Also, note that El Nino is a seasonal phenomenon. At the decadal level, the things that matter are probably PDO/AMO/solar activity, in addition to greenhouse gas forcing.
(There are some claims about some kind of relationship between El Nino frequency and PDO phase, but I wasn’t really able to get a good understanding of the overall state of current research).
Also, note that El Nino is a seasonal phenomenon. At the decadal level, the things that matter are probably PDO/AMO/solar activity, in addition to greenhouse gas forcing.
(There are some claims about some kind of relationship between El Nino frequency and PDO phase, but I wasn’t really able to get a good understanding of the overall state of current research).