Changing urban risk: 140 years of climatic hazards in New York City

Weather-related disasters are on the rise. The causes, whether driven by climate change or changes in exposure and vulnerability of social-ecological-technological systems are still uncertain. Here, we address this issue with an in-depth study of the variability in climate-related extreme events which have impacted New York City (NYC) over the past 140 years. NYC has not historically been viewed as a particularly hazard prone region. However, this perspective is changing, particularly after the disastrous consequences of Hurricane Sandy (2012). We constructed a systematic database of impactful climatic events and assessed multi-sector impacts. Results indicate that hazards have systematically affected the city, with heat waves as the deadliest events and hurricanes as the costliest. We analyzed climatic hazard trends focusing on heat waves and flooding only, since data for these events are available over the full-time frame of the study. We then examined impacts of the most severe of these two hazards using data from The New York Times. Our analyses show that flooding and heat wave extreme events have regularly affected the city over its history with a trend toward increasing mean number of hazards per decade. We highlight a trend of decreased mortality due to heat waves over time and increase in the impacts of heavy precipitation, primarily related to the expansion of the transportation system and potentially to climate change over this time period. We suggest that, especially in urban areas of developed countries such as NYC, changes in built up infrastructure may be the primary drivers of risk to natural hazards.