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TOM WHEELER:

Welcome to the Econews Report. I'm your host this week, Tom Wheeler, Executive Director of EPIC, the Environmental Protection Information Center. And joining me is a friend and colleague, JP O'Brien. JP is a PhD climatologist based out of Fort Bragg, California. JP did his postdoctoral work at the National Center for Atmospheric Research in Boulder, Colorado, and is a former research affiliate with Lawrence Berkeley National Laboratory in Berkeley, California. Welcome to the Econews Report, JP

JP O'BRIEN:

All right, Tom, thank you for having me.

WHEELER:

All right, so we are talking about the Super El Niño that is predicted for this coming year. I admit that I've seen a lot of news stories about this and from seeing news stories about this, I've realized how little I know on the subject and wanted to get in an expert like you to help inform me and inform the broader community about what's going on with the Super El Niño. And so every time I see something, a news article and think of a show like this, I'm reminded of a quote from the French Revolution. There go the people, I must follow them for I am their leader, right? So I've seen all of these other news articles getting written so here I am doing a show on it too.

All right, so Super El Niño, as I said, seems to be a lot in the news. Senator Mike McGuire recently had a town hall with climatologists to discuss the Super El Niño and its impacts on the North Coast. So let's start off by just defining what an El Niño is and then from there, what a Super El Niño might be.

O'BRIEN:

Sure. Well, El Niño, just zooming out, is the positive phase of a natural climate oscillation that occurs every two to five years about. So ENSO is the El Niño Southern Oscillation, that is the full climate oscillation, and El Niño is the positive phase of that, and La Nina is the negative phase of that. El Niño typically is defined by warm, anomalously waters in the tropical East Pacific, as where La Nina is going to be the opposite of that, anomalously cool waters in the tropical East Pacific.

So there's different ways to define the strength of an El Niño. The most common is just an intensity-based metric of how warm the water is in this region called the Niño 3.4 region, and it's a region off the coast of Peru, a thousand or so miles. And the thresholds are typically, the threshold NOAA uses is if the three-month running mean exceeds 0.05 degrees Celsius, that is the minimum threshold to be considered an El Niño. One degree C is a moderate El Niño, 1.5 degrees C is a strong El Niño, and anything above 2 degrees C would be considered a very strong El Niño. So those are kind of the rough categories. There's different ways to define it, but that's kind of the most common.

I will say right now, the superlatives that you are hearing going around are indeed justified. This is something that we have never seen before. We have never seen water temperatures this high, this early in the development cycle of an El Niño. So typically SSTs in the Tropical East Pacific, in that Niño 3.4 region, will peak around December, November-December, and we are already in August at 2.7 degrees C. So we're already in this threshold of strong El Niño far, far, far earlier in the year than we have ever been before. The peak, the record of Niño 3.4 temperature was set in 2015-16 at about 3.1 C. We're already at 2.7 C, and we have three, four months to go before it peaks.

WHEELER:

Is there any ability for this to correct itself? Is there any way for that temperature to not continue to rise steadily, or is it just baked in now that we are going to pass that 3.1 record from 2015?

O'BRIEN:

I mean, nothing is baked in. I mean, we can't see the future, but every metric that we look at, whether it's the progression of SSTs, the shoaling of the thermocline, which is the subsurface temperatures under the East Pacific, around 200 meters below, the water temperatures are like 10 degrees C warmer down there. So there is nothing to indicate any slowing down. I mean, it could happen, but there's nothing to suggest that it's going to slow down.

The model forecasts, which just came out on Monday, the most recent model forecast initialized in August, suggest a peak SST of 3.9 to four degrees C. And remember, that's a whole degree C higher than we've ever experienced, which as a climate scientist, to see something of that record of that magnitude, if that does indeed come to pass, is just astonishing if that happens. And that's actually the central estimate right now. The upper tail of the model estimates are peaking at like five degrees, which again, is just like ridiculous. I don't think that will happen, but I think right now, based on every metric that I've looked at and the coherency between the multi-model forecasts, I think it's unlikely we will see anything below 3.5 degrees, which again, it's just kind of astonishing that we're just below through this record. It's such a, that it appears that we're going to be doing that.

