This post is by Phil, not Andrew.
It’s hurricane season, which means it’s time to see the routine disclaimer that no single weather event can be attributed to global warming. There’s a sense in which that is true, and a sense in which it is very wrong.
I’ll start by going way back to 2005. Remember Hurricane Katrina? A month afterwards some prominent climatologists (Rahmstorf, Mann, Benestad, Schmidt, and Connolley) wrote “Could New Orleans be the first major U.S. city ravaged by human-caused climate change? The correct answer–the one we have indeed provided in previous posts (Storms & Global Warming II, Some recent updates and Storms and Climate Change) –is that there is no way to prove that Katrina either was, or was not, affected by global warming. For a single event, regardless of how extreme, such attribution is fundamentally impossible.”
Well, that’s just nonsense. How on earth could Katrina not have been affected by global warming? There’s no way. You can argue that a major hurricane might have struck New Orleans on August 29, 2005 with or without global warming — sure, could be. Or maybe it would have happened a day earlier or a week earlier or a year earlier or a decade earlier. But sure, OK, maybe it would have happened on August 29, 2005. It’s extremely unlikely but not impossible. But there’s no way, literally no way, that it could have been the same storm. Katrina was definitely affected by global warming.
Does it matter? “We all know what they meant”? Well, I don’t know what they meant! And I’ve seen similar statements hundreds of times.
The weather is different than it would have been without global warming, every day and in every location. In some places and at some times the differences are large and in some places they are small. On some days there are fewer tropical cyclones in the Atlantic than there would have been, and on some days there are more; on other days there are exactly the same number of tropical cyclones but they are not in exactly the same places with exactly the same winds.
To say we don’t know whether a given city would have been destroyed by a hurricane on such-and-such a date in the absence of global warming, OK, fine, coincidences happen. But to say that we can’t say whether the storm was affected by global warming, that’s just wrong. That goes for Hurricane Dorian, too.
I’ve been waiting 14 years to get this off my chest. I feel better.
This post is by Phil Price