Increased Flood Risk resulting from Climate Change over an Urban Catchment: A CMIP6 Multi-model Analysis

Precipitation extremes are increasing globally. The increased frequency and intensity create a higher risk of urban flooding. There is a need to quantify this increased risk for the protection of life and property as well as for better infrastructure planning and design. We used 14 CMIP6 model outputs to identify flood-producing storms, their frequency, and intensity in the historical period for southeast Michigan. We place special emphasis on the meteorological mechanisms that lead to extreme precipitation. The uncertainties of these extreme precipitation occurrences in the medium (ssp245) and upper medium (ssp370) pathways of future greenhouse gas emissions are also analyzed. Frontal systems are the dominant mechanism of flood-producing storms in the region. As such, we identify the frequency, and intensities of frontal systems during the historical period and projected future simulations. This study aims to explore two primary questions related to climate change impacts on flood risks over the urban catchment. (1) How are flood-producing events represented in the historical and pre-industrial era, and how will they change in the future? (2) how can changes in temperature due to climate change, precipitation intensification, and increase in population affect flooding potential for at-risk populations in the future?