Monday, September 28, 2009

Ketsana and crying wolf about climate change

Ketsana is a deadly reminder that a tropical storm does not need to be powerful, by the conventional measure of wind speed, to do immense damage. Unfortunately for the people of the Philippines, another tropical storm may be on its way.

The image at right (thanks to Jeff Masters) shows the rainfall rate from NASA's TRMM satellite just before Ketsana passed Manila. Note the area in white is off the scale of the chart. The storm dumped one third of a meter of rain on Manila in less than six hours, flooding out much of the city, killing at least 140 people, and leaving hundreds of thousands homeless.

The combination of intense rainfall and a dense population living on deforested slopes has led to a tragedy reminiscent of Hurricane Mitch in 1998. Although Mitch was a far more powerful storm, it was the flooding not wind damage that led to thousands of deaths in Honduras.

The climate policy talks in "nearby" Thailand have led to a number of sloppy media reports and climate activist statements about the role of climate change in Ketsana. For once, I actually agree with Roger Pielke Jr, that people need to stop crying wolf about climate change and extreme events. Asking about climate change after a prolonged summer heat wave that could have come right out of a doubled CO2 regional climate model simulation is reasonable. The effort to draw a link between climate change and tropical storms during a rather middling storm year (in terms of power) is scientifically questionable. When the storm in question has had such a terrible human tool, it is also a bit tasteless.

For those wanting to help in the recovery, donations are being accepted through the Philippine Red Cross.

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