While reading this week's portion, I was wondering why did Noach have in particular the merit to save the animals of the created world? They could have been saved in other ways, for example the Land of Israel was not flooded according to Bereishit Rabbah 33:6, but Hashem could have done a miracle or recreated them.
I think it is related to the fact that he was then allowed to eat the animals (after the mabul). If they don't owe man their lives, why would man be allowed to take their lives for his needs?
Edit: I have found this opinion at Nachmanides on Genesis 1:29.
Rabbi Belsky had a related question, and his answer will answer your question as well. This is printed in his Einei Yisroel on Torah, but I heard it from him live.
He asked why was Noach the tzadik chosen through which the world was saved? Chazzal imply that Mesushelach and Shem were actually greater tzadikim than Noach. See Sukkah 52b which calls Mesushelach one of the seven Shepherds and Shem ben Noach (according to Rashi there) was one of the four craftsmen mentioned in Zecharia 2:3. Noach was on neither of these lists. So why choose Noach And not one of them?
He answered the following. Hashem decided to destroy the world reasoning that all life was reprehensible. So who can prove that life, gashmius, deserves to exist? Through people who were so perfect that they are practically on the level of angels, pure ruchnios? It wouldn't work. Their greatness was attained by removing themselves from this world, not from being involved in it. They could not prove that the world should survive. Rather a tzadik like Noach, described as a man of the land (9:20) was the perfect representative to prove that physical life deserved to exist.
Getting back to your question. The point of Noach, according to this, was not simply to be a vehicle for saving the world. His behaviors and his actual being were part of what was necessary to save the world.
I would add that this approach also helps us understand why we have opinions in drashos going out of the way to point out that Noach was only considered a tzadik in his generation (תָּמִ֥ים הָיָ֖ה בְּדֹֽרֹתָ֑יו) and that Noach, unlike Avraham needed support for his righteousness (אֶת־הָֽאֱלֹהִ֖ים הִֽתְהַלֶּךְ־נֹֽחַ). Also his partial disbelief proven by his not going into the Teivah until the water forced him to (מִפְּנֵ֖י מֵ֥י הַמַּבּֽוּל). (See Rashi on all these pesukim). Noach's greatness was not in his otherworldly greatness like other tzadikim. His greatness was a different type. The type needed to prove that the world deserves to exist. All of Noach's imperfect actions up until his ignoble forced exit from the Teivah (הוצא) [הַיְצֵ֣א] 8:17 (see Rashi) and perhaps even his drunken behavior after exiting, are all part of the complicated figure we know as Noach who was able to prove through his imperfect perfection that man and the world deserve to exist. And as mentioned before, this was more than just being the vehicle for Hashem's decision.