15 Sep 1932, 4 – The Blocton Enterprise at Newspapers.com
NASA says earth was very cold from 1871 to 1932.
Here’s my plot of storm frequency (USA only), showing an upward bulge around 1930 to 1940 and a dip around 1970 to 1980. The source data URL is at the top.
It does look like the cooling in the 70’s was somewhat exceptional, from an historic perspective. That’s presuming all the data is available.
NOTE: I used the R function “density” to do the kernel smoothing and estimate the per-year storm activity at each different barometric pressure cutoff. Lowest pressure approximately equates to the most severe storms. Each colour represents a different cutoff so if you see a dip at every level (such as in the 1970’s) then it’s confirmed regardless of what type of storms you choose to count. In other places it’s somewhat more ambiguous but around 1930 most of the bulges go upwards.
Other points: the Bandwidth of 7 Years in the R way of doing things (what the statistical people do) means the Standard Deviation of the smoothing Gaussian … but people with a signal processing background would see bandwidth in -3dB or -6dB terms so at least double that to 14Y and add a bit more, it’s probably more like 16Y or there abouts. Because of the way this density estimation works (or any density estimation) you can’t trust the results at the edge of the graph, we don’t know that recent years are trending downwards because there’s not enough data to see a trend yet. These statistical calculations always give you more hindsight than foresight … it’s up to you to interpret the results.
I say there really was indisputable cooling in 1978. For the USA at least, it’s not so pronounced in the Southern data.
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