As you can see from the chart below, El Nino tends to occur away from the peak of the solar cycle. One of the outcomes of this is that the solar cycle’s effect on temperature gets underestimated, because El Nino lifts global temperature at times of low solar activity, and is suppressed at times of high solar activity. La Nina often occurs near the peak of the solar cycle, bringing a couple of cold winters with it. This fact is conveniently disregarded by Dr Leif Svalgaard, who continues to claim the effect of the solar cycle on temperature is only around 0.07C. Rubbish, it’s at least 0.2C, probably more, further amplified by cloud cover change. This means the steady rise in solar activity over most of the C20th was responsible for most of the warming observed, given the over-egging of the global temperature record by Phil Jones at UEA-CRU and James Hansen at NASA-GISS.
There is an exception to the rule around 1900 but temperatures were low then anyway. My theory, backed up by calculations I have done on steric sea level rise and the gradient of temperature to the thermocline, is that heat-energy is forced into the ocean as sun spot numbers rise, and is released back out of the ocean on the downslope of the solar cycle and just after minimum. The low run of solar cycles around 1900 allowed the ‘upwelling’ of energy to build up ‘momentum’ and so the heat release continued through the upturn of the low solar cycle. Something similar happened during low solar cycle 20.
The currently high global sea surface temperature is nearly at the same level as 1998, but this is not the whole story. Whereas 1998 was a full blown Pacific Warm Pool event, the current El Nino is a ‘Modoki’ event. This means heat-energy is rising out of the oceans over a broad area of the globe, but the SST’s are not very high in one particular area. This means that much of the heat will escape to space instead of being trapped in by high humidity and then spread around by the trade winds.
This is why temperatures over the continental masses are low, while global lower troposheric temperature is high. Blocking patterns have allowed warm air over the oceans to migrate to the poles, displacing cold air down over the northern hemisphere continents.
The question is, what will happen next? Looking at a similar situation in the past may help. Around 1880, global SST’s peaked in a huge El Nino event, then started to decline, with another big El NINO event 12 years later. Sound familiar? Look how similar the solar cycle phase was then and now.
I expect we will see a significant downturn in SST over the coming year. My prediction, for what it’s worth, is that global SST will be 0.1-0.15C below Jan 2008 levels by spring 2011.