Research has shown that Southern Oscillation is known to influence global surface temperatures, with El Nino conditions leading to warmer temperatures and La Nina conditions leading to colder temperatures.
A new study shows that some types of El Nino do not have this effect, a finding that could explain recent decade-scale slowdowns in global warming.
The authors examine three historical temperature data sets and classify past El Nino events as traditional or central Pacific.
They find that global surface temperatures were anomalously warm during traditional El Nino events but not during the central Pacific El Nino events.
They note that in the past few decades, the frequencies of the two types of El Nino events have changed, with the central Pacific type occurring more often than it had in the past, and suggest that this could explain recent decade-scale slowdowns in global warming.
The study is published in Geophysical Research Letters.