Understanding the Impacts of Climate Change on “Billion-dollar Disaster” Precipitation Events in the United States

Abstract:

Extreme precipitation and associated flooding are two of the most common and destructive natural hazards, accounting for tens of billions of dollars in damage each year in the United States alone. Additionally, there is growing evidence that precipitation extremes have been intensifying, with many of these changes attributed to anthropogenic climate change. Understanding how climate change affects extreme precipitation, and particularly the events that lead to large flooding-related disasters, is critical to effective climate change mitigation and adaptation. Current understanding of how global climate change affects local or regional precipitation extremes is still limited by the fact that general circulation models (GCMs) do not explicitly resolve precipitation processes. However, extreme precipitation events in a given region typically occur during a subset of large-scale atmospheric circulation patterns, which are well resolved in GCMs. Thus, to better understand the link between changes in climate and localized precipitation extremes, we use pattern classification methods to identify the atmospheric circulation conditions associated with historic extreme precipitation events. We initially focus on ‘billion-dollar’ flood disasters (those with greater than $1 billion dollars in damage) that have occurred over the U.S. Midwest region. After determining the conditions associated with these historical extremes, we use global climate model simulations from the CMIP6 project to analyze whether the frequency and intensity of these circulation patterns are changing with anthropogenic climate forcing. Overall, this research provides insight into how climate change is impacting the most devastating precipitation events.