The Climate in Emergency

A weekly blog on science, news, and ideas related to climate change


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How Normal Is this Abnormality?

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.

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How About that Weather?

Recently, a friend of mine posted a picture on his Facebook page, commenting that he “didn’t know it was that bad.” I didn’t, either, though I did suspect it, and it does not seem to have made the news at all. I’m talking drought figures. Frankly, I am confused by the legality of re-posting pictures online, so I usually don’t. In the interests of avoiding a thousand extra words I’m making an exception and providing the picture. Please, if you own this one and don’t want it here, let me know and I’ll take it down.

 

The legend at the top indicates this is a map of how many more inches of precipitation different parts of the United States would need to get to “PDI -0.5.” A bit of poking around online reveals that PDI is probably the same thing as the Palmer Drought Severity Index, or PDSI, and that -.5 means is more or less the drier boundary of normal for a given area. According to this map, then, as of June 6th, to get to Normal, parts of California would need 9-12 inches of rain, which is a problem because that’s about as much as what that area gets all year.

But we knew California was in trouble. That’s not the surprising part.

The surprising part is the serious drought in the East. Southern Florida apparently needs 12 to 15 inches of rain to get to normal, parts of Vermont, and some parts of the Southern Appalachians need 6 to 9 inches. Where I live, in Maryland, needs up to 3 inches, which might not sound like a lot, but we did just get a solid week of rain. Much of the rest of the East is at least mildly dry. It’s not that any of this is severe (Florida is very rainy, so a proportionately mild or moderate deficit still has a lot of inches), it’s that people act like it’s invisible. I have heard no mention of it on the news, heard nobody (except the friend who posted the picture) talking about it, and I have not found anything discussing any of this online.

According to another graphic on the same site, much of the Eastern US has gotten about half to three-quarters of its normal amount of rainfall so far this year. Another site, one run by the USDA, lists Maryland as having no drought as of June 2nd, with some areas merely “abnormally dry” the week before. The disparity could be due to the use of different methods–calculating the severity of drought is somewhat complicated, since it depends on knowing not only how much moisture a place has but also how much it needs. The dates on the two sites (June 2nd vs. June 6th) could also be relevant.

Personally, I’d go with the site that says Maryland has a bit of an issue. It has been a dry spring. with some parts of the state (like ours) getting no rain at all for weeks on end in April and May. We have also had some fantastic rainstorms, most recently a series of interrelated storms that lasted almost a solid week, but much of that water probably ran off without soaking in–heavy rains on dry soil tend to slide off. I spoke with a farmer who said her neighbor found completely dry soil just a few inches down after the first big downpour of that rainy week.

Which brings up another reason why the reports of Maryland’s drought could be wrong–measured by actual inches of rain as compared to what we typically receive, we could be ok. Measured by soil moisture and groundwater recharge, we might not be; the thing is, Maryland currently has no effective way of checking whether its groundwater is being recharged.

All of this is, of course, weather rather than climate. And in the grand scheme of things, my state’s drought is, at worst, still mild. But the situation is still worth noting for two reasons. One is that this is what climate change looks like–larger, more intense rainfalls less often. It’s not dramatic for us Easterners this week, but it is vaguely, eerily, different from what we’re used to, and we should notice. More importantly, a society that isn’t in the habit of noticing the weather, either as individuals or through the news media, leaves itself vulnerable to being told lies. Like when pretty much everybody except the Eastern US was horribly hot last winter and various climate-denying wags asked “where’s global warming” because the East happened to be snowy.

Personal, casual observation of the weather is not, of course, a reliable measure of climate, that’s why we have climate scientists and data collection protocols and big, giant computers, etc. There are important patterns that just aren’t visible without analysis. But if we abandon looking for those patterns we can see, the step into a dangerous apathy becomes very short.

