Well, if it makes a testable prediction, which is borne out by empirical evidence, then it's worthy of investigation and further development.
Here are my reservations about it:
* There's no trace of a plausible explanation for why cooperativity would foreshadow El Niño the next year. Of course, if it's a real empirical discovery, then the explanation could come later.
* The result could be fluke resulting from an arbitrary conjecture whose parameters were optimized using too small a dataset. The training and predictions periods are each about thirty years long. I saw it stated that during the training period there were ten El Niño events. Can statistics be applied here, to help address this concern? (Though we'd have to view statistical reassurances also with a grain of salt.)
In other words, I'm concerned that this is like applying machine learning to the predictions of a set of Tarot cards.