Increased threat of tropical cyclones and coastal flooding to New York City during the anthropogenic era

• Published in: Proceedings of the National Academy of Sciences
• Main Authors: Reed, Andra J., Mann, Michael E., Emanuel, Kerry A., Lin, Ning, Horton, Benjamin P., Kemp, Andrew C., Donnelly, Jeffrey P.
• Format: Report
• Language: English
• Published: 2015
• Subjects: Tropical cyclones; Flood height; Storm surge; New York City; Relative sea level; Hurricane; New Jersey; North Atlantic
• Online Access: https://hdl.handle.net/1912/7564

Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 112 (2015): 12610-12615, doi:10.1073/pnas.1513127112. In a changing climate, future inundation of the United States’ Atlantic coast will depend on both storm surges during tropical cyclones and the rising relative sea-levels on which those surges occur. However, the observational record of tropical cyclones in the North Atlantic basin is too short (AD 1851-present) to accurately assess long-term trends in storm activity. To overcome this limitation, we use proxy sealevel records, and downscale three CMIP5 models to generate large synthetic tropical cyclone data sets for the North Atlantic basin; driving climate conditions span from AD 850 to AD 2005. We compare preanthropogenic era (AD 850 – AD 1800) and anthropogenic era (AD 1970 – AD 2005) storm-surge model results for New York City, exposing links between increased rates of sea-level rise and storm flood heights. We find that mean flood heights increased by ~1.24 m (due mainly to sea level rise) from ~AD 850 to the anthropogenic era, a result that is significant at the 99% confidence level. Additionally, changes in tropical cyclone characteristics have led to increases in the extremes of the types of storms that create the largest storm surges for New York City. As a result, flood risk has greatly increased for the region; for example, the 500 year return period for a ~2.25 m flood height during the preanthropogenic era has decreased to ~24.4 years in the anthropogenic era. Our results indicate the impacts of climate change on coastal inundation, and call for advanced risk management strategies. The authors acknowledge funding for this study from NOAA Grants # 424-18 45GZ and # NA11OAR4310101 and National Science Foundation award OCE 1458904. 2016-03-28