08:30 AM

Ask the Experts: Drought and Climate Change in California

By Brian Hiro

California’s water year begins every Oct. 1, and as this month started, the state put a distressing cap on the driest three-year period in its history.  

Alarming signs of drought are everywhere, from the early loss of snowpack in the Sierra Nevada mountains to fields of crops lying fallow to mandates imposed by water agencies throughout California. And there’s no end in sight: Initial forecasts are that the state could see a third straight year of La Niña conditions, in which desperately needed precipitation is scarce.  

What sometimes feels like permanent drought is perhaps the most visible manifestation of the ravages of climate change on California, but there are plenty of others – heat waves, more frequent and intense wildfires, even (paradoxically, given the overall lack of rain) flooding.  

To delve into this new normal, we turned to Tihomir Kostadinov and Elizabeth Ridder, two Cal State San Marcos geography professors. They specialize in different areas – Kostadinov in marine science and Ridder in human-environment relationships – but they both spend much of their time thinking about the effects of drought and climate change on the place they now call home.  


Question: I've lived in the San Diego area for more than two decades, and in that time I’ve experienced many years of drought and other years where we got a lot of rain and snow to make up for previous shortfalls. But now, the sense I have is that drought is becoming kind of a permanent condition of life here. Do you have a similar sense of what we're facing? 

Elizabeth RidderElizabeth Ridder: Drought tends to be a temporary condition. And there are different ways of defining what we mean by drought and whether it's short-term or long-term – it can be short but very intense, or it can be prolonged and not quite as stressful on the ecosystem. It does seem that California, in general, is shifting toward changing precipitation type. In the Sierras, for example, the timing of precipitation is changing as well as the form, so instead of snowfall, more rainfall, which has knock-on effects later in the year. When rivers and ecosystems and people rely on that snowmelt, well, the water is already gone to the ocean.  

We’ve had quite a few droughts; Mediterranean environments have them. But they are becoming slightly more severe. We had that one from 2015 to 2018 that was a 1,200-year record. So, yes, it's been dry before, but we're seeing it be dry more frequently. We're seeing it not just as meteorological drought, where there's a lack of precipitation, but also as an agricultural drought, where soil moisture is lost and has impacts on vegetation. And, of course, with California being really reliant on its agriculture, we're seeing a lot of politics around that change in water.  

Tihomir Kostadinov: We’re in what you might call a megadrought. This is the 22nd year of it, going back to 2000. The last two years were really bad, and this year is proving to be not good so far. It started off OK – the Sierra Nevada had some record snowfalls in December, then later during the normal times when it snows, we didn't get that much. So the snowpack was low at the end of the year and it was very erratic, which brings me to this: Variability is expected to increase with climate change – bringing both big droughts and big floods, and general variability of what's called the water cycle. Increases in climate extremes are the general pattern coming with climate change, and observations in the news lately are consistent with that. 

ER: To that point about variability, Death Valley received almost all of its annual rainfall over a period of 48 hours in August. All the roads were washed out, a lot of the park was closed down. It doesn't get much rain, but when it gets it all at once, we see things like flash flooding that goes along with more intense thunderstorms and the soil not being able to soak it all up fast enough. Those kinds of disasters could be more frequent in the future.  


Q: On that subject, there was a study released in August with dire predictions about a megaflood that could hit the entire state and cause unimaginable damage. Did you read about that? 

Tihomir KostadinovTK: Yes, and the chances of it are increasing. Something that occurs only once in 100 years normally, with climate change is expected to occur maybe once every 20 or 30 years. Instead of once in a human lifetime, it might occur three times and destroy properties, agricultural fields and other infrastructure. These are the atmospheric rivers that affect us in the winter, that can dump a lot of rain over a short period of time and the Scripps Institution of Oceanography has a special team that’s studying just those. So yes, ironically, at the same time we’re dealing with a megadrought, we might get a megaflood as well. Everything in the Earth system is interconnected. That's what we teach in our classes – everything on our planet, including the human system and the economy, is interconnected with each other. 


