Climate extremes similar to what was seen in 2010’s Pakistani flooding and 2011’s Australian flooding are likely to continue as the world gets warmer, say scientists behind a new report.
Researchers from the Universities of Oxford and Leeds have found that the El Niño Southern Oscillation (made up of El Niño and La Niña) will likely continue into a warmer Earth, based on findings that showed ENSO continued during Earth’s last great warm period, the Pliocene, when global mean temperatures were about 2-3ºC higher than today and carbon dioxide levels were similar to the present day.
Because of the similarity in carbon dioxide levels and the added bump in temperatures, the Pliocene is a good predictor of what Earth’s climate is likely to look like over the rest of the 21st century.
The results of the study showed that the swinging between El Niño and La Niña continued during the warmer Pliocene, when scientists had expected El Niño to remain a constant factor in the Pacific. Instead, they have found that not only are El Niño and La Niña likely to continue to swing back and forth, but that they could even do so with more frequency.
“We know from previous studies that the mean state of the Pacific during the warm Pliocene was similar to the climate patterns observed during a typical El Niño event that we see today,” said lead Scientist Nick Scroxton from Oxford University’s Department of Earth Sciences.
“However, until recently it was believed that a warmer Pacific would reduce the climate swings that cause the dramatic weather extremes throughout the region leading to a permanent state of El Niño. What we didn’t expect was that climatic variability would remain strong under these warmer conditions.”