In the late 1990s, a particularly strong El Niño oscillation scourged the world with droughts, floods, and disruptions to the food supply. Carrying the energy equivalent of a million Hiroshima bombs, the titanic climate event was ultimately responsible for 23,000 deaths and at least $35 billion in damages.

In a scenario of unimpeded climate change, this kind of large-scale mayhem could become routine, according to distressing new research. Whereas the planet now receives an especially potent El Niño every 20 years—the term describing unusually warm waters in the equatorial Pacific—it could soon start facing them every decade, say scientists from NOAA and the ARC Centre of Excellence for Climate System Science. That would mean significant social and economic disruptions to countries in the climate phenomenon’s path, such as Australia, Indonesia, Ecuador, and Peru.

People have wondered for decades how global warming will affect El Niño; this study in Nature Climate Change provides the “first comprehensive examination of the issue to produce robust and convincing results,” says one of its coauthors. It’s not a pretty picture, as the resulting changes in the global rainfall cycle will likely have deadly repercussions over vast distances. Say the scientists:

“During an extreme El Niño event countries in the western Pacific, such as Australia and Indonesia, experienced devastating droughts and wild fires, while catastrophic floods occurred in the eastern equatorial region of Ecuador and northern Peru,” said lead author, CSIRO’s Dr Wenju Cai In Australia, the drought and dry conditions induced by the 1982-83 extreme El Niño preconditioned the Ash Wednesday Bushfire in southeast Australia, leading to 75 fatalities…. “For Australia, this could mean summer heat waves, like that recently experienced in the south-east of the country, could get an additional boost if they coincide with extreme El Ninos,” said co-author, Professor Matthew England from CoECSS.

The researchers reached this grim conclusion after using 20 climate models to simulate how rainfall will change over the next 100 years. Here’s a visual representation of where they expect the uptick in extreme weather to develop (it’s the trans-Pacific red zone at bottom):

Just as a reminder, the latest heat wave to strike this part of the world had professional tennis players either vomiting on-court or hallucinating about a cartoon dog.

This originally appeared at Atlantic Cities. More from our sister site:

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