El Niño and La Niña, the notorious climate influencers, have been part of our planet’s weather system for an incredibly lengthy period.

According to new research, the dynamic between El Niño and La Niña has been present on Earth for at least 250 million years, and has frequently been much more robust than the fluctuations we experience today.

This entire phenomenon is referred to as the El Niño-Southern Oscillation (ENSO), which is a crucial climate pattern influencing weather globally.

El Niño occurs when the surface temperatures of seawater in the central and eastern tropical Pacific Ocean rise above normal.

The interplay of water temperatures in this area—whether they are warm (El Niño) or cold (La Niña)—produces varied and powerful effects on worldwide weather, leading to droughts, snowstorms, or hurricanes.

Currently, experts are watching the strong El Niño that began in 2023, anticipating its transition to a La Niña phase, though this change has not yet occurred.

A typical La Niña winter in the United States typically results in cold temperatures and snowfall in the Northwest, accompanied by unusually dry conditions across much of the Southern states, as noted by the Climate Prediction Center. Additionally, the Southeast and mid-Atlantic regions often experience higher temperatures during these winters.

Understanding El Niño

El Niño translates to “the Little Boy,” or “Christ Child” in Spanish. Its discovery dates back to the 1600s when fishermen off the South American coast noticed unusually warm Pacific waters around Christmas.

The comprehensive natural climate cycle is formally known as the El Niño-Southern Oscillation (ENSO), which alternates between warm and cool ocean surface temperatures along the equator in the tropical Pacific. La Niña is characterized by cooler-than-normal ocean temperatures in the same region.

Researchers focus on El Niño because it can significantly impact the jet stream, drying out the Northwest while bringing excessive rainfall to the Southwest, per a statement from Duke University. Conversely, La Niña tends to push the jet stream northward, leading to drier conditions in the Southwestern U.S., while also causing droughts in East Africa and intensifying the South Asian monsoon.

Significance of This Study

“Understanding past climates can guide our future,” stated Xiang Li, the lead author of the study from Duke University, in correspondence with YSL News. “Studying historical climate changes enables us to comprehend the driving forces behind future climate fluctuations, leading to reliable predictions. ENSO is the most significant climate variability mechanism, impacting extreme weather and climate worldwide.”

“Thus, studying past ENSO changes is of utmost importance,” Li emphasized.

Exploring the Distant Past

For this study, researchers employed the same climate modeling tools used by the Intergovernmental Panel on Climate Change to forecast future climate change, but they ran it in reverse to explore the deep past.

“In all our experiments, we observe an active El Niño Southern Oscillation that is predominantly stronger than what we see currently, with some instances showing significant increases,” remarked Shineng Hu, a co-author of the study and an assistant professor of climate dynamics at Duke University.

“In historical times, solar radiation hitting Earth was roughly 2% less than today, yet CO2 levels were much higher, causing a hotter atmosphere and oceans compared to modern times,” Hu noted.

During the Mesozoic era, around 250 million years ago, South America formed the central region of the supercontinent Pangea, and the oscillation took place in the expansive Panthalassic Ocean to its west.

Were the Findings Unexpected?

Li conveyed to YSL News that “as far as we know, there haven’t been other studies systematically examining ENSO’s geological history due to sparse geological data from the distant past.” By employing a cutting-edge model, “our research reveals the geological history of ENSO extending back 250 million years, showing significant variations in its intensity throughout history, which is both surprising and thrilling,” Li explained.

Hu succinctly concluded: “If we want to  make more accurate predictions about the future, it is essential that we first comprehend historical climates,” Hu stated.

The research was made available on Monday in the Proceedings of the National Academy of Sciences.

(This article has been updated to include additional information.)