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How does El Niño affect Michigan and the Midwest?

| 18 minutes | Media Contact: University Communications

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Summary

What exactly is El Niño? And how will it impact the weather and ecosystems in the Midwest? 

Guest: Zach Johnson, climate scientist and assistant meteorology professor at Central Michigan University. 

Summary 

In this episode of The Search Bar, host Adam Sparkes interviews assistant meteorology professor Zach Johnson, to discuss how El Niño affects Michigan and the Midwest. El Niño is a climate phenomenon characterized by warmer than average sea surface temperatures in the tropical Pacific. It impacts the atmospheric circulation globally and can lead to changes in weather patterns and ecosystems. El Niño is part of a larger climate cycle called the El Niño Southern Oscillation, which oscillates between El Niño and La Niña phases. El Niño is associated with weaker trade winds, which allow warm water to move eastward, causing positive sea surface temperature anomalies. In the Midwest, El Niño typically leads to warmer winters and less precipitation. However, the impact of El Niño can vary depending on the location and is less significant in the Midwest compared to other regions. Predicting El Niño is challenging, and there is ongoing research to improve its predictability. Climate change may also influence the frequency and intensity of El Niño events, which could have broader implications for ecosystems and industries reliant on weather patterns. 

Transcript

Chapters 

Introduction

Adam: Hi, what exactly is El Niño and how will it impact the weather and ecosystems in the Midwest? Welcome to The Search Bar. You've got questions. Let's find some answers. I'm your host, Adam Sparkes, and today I'll be chatting with Zach Johnson, a climate scientist and meteorology professor here at Central Michigan University. Well, Zach, thanks for being here with me today. I appreciate you coming in to talk about the weather as good Midwesterners do.

What is El Niño?

Adam: Today, we're going to start by trying to expand a little bit on our audience's understanding of what El Niño is. Now, what else should we know about El Niño and what it is other than it is Spanish for “the Niño.”

Zach: Right. No, that's a great question. Well, originally the terminology for El Niño came from folks in Peru in South America where they noticed that the ocean was warmer in December. And so, they referred to this warming is El Niño de Navidad to refer to Christ because it was in December. This warming of the tropical Pacific, which is adjacent to Peru in South America, they noticed that there was not as many fish being produced. So, fishing became an issue during an El Niño. And of course, obviously as the field of climate science became more prevalent, we now understand the physical mechanisms of El Niño. So, El Niño really is, it's this warming of the tropical Pacific where we have warmer than average sea surface temperatures. And that in turns actually impacts atmospheric circulation all over the globe, for instance. So, we have this El Niño, which is warming of the tropical Pacific, but then sometimes it becomes cooler than average, and that's considered, that's called an La Niña. And so that's kind of where the terminology came about, and this kind of back and forth between El Niño and La Niña. It takes about two to seven years to oscillate back and forth, and we call this the combined effect of El Niño and La Niña, the El Niño Southern Oscillation.

Adam: This is coming from no scientists. The thing that I thought was kind of fascinating, or at least the way I kind of started to wrap my head around it was imagining a thermocline is kind a teeter-totter, kind of pointing towards Asia and then pointing towards the Americas, depending on whether you're an El Niño or La Niña. Am I?

Zach: Yeah, you are our spot on. So, I didn't want to get into all the jargon. Let's do it, but let's do it. So this thermocline is this boundary in the ocean about maybe 300 feet deep in the tropical Pacific. And it's the interface between the upper part of the ocean, which is well mixed by wind and is warm, and then the deeper part of the ocean. And so, when it's warmer, the thermocline is deeper, and when sea surface temperatures are cooler, the thermocline is shallower. And so yeah, over this east west thermocline, this boundary can tilt back and forth over the entire tropical Pacific. So, it's this really large-scale phenomenon, and we're most interested as climate scientists, how El Niño and La Niña impacts the upper ocean and the atmosphere. So yeah, we could get into the jargon and the physical mechanisms of El Niño. It gets really complicated really fast. It involves some pretty hardcore physics wave theory and whatnot. And so that also involves complicated partial differential equations to describe this warming and cooling patterns of the tropical Pacific

What happens to trade winds during El Niño?

