Assessing storm surge impacts on coastal inundation due to climate change: case studies of Baltimore and Dorchester County in Maryland

Hurricane Isabel (2003) generated record flooding around Chesapeake Bay and caused extensive damage in rural Eastern Shore of Maryland and metropolitan cities like Baltimore. Regional atmosphere–ocean models are used to investigate the storm surge and coastal inundation that might be produced by a similar storm under the warmer ocean temperature and higher sea level projected for the future climate. Warming causes the storm to intensify, with the minimum sea level pressure decreasing from 955 mb during Isabel to ~ 950 mb in 2050 and ~ 940 mb in 2100. The stronger storm and higher mean sea level amplify the peak water level by ~ 0.5 m in 2050 and ~ 1.2 m in 2100. The total inundated area over Chesapeake Bay expands by 26% in 2050 and 47–62% in 2100. Over the rural Dorchester County, the inundated area shows moderate expansion in the future climate but the average inundation depth is 30% higher in 2050 and 50–70% higher in 2100. The number of houses flooded increases from 1420 during Hurricane Isabel to 1850/2190 in 2100 under the climate change scenario representative concentration pathway (RCP) 4.5/8.5. The inundated area in Baltimore is 2.2 km² during Hurricane Isabel, expands to 5.1 km² in 2050, and reaches 8.1/9.1 km² in 2100 under RCP 4.5/8.5. The estimated flood damage to Baltimore increases from $29 million in 2003 to $98/100 million in 2050 and $150/162 million in 2100 under the median projection of RCP 4.5/8.5. These estimates are subjected to uncertainty due to different climate change scenarios and different climate model projections.