WHEELER:

Yeah, well, and so here is something that I've seen folks on the political right say is proof against the existence of climate change, that we have these periods of variability and that there's oscillation in climate and this is somehow proof that climate change is not real. I've also seen what I imagine to be more accurate. A lot of news reports linking this El Niño, the super El Niño, to climate change, that we are creating unpredictable weather patterns, that we are supercharging these things through a warming ocean and a warming planet. To what extent can we understand the causation between anthropogenic climate change and this particular anticipated super El Niño?

O'BRIEN:

So what we what we know for sure is the background SST warming is 100%. It shows signals of climate warming. What is less certain is whether El Niño itself, the oscillation, how that is being affected. The preponderance of evidence right now suggests that El Niño's will become more intense. That oscillation between extreme El Niño and extreme La Nina amplifies under future warming.

But there's a pretty wide spread in that because natural variability in ENSO is quite large. So that means there's a pretty large, the signal to noise ratio is a little bit lower because of the natural variability in the ENSO system. But the preponderance of evidence that we have right now suggests more intense El Ninos. So this could definitely be an example of that. This certainly would not be an example of climate change not playing a factor in this. But just the background warming, when you look at just the rate of background warming, you can see it, you know, through period like this, like this is very, this El Niño that's forming is very, very reminiscent to what happened in 1997-98. And if you look at that year, that winter compared to this year, just the background climate is just the background SSTs are just so much warmer than in 1997-98. Even though the ENSO pattern itself looks roughly the same, it's just on top of being superimposed on a much warmer background SST field.

WHEELER:

So the year 1997, 1998, if I'm remembering correctly, I was a kid, I was living in Seattle, Washington, and one of my favorite things to do was go skiing. And if I'm getting the year right, that was the year that I remember they had to dig out the chairlifts, that there was so much snow that we set records at Mount Rainier, and they had to close chairlifts at my ski area because the accumulation of snow was just so unprecedented. It was a heavy, wet snow, what we called Cascade Concrete, but there was a lot of snow. This gets to a question about what are we likely to see as a consequence here, perhaps generally in the Western United States, and then maybe more specifically, if we are able to tell something about Northern California, where you and I are both based.

O'BRIEN:

Yeah, so typically, so there's, the way people talk about it is, there's ENSO, there's El Niño, which is the pattern of SST variability and warming that happens in the tropical East Pacific. And then there's its associated remote impacts, what we call the teleconnection.

How does warm SSTs in the tropics 10,000 miles away affect precipitation in Northern California? And it's really comes down to the tropical deep convection that is sustained by those warm SSTs, perturbs the atmosphere in such a way that it sets up a stationary Rosby wave that alters the location of the jet stream. Typically for El Niño, places farther North like Washington actually typically see a decrease in precipitation because the jet stream shifts further South directing storms further to the South, which is why California typically gets hit during strong El Niño years.

The hydroclimate response is fairly unpredictable. Canonical indices like Niño 3.4 only explain about 7% of the variability in annual precipitation in any given year. But for these really strong El Ninos, these El Ninos where the water really moves to the far East, the hydroclimate response is much more predictable. And the two classic examples of that is 1982-83 and 97-98. Those were two El Ninos where the central warming of tropical SSTs moved way far to the East. And that really drove the jet stream South and California really got hit those two winters.

People call 2015-2016 a super El Niño and by the SST metric of just intensity-based warming, it was, but what was different about that is that central location of that warming was further out into the Central Pacific. So what happened is the jet stream didn't move as far to the South. And in that year, Northern California got about 150% normal precipitation as where Southern California got only about 50%. So there was a really strong dipole and California on average only ended up at about average that year. The location of warming in the tropical East Pacific right now is very far East, touching record levels again for this time of year.

So this suggests that we're going to have, if everything continues and there's nothing to suggest that it won't, if everything can kind of continues as it looks, it will, this winter will be very similar to 82, 83 and 97, 98. And so for California, that means it's very likely that we will have a very wet winter. And given the background SST warming and given the strength that it really looks like this is going to be kind of a record year, it's very likely or it's quite likely I would say that we might be seeing all-time record precipitation for California.

WHEELER:

You are listening to the Econews Report. And we're talking with JP O'Brien, climatologist based out of Fort Bragg, about the coming Super El Niño and its impacts here on the north coast of California. And this precipitation, is it going to come in steady, predictable daily rain, or is this going to be the atmospheric river deluges where you have one large storm event that drops just a ton of rain? Thinking about 1964 and some of the flooding that we had here, what are we to expect? How is the precipitation likely?

