2017 to be one of the hottest years

Weak El Nino root cause of increased surface temperature, say researchers

Washington, April 28: 2017 will be among the hottest years on record, say scientists who have developed a new method for predicting global mean temperature.

Researchers at Yale University in the US found that weak El Nino activity from 1998 until 2013, rather than a pause in long-term global warming, was the root cause for slower rates of increased surface temperature.

They also found that volcanic activity played only a minor role. “From a practical perspective, our method, when combined with El Nino prediction, allows us to predict nextyear global mean temperature,” said Alexey Fedorov, professor at Yale University.

“Accordingly, 2017 will remain among the hottest years of the observational record, perhaps just a notch colder than 2016 or 2015,” Prof. Fedorov said.

El Nino events contribute to year-to-year variations in global mean temperature by modulating the heat released from tropical oceans into the atmosphere, researchers said.

El Nino warms the atmosphere, while the cold phase of the phenomenon, La Nina, cools the atmosphere. The new model closely mirrors global mean surface temperature (GMST) changes since 1880, including the socalled global warming hiatus and the more recent temperature rise.

“Our main conclusion is that global warming never went away, as one might imply from the term ‘global warming hiatus,’” Prof. Fedorov said. “The warming can be masked by inter-annual and decadal natural climate variability, but then it comes back with a vengeance.”

Multiple strong El Nino events occurred in the 1980s and 1990s. This was followed by much weaker El Nino activity, which lasted until 2014.

“The recent rapid rise in global temperature mainly resulted from the prolonged 2014-2016 El Nino conditions in the tropics that reached an extreme magnitude in the winter of 2015,” said Shineng Hu, author of the study published in Geophysical Research Letters. — PTI