Adam: I mean, a big part of that too is Tradewinds, right? I also, I've only ever heard the term, could you explain what a trade wind is for a climate scientist?

Zach: Yeah, yeah. So, in the mid-latitude where we live, we have winds coming from the west and going east in the Tropics winds go from the east to the west. So, we have easterly winds in the tropics. So, the trade winds, they go from east to west along the equator and straddling the equator north and south. So, for instance, in Hawaii they have trade winds in the Caribbean there's trade winds. So, these trade winds pull water in the tropical Pacific and they help pile water up in the western tropical Pacific. And so, this water gets to travel across the entirety of the tropical Pacific warming from the sun. And so, the western tropical Pacific is really warm. And warm waters, if you're a meteorologist or a climate scientist, warm waters induce lower sea level pressure. So, we have low pressure in the western tropical Pacific, and then those cooler waters in the Eastern tropical Pacific, they're relatively colder than the Western tropical Pacific, and that induces high pressure.

So, you have this difference between high pressure and low pressure across the entirety of the Pacific, and that induces wind. So, we have Easterlies and the tropical Pacific. So, when we have an El Niño, the trade winds weaken. So, those winds that are coming from east to west, they're not as strong. And that means that warm water that's been piled up in the western tropical Pacific can move eastward. And that triggers the El Niño event where this warm water in the Western tropical Pacific migrates to the east because the trade winds are weaker. And that in turn causes a positive sea surface temperature anomaly, right? Warmer than average temperatures. And then that is the essence of El Niño. And then all of a sudden, we have a change in the atmospheric circulations. And that warming of the tropical Pacific can alter weather and climate patterns all around the world.

What's the difference between weather and climate?

Zach: I like to always, when I'm trying to decipher between weather and climate, I like to think of weather as your mood and climate as personality, right? Your mood changes from day to day. Sometimes you're in a good mood, sometimes you're in a bad mood. That's human behavior, but your personality is something that sticks with you throughout your lifetime. So climate really is this much, much longer term concept compared to weather, where weather changes from day to day, week to week. Climate, we're thinking on decades, we're thinking on centuries. So, I really like that idea.

What is the impact of El Niño on the Midwest?

Adam: So, let's talk about the impact of El Niño. We're going into El Niño year, right? 2024 is going to be. What are those Peruvian fishermen seeing? Because those are, they named it. What happens there? And then as it comes over to say, us in the Midwest, what can we expect to see?

Zach: Right? I mean, there's so many angles to look at this. There are ecosystem impacts, which I think the Peruvian fishermen we're seeing, right? If we cause warmer sea surface temperatures, maybe there's going to be more algae blooms or plankton, maybe the fish can feed on it or something like that. And that's what the Peruvian fishermen we're dealing with. For us here in the Midwest. Why do we care about El Niño? Why do we care about something that's thousands of miles away? Well, like I said, El Niño causes a change in the atmospheric circulation, and that change can propagate to us here in Michigan. And so, El Niño typically favors a change in the jet stream, a northward or southward migration of the jet stream. And so here in Michigan, because of this climate phenomenon in the tropical Pacific, it induces this change in the jet stream. And that is going to cause typically warmer, it favors warmer winters here in Michigan and a less precipitation. So yeah, we are going into this El Niño pattern usually peaks in December and January, which is why the Peruvian fishermen realized this phenomenon. And so, we see the greatest impact in the winter here in the United States, including Michigan.

Adam: I'm just trying to give people pictures too. I think, again, correct me if I'm wrong, cause I'm probably way oversimplifying this, but it depends on what side of that jet stream you're on too. As that comes in, right, you're going to get, so there's a difference between where you're at in that jet stream and what kind of weather phenomena you're going to see from El Niño, correct?

