Here are the two El Niño maxima of the last 20 years, both of which caused peaks in global temperatures for the following year (1998 and 2016)
The Pacific releases vast amounts of acquired heat to the atmosphere roughly every 18 years as water sloshes back from Indonesia. If anything 1997 looks the stronger of the two.
Here is an animation of the period January 1997 to October 2017
Maybe something else, at least in part, is taking place. GMST peaked in the 1st quarter of 2016. The ONI dropped in the 1st quarter of 2016. OHC, 0 to 2000 meters, peaked the 1st quarter of 2016. So it appears to me that some of the OHC loss that people think is being vented to the atmosphere is actually dropping below the 2000 meter level in the Western Pacific. That would reduce OHC, as measured, but it is not lost to the atmosphere.
The recent El Nino appears clearly in the Tropical SSTs. In contrast to 1998, there were also summer warm pulses in the North Atlantic adding to annual warming.
https://rclutz.wordpress.com/2017/11/15/october-ssts-warm-slightly/
Another reflection: The global SAT trend between 1998 and 2016 has not been quite as high as suggested by the model average ( about 0.2 C/decade).
However, the change between the Nino peaks (the annual temperatures of 1998 and 2016) suggest a trend of around 0.2 C/ decade.
So it looks like the global warming has been latent, with global SAT suppressed by strong trade winds and cooling of the equatorial Pacific, but when the trade winds relax the SAT quickly pops up to the expected levels..
It is the steady increase in OHC that constitutes the basis of global warming, whereas SAT and troposphere temperatures are highly variable, reflecting the current state of the atmospheric circulation and oceanic interaction.
That sounds correct to me. Nearly 70% of the earth’s surface is Ocean and SSTs dominate the global average. Heat is absorbed mainly in the top mixed layer, so surface warming is slowed by extra heat capacity. El Nino is a way of releasing some of this stored heat back to the atmosphere. However this is a completely natural process.
Once CO2 levels stabilise so will ocean temperatures as a new dynamic equilibrium is reached.
It appears to me that in most El Niño events there is no discernible loss of OHC. Trenberth noted that there was a major drop after the 97-98 El Niño, but most of that appears to have taken place during the deep and long La Niña that followed. The GMST goes way up during an El Niña because lack of wind allows the Eastern Pacific to be free of upwelling. That means SST there spikes upwards, the water is holding relatively still and the sunlight that is being drilled into each day stays right there in the Eastern Pacific. Presto, instant and persistent heating. Consequently there is an upsurge in equatorial evaporation.
It’s the wind, or lack there of, as Olof notes. Matthew England has a new paper this month that extends his paper on the intensified trade winds that visited the Eastern Pacific during the period that was once called “The Pause”. It does not appear to me that anybody really knows what caused the intensified winds. One paper suggested Chinese aerosols. Nobody knows if they are coming back. The current La Niña condition appear to be punchless. They intensified trade winds are not back now, so the thing that was holding the trend of the GMST below .2 ? is currently absent. That could mean the trend will soon be .2 ? per decade.
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