"Es waren" in:"...absurder, als seine wildesten Träume es waren"

Question

Es war absurder, als seine wildesten Träume es waren.

While I would translate it with the omission of es waren.

It was more absurd than his wildest dream.

So what does es waren actually mean? It is necessary to add it?

Answer 1

It is not necessary but it in fact part you can think of it as being part of every comparison.

Ich bin größer als Stefan (groß ist).

The "groß ist" is redundant and boring but for stylistic reasons I might use it. And of course I can replace "groß" by the generic pronoun "es". The other answer claims that the verb is there for grammatical reasons. I doubt that, because if this were the case, the following sentence would need one as well.

Ich trinke mehr Wasser als Maria und Thomas zusammen.

It would be not wrong to add "trinken" but I'd say most of the time people do not say it and it is totally fine to write that.

So why is it there? Maybe simply for stylistic reasons or to make clear that we're talking about dreams he HAD as opposed to dreams he HAS, which could be understood without the "waren" signaling past tense. Just compare these two examples:

Ich bin größer als Stefan. ("ist" is implied)

Ich bin größer als Stefan war.

If you want to read more about the underlying side sentence structure and how it explains why the comparing part comes after the final verb, I recommend this post on my blog. The relevant part is toward the bottom.

Answer 2

It is necessary because it puts the verb in the right number. The first "war" is in singular since it refers to "Es". "Träume" on the other hand is in plural so the verb needs to reflect that. Hence we need "es waren". In more words it says:

It was more absurd than his wildest dreams were absurd.

So actually it's basically the same as in English.