The Great Simplification with Nate Hagens - Steve Vavrus: "Arctic Fever? Taking the Arctic's Temperature"

Episode Date: September 7, 2022

On this episode, Climate Scientist Steve Vavrus joins Nate to discuss the Arctic and its critical impact on climate science. Why are the effects of warming so extreme in the Arctic, and what are the implications for weather events and average temperatures on the rest of the planet? Do runaway arctic feedback loops mean disaster 'Blue Ocean' scenarios?  Steve explains why the answers to these questions aren't as simple as they may seem and talks about the challenges and hopes he sees for the future of humans and global climate.  About Steve Vavrus: Steve Vavrus is a Senior Scientist in the Nelson Institute Center for Climatic Research at the University of Wisconsin-Madison. He uses computer climate models and observational data to understand how our climate is changing across the world, including in Wisconsin. Extreme weather events are an important theme of his research, particularly how they might be affected by climate change. Steve is co-director of the Wisconsin Initiative on Climate Change Impacts (WICCI) and has been a long-time member of its Climate Working Group. Steve received Ph.D. and Master's degrees in meteorology at the University of Wisconsin and a Bachelor's degree in meteorology at Purdue University. For Show Notes and Transcript visit: https://www.thegreatsimplification.com/episode/35-steve-vavrus

You're listening to The Great Simplification with Nate Higgins. That's me. On this show, we try to explore and simplify what's happening with energy, the economy, the environment, and our society. Together with scientists, experts, and leaders, this show is about understanding the bird's eye view of how everything fits together, where we go from here and what we can do about it as a society and as individuals. Today's guest is senior scientist at the Nelson Institute for Environmental Sciences at the University of Wisconsin, Professor Steve Vavris. Steve is a climate scientist with a specialization in Arctic climate dynamics and has contributed to IPCC modeling of Earth's paleo-climate and future climate.

Today, Steve and I discuss the state of current climate modeling, the potential implications of an ice-free Arctic, and other aspects of our climate. rapidly changing environmental situation. Global warming and human macro systems are incredibly complex. I found our discussion helpful to understand the context of our current climate situation, and I hope you do too. Please welcome Professor Steve Vavris. Hello, Steve. Good to see you. Nice to see you too, Nate. You are an IPCC climate scientist and an environmental science professor at the United University of Wisconsin, but going way back, and I don't know the answer to this because

we've never talked about it, how did you first get interested in the environment and studying Earth's climate? Well, my interest in climate is kind of a combination of my long-term interest in weather since I was a boy growing up in Indiana where we had lots of tornadoes and thunderstorms and blizzards and the like. So I was interested in weather for a long time. And then when I got to college, I developed an interest in environment. issues. And one of the big issues at that time was acid rain. And that's a natural for anyone with

an interest in weather. And so this was sort of mid to late 80s. And just at that time, climate change was emerging as another major environmental issue by the late 80s. And so that became natural to merge my interest in weather with environmental concerns, acid rain, and then climate change. And so then when I had time to pick grad school, decided that the climate would be the way to go. And so I followed that path and have it look back. Not to go down a sidetrack, but whatever happened to acid rain, I used to think that all the lakes in upstate New York and Ontario were infertile for fish or things like that. But I haven't heard much about acid rain lately. Do you have a 30-second update on that? Yeah, it's a great policy success. So it was a combination of policies that I think a,

major national cap and trade system put in place that worked. And then another solution was people built taller smoke stacks to kind of spread out some of the pollutants so it wasn't so concentrated in the Ohio Valley. And so the combination of those things has meant that we virtually never hear about acid rain anymore in this country at least. So it's encouraging. It means that policy can be effective in these kind of issues. So in that case, the pollution from burning coal, for instance, was a local and regional thing.

So if they're coal plants in China, they didn't result in acid rain in the Adirondacks, but CO2 is a different story. Exactly, yeah, CO2 methane, those are globally mixed. And so the solutions do require some different strategies. So it is true that acid rain is much more of a localized problem. And the other reason why it's become less of an issue is because we burn a lot less coal than we used to. So that's yet a third reason. But that's not true everywhere. Obviously in China, it's still a big coal-burning country.

Does China have an acid rain problem today? It's a good question. I don't know. I would assume they do, but I haven't followed. I think India might be in the same boat. We know that there's some really bad air pollution at times in China and India that make the news every winter when the air is more stagnant. So I assume so, but I haven't really followed that. Okay. Thanks.

