A lot of things that might have been a catastrophic disaster 150 years ago are much less disastrous now due to our much-improved technology and better building practices. Conversely, because of our MASSIVELY increased population and the enormous size of our cities and coastal populations, some disasters that in the past were bad but not nearly the number deaths can now have death numbers in the hundreds of thousands. On the good side is that modern aid gets to the disaster area and that saves a lot of lives that in the past would have been lost in the after-effects of the disaster.
In the future, there will be major disasters but many of them can be greatly lessened if people will use their common sense. What happened in New Orleans was more the result of people sitting there and letting a cat 5 hurricane roll past them. Understand though it MISSED New Orleans and it was the backside winds coming from the north that caused the flooding. Had it hit dead on or to the west there would have been a storm surge and the deaths would have been unimaginable.
We need to evacuate when a HUGE hurricane is rolling in. We need to stop building massive cities on top of known big fault lines and stop building on the side of hills with heavy brush. WHEN not if these things bite us in the butt I would hope that the Government won't allow rebuilding in STUPID places like they did in New Orleans. They rebuilt in holes that are 12 feet below sea level. If a 35-foot storm surge rolls in EVERYONE in those holes will die...needlessly.