What comes after that is likely to be neither El Niño nor La Niña. Instead, we’ll be in a phase affectionately nicknamed “La Nada.”
The more technical name is “ENSO-neutral,” characterized by the absence of both El Niño and La Niña. Neutral “La Nada” times can make predicting seasonal weather a bit more challenging.
It's more of a wildcard. There may be some crazy weather patterns over the US that are not entirely predictable, like that tornado spree that happened a few days ago.
That is a really good/complex question! The earth is just a system of systems. We do have an effect on it. A lot of our problem is our contribution to trends that are already happening and disrupting them. It's basically always trends not single events/things. Life has always been a huge driver, and as we are so dominate we have an effect on the velocity of these big systems.