O'BRIEN:

I mean, for California, most of our precipitation comes from atmospheric rivers, and that is going to be no different this year. There's a couple of things going on. There's going to be a very strong jet stream just due to the strength and the persistence of the atmospheric Rosby wave that will be set up by the convection in the tropics. There's also another climate oscillation called the quasi-biennial oscillation, which is a stratospheric wind, which again modulates that atmospheric Rosby wave. And that's going to be potentially moving into its western phase. It looks like that, which amplifies storms.

So I mean, basically what I would expect if everything continues on as it's looking to continue on, I would expect kind of this winter to be characterized by quite literally atmospheric river after atmospheric river after atmospheric river after atmospheric river kind of thing. And yeah, quite strong storms, quite wet storms, and accompanied by probably quite intense low pressure systems coming out of the Gulf of Alaska. These extra tropical cyclones, you know, sometimes people call them bomb cyclones, depending on how quickly they deepen. But that kind of mechanism provides the dynamic uplift, which allows the moisture that is flexing from the tropics to precipitate out. So yeah, I would be expecting a series of strong atmospheric rivers pretty much all winter long.

WHEELER:

And so, so much of the West is reliant upon snowpack to maintain its water throughout the spring and early summer. How might the Sierras fare this year? Should we expect this to come down as snow, as rain? Are we expecting a heavy snow year, or is this going to be one that snow never is able really to get set because the atmospheric rivers are just too dang warm to follow snow?

O'BRIEN:

Yeah, so a lot of the atmospheric rivers that are associated with El Niño events are called pineapple express type storms because they essentially they are flexing moisture up from around the Hawaiian islands and that moisture is very warm. So typically during an El Niño year we actually see the snow level elevation increase. The storms are generally warmer and so canonically if you look at the data El Niño years actually have a typically a little bit lower snowpack. Now if you're up around in the Sierra up above nine or ten thousand feet they will probably see good snowpack up there but for lower elevations where typically like during a La Nina year which typically is cooler if you get rain the snowpack can exceed much lower.

So, yeah, it just depends on individual storms. If a storm is accompanied by a low pressure system that's coming out of the Gulf of Alaska that can help lower the temperatures and you can get some good snow accumulation but in general the the type of moisture that we're getting is is on average warmer and so that tends to raise snow levels.

WHEELER:

So, thinking about this coming wet weather year, when should we start to see the effects of the super El Niño in our weather? Are we seeing it now? It feels like an unseasonably warm summer. Is this related to this El Niño?

O'BRIEN:

Probably not up here, so to speak. There's certainly, I don't know if you've been paying attention to what's happening down in Southern California and San Diego, it's they're very warm ocean waters and the dew point has been being around 70 degrees, which is very tropical, very moist. And that has a lot to do with the warming of El Niño and the ocean temperatures there. We're not really seeing that up here quite yet. There will probably be some SST effects that we'll see in the coming months, but we won't necessarily see that in the weather. The canonical teleconnections in terms of precipitation and storms probably won't develop until late October, November, when we start seeing storms arriving on our shores.

The historical relationship between El Niño and autumn is not strong. It usually makes its effects November, December, January, February, March.

WHEELER:

So as I understand it, an El Niño event is often then followed by La Niña the following year, so we can have this whiplash effect where you have very wet weather years followed by very dry summer. Can you talk about this whiplash and what this might mean for things like fires in the state of California and what we should be doing as a state in perhaps anticipation of this coming El Niño?

O'BRIEN:

Yeah, it is. Yeah, the relationship is, is typically large La Ninas or large La Ninas follow large El Ninos. So again, we don't know what's going to happen for sure. We don't have that kind of confidence in our models. But the data said the relationship is that we will probably get a strong El Niño next year. And that does typically lead to drier winters and hotter, drier summers. And so that whiplash has practical implications for the kind of vegetation load. They're probably, you know, depending on how this winter plays out, there might be a lot of downed trees and a lot of vegetation growing during the spring, next spring because of all the moisture. And that could lead to a very consequential fire hazard for next summer and next fall. So that's definitely something to be thinking about.

There's a lot of ways these interactions can play out like this winter. You know, there's going to be probably a lot of sedimentation and slides that will affect the rivers and fire scars like the fires in Southern California last winter could be seeing lots of slides and like what happened in Montecito, Santa Barbara a few years back. So yeah, I mean, there's going to be a lot of downstream impacts. Even if we don't have a record winter, there will be impacts that we definitely need to be thinking about.

