In case anyone hasn’t noticed, there’s a real possibility that we could lose another city to a monster hurricane next week.
(Yes, we haven’t lost Houston permanently, just like we didn’t lose New Orleans permanently after Katrina. I don’t mean to imply otherwise, only that we’re looking at very big-deal phenomena, here)
Hurricane Irma is, as I write, the most powerful storm ever recorded in the Atlantic (Pacific storms have been stronger) and it’s pointed, more or less, at Florida. It will certainly wreak havoc in the Caribbean, although which islands will be most strongly affected is still unclear. The various computer models all agree that it will head more or less arrow-straight for the Straits of Florida, when it will abruptly turn some species of north. Why will it turn? I haven’t found an explanation. It’s tempting to say that the power of the wishes and prayers of the people of Houston are having an impact, but if wishes and prayers worked like that, Houston wouldn’t have flooded to begin with. Probably there is an entirely prosaic explanation the TV weather people aren’t bothering to talk about. The important part is where will Irma go after it turns? It could enter the Gulf. It could buzz-saw up the East Coast (and hit me, not incidentally).
Or, Irma could send a 20-foot storm surge across Miami, a city of almost six million people less than seven feet above sea level–one that’s already starting to flood regularly on the highest tides.
I want to be very clear–I’m not saying that Irma will destroy Miami, since the meteorologists aren’t saying that yet, and they know better than I do. I’m also not saying that Miami, which might well escape, is somehow more important than Antigua and Puerto Rico and parts of Cuba, and the other places that almost certainly won’t escape. This is going to be very, very bad somewhere, regardless of where that somewhere turns out to be. What I am saying is that this is how national-scale climate disasters are going to happen, maybe this year, maybe in the future.
If Miami floods catastrophically next week (or if New Orleans floods again, which is also possible), the United States will be dealing with three such floods simultaneously (the third is Baton Rouge, which flooded due to a rather bizarre weather pattern last year and has still not fully recovered), two of them in major cities–and the hurricane season still has two months to run. A third major hit this year is not out of the question (say, New York? or Boston? or Washington DC?). I don’t mean to make like Chicken Little–just because catastrophe sounds plausible does not mean it’s going to happen–and the United States, as a nation, is very rich and can probably absorb all these costs. State and local officials will likely do excellent jobs to protect life and limb in the teeth of yet another storm, and together we will get through this. But you can see how the costs of multiple disasters can pile up. And then pile up again.
Climate change makes disasters more likely. This summer may be showing us what the future looks like.
But is that the same as saying that the frequency of disaster has actually increased, yet. The way the laws of chance work, a clump of bad luck doesn’t necessarily mean anything. You can get heads three times in a row–the unusual run is just balanced out by more tails, if you flip your coin enough times. Humans are notoriously bad at telling the difference between a clump of luck and actual meaningful pattern, which is why we invented statistics. Personally, I’m guessing that we are in the midst of meaningful change, but as I’ve written before, I haven’t been able to find real figures on whether our rate of extreme weather events is changing. I am fairly confident that such figures exist, and I wish they were easier to find.
Even without figures on whether extremes as a group are occurring more often, we can look at certain types of extremes. Hurricanes, for example, have been studied extensively but with difficulty, because of problems in the historical data. Whether hurricanes are getting more frequent is therefor hard to say, though the proportion of hurricanes that grow to category 4 or 5, or that reach higher latitudes, does seem to be increasing, and storm surges are definitely getting worse because of sea level rise.
But say there’s a category of disaster that could be being increased by climate change but isn’t, yet. So? What we know is that climate change is real and that it makes catastrophe more likely. Must we wait until all types of catastrophe are obviously worse before we act?