Knowing the climate of the past often opens a window on our future. A study published on September 25 in Nature illustrates it once again. Based on past glacial changes, it demonstrates that extreme El Niño events will become more frequent as our planet warms.
El Niño is the warm phase of the natural phenomenon known by the acronym Enso (for El Niño – Southern Oscillation). It is an irregular cycle between higher and lower than average temperatures in the equatorial Pacific Ocean, which amplifies climate variability across the world. The influence of anthropogenic warming on Enso has until now been a highly debated question.
By analyzing tiny shells – planktonic foraminifera – that lived 21,000 years ago, when the last ice age was at its peak, researchers were able to estimate the temperatures of the Pacific Ocean at that time. Then they compared this variability to what the numerical models give for that time.
The idea, explains New Scientist, it’s that“a match between the two would demonstrate the accuracy of modeling of past El Niño behavior, when
