Those gravity-defying levees, along with pumping stations designed to move water away from the center of the Earth, kept the city pretty darn dry.

NPR: Defying Gravity, and Odds, in New Orleans

According to his calculations, about 20 years of lead time would be sufficient for solar radiation to move the asteroid away from its current course causing it to come nowhere near the Earth.

FORBES: An Earth-Killing Asteroid Could Be Deflected With Paintballs