Sunday, April 26, 2015

Identifying specific people in the Philippines who were killed by climate change

We know people have been killed by climate change. That's true both in the broader sense that every single weather event we experience is different from a parallel Earth that didn't go through decades of human GHG emissions, and more specifically that some killer weather has been made worse in general (e.g., heat waves). What's been difficult to say is whether a specific killer event is randomly-caused as opposed to being exacerbated by climate change (although maybe not always impossible). And even when you can definitively say a specific killer heat wave was made worse, it would be hard to say who was killed by the "natural" level of the heat and who was killed by the anthropogenic increase in severity.

Enter sea level rise.

SLR is the one thing that's different from weather - if an effect can be traced to sea level rise, it can be traced to climate change. In the case of mass casualties from tropical storms, this should be possible to figure out.

Haiyan/Yolanda's effects on the Philippines is the best example so far, although there doubtless will be more. Six thousand people were killed, with the storm surge considered the deadliest effect. Worst-hit areas had storm surges of 13 to 17 feet, with many people drowning in an evacuation center where the lower floors were submerged.

In most of the world, the present SLR is only a few inches, making it harder to attribute damage from sea level rise as opposed to the natural level of storm surge. Philippines is different, with three to four times the amount of sea level rise as the global average, making the surge about a foot higher than it would have been.

My assumption is that deaths attributable to Yolanda storm surge decreases with elevation, and that above a certain level, the amount of surge wasn't enough to collapse structures (people would have died above that elevation, but from other causes). The storm surge deaths in the foot of elevation below that certain level were caused by sea level rise and by climate change, and that foot of elevation change can be a pretty wide swath of flat land. Maybe someone can go and find who those people were.

Not all the storm deaths within that band would've been caused by the surge, but deaths from collapsing structures seem to be pretty likely candidates. Many people lower down would've also been killed by sea level rise, or others higher up killed by other climate change effects on the storm, but they're hard to identify. What I'm trying to show here is the faces of people we could say with a fair degree of certainty were killed by climate change.

And if no one gets to figure this out with respect to what happened in the Philippines, then there's always next time.