Sea surface temperature in the Indian Ocean. Image from the earth|nullschool real time visualisation of wind and ocean conditions
There is a 60% likelihood of an El Niño being fully established between June and August, increasing to 75-80% for the October to December period, according to an El Niño Update issued by the World Meteorological Organisation (WMO). Many countries have already started preparing for the arrival of El Niño, which is associated with regional-scale drought and flood situations in different parts of the world and has a warming influence on global average surface temperatures.
El Niño is characterised by unusually warm ocean surface temperatures in the central and eastern tropical Pacific, coupled with typical atmospheric circulation patterns. It is a natural phenomenon with a recurring interval of 2-7 years and has a major impact on the climate around the world. The last El Niño was in 2009-2010.
The latest WMO outlooks suggest that central tropical Pacific Ocean surface temperatures are likely to warm further into the third quarter of 2014, while the atmospheric patterns associated with El Niño are also expected to form and strengthen.
The WMO expects that El Niño will reach peak strength during the fourth quarter and endure into the first few months of 2015 before dissipating. The substantially above-average oceanic heat content beneath the sea surface of the central and eastern tropical Pacific Ocean, triggered by strong westerly wind events earlier this year, suggested an event of significant strength. However, the delayed atmospheric response, and a potential lack of subsequent westerly wind events in the coming months, may limit the peak strength of the El Niño, said the WMO.
Already, the second quarter of 2014 set new global atmospheric heat records. According to NASA, this May was the hottest in the global measure, meanwhile, the Japanese Meteorological Agency marked the March-April period as the hottest spring in all of the past 130 years (NASA showed the same period was second hottest). Rising Pacific Ocean surface temperatures by themselves were enough, when combined with raging human greenhouse gas heat forcing, to nudge atmospheric temperatures into a new record range. But the emergence of full-blown El Niño will likely push current record readings even higher.