It sure looks impressive on the pictures you posted. But if you compare the scales carefully you will notice quite an off-set. I only compared two pictures the one of 2005 and the one of 2008.
2005: the orange tone starts at around 27°C
2008: the orange tone starts at 25°C
This off-set of around 2°C makes it look very dramatic while in fact it probably is not that bad. I'm not saying that SSTs are lower than average since i did not look at the numbers themselfs. But be carefull when looking at these pictures and compare their scales carefully.