German daily Bild here reports on a study commissioned by the Hamburg Environmental Office. The study, which projects what Hamburg’s climate will be like in 2050, was carried out by the University of Hanover and a company named Geo-Net.
To say the least, the study appears to be another example of customized science for pay. The study’s conclusion Bild writes (like we’re really surprised):
The number of days with a maximum temperature of over 25°C increases: At the moment the number is 21 in the city centre, but in 2050 it will be up to 29!”
To me that sounds like a welcome improvement. Who wouldn’t mind a few extra warm days in cool, dreary Hamburg? And what’s the reason for the extra warm days? Climate change of course, the study says. But, surprisingly, it also cites the urban heat island effect as a reason.
Number of 30+°C days will almost double
Of course, every environmental study needs something dramatic with which to scare public. Bild adds:
There are also going to be more heatwave days with temperatures over 30°C: In the city there are now 6 per year. In 2050 that figure will be 11!’Because of climate change, the figures will almost double,’ the scientists say.”
Now there are a few things about the number that seem peculiar. Firstly, today 21 days are over 25°C – of which 6 are above 30°C (29%). But in 2050 the numbers change to 29 over 25°C, of which 11 will be over 30°C (38%). Or, in other words, of the 8 extra days over 25°C, 5 will be over 30°C. If one imagines a Gaussian distribution curve, the study’s mathematical claim is pure nonsense. Shifting the curve to the right will not create such a result.
The second point is: what trend are we seeing now? Are we really getting more and more hot days in Hamburg?
I went back into the records for the last 10 years and here’s what I found for the number of days over 30°C:
The first 5 years saw 26 days of 30+°C (average = 5.2 days). The second 5 years we saw 24 days (average = 4.8 days). Here we see that the last 10 years are below the average of 6 days per year that the study says is normal for Hamburg. Moreover, the last 5 years were less than the 5 years before, indicating heat days are likely declining, and not increasing.
Of course this is just a crude, first-check analysis, and a better, more scientific approach needs to be applied. But this simple preliminary check does raise red flags. There are no numbers that indicate heat days in Hamburg are increasing or going to increase. Granted I need a copy of the report to see how it reached its conclusion.
The increase appears to be purely in crystal ball models loaded with dubious warming assumptions. They do not even fit with normal data distributions one invariably sees in such datasets. And they appear not to agree with observations.
Gaussian distribution curve.
To the scientists at the U. of Hanover, you might want to go back and check your crystal balls again – compare them to real observations. And your client, the Hamburg Environmental Office, and taxpayers, may want their money back for what appears to be worthless fortune telling.
We’ll be keeping an eye on Hamburg over the years ahead.