Q: Liz, you mentioned earlier the threat of drought to agriculture. I saw a story recently that, in terms of major crops, California is expecting 30% lower yields in the next year than even a couple of years ago. What will that mean long term? What will it do to the availability of food? 

ER: As it gets warmer, plants aren't as efficient, just like people. They have these little pores on the underside of their leaves, and they shut those to prevent water loss. But that also means they can't cool off because it's that evaporation of water that helps cool down plants, similar to our evaporation of sweat. So they reach this threshold, and you start to see plants dropping leaves earlier than you would expect, because that internal water is not enough.  

Our agricultural industry is $50 billion per year, and about 80% of our water is allocated to agriculture. When we’re in droughts, they start to shunt water around our state in different ways, which diverts it from things like marshlands, other ecosystem services, maybe restoration sites. In terms of agriculture, California's economy is going to slow as we're experiencing water shortages, variable precipitation, lack of reliance on Sierra snowmelt. The citrus will probably stay, but we’re going to have to start growing things that are less water intensive but also can handle the increased heat. When you're both limited by water and have increased temperatures, then there are some serious issues in terms of the vegetation. 

Megadroughts and megafloods are going to have serious impacts on agriculture production and on people's livelihoods at the industry scale. But also, day to day, the jobs of agricultural workers are going to become riskier in terms of the conditions under which they work. There are health impacts to those sorts of changes as well. 


Q: What do you think are some ways that Californians need to change to develop water resiliency in the face of persistent drought conditions? 

ER: People hate it, but lawns. We spend a lot of money and a lot of time and effort maintaining these green fields. Grasses here don't grow like that. If you look around, the native grasses are brown and dry in the summertime. So using all that water to maintain lawns is wasteful. That said, households aren’t the major user in our state. It's going to have to be at the industry, agricultural level in terms of how we reduce our water consumption.  

TK: Humanity as a whole needs to learn not to waste things – water, energy and everything else really. I'm not an expert on agriculture. I can't tell you whether they can or how they will adapt to drought on the agricultural side. But in terms of households, we need to look at things like lawns and other ways to conserve water.  

The other way to adapt would be desalination. Our area has a desalination plant, and we get a third of our water from it. But it has its own host of issues, which teaches us a lesson: There's no free lunch. Everything that we do on the scale that we want to do it to achieve the comfort that we want to achieve for eight to 10 billion people is going to be challenging, and it's going to have global effects. Something has to give, and maybe we have to give up some lifestyles. Just as an example, I'm from Europe and I miss certain foods, so I eat imported food, and a lot of it comes from somewhere half a world away. California has to reconsider all these exports that are water heavy. We grow a lot of alfalfa that is watered with California water, but it is exported somewhere else. That means exporting water in some sense as well. These things need to be reconsidered, just like everything else around climate change. 


Q: I'm glad you mentioned desalination. For years, there has been a big push to build another one of those plants in Huntington Beach, but this summer the proposal was rejected. Do you think more of those facilities should be built in California? 

TK: After several global events in the last two or three years, I saw how important it is to be independent locally, to the extent feasible and reasonable, with the basics, which include medicine and food and energy. My opinion is that it’s better to produce your own medicine and food and have water locally, too. So unless we all want to move from here, I think we need to desalinate some water in Southern California and carefully assess how to deal with the salt that's left behind. The very salty water that is left is called brine, and that brine can wreak havoc on local ecosystems when it's released in large quantities. But in the larger scheme of things, this sounds like a solvable issue to me – you can probably figure out more easily what to do with this extra saltwater than what to do with the CO2 in the atmosphere.  

Plus, only certain areas of the planet will need desalination. Some areas will get wetter, actually. The outlook in Southern California is uncertain long term, until 2100. It probably will be drier, but predicting rainfall is much harder and less certain than temperatures. 


Q: But however long this current drought lasts, it will have an end date? 

