Hi Jennifer,
I’ve only just noticed this week’s Jakarta floods.
Most of the reportage has concentrated on the immediate disaster and the associated political recriminations, but I see in the Sydney Morning Herald that, “meteorologists have claimed climate change contributed to the disaster, with a delayed monsoon season bringing unusually high rainfall.”
I think this could be worth a post in itself, for a number of reasons.
First of all, this is a major weather disaster. Almost half the capital of south-east Asia’s biggest country just spend a week under water. This is happening just to our north.
Second, it would be of interest to understand the cause and effect here. How often does this happen? Why does it happen? The capital is flooded annually and there were big floods in 1996 and 2002.
According to the Jakarta Post, “the floods are worse than the last major inundation in 2002. It has been argued they are the result of weather abnormalities that occur every five years.”
Third, perhaps we could have a general discussion about the evidential value, if any, of such large events in the AGW [global warming] debate. The debate over Atlantic hurricanes like Katrina may serve as a prototype.
Cheers, Mitchell Porter
—————————————–
This is an edited version of a note from Mitchell originally posted as a comment here: http://www.jennifermarohasy.com/blog/archives/001874.html . Thanks Mitch.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
My mother has just retuned from Jakarta. She said the water was over her feet in the taxi on the way to the airport and tiny kids were riding bits of rubbish in the wakes ahead of the cars but no one was game enough to slow down to avoid hitting them in case their cars stalled. I had a text this afternoon from a young lad I am putting through school who lives in one of the shanty areas. Surprisingly he and his family were doing OK.
Part of the annual flooding is caused by the build up of rubbish around the drainage systems, the loss of areas to sop up any rain and the general low geography of the city.
It is hard to know whether the meteorologists have evidence it could be linked to AGW, or if it is part of a general blame game everyone seems to be playing there at the moment. It would be good if there was some hard data to suggest this is something unusual or otherwise. There are a few readers of this blog who have lived in Indonesia, so it would be good to get some insight from them on their experiences.
Your post says, ” It has been argued they are the result of weather abnormalities that occur every five years.”
I am puzzled how circumstances can be considered abnormal if they occur every five years.
Sounds to me like a cyclic event.
No doubt it will fit climate change modeling, precedent or not.
The Jakarta floods are getting bigger for the simple reason that the paved area of Djakarta is getting bigger. Jakarta is booming and that means urban sprawl which means concrete and bitumen.
In high rainfall areas like Jakarta the annual runoff from fields and forests can be as high as 50% of total rainfall. But when that field is covered with roofing iron or pavement the runoff increases to 100%.
If planners and developers are doing their job properly they will ensure that storm water drainage lines are expanded to cope with the additional water. But this is not always done here in Australia, let alone in Suharto era Jakarta when much of the expansion took place.
Now much of the earlier development would be precluding proper works to cope with the additional load. And in these cases we get bright new developments with shmick drainage and environmental certification that extends only to the property boundary where the big new pipe just feeds into the small old one.
But these climate spivs will stoop at anything for a head line, won’t they.
A footnote to this story:
http://thejakartapost.com/climate/index.php?menu=stories&detail=4
“Global, regional warming to blame for Jakarta floods”
… along with “poor city planning, bad zoning systems and a lack of infrastructure”.
The GW contribution is said to consist in shifting rain and sea level rise. But actually, the “climate change expert” quoted attributions the change in rain patterns to a “regional warming” caused by Jakarta’s pollution. (?)