We get a lot of readers sent to us from European sceptic sites, for example http://www.staatvanhetklimaat.nl/ which is in Dutch, and which I recommend strongly to anyone who thinks they’re not gifted for languages. Just read it aloud with a Norfolk accent, and you’ll get the gist.
This article is from our French sister site Skyfall. It’s by Nicias, and I reproduce my translation, with his permission. The original is here.
How many Irmas in 2100?
I couldn’t help it. Yesterday I switched on the tv and an “expert” looked me straight in the eye and asserted that these cyclones in the Atlantic were all the fault of global warming.
But what does the IPCC say?
The IPCC makes forecasts because that’s its job. And they predict that the number of cyclones of categories 4 and 5 could increase by 200% or decrease by 100%. with a most probable value of + 50%. Skyfall, in cooperation with its Russian hacker friends, procured the exchanges that led to the production of this part of the IPCC report:
– OK guys, never mind the text, nobody’s going to read it. We need an image.
– Yes, in colour.
– And statistics. We have to quantify. We’re doing science.
– You’re right. It’s got to be clear, with a median and a 66% confidence interval as required by the report guidelines.
– What does the literature say for the projections to 2100? How big is the increase for category 4 and 5 hurricanes?
– It says we don’t know.
– Tom K. wants a number if you want to hold on to your budget. To your calculators guys, you’ve got 5 minutes.
– So Kerry, what’s the upper limit of the forecasts?
– Plus 200.04%. We could round it down to +200%.
– Paul, the lower boundary?
– What”s the lowest estimate?
– Er, minus 157%.
– You’re sure ?
– I’m not going through the calculations again!
– Oka-ay. You’ve got the imprint of your keypad on the left cheek.
– It’s jet lag. I was at a conference in Miami yesterday.
– OK. So we’ll round it up to minus 100%. For the “best guess”, we only have to average. 200 minus 100. I divide by 2, this gives us + 50%. In any case we need a positive value, otherwise we’re going to have to discus droughts caused by the lack of cyclones, and there”s no more space in our chapter.
– At least, with a range like that, we can hardly be wrong. Done. Thanks guys. Now I have to fetch my wife at Honolulu airport.
Just as seriously, the IPCC tells us that globally the number of major cyclones will increase, but we don’t know where. Not in the Northern Hemisphere (“insufficient data”), nor in the Southern Hemisphere. So it is elsewhere (on the Oceanus Procellarum?).
The embarrassing thing is that the IPCC knew all this at the time of AR4, and the media believed them. We all make mistakes. But in AR5, they no longer know, but they can’t bring themselves to say so.
Addendum: Here is the text of the graph in question, a clever mixture of wet finger technique and false calculations that look serious:
Projected changes in tropical cyclone statistics. All values represent expected percent change in the average over period 2081–2100 relative to 2000–2019, under an A1B-like scenario, based on expert judgement after subjective normalization of the model projections. Four metrics were considered: the percent change in I) the total annual frequency of tropical storms, II) the annual frequency of Category 4 and 5 storms, III) the mean Lifetime Maximum Intensity (LMI; the maximum intensity achieved during a storm’s lifetime) and IV) the precipitation rate within 200 km of storm center at the time of LMI. For each metric plotted, the solid blue line is the best guess of the expected percent change, and the coloured bar provides the 67% (likely) confidence interval for this value