Pliocene El Nino

The Pliocene Epoch is the period in the geologic timescale that extends from 5.3 million to 2.6 million years before present. The global average temperature in the mid-Pliocene was 2-3°C higher than today, global sea level 25 meters higher and the Northern hemisphere ice sheet ephemeral. A few years ago, however, Brierley’s team found evidence suggesting that the tropical Pacific was even warmer during the Pliocene than anyone had expected. The results were found in sediment cores drilled from the ocean floor. By analyzing the chemical properties of the sediment, researchers were able to determine the ocean’s temperature in the past. Their findings showed that a huge pool of warm water covered the vast majority of the Pacific and that the temperature gradient of sea surface was smaller than previously predicted—that is, the warm pool in the central Pacific was larger and more uniform in temperature. This warm pool is similar to the effects of the periodic El Niño phenomenon, which causes warming of the Pacific near South America. However, because the Pliocene pool was sustained, it has been dubbed a permanent El Niño