That's not why I asked you on. You are a climate expert, but also specifically an Arctic specialist, just to get us off in the right direction. Can you give an overview of the importance of the Arctic for Earth's climate and with respect to climate change? Yeah, so the Arctic and the Antarctic are Earth's freezers in the climate system. So they're the one end of the temperature spectrum, the tropics being the other end, the hot end, the oven. And so between those two extremes, our weather happens. And the reason why we have interesting weather in the middle latitudes, especially, is because of that competition. between the polar regions and the hot tropics. And sometimes one gains the upper hand,

sometimes the other end gains the upper hand. But it's that dynamic, that in equilibrium that results in our day-to-day weather patterns and the storms that we get and jet stream meanders and all sorts of things that we can talk about later. But the Arctic is critical then because it is one of the poles or one of the bookends of the system. Another reason is that we have so much snow and ice locked up in polar regions. If that substantially melts, it means, for one thing, that sea levels will rise, and that's a major climatic concern these days. So I've read just recently that the Arctic is warming roughly four times the average of the whole world. So what are the implications of that? And my understanding of global hydrological

wind cycles is that they are based on the temperature differential from the equator to the poles. And if the poles are warming rapidly, that temperature differential declines, does that have an impact on our weather and our wind and all that? Right. So in terms of global weather patterns, this is the concern, is that the weather, the jet stream, say the speed of the jet stream winds that really are the highway for our day-to-day weather systems, that strength and how meandering the jet stream is depends on this temperature difference between the warm tropics and the cold poles. The bigger that temperature difference, generally the stronger the jet stream and the more west to east it flows. With climate warming,

the tropics warm, but the Arctic warms a lot more, as he said, up to four times as much. And so that reduces that temperature difference between high and low latitudes, and it means that it should slow down the jet stream winds, and it makes them more prone to meanders, too. And that combination of a more meandering jet stream and a slower moving jet stream can often lead to extreme weather events that are very prolonged and persistent over a number of days, whether it's drought, heat, or flooding. So we both live in Wisconsin in the last few winters and summers, if I recall. We've experienced polar vortexes and these heat domes.

Are these related to global warming, the mechanism you just mentioned and the jet stream? And can you specifically describe the mechanics of how this polar vortex comes into being and stays? This is a huge topic and it's a controversial one. There's a lot of people doing research on it. And one of the questions that you asked is how it's related to climate change. It's such a difficult one to answer because these sorts of polar vortices and heat domes are. natural too. I mean, regardless of climate change, they've been happening forever. So when one of them occurs, it's difficult to pinpoint and say, well, this one is because of climate change,

that one wasn't. What we need to do is look partly at statistics to see if the frequency of these are changing, in which case that might be related to climate change, and whether the intensity of these is changing, which might be a result of climate change. So, for instance, just this past summer, just a month or so ago, Europe broke all time. heat records got up to 104 degrees around London, unprecedented there. And so that would be an example where we could say, well, yeah, they've had heat domes before, but never won this intense. And similarly last summer in the Pacific Northwest, Canada set its all-time temperature record, 121 degrees Fahrenheit, I think. And so when you start to get intensities of events that are

outside the historical record, then we take notice and possibly attribute it to climate change. in this case, a warming climate. So in your research, does it suggest that polar vortices are going to get more common in the future? Or is that not something that comes out of the models? The jury is still out on that. So this is a topic that I've been studying for about a decade. And it's a mixed bag between what the climate models project and what some of the observational evidence shows. theoretically, like I said, with a weakened jet stream winds tending to be more meandering as the Arctic warms faster than lower latitudes,

one would expect that these polar vortices breaking off from Arctic air masses would become more common. But at the same time, as the Arctic is warmer, it means that the formation of these air masses is also warmer. And so it's possible that we might get more frequent Arctic air masses in the future, but they wouldn't be as intense as they used to be. So instead of maybe minus 30 degree air, maybe they'd be more like minus 10 degree air, which is still cold, but it wouldn't be as severe as before. But it is a conundrum. In the past decade, we've had two very high-profile extreme cold waves in Wisconsin, 2014 and 2019, including some of the coldest temperatures on record in southern Wisconsin and northern Illinois. And yet it's happening in a warming climate. So it shows that it is possible to have these counterintuitive daily weather extremes, even though the climate is unmistakably getting warmer.

Except we are emotional creatures, we humans. And I remember those cold snaps here in Wisconsin. And you go out and talk to people and they're like, climate, global warming is bullshit. It's 30 degrees below zero. Because they can't see the longer term distribution. And these are still tail events within a warming. distribution. Right. Exactly. We all have a recency bias. Yes, exactly. Can you walk us through, there's lots of discussion about positive feedbacks and tipping points, especially in the Arctic.

Can you give us a kind of an overview and a mechanistic understanding of various tipping points in the Arctic? Yeah, so if positive feedback is a vicious circle, so if something happens, that causes something else to happen that reinforces the initial forcing. So, for example, the Arctic is full of these positive feedbacks, like with ice cover. The climate starts to warm. We start to melt ice cover. Melting ice exposes either dark ocean or darker land. That allows more sunlight to be absorbed. More sunlight being absorbed warms up the surface even more, so you get even more snow and ice melt. And so it just feeds on itself, and it makes it even warmer than it would have been without these amplifying feedbacks. And so one of the reasons the Arctic is warming so much faster than the

rest of the world is because of these positive feedbacks in that region. And snow and ice is a lot more prevalent in the Arctic and the Antarctic than it is elsewhere in the world. So there's the potential for these initial warmings from more heat-trapping gases in the atmosphere to have a much bigger temperature response in high latitudes than they do even in mid-latitudes and certainly more than lower latitudes. And so that is the concern. There's still plenty of ice and snow cover to melt in high latitudes. And so as the climate continues to warm, these positive feedbacks will continue to be operative.

