How much less flooding would there be right now without climate change?

General estimates are that El Niño is 30-60% more intense due to human caused climate change and will only get more intense.

We are adding energy to the system via our excessive consumption. The ocean sucks up a massive amount of that energy. Warm water expands, among other things(hurricanes).

probably as much flooding as during a typical pre-climate change El Nino.