Paul Douglas’ Claims Don’t Stand Up To Scrutiny
By Paul Homewood
I return to that piece in the Guardian last week, in which US meteorologist claims that he can see global warming’s effect on weather.
It is sometimes useful to look at things at the local level. Douglas, who lives in Minneapolis, claims that rainfall rates are increasing there and that flooding is worse.
If we look at the NOAA precipitation chart for Minnesota, we can see rainfall does appear to have increased in the last few decades.
However, Minneapolis itself has precipitation records going back much further than 1895, indeed right back to 1836.
[This is an interesting story in itself. The earliest weather observations, up to 1858, were taken at Fort Snelling by the military, after which they were taken over by St. Paul Smithsonian, by which time Minnesota was a fully fledged territory. The 19th records have been thoroughly researched, and much more detail can be found here.)
There is a USHCN station at Minneapolis, so we can look at the long term precipitation data back to 1836.
Lo and behold, we see that annual rainfall totals in recent decades are little different to the late 19th and early 20thC. Indeed what we can see quite clearly is the long period of drought from the 1920s to 50s.
The Climate Stations website, which has archived the historical records mentioned above, have this chart, starting in 1859, which perhaps shows rainfall trends more clearly.
Now, I am not going to attempt to make a value judgement between drought and floods. But it is clear that any recent trends in rainfall must be looked at in terms of a much longer perspective, one which makes it apparent that global warming has not had the claimed effect.
Of course, these are only annual numbers, so maybe Douglas is correct that extreme rainfall is increasing?
Unfortunately for him, though, USHCN also have this whisker plot of monthly rainfall.
There is absolutely no evidence that monthly totals are becoming more extreme. By far the wettest month was a long time ago, in July 1987.
USHCN only plot daily data back to 1938, but even this offers no evidence that daily extremes are on the increase.
Either Paul Douglas is not aware of the long term climate in Minnesota, in which case he is totally incompetent, or he is lying.
Of course, this is only one city. But Douglas is making claims about global weather events, when his claims in his own backyard don’t stand up to scrutiny. When that happens, I call BS!!