So you mentioned ice and snow having a lower albedo than dark water. But what are the other feedbacks? A higher albedo, higher reflectivity. A higher albedo, higher reflectivity of incoming sunlight. What are other feedbacks? What about the permafrost? Is that considered part of the Arctic feedback potential and tipping point? Yeah, so one of the concerns about permafrost is that there's a huge amount of carbon stored in the frozen soils of the Arctic. In fact, there's more carbon stored in Arctic permafrost than exists in the entire atmosphere. And so if even some of that carbon were released into the atmosphere because of thawing soils, permafrost degrading and that carbon getting back into the atmosphere,

the atmosphere, that could be a really strong positive feedback. So that's one additional positive feedback potentially in the Arctic. The jury is still out on how powerful that might be or how and when it might happen. But another one is the loss from ice sheets. So Greenland and Antarctica and the other hemisphere are prone to potentially rapid ice loss. And we're seeing it right now through a phenomenon in which the warming waters of the upper ocean get underneath the glaciers and help to melt it from below. And they melt these ice shells, which are kind of like door jam, stopping the backed up ice sheets from flowing into the ocean. And when you remove that stop, it allows a lot more glacial ice to cab into the ocean. And so it could really accelerate

how quickly the ice sheets in Greenland and Antarctica melt. And so that's another potential feedback that could be very important. And then a third is the boreal forests. So right now we have a lot of tundra as you get far enough north, a little bit south, we have extensive tree cover, the so-called boreal forest, which is dark. And if the boreal forest spreads far enough, that provides a lot darker surface potentially year-round compared to the tundra, which is white in the winter. And so that, too, could absorb more sunlight and act as a positive feedback. So scientists are interested in the Arctic because of all these positive feedbacks, and it's a very sensitive region of the climate system. as a result. So the last I looked at the primary literature, granted it was a few years ago, it seemed

that the RCP 8.5, which you and I have talked about before, which is now being finally recognized to being biophysically implausible, like we likely don't have that much affordable carbon to burn, was the only scenario where huge positive biological feedbacks occurred, like permafrost, methane, some of the things you're going to be. you just mentioned, if we would to use more realistic fossil fuel scenarios like the recent IEA or the AR6 moderate action scenario, what does that imply about some of the feedbacks that you just mentioned? Are they moderate?

Do they not kick off at all? Or does it not matter? We're going to hit them regardless? Or what is this recent sign suggesting about that? Well, it does stand to reason that if we have a lower estimate of future. carbon emissions that some of these tipping point feedbacks that are really potentially extreme, like massive permafrost thaw and ice sheet collapses, that those become less likely, at least in the near term. I mean, eventually beyond 2100, it's really hard to say when you go beyond a century

in the future. But one of the few pieces of good news, I would say, in recent years regarding climate change, is the realization, as you've talked about for a long time, that some of these high-end emissions scenarios are implausible. And so maybe more of the moderate expectations or scenarios are probably the future that we're most likely looking at. I remember like 10 years ago or whenever we first met, you would get in a better mood when you would talk to me because I would explain that to you. And you were so worried about climate change that any news that we weren't going to hit those

outlier eventual RCP high numbers that made you more hopeful about the end of the end result. Definitely. And that's something that a lot of climate modelers like me have been slow to grasp. Most of us traditionally have used the very high end, RCP8.5, and it's equivalent, without realizing understanding, really, that the economics and some of the other factors, societal factors, would probably make that very unlikely. And so I've made a lot of climate modelers happier because of that information. Well, I don't think we're out of the woods because even though I think it's becoming more widely known that we don't have that amount of fossil hydrocarbons to burn. And the IPCC may be overly optimistic on how much of that is in the system.

I think possibly the complexity and rapidity of the biological feedbacks may be underestimated in these global models. Do you have a thought on that? It could be because the biochemical aspects of the system are the hardest to predict, including human behavior. I mean, we're bio, right? And so trying to predict human behavior is extremely hard anyway. But even if you limit it to more of the traditional biosphere, I think those are a lot of wild cards that we don't have as good a handle on. Whereas the climate models, when they were designed, they were based on fluid dynamics, which is something that doesn't have the agency of thinking the way, say, tree cover, like boreal forest expanding, would have.

And so the biological feedbacks are a lot harder to anticipate. Yeah, not only that. I mean, the climate models, the new ones, are some of the most complex models ever created. But that's just the climate system. If we add on to that, the social, the financial, the complex six-continent supply chