Is California in a Megadrought? (Transcript)

California is in drought. Again. And the infrastructure used to sustain the state’s 40 million residents — and $50 billion agriculture industry — hasn’t kept up with changing climate patterns. The Bay Curious podcast will explore new ways of thinking about the future of water in our state as part of a six part series: State of Drought.

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Olivia Allen-Price: [00:00:02] You’re listening to the Bay Curious State of Drought series, I’m Olivia Allen Price. A few weeks ago, we asked you, our audience, what you wanted to know about drought in California. And there was one question that came in that really caught my eye. It came from Nicholas Hardy.

Nicholas Hardy [00:00:18] Are we in the start of a drought or are we actually in the middle of a megadrought with some wet years thrown in?

Olivia Allen-Price: [00:00:26] Megadrought. The word alone sounds almost like a science fiction movie … something you’d spot at a video store alongside the movies Sharknado and San Andreas … if video stores still existed, that is. But megadrought is not fiction. It is a very real climate phenomenon. Today, we find the answer to Nicholas’s question and learn some fascinating things about our long term climate along the way.

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Olivia Allen-Price: [00:00:50] All right, so we’re setting out to answer Nicholas’s question about megadrought. Here to help us out as reporter Amy Mayer. Hey, Amy.

Amy Mayer: [00:00:58] Hi, Olivia.

Olivia Allen-Price: [00:00:59] So looking around, I see the hills are dry and brown, but they’re always brown this time of year. Can you first explain how do we know it’s because of a drought and not just seasonal dryness?

Amy Mayer: [00:01:10] You really have to go back to the past winter. We didn’t have a lot of rain here, and especially in the mountains, there wasn’t a lot of snow. Plus parts of the state have really been hot this summer. So those are some of the measurements that go into something called the Drought Monitor, which is a map put together by a bunch of federal agencies and university scientists. They update it weekly based on certain concrete measurements, like soil moisture and stream flow, but also observations. They have UC Extension agents all over the state who are watching for different things. So the end of August of 2021, the whole state was in at least moderate drought.

Olivia Allen-Price: [00:01:45] And it’s not just California. Right. I know I’ve heard about low water levels across a lot of the West.

Amy Mayer: [00:01:51] That’s right. Yeah. The drought conditions extend across Arizona and Nevada, even Oregon. And the heat and low water obviously also have an impact on the Colorado River and everyone who uses water from that river.

Newscaster: [00:02:04] For the first time ever, the federal government has declared a water shortage on the Colorado River. Two decades of drought means reservoirs that store runoff are depleted and there’s not enough water to meet demand.

Amy Mayer: [00:02:18] So there’s five stages in that drought monitor. Nearly half of California, plus a large swath of Nevada right now, are in exceptional drought. That’s the top category. That includes six Bay Area counties. Paul Rogers of the San Jose Mercury News pulled out some old data showing that San Francisco is seeing its third driest year since the gold rush and San Jose experienced its driest year in 128 years of record keeping.

Olivia Allen-Price: [00:02:47] All right, so it’s bad. I know that we’ve been flirting with exceptional drought on and off for many years now, so much so that people, like our question asker Nicholas, bring up this term megadrought. What is a megadrought and are we in one?

Amy Mayer: [00:03:03] Well, yes, we are in a megadrought and it’s not really because of this summer’s conditions or the things we’ve been talking about this year. Megadrought is not a weather term. Mega drought is a climate word. And we’re in one now because across the southwest, these drier conditions and these hotter conditions have been going on for decades. So, Olivia, you might remember after what seemed like the last drought, roughly 2011 to 2017, we got some wet years. But it turns out they weren’t enough to overcome these drought conditions. Richard Seager is a climate scientist at the Lamont-Doherty Earth Observatory in New York.

Richard Seager: [00:03:41] In the Southwest, it’s been overall drier since the late 1990s. So we’re talking about a 20 year dry period here now. And using the term megadrought is justifiable because it stacks up in terms of the severity and the length with the ones that we’ve inferred from tree ring data back in the medieval period.

Olivia Allen-Price: [00:04:04] Tell me more about those tree rings. What’s that about?

Amy Mayer: [00:04:07] Well, in a dry year, trees just don’t grow as much. A lot of people are familiar with the rings that a tree adds each year, and when they’re closer together or they’re thinner, that tells scientists that a drought has happened and it can allow them to figure out how long a drought lasted. John Abatzoglou, is a professor at UC Merced and he looks at droughts both past and present. He was part of a big team that published a look at historic megadroughts. The paper came out last year and they looked at a lot of tree records across the southwest.

