NCEI (the National Center for Environmental Information) has some fascinating data about the number, and cost, of billion-dollar climate related disasters in the U.S. since 1980. Cost estimates are adjusted for CEI (the Consumer Price Index) in order to make older costs comparable to their modern counterparts.



Perhaps most basic is the number of such disasters each year, which is usually presented in a graph like this one:

I prefer this graph, which is not as attractive but is, I think, just as informative — and I’ve fit a trend line using Poisson regression:

Clearly it has been going up, and tied the record in 2017 (the most recent complete year). That year also broke the record for total cost of billion-dollar disasters in the U.S., over $300 billion total:

Since the data report individual types of disaster, I was interested in which ones show statistically significant change over the period of record.

A few things to note are that some categories are actually multiple; for example, “drought” includes heat waves. Also, some categories don’t count individual events, they simply record “an event” if that category cost a billion dollars or more throughout the year. Wildfire, for instance, is never reported as multiple events, it’s either zero (when the total yearly cost is under a billion) or one (when it’s a billion or more). With those caveats in mind, I looked for statistically significant changes in both the number, and the cost, of each of the seven categories of climate-related disaster.

Three different categories passed statistical significance at 95% confidence. First is flooding, for which the number of billion-dollar floods has gone up:

The second category is severe storms, for which both the number and the total cost has gone up:

Last but not least is wildfire, and again both the count (despite always being zero or one) and the cost have risen:

What is abundantly clear is that the number of billion-dollar climate-related disasters has risen, both the total and at least three of the individual categories. All are going in the direction expected due to man-made global warming. That’s because they are due to man-made global warming.

Cue the climate deniers to invent excuses (often ridiculously contorted, sometimes outright lies) to blame it on something — anything — other than climate change.

Cue the American taxpayer to foot the bill for $300 billion in climate disasters.

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