Factors affecting temporal fluctuations in damaging storm activity in the United States based on insurance loss data

Insured weather losses in the US reached record highs in the early 1990s, leading to major concerns in the insurance industry about the causes, including the possibility of climate change due to global warming. Several studies addressing the interpretation of the record high losses used historical insurance data sets, those for crop-hail losses and others based on the catastrophic events to the property insurance industry, both covering the 1949-1995 period. The past loss values were adjusted by insurance experts for shifting coverage, inflation, and evolving construction practices. The resulting adjusted values of crop loss and costly catastrophes to property both showed similar distributions for 1949-1995, with losses being high in the 1950s and again in the early 1990s. This distribution was found to have a weak relationship with extra-tropical cyclone activity in the US, but most of the recent increase in weather losses to insured property was found to be related to shifting societal factors that have put ever more property at risk in storm-prone areas, including coastal areas and large metropolitan areas. The low property and crop storm losses of the 1966-1985 period had created an incorrect perception of the weather risk in the insurance industry, which did not understand nor appreciate the existence of the decadal-scale fluctuations that exist in climate conditions.