Effect of Climate-Related Sea Level Rise on Sandy Flooding and Damages in New York City

Abstract:

Quantifying the contribution of climate change to observed extreme weather events and the damages they inflict is important for weighing costs and benefits of climate change mitigation efforts. Especially the attribution of observed extreme events, like hurricane Sandy, to climate change is often hotly debated. This can, however, be resolved in part for coastal flooding by evaluating the additional damage caused by the incremental increase in flood depth and extent from climate change-driven sea-level rise -- separate from the question of whether climate change contributed to the strength, path or origin of a storm. Here, we analyze Sandy by accurately simulating the observed flood with the ADCIRC model, and then simulating the same event but using a lower sea level. We find that in the absence of ~20cm of sea level rise caused by climate change, Sandy would have flooded significantly less land, houses and population, resulting in at least 10% less direct flooding damages in New York City than observed, translating into a difference in absolute terms in the billions of dollars.