Is the El Ninyo/El Ninya (and I spelled it that way on purpose, ie, why do we spell "canyon" like we do) caused not by global warming, but instead by underwater volcanos?

Maybe so.  More research needs to be done, but in the meantime, look at these charts of water temperature in the Pacific.

In February of 2009, there is the development of hotspots off the coast of Costa Rica, inside the red rectangle.

Next, several months later, the temperature picture is much hotter, and the point sources of that heat are clear.  Those sources are right at the boundry of the Cocos Plate, which plunges under the continent at those points, a very likely spot for the formation of volcanos.

Mystery solved?

In the article, the point about the heat from the sun and atmosphere not being enough to warm the volume of water needed is interesting.  I'd like to see some research that investigates that more thoroughly, since if that heat source is clearly disproved, then it's only the volcanos that can be to blame.