Hong Kong Observatory director Dr Chan Pak-wai tells us that the HKO expects "five to eight typhoons to approach within 500km (311 miles) of the city this year". He added: "This is an above-normal level", and went on: "It's hard for us to forecast the intensity of the typhoons, but due to climate change, we expect a greater number of stronger typhoons." (Hong Kong braces for another sweltering year, with 5 to 8 typhoons predicted. 21 March)
I'm not a meteorlogist, but I do know numbers. But first, Definitions. "Tropical Cyclones" covers a class of storms, from Depressions to Super Typhoons. [Here]. A Depression is a storm with 41-62 kph mean winds, a Typhoon 118-149 kph and a Super Typhoon 185 kph or more.
According to data on the HKO website, what has happened in the last quarter century? Here are my calculations:
- The number of Tropical Cyclones per year in our region has dropped slightly from an average of 30 (1961-1990) to 27 (2000-22).
- The number of Typhoons per year in our region has dropped slightly from an average of 15 (1961-1990) to 13 (2000-22).
- The number of Typhoons per year affecting Hong Kong is steady, from an average of 6 (1961-1990) to 6 (2000-22).
There is little data here to support the statements by Dr Chan.
The number of typhoons affecting Hong Kong has a Standard Deviation of 1.78. Let’s round it to 2. Therefore, this year, statistically , we can expect between 4 and 8 typhoons (two above and two below the average of 6). Not much different to Dr Chan's "five to eight" and hardly "above normal". If it turns out we have nine typhoons this year, that is no reason to say it's "climate change". Just at it is no reason to say "there's no climate change" if we happen to have only two or three typhoons this year.
Dr Chan's conjectures are simply that: conjectures. I grant that he discusses El Nino and La Nina, which affect climate patterns; but so too have they in the past.
Nor is there reason to assume that there will be "stronger typhoons" as Dr Chan claims. At least based on historical data.
When I challenged a similar statement by the HKO last year, their senior scientific officer, Lee Sai-ming acknowledged that their "statement regarding the increased proportion (not absolute number) of intense tropical cyclones… does not conflict with your correspondent's analysis of past tropical cyclone numbers." ["your correspondent" being me].
There's another important point. Since 1960, the earliest records on the HKO site, the number of people killed by typhoons has dropped from 275 per decade to just 8 per decade [My spreadsheet, based on HKO figures]. That is, less than one person per year is killed by a typhoon. The decline in typhoon-related deaths was swift in the 60s and 70s, due to the removal of squatter villages. The reduction has been steady since then, with increased safety measures. The reduction in deaths is mirrored by a reduction in injuries and property damage.
This shows that we can handle natural disasters and even if they are made worse by climate change. I do not say this to minimise our need to reduce carbon emissions. We must continue to do that. We have done well so far, bringing our per capita emissions down to just 4.1 kg per year, a third of the US, and half of China's. We did this by shifting to nuclear power and natural gas for our electricity.
The point remains: we can and will handle what the climate throws at us, whether it be rising sea levels, or more severe typhoons (assuming they do happen).
We ought to think more often about this. That we are capable of handling natural disasters and climate change.
Rather than constantly painting the bleakest pictures, as in your article above and as the HKO regularly does.
Enough of the panic, already!
P F, etc....
References:
Hong Kong Observatory misinformation. 24 March 2024
Slightly fewer typhoons of about the same strength: the ACCURATE (but boring) headline. 20 August 2023
We need to be honest about the effects of climate change. Published letter, 11 August 2023
A 1,000-Year History of Typhoon Landfalls in Guangdong…. September 2001
