“Slightly fewer typhoons of about the same strength” : the ACCURATE (but boring) headline. Instead of which …

This is the actual front-page headline
in the South China Morning Post 

The headline at the very top is what would have been correct. Accurate, but boring. Both by my analysis of past weather records from the Hong Kong Observatory and from the HKO itself. Note, for example, the last line in the HKO letter, below, that its Chief Scientific Officer wrote to the Post, in response to my letter, in which the CSO says our views “are not in conflict”:

The key sentence is “…projected increase in the proportion (not absolute number) of intense tropical cyclones…”

In the original article with the catastrophist headline above they did not say “not absolute number”. Just that there would be a higher proportion of intense tropical cyclones (aka “typhoons”). By which we were clearly invited to assume there would be more. And which gave us the scary front page headline. 

Here’s how that works: say there are 12 tropical cyclones (TC) each year that affect Hong Kong, of which four are intense cyclones (IC) ie typhoons. That’s four in twelve or 33%. If the number of TCs reduces to 10 per year, and the same number of IC, then the proportion, four in ten, increases to 40%. That the only way you get to have a higher proportion without increasing the absolute number. It’s by fewer total TCs. And in this both the HKO and myself are agreed, as Chief Scientist Lee says.  

So: the reality is that we expect slightly fewer TCs and about the same number to be Typhoons. But that has been spun into “Stronger typhoons to batter Hong Kong”. Which at the very least is misleading. If not outright false. Misinformation one might say.