John Abatzoglou: [00:04:35] We can actually compile trees both that are living today, as well as trees that may have died, but their skeletons remain and sort of piece those together to go back a bit further through time.

Amy Mayer: [00:04:46] So these tree skeletons led them back thousands of years to droughts during medieval times that lasted for decades. And that helped them conclude the 20th century was anomalous for its lack of droughts in this area.

Olivia Allen-Price: [00:04:59] Wow. So that really turns everything on its head. I mean, really, California became what it is during a time when there was more water than historically there would have been.

Amy Mayer: [00:05:09] Yeah, that’s exactly what their studies have found. Even though we thought of California as dry.

Olivia Allen-Price: [00:05:14] Huh. So have we as humans played a factor in this megadrought?

Amy Mayer: [00:05:19] Well, these climate guys are confident that a megadrought would have come regardless. It’s just part of the climate cycle. But, yeah, having so many people and also the fact that we grow so much of the country’s fruits and vegetables and nuts, that likely makes it worse because we’re used to using more water and the water has always been there to use … even though this region was generally considered rather dry. So Abatzoglou says the water supply coming into this megadrought may have actually been lower than it was in the past when the area entered other megadroughts.

John Abatzoglou: [00:05:52] We have increased population. We have the bountiful Central Valley that is basically all irrigated. That has increased the demand through time, right? A human driven increase in demand. And that makes it easier to actually realize drought impacts.

Olivia Allen-Price: [00:06:09] That really gets us to a question that we heard from a lot of listeners, which was: long term, can a drier California be home to so many people?

Amy Mayer: [00:06:19] Well, both Seager and Abatzoglou think so, but how water is used and for what is probably going to need to change some. And of course, they both mentioned farming. Here’s Seager again.

Richard Seager: [00:06:30] A lot of agriculture in the United States is going to have to move from California in the southwest to other water rich areas of the United States.

Amy Mayer: [00:06:38] That would be a huge change for a lot of people. But Abatzoglou says maybe not so fast. Ingenuity and engineering might offer some solutions. And at UC Merced they’re actually putting in a smart farm to test a wide variety of ag tech research efforts, a lot of them aimed at better resource use, including water.

John Abatzoglou: [00:06:58] Some of these changes could actually lead to beneficial climate adaptation strategies being more efficient, like revolutionizing how we work with land, how we work with water. So there may be some good things that come out of dealing with hardship, which is what we’re going through in California.

Amy Mayer: [00:07:14] For example, sensors that could determine exactly how much water a specific plant needs so that custom micro irrigation can deliver just that amount and at the right time.

Olivia Allen-Price: [00:07:24] That’s a really cool idea. But ultimately, I think a lot of people want to know when are we going to get out of this? Are we going to get out of this?

Amy Mayer: [00:07:32] Right. Sure. That’s the big question. And again, there’s two parts to it, the short term and the long term. So first, when is there going to be more water? When are we going to get out of this acute drought situation? Abatzoglou says he and others are working on better ways to tell us what’s coming in the next water year. If we knew, then we could make smart decisions and he says that could help us not feel the impacts quite so severely.

John Abatzoglou: [00:07:55] Because drought is one of these sort of sneaking phenomenas or creeping phenomenas. Usually you don’t know you’re in a drought until it’s a little bit too late.

Amy Mayer: [00:08:04] But longer term, climate scientists are trying to develop tools to predict when overall drought conditions might change. That would help to define, you know, how long a megadrought might last year when another one might be starting. That would mean they would need better ways to forecast the ocean temperatures, because that’s one of the things that controls drought conditions. Seager says so far they just can’t project that out more than about a year.

Richard Seager: [00:08:27] There are big international research efforts to do that. But in the Pacific Ocean, that research to date has not met with a tremendous amount of success. It’s been rather disappointing in progress.

Amy Mayer: [00:08:45] We’ve got a new water year starting October 1st, and Governor Newsom is already saying that if it’s dry again this winter, he might need to impose some mandatory water reductions, possibly statewide.

Olivia Allen-Price: [00:08:56] Well, something to keep our eyes on. Reporter Amy Mayer, thanks for speaking with me.

Amy Mayer: [00:09:01] Thanks for having me.

Olivia Allen-Price: [00:09:05] That’s it for the third installment in our State of Drought series. Tomorrow, we’re going to start talking about solutions, beginning with what we as individuals can do in our own homes. Bay Curious is made by Katrina Schwartz, Brendan Willard, Sebastian Miño-Bucheli and me, Olivia Allen-Price. We’re a production of member-supported KQED in San Francisco.