El Niño: A Historic Climate Oscillation Spanning 250 Million Years

A new study from Duke University indicates that the El Niño oscillation has existed for at least 250 million years, often exhibiting greater intensity than current occurrences. The research, published in the Proceedings of the National Academy of Sciences, highlights the significance of ocean thermal structure and atmospheric wind patterns in influencing these climate oscillations.

A recent study from Duke University reveals that the El Niño oscillation—characterized by warm ocean waters in the tropical Pacific that impact global weather patterns—is not merely a contemporary event. This research indicates that El Niño, alongside its cooler counterpart La Niña, dates back at least 250 million years and exhibited magnitudes often more significant than those observed today. The findings, published in the Proceedings of the National Academy of Sciences, indicate that the intensity of these temperature fluctuations was heightened in earlier eras, even with continental configurations differing from the present. Shineng Hu, an assistant professor of climate dynamics at Duke’s Nicholas School of the Environment, notes, “In each experiment, we see active El Niño Southern Oscillation, and it’s almost all stronger than what we have now, some way stronger, some slightly stronger.” The El Niño phenomenon affects weather by altering the jet stream, leading to drier conditions in the U.S. Northwest, while simultaneously causing excessive rainfall in the Southwest. Conversely, La Niña tends to shift the jet stream northward, resulting in droughts in the southwestern U.S. and intensifying dry periods in regions such as East Africa. Utilizing a climate modeling tool similar to that used by the Intergovernmental Panel on Climate Change (IPCC) for future climate predictions, researchers conducted simulations for the deep geological past, although they could not analyze each individual year due to computational constraints. Instead, they divided their study into 10-million-year segments and executed 26 such simulations. The study reveals that two critical factors influencing the magnitude of historical oscillations are the ocean’s thermal structure and the atmospheric noise generated by ocean surface winds. Hu emphasizes that past research has been predominantly focused on ocean temperatures, thereby neglecting wind patterns which are crucial for comprehending the oscillation’s dynamics. Hu illustrated the interaction of these components with a metaphorical comparison to a pendulum, as he stated, “Atmospheric noise – the winds – can act just like a random kick to this pendulum. We found both factors to be important when we want to understand why the El Niño was way stronger than what we have now.” Furthermore, he asserted, “If we want to have a more reliable future projection, we need to understand past climates first.” This pivotal research was funded by the National Natural Science Foundation of China and the Swedish Research Council Vetenskapsrådet, with simulations executed on the High-performance Computing Platform of Peking University.

The El Niño Southern Oscillation (ENSO) is a climatic phenomenon that can substantially influence global weather patterns. While often viewed through the lens of contemporary climate science, emerging evidence suggests that variations in this oscillation precede human existence by millions of years. This study by Duke University researchers adds significant depth to the understanding of ENSO by revealing its historical prevalence and intensity, highlighting critical variables that shape its behavior.

The study from Duke University establishes that the El Niño phenomenon has been an active force in Earth’s climate system for at least 250 million years, showcasing oscillations of greater intensity than those observed in the present. This research underscores the importance of considering both ocean thermal structures and atmospheric dynamics in understanding historical climate patterns, which may aid in improving future climate predictions.

Original Source: www.eurekalert.org