources can become exacerbating factors in economically or politically vulnerable countries.
Unlike ENSO, where only one phase (El Niño) seems associated with increased risk, both phases of the Indian Ocean Dipole are associated with the emergence of conflicts, particularly in the Horn of Africa and Southeast Asia. “This is a very different pattern. The Indian Ocean Dipole operates on shorter time scales and can evolve rapidly, creating sudden climatic variations that can destabilize already vulnerable regions,” summarizes Professor Sylvia Dee, who considers it as a “threat multiplier.”
Even though the authors emphasize that climate does not directly cause wars, they believe that certain climate models indeed modify the probabilities of their occurrence. As El Niño or the Indian Ocean Dipole can be predicted several months in advance, the researchers hope that their study will help improve alert systems and humanitarian preparedness in the affected parts of the world.