WHEELER:

So as someone who studies something like this, do you have kind of a mixed emotional reaction? Like, is any part of this exciting to you that you get to witness what might be the largest El Niño, the most strong El Niño on record? Are you nervous about this? Tell me about how you are emotionally processing this anticipated super El Niño.

O'BRIEN:

Yeah, I actually am quite excited about this. A lot of my PhD was on El Niño, and how it will change in the future. And to see something like this of this magnitude developing is something we saw in the models, for sure. So while we can't attribute this concretely to climate change, this is definitely something that we saw that is suggested by the models.

But yeah, it's going to be, it potentially could be really bad, right? I mean, you know, if if there is, personally, like, if I lived within a 100 or 500 year flood plain, I would strongly be considering buying flood insurance. If levies break in the Central Valley, there could be a lot of flooding, flooding, flood substations. And if there's a lot of trees down, if you live in rural areas, it's very possible PG&E could just get fully overwhelmed by the number of power outages, and some places potentially could be out of power for a month, right, depending on how bad it is. So, so personally, I mean, so that really does concern me.

So yeah, I mean, that, you know, that's something I'm still thinking about how much I want to personally prepare in advance. I think I'm not in a flood prone area, but I am in an area that when trees go down, my power is always the last to come back on. So I am thinking about how many days or weeks do I want to prepare in case the power goes out. And I will be closely monitoring how this El Niño develops. And probably by mid-October, I will be making a plan about how many days I want to prepare for based on how we see these metrics kind of continue to evolve. Again, there's nothing to suggest that it is going to slow down right now.

WHEELER:

Well, that's an important reminder. Folks here in Humboldt County will know that during wet weather winters, the roads in and out of the county often fail. Sometimes we're left with only one road in and out, and so stock up on groceries, perhaps consider investing in a solar battery or solar generator, or start making your preparations for what might be a wet and wild winter.

Speaking of wet and wild winter and flooding, as you mentioned earlier, briefly, let's talk about king tides and sea level rise and El Niño. So as I understand it, El Niño is also likely going to give us a preview, this super El Niño is going to give us a preview of what sea level rise might look like in the future. As a consequence of the warmer waters, water expands slightly, I guess, when it's warm, and we always have these king tides in the winter. If we have a king tide paired with one of these large atmospheric rivers, we might see a level of coastal flooding that is unprecedented. Taken away, what else are we going to see? How is this going to affect us coastal residents here?

O'BRIEN:

Yeah, well, I mean, there definitely has already been climate change caused sea level rise to the tune of around, you know, 10 centimeters or so. And then El Niño itself generates what's called a coastally trapped Kelvin wave, which is a type of geophysical fluid wave that migrates up from the tropics and hugs the coast. So that on top of that, climate change induced sea level rise will add another component of sea level rise, probably again to the tune of six or so centimeters. What tides themselves, like king tides, are generated by the gravitational fields of the moon and the sun. And those are very predictable.

And unfortunately, it's like kind of a perfect storm kind of thing. The astronomical tides predicted for this winter are as high as they get. So the king tides this winter will be as high as we ever will see them. So combine that with sea level rise, combine that with the sea level rise generated by El Niño and flooding from storms and storm surge generated by the storms, the wind of the storms could lead to coastal flooding that we've actually never seen before. And so yes, I would, you live in a coastal zone, near streams, near rivers, where they are tidally influenced, even if you're kind of out of that tidal zone, I would really strongly consider being very well prepared, because we know, even if nothing else comes to pass, we know the astronomical tides very well, and those will be as high as we've ever seen this winter.

WHEELER:

And my friend Jen Kalt at Humboldt Waterkeeper has long done this King Tides project, where her and other volunteers will go out and take photos at the peak of King Tides to give us an understanding of what future climate change and what future sea level rise might look like here in the Humboldt Bay region. Check out humboldtwaterkeeper.com for more information about that project.

JP, unfortunately we are just about out of time. I would love to have you on again in the spring perhaps after this is over to do a debrief on what we saw and what we may have learned what climatologists like you learned and what stood out about this super El Niño. Thank you so much for joining the Econews Report.

O'BRIEN:

All right, thank you, Tom.

WHEELER:

All right, join us again next week on this time in channel for more environmental news from the North Coast of California.