Zach: Yeah, exactly. So, the jet stream is this kind of river of storm systems. And so, if the jet stream is further north, your storm systems are going to be further north. And also, the jet stream separates really cold air in the Arctic and Northern Canada and warm tropical air in the southeastern United States or the southern part of the United States. So, when this jet stream is migrated further north during an El Niño, that means we are going to have warmer weather, and if the storm systems are going to be further north, that means we're going to have less precipitation. So, you have this effect where here in the Midwest we have less precipitation and warmer conditions, and so that usually occurs in the winter. We see the greatest impact in the winter, and it'll be interesting to see how it plays out this winter.

What are signs of El Niño's impact?

Adam: Are there things that people can expect to see as far as signs that it's happening? I think sometimes, I'm really trying to address this. I know that when I'm with biologists and climate scientists and geologists here, it seems like there's a lot of subtle things that are going on. And I think if you're just consuming this kind of on your morning news, it's easy to go. And I think that was kind of the joke with Chris Farley, "it's El Niño!" and at the time in the nineties when we really first started talking about it, at least that's when I remember hearing about it so I can date myself. I was very young. We'd have a rainstorm that year. I think it was '97, or '98 was the year it was really. Might've been '94.

Zach: It was '97. Was the greatest. It was the big one.

Adam: El Niño. That was the year. Okay. It was '97. I remember it would rain and I was a kid and we'd be like, it's El Niño. But what are signs that you might be seeing in your community that you are being affected by this phenomenon?

Zach: Right. It's really hard to see it from day to day. So, when we look at the weather forecast, it's really hard to see it. But if we average all of the weather over the course of the winter, we might be able to look back and say, oh yeah, it was warmer than average. Yes, we had less precipitation than average. But when you look at it in terms of a weather timescale, you probably won't see it. We're still going to have heavy snow; we're still going to have cold snaps. We'll have warm periods, potent storms this winter. But again, if you average all of the weather that happened this winter, you might be able to see the change at the end of the winter, not during the winter.

Adam: Yeah, so it's not really, unless you're one of these people who are on the weather Facebook groups and stuff. We have a guy in Michigan, I forget his name. He's super famous for having, he's not a meteorologist. I'm sure meteorologists hate this, but he's like a hobby weather guy who has these massive online communities club. But unless you're in there, you're likely to just go up two or three months later. "Man, it was more rainy than snowy this winter."

How can you prepare for El Niño in the Midwest?

Adam: Is there a preparedness that's necessary for this or for us here in the northern Midwest? Is this more of just like at least day-to-day, more of an inconvenience if the weather's not what we are normally used to?

Zach: Is there preparedness? That's an interesting question. If you're interested in the long-term, yes, you might be able to say, wow, I'm not spending as much money on heating this winter. You might be able to notice that in terms of day-to-day activities, no, I don't think you can prepare. We're still going to have snow here in Michigan. There just might not be as much of it. So, depending on the way you look at it, if you're interested in energy or winter sports, these are things that you care about. Long-term changes. For instance, snowpack, right? Winter sports, they want snowpack, they want ice for ice fishing. Folks in those industries, they might notice and they need to take preparations, but your average person that cares about the weather day to day, I don't think you could really prepare for El Niño.

Adam: But it's going to snow less. You heard it here, Zach said it's going to snow. If there's a lot of snow this year, we'll put Zach's email up in the YouTube video and on the Spotify video you can email him. Not me. I think it's going to snow a lot.

Zach: And you might be right. That's true.

Adam: Well, I mean, the thing about living where we live and there's other things going to affect that precipitation, maybe not here in the middle of Michigan, but certainly Michigan is coastal. We have a lot of lake effect snow, and that's more weather than climate, at least the day that it happens, right? It's not as predictable long-term.

Zach: Yeah. But you might think, okay, there's a big lake lake or snow lake effect pattern. Maybe you're in Grand Rapids and all of a sudden you have three feet of snow on the ground and you're like, "wow, this doesn't really feel like an El Niño." And locally in Grand Rapids, you might see that it snowed more due to lake effect. But I think if we average over the entire state of Michigan, when it comes springtime, you might see, okay, yeah, we did have less snow than normal, or the snowpack, that line, was further north than normal because it was warmer than normal.

What's the importance of studying and teaching about El Niño?

