2015 El Niño is Unique

Many governments around the world are implementing contingency plans to limit the impact of the ongoing El Niño, the strongest since 1997-1998 and potentially among the four strongest events since 1950.

WMO announced on 1 September that the El Niño is expected to peak sometime during October 2015 to January 2016. It is likely that surface water temperatures in the east-central tropical Pacific Ocean will exceed 2° Celsius above average – well above the El Niño threshold of 1° C. National Meteorological and Hydrological Services in affected countries have been active in providing tailored advice to the general public and all levels of government to cope with related drought, floods and other extremes.

“Compared to the last major El Niño event in 1997/1998, there is much more information available,” said Maxx Dilley, Director of the WMO Climate Prediction and Adaptation Division. “We have better models and are much more prepared.” Mr. Dilley added that this El Niño “is a test case for the early warning systems and climate information systems of WMO Members. We are hoping that they will be of assistance to affected countries.”

Ahead of the full onset of this El Niño, 2014 was nominally the warmest year on record, with record ocean heat and high land-surface temperatures. This trend has continued in the first seven months of 2015, which have witnessed many extreme events ranging from devastating flooding to extreme heat and drought. No two El Niño events are the same, and other climate phenomena also play a role. The inter-play between the El Niño Southern Oscillation (ENSO)* and climate change is the subject of concerted research.

David Carlson, Director of the WMO co-sponsored World Climate Research Programme (WCRP), said that the 2015 El Niño is the first to take place in an environment of rapid melting of Arctic sea ice and snow cover. “The last big El Niño was 1997-1998. The planet has changed a lot in 15 years,” said Mr Carlson. “We have had years of record Arctic sea ice minimum. We have lost a massive area of northern hemisphere snow cover, probably by more than 1 million square kilometers in the past 15 years. We are working in a different climate and we do not fully understand the new patterns emerging.”

El Nino taking shape in 2015 A new animation compares the blockbuster 1997-1998 El Nino to the strong El Nino taking shape in 2015. Carlson explains that the 2015 El Niño is unique because of the unprecedented combination of the Equatorial influence of El Niño, and the Arctic influence of low sea ice and snow cover in place at the same time.

“This is a new planet. Will the two phenomena reinforce each other or cancel each other out? We have no precedent. Climate change is increasingly going to put us in this situation. We have not had a previous event like this,” he said. In order to maximize understanding of this El Niño and to boost research into the phenomenon, WMO and the International Research Institute for Climate and Society are organizing a major conference in New York on 17-18 November.

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