The causes of the warm SST anomaly are discussed in a new paper by Bond, Cronin, Freeland and Mantua. http://onlinelibrary.wiley.com/doi/10.1002/2015GL063306/abstract They show that anomalously high atmospheric pressure in middle latitudes leads to less cooling of the ocean water during the winter season. The atmospheric high pressure anomaly is, I have argued, organized by the SST anomalies in the Tropics. But let's think about the energy involved in warming the North Pacific. The warm anomaly extends over an area of about 1000 by 3000 kilometers and is about 100 meters deep. To warm that volume of water by one degree requires about two million Tera Joules of energy. The two nuclear bombs dropped on Japan during WWII totaled about 147 Tera Joules, so they would provide a negligible fraction of the energy necessary to warm the ocean. During the single month of July the sun makes available about five million Tera Joules to the same patch of ocean. So heating from Fukishima can do very little to affect the temperature over such a large mass of ocean, in comparison to the natural processes that move solar energy through the climate system. By changing the greenhouse gas composition of the atmosphere, though, humans can affect the flow of energy through the climate system and influence the global surface temperature that way, just to be clear. (A Tera Joule is 10^15 Joules. A Watt is a Joule per second.)