Adam: From the perspective of someone who is a faculty member and a researcher, what's the value? What's the importance of making sure that this is both studied and taught?

Zach: So, here in Michigan, in the upper Midwest, the impact of El Niño is actually quite a bit less than a lot of places. So, for instance, during an El Niño, Australia goes through crazy droughts in wildfires. I mean, that's been in the news in the past several years. And for instance, maybe in the Amazon rainforest is highly impacted by El Niño and La Niña. California, for instance, is heavily impacted by El Niño and La Niña in terms of rainfall, right? And out there, they're very sensitive to rainfall. They have major water resource issues. Here in Michigan, we don't have as great of an impact in terms of studying this. It's really important for my research to understand how El Niño forms, what are the physical mechanisms. That's kind of what I'm studying. And then I also try to improve its predictability. If we can predict El Niño on a longer timescale than folks that are really susceptible to El Niño and La Niña, they could prepare more. Here in Michigan, we don't have to do as much preparation because the impact of El Niño and La Niña is not as great compared to other places. There's this differential impact.

What are the challenges in predicting El Niño?

Adam: Although a lot of people who watch the news would tell you it's not. Weather's easy to predict, but climate events are not so much like you were talking about earlier. There's so many, even though climate science in the last 20, 30 years has gotten a lot, the focus is there now. There's more and more of it. We also, it's harder to predict an event as big as El Niño. It's not as obvious until it's upon us, right?

Zach: Yeah. We as climate scientists have this. We're trying to improve the predictability of El Niño, and it's been actually a really immense challenge to improve the predictability of El Niño. There's this concept called the spring barrier, and it's this idea that we can't really predict El Niño in the winter in the preceding spring or before that there's this six-to-nine-month limit on predictability and trying to overcome this concept, this abstract concept of the spring barrier is really, really challenging. It's something that a lot of folks in my field are trying to overcome. And so, there's this kind of limit to predictability of El Niño and La Niña in terms of weather forecasting. I think it is really challenging to forecast weather. We've gotten good at it in the short term, but long-term, thinking upon weeks and greater, we're starting to think about climate and El Niño and La Niña plays a huge role in those forecasts. So, I think understanding the physical mechanisms, why they occur and trying to improve the predictability of El Niño and La Niña, it could be very beneficial to folks like you and I, but also has really huge implications on economies and industries too that are reliant on changes of our environment.

What's the connection between El Niño and climate change?

Adam: Alright. So yeah, in terms of things like winter sports, when you're talking about having snowpack, not having to break the snow, making machines out, whether ice is safe for ice fishing, I mean, that's just a few of the things that people are going to have a big personal impact on potentially, not just with this, but with bigger climate change globally.

Zach: Yeah, no, there is a lot to talk about in terms of climate change. And I think one of the interesting questions in terms of El Niño and La Niña El Niño is this warming of the tropical Pacific and climate change. We are seeing warming. So, the question becomes, will we see more El Niño impacts around the world that we already see today with El Niño in terms of climate change? And I think it's an interesting topic to touch on, especially its impacts, for instance, like you said, maybe a change in snowpack in Michigan that might impact winter sports, that also has ecosystem impacts, right? If you change the amount of snowpack in Michigan, then all of a sudden, you're altering maybe changes in lake level and things like that. If there's less ice coverage over Lake Michigan, then all of a sudden you change the amount of evaporation that occurs, and maybe in the future, lake levels might decrease. And so, it really is an interesting topic to discuss the impact of climate change.

Adam: That's awesome. And if you want to hear more about climate change, make sure you stay tuned into us, because Zach and I are going to have another conversation that's touching more on climate change in the Midwest. I wish we could go on; I feel like I could write 10 more questions here, but I'm going to wrap it up. Zach, thank you so much for giving me your time.

Zach: Yeah, thank you so much. It was a pleasure to be here and I think we had a really good conversation.

Adam: Awesome. Alright, until we meet again.

Zach: Sounds good.

Adam: Thanks for stopping by The Search Bar. Make sure that you like and subscribe so that you never have to search for another episode.

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