Making Climate Change Personal: Enabling Action Through Communication of Flood Risk Science to Individuals

Abstract:

The First Street Foundation has delivered a new flood model to communicate climate change risk for each of the 142 million properties in the contiguous US. First Street developed this product to raise awareness of the past, present and future flood risks, and to empower individuals to take steps to mitigate climate impacts on their homes and properties. First Street developed a 3 m resolution model total risks from combining fluvial, pluvial, tidal, and surge flood elements built upon existing peer-reviewed scientific information products. These include a nationwide 30 m hydraulic simulation by Fathom (Wing, et al, 2017), as well as coastal sea level and surge impacts by the Rhodium Group (Kopp et al, 2017; Emanuel, 2017). These models are driven by open data from the USGS (DEMs, river gauges), NOAA (rainfall frequency distributions, tide and river gauges), and USACE (levees). Scenarios modeled include current (2020), and future (2035, 2050) climate conditions from IPCC CMIP5 outputs (NASA NEX-GFFP) under RCP 4.5 assumptions (Moss et al, 2010). Flood hazard depths and risk probabilities were calculated for multiple annual flood probabilities from 0.2% (1 in 500 years) to 50% (1 in 2 years) for each of the 142 million U.S. properties. The complexity of these climate change and environmental inputs are distilled for the individual property owner into a single 30-yr cumulative flood risk score ranging from 1 (minimal risk) to 10 (extreme). These estimates are presented to the public for free at floodfactor.com, along with local statistics and visualizations of historic, current and future flood scenarios, as well as suggestions for addressing those flood risks. By democratizing access to this information, First Street enables individuals to act on sound science and removes the asymmetry typically associated with the availability of flood data. The Foundation’s costs associated with the model and the public dissemination of the risk estimates are being offset by the commercial value of bulk data access for industry. The First Street Foundation Flood Model is the first property level, nationwide flood risk assessment ever available for the U.S., and enables the public to understand their future risk and take action to address it.