When will climate science be able to distinguish clearly between a global-average manifestation of El Niño-driven global weather effects, and an explanation of global average warming associated with El Niño?
Concerning the latter aspect the World Meteorology Organization seems not able and willing to do the simplest considerations (Hottest Year). The feature is about a temporary warmer than normal SSTs across the central and eastern equatorial Pacific (ENSO), which looks like one water bubble or pool. Compared to ocean dimension it is merely “a drop in the sea”, and only a tiny fraction warmer than usual, namely about 0,5 to 3°C, with a little dip down to a depth of 100 meters (max 150m), whereas the mean Pacific depth is 4,280 m. Any rough calculation shows that there is not much El Niño can offer to heat the world and contribute to global warming. The water volume is not more than about 0,06% of the Pacific volume, and the ENSO area with higher than +3°C of average may possibly account for about 0,10% (Further details here). All oceans and seas contribute permanently heat to the atmosphere. El Nino is negligible in this respect. WMO should undertake more competent considerations, and talklessemptystuff.