Shavua Tov. Every year when reading Parshat Noach, we make comparisons between the righteousness of Noach as compared to Avraham Avinu. Emphasis is placed on the word בדורותיו, “in his generation”. This implies that had נח lived in a different generation, like Avraham’s, he would not be seen as such a great צדיק.
The common view of most commentators is that the main point that separated Avraham from Noach, was his concern for the masses. We do not find Noach pleading with Hashem to save the world in the manner that Avraham tried to save the cities of Sdom.
A true leader is meant to feel the pain of other human beings, even if it does not affect him directly. This is particularly taught in Pirkei Avot when it says, אל תפרוש מן הציבור, that one should not separate himself from the community. The pain of one Jew, is the pain of every Jew.
In addition to all of this, the Torah says that נח entered the Ark מפני מי המבול, because of the waters of the flood. The Rabbis explain that Noach was weak in his Emuna. He himself didn’t even believe there would be a flood until the rains came. Avraham was a man of faith. Hence, Avraham was considered far greater than Noach.