Ok, I was going to write about politics or something this week, because we all know climate change causes extreme weather already so why should I have to write the same post about floods and droughts over and over and over and over again, but really? Baton Rouge? There’s a time and a place for just acknowledging what’s going on because people are dying down there. One area resident, who also happens to be the Louisiana state climatologist, told Scientific American (see previous link) the scale of devastation was like that of Hurricane Katrina and that “This is a pretty big deal, many, many, many homes flooded; it is hard to capture that in any one scope of a camera. It’s worse than it appears on television.”
So, however bad it looks to us from the outside? It’s worse than that. We’re going to be coping with the effects of this storm, as a nation, for years.
Again, according to Scientific American (same link!), this specific event can’t be linked to climate change, but extreme weather in general, including flooding, is a sign of climate change. That’s the standard story, and I’ve told it before. But I don’t actually think it’s true anymore. Not in this case, anyway.
The thing is, the reason this storm has been so achingly, awfully bad is that a high pressure zone sat itself down on the East Coast and refused to move, so, therefore, this storm full of Gulf Coast moisture had nowhere to go and just dumped all of its water right there on Louisiana (same link again!). And the thing is, I’ve heard that before.
It seems like every severe weather story I hear lately is the direct result of a blocking high.
So, I went looking around on the internet for a while, trying this search term and that, and finally found an article explaining that yes, stationary high pressure zones, caused by an erratic jet stream ARE the major proximate cause of many different types of extreme weather and, yes, these highs ARE getting more frequent. Because of climate change. Granted, the author was talking about winter extremes, but I see to reason to suppose the same mechanism might not work in the summer, too. The exact mechanism for the more erratic jet stream is still being debated, but seems to have something to do with the fact that the Arctic is warming faster than the lower latitudes are.
So, why did it take me twenty minutes online to find information Scientific American said didn’t exist? I don’t suggest a conspiracy–we’re probably looking at the result of a legitimate editorial decision about how much detail to get into for a popular market article. Also, what, exactly, it means to say a weather event was or was not caused by climate is a bit philosophically murky, anyway.
In the meantime, there are also various droughts (if you click on that link more than a week after I post this you won’t see the information I used, but rather the new, updated drought map. I wish I knew a way around that, but I have bigger fish to fry at the moment). Some of these droughts are garden-variety, others are severe and unprecedented. California continues to just plain dry up. It’s horrible. Part of Massachusetts are in an Extreme Drought for the first time since the category came into existence (in 1999, but still!). There are other examples. But I’m unable to find out if any of this, except California, are really unusual. Is the US having bizarre weather at the moment?
It’s an important question. Somewhere the weather is always extreme. I don’t know if that’s literally true, but it must be nearly so. It’s a big planet, and a couple of extremes somewhere at any given time is about what you’d expect. Put another way, a certain amount of abnormality is normal. So, if we’re going to talk about evidence of climate change seriously, it’s not enough to just see what extreme weather is making the news lately–we have to know if the extremes we’re seeing are themselves unusual in some way.
It’s like temperature. It’s easy to notice that it’s hot today, but to know what that heat means, you’ve got to look at it in context–is today’s high above or below the average for your area at this time of the year? 80° F. is just not that impressive in Delaware in August, for example, even if you, personally, are over-heated. Human perceptions of “normal” are easy to fool. So, are we looking at a normal level of abnormality this week or not?
I haven’t been able to find out. Really, what I’m looking for is an extreme weather index, a site that keeps track of, perhaps, the number of weather records broken this week or the number of events labeled “extreme,” and color-codes each part of the country according to whether that number is typical or not. And there is something like that–the Climate Extremes Index, by the National Oceanic and Atmospheric Administration. Except it hasn’t been updated since July of 2015.
This is the National Oceanic and Atmospheric Administration we’re talking about. You’d think they’d be on this sort of thing.
Maybe the up-to-date website I want is out there somewhere and I just don’t have the right search term yet or something. I’m not saying the information doesn’t exist, only that it’s disappointingly hard to find. It’s not on the tip of my search engine. That tells me most people aren’t asking the question.
And that is scary.