[erghjunk]

> The degree of "El Nino" influence is presumably known, and if its strength is not related with global warming in complicated and unknown ways it would be good to overlay it as a distinct effect.

A brief web search suggests this presumption is incorrect and that climate change is having an effect on the cycle, rendering this division somewhat meaningless - the old El Nino is "gone," in a sense, and only the climate change effected one remains.

from: https://research.noaa.gov/2020/11/09/new-research-volume-exp...

“No two El Niños or La Niñas are perfectly alike,” Capotondi said. “We’ve seen how diverse ENSO events can be. This diversity adds another degree of complexity for understanding how climate change will influence future ENSO events.”

So how are ENSO impacts likely to evolve in the coming decades?

“Extreme El Niño and La Niña events may increase in frequency from about one every 20 years to one every 10 years by the end of the 21st century under aggressive greenhouse gas emission scenarios,” McPhaden said. “The strongest events may also become even stronger than they are today.”

and here is the full book: https://agupubs.onlinelibrary.wiley.com/doi/book/10.1002/978...

[nologic01]

The chapter on "ENSO Diversity" seems the most relevant for this discussion but it is alas behind a paywall.

The available summary does not hint there is something conclusive yet on these interactions: "Current research seeks to determine whether such changes in ENSO characteristics were the result of anthropogenic greenhouse gas forcing or just a manifestation of natural variability, and whether and how climate change may affect ENSO diversity in the future."