 

 

 

 


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The California Drought Continues

California is still in a drought. It has been for four years straight. The rains in December, while dramatic, were not enough to break the drought. Voluntary water reduction has not worked, so the state has now enacted mandatory restrictions, but these do not apply to the heaviest users of water in the state. The drought is not likely to ease up.

There are a couple of subtleties here.

One is that California water years run from the end of September to the beginning of October–that means that the December rains count as part of this water year, not last, a point that could conceivably confuse some people who look at the records. No mere technicality, the concept of a water year reflects the principle that it is impossible to water the land retroactively–December’s rains could not have changed the dire straights of 2014 no matter how heavy they were. They could have eased the situation for 2015, but have not. Instead, precipitation for the year is already at or below average. To ease the drought, precipitation would have to be above average in order to make up the deficit.

Another is that the scary headline, that California only has one year of water left, refers only to stored water and not ground water or any new water that might come into the state over the next year. The figure also refers to a year of normal use and, thanks to the new regulations, use should be well below normal. So the situation is not quite as dire as it may seem. But it is dire enough.

Finally, droughts are relative. A drought is when there is less water than the users of water want–in practice, when there is less water than is necessary for whatever normally goes on at any given locality. That is why we don’t say deserts are in a state of permanent drought. But the relative nature of drought also means that any drought in California is worse now than it would have been a generation ago because there are more people in the state demanding water. This is one of the reasons the current drought is so historic.

And yes, climate change is relevant. These three years of drought have also been the hottest in California’s history. As the planet as a whole warms up, hot years like these become more likely. Hot weather increases evaporation and transpiration, meaning that the land needs more precipitation to get the same amount of soil moisture. That, too, makes any drought worse. It makes the possibility of another regional mega-drought, one lasting decades or centuries, even more serious.

But the very fact that demand makes drought worse also means that lessened demand could ease the drought. California could use less water.

Which is exactly what it’s doing now, of course, but I’m talking about something a good deal more radical. For example, California is an arid state, so why is it a major agricultural area? Why are there green lawns and swimming pools? I am struck by the fact that the water restrictions specify what people are allowed to do with water (e.g., not water lawns every day) not how much water they are allowed to use. The latter would, of course, make more sense–estimate how much water there is available, divide by the number of people, that sort of thing. But that is not how we normally do things–we don’t start with what we have and figure out how to adapt to those limits, we start with what we wished we had and go into debt in order to get it.

With water, going into debt means exhausting reservoirs and aquifers.

Much has been made of the fact that the water restrictions do not apply to California’s agriculture, despite the fact that it’s responsible for about 80% of the state’s water use. The simple, obvious explanation is that “big agriculture” has somehow gamed the system, although it is hard to see how it could, given that agriculture is only responsible for 2% of the state’s GDP. More likely, the fact that farming feeds people is relevant, as is the fact that almost, pistachio, and walnut trees, which together account for much of California agriculture, are long-lived perennials. If they die in a drought, that is a long term loss for the state–even for the country. If California’s agriculture fails, or if the industry has to pay a true free-market price for access to the region’s limited water, food prices across the country will respond.

California’s water woes are not just the result of global warming (in part), the situation also exemplifies why global warming is a problem to begin with–at bottom there is a fundamental refusal to treat the limits on our available resources as real. But layered on top of that are serious logistical, political, and moral complications that make a supposedly simple fix–use less–harder to realize. Is the US as a whole really willing to give up California’s agriculture? The irony is that, if we did stop sourcing our food from the other side of the country, we’d use less fossil fuel and contribute less to global warming.

The final thing that strikes me about the coverage of the drought is that while some people are clearly acknowledging that this is a new, climate-changed normal, I have not found anybody using the drought to call for reducing emissions. No one (that I have encountered) is demanding climate-sane political representatives and climate-sane policy to please save California. I hear people talking about maybe adapting to the new normal, but nothing about changing the disastrous course that is creating it.

California has 55 Electoral College votes, more than any other state in the country.