ER: Based on how drought is defined, yes. We'll either have multiple years of precipitation or it will recharge groundwater or streams to counter the hydrological drought or the soil pores will again become saturated so then we’re out of agricultural drought. It depends on which scale you're looking at. But at some point, we can say, ‘OK, this drought is over because we've met whatever conditions that term it so.’ That doesn't mean it's wetter; it just means that we've managed to go over that threshold of not being in lack of precipitation.  

Going back to desalination, the other thing that we have in San Diego that I don't know if people know about is the Pure Water recycling system. I know it freaks people out, but it is sewage recycling. I got to tour the facility before the pandemic, and Pure Water has this crazy set of filters and different ways that they treat the water that it basically meets drinking water quality. But then they dump it back into one of our reservoirs, and it goes through the reservoir system. And then they treat it again before they send it out to people. That recycling can be improved. The water that comes out of your dishwasher, your tub, your kitchen sink – that all can be used to water other things, like your grass. The hard part is getting the permits that allow you to recycle this water on your own property. But it would be a great use, because not only is it watering your plants, it's helping keep that soil moisture and all those other hydrological functions up without just sending it down the sewer system. Yes, it eventually goes back to the ocean, but you can use it in multiple stages, which would reduce how much water we're using from the reservoirs and how much water we need to desalinate. So it lessens the stress on other systems.  

TK: Everybody would like to drink mountain water instead of recycled water. But we need to learn how to recycle water more and perhaps capture more of it. Maybe we should have better dams to collect the local rains, from atmospheric rivers when they come by and other rainfall, instead of letting the water run out to the ocean and then worrying about how to desalinate it. Things in nature recycle, and the ecosystems provide these things for us. If we mess them up or we go to a place where they are not sufficient for our population, then we run into issues, a little bit like trying to send people to Mars. 


Q: Tiho, what did you make of the recent report that the melting of the ice sheet in Greenland will cause almost a foot of sea level rise? 

TK: I'm not a specialist in that area, but glacial science is very complicated. What’s important to understand is that this issue has many nonlinearities, just like a lot of things in climate analysis. If, say, 100 tons of ice have melted over the last decade somewhere, it definitely does not mean that another 100 will melt over the next decade. There can be an explosive tipping point, and the system can rapidly accelerate its change. There are many factors involved. The thing that few people think about but is really critical for ice on our planet is that it affects how mirror-like our planet is, how reflective it is. The more ice and snow we have, the more reflective the planet is, keeping it cooler than it otherwise would be. Once we start melting areas in Greenland or Antarctica, the whole planet is going to warm more on top of what it already is doing by virtue of the fact that ice is replaced by something darker. That's called the ice-albedo feedback. Albedo is the reflectivity of the planet, meaning how much of solar light that hits our planet is reflected back to space as a mirror and doesn't participate in the warming of the planet. Imagine Earth covered completely in a perfect mirror. Then it would not warm at all; it would be at absolute zero, like space. Instead, the planet is using 70% of the solar energy that falls on it; the rest is reflected. 


Q: You're painting a pretty frightening picture of additional warming on top of the already dire warming. 

TK: I was impressed and also a little bit scared when I learned about student climate anxiety. Our students get genuinely concerned and even depressed, I believe more so than I do. I think the planet as a whole is fine. It has had severe climates in the past multiple times; the dinosaurs lived in a very different climate than we do, and CO2 then was much higher than what it is now. But when the planet has changed a lot, species have disappeared a lot. And in the end, the concern is about humans. The planet as a physical entity will be fine. Some species will survive, some will not, as it has always been that way in the past. But human suffering and the inequalities behind it are a big concern. For me, I'm more concerned about the effects on agriculture, probably because I like food a lot. In addition, there is of course the big concern of unnecessary animal suffering and species extinctions and biodiversity loss caused by the actions of humans. 

ER: Tiho and I see a lot of environmental studies students who think about environmental problems a lot already. They're thinking about justice questions – who has access to what, who will be able to weather the storm or not, who has more capacity. Living in California, they already are seeing themselves as being priced out of a place, having to choose maybe between owning a home or having a family. On top of all the injustice issues, they’re thinking about, “Is this all going to collapse around me? How are we going to feed 8 billion people on the planet? How do we address these inequalities?” Climate anxiety, justice issues – our students are really thinking hard about these things, how to address them and what kinds of decisions are coming at them in the next five to 10 years. 


Q: I can only imagine because I feel that kind of anxiety, too. I assume you feel really sympathetic to what they're going through. 

TK: It's more intense with them, which I understand better now that I've been here more years and I understand my students better. But at first, I was surprised that they seem more concerned about these things than I am as an environmental scientist who studies these things and is deeply concerned about them. But they are more directly anxious about it – which is good and bad at the same time. 


Q: Good that they're conscious of the problem, but bad for their mental health, right? 

TK: I have to think harder about what to tell them. Something along the lines of what I said earlier: The planet is fine, but we have to be concerned about human well-being and many other species. It’s very hard to stay positive, but good changes are coming, even if it doesn't look like they're coming fast enough at this stage of affairs, the way I see it. For example, 30% to 40% of electricity in California is now made by renewables, and if we can move farther in that direction, that's a big win. Plus the news that only electric vehicles will be sold here starting in 2035, which is not that far away.  

ER: I teach a climate change course, and I'm a little sarcastic and grim in general. I tell my students, “The planet will be fine until the sun burns out or the interior of the earth completely solidifies and stops rotating.” In thinking about climate change or droughts, humans haven't been on the planet that long. We have huge capacity for change, huge capacity for innovation, for all kinds of generosity. Very few organisms have engineered their environments to the degree that we have in such a short time and been so successful. The human footprint is everywhere. So I guess that makes me hopeful that, in such a short time, we've come to a certain place and we can look back and say, “Shoot, we did a bunch of stuff wrong, but what can we do moving forward is far more fascinating than thinking we just messed everything up.” 

In the past, technological changes and scientific endeavors really didn’t put human inequities and justice questions at the center. But I think we're putting those at the center now, which will change a lot of different ways of organizing ourselves on the planet. 


Q: What are some ways that climate change is affecting the landscape and vegetation of San Diego County? 

ER: It's mostly in invasive species. Some of the vegetation here, like chaparral, generally has very shallow root systems. It can capture water quickly, even small amounts of water, should we have any rainfall. But when there is prolonged drought, those plants don't have a deep tap root to get into some of that deeper soil moisture or water resources. So they tend to die out and get replaced by things that can deal with that over time. It's mainly the transition from shrub lands to grass lands, and that increases fire vulnerability to have non-native grasses that are browning and helping carry fuel loads. Getting rid of invasive species can do a lot of fire hardening.  


Q: Let’s say you were appointed U.S. climate czar for a day. What’s the first thing you would do?  

TK: I know it's not very popular to say this, but it would be something like a nationwide ban on leaf blowers, for example. First, because I hate them; they're completely useless machines. Second, because their kind of engine is worse than many cars because cars have a lot of cleaning systems. Leaf blowers are very dirty and very sound-polluting, though at least the electrical ones are much better. That's a small thing. A bigger one is everyone driving more efficient cars or switching to electric, like is happening in California but nationwide. Or some kind of regulation that existing power plants have to capture their CO2 in some way, even if it costs more and we as a nation absorb the cost. But I don't know if there's one silver bullet. 

ER: I would upgrade our transportation system. Funding things like high-speed trains is expensive, but it's more expensive to do nothing in the long run. You might think, “How can we afford all that?” We can't afford not to. You'd need a really savvy PR individual to convince people that the cost of delaying is much greater than the cost of making our communities the communities we want. Lots of us want public transportation, lots of us want cleaner air and water, lots of us want these societal goods. Is it going to be expensive? Yeah. Does it mean some of us might have to change? Oh yeah.  

TK: Inertia is a huge problem. How can we change existing infrastructure? It's very, very difficult and costly and hard to convince people to do things. And of course, we all enjoy the positive sides of suburbia. But sometimes I wish there was a place I could walk out and get a snack. 

Media Contact

Brian Hiro, Communications Specialist

bhiro@csusm.edu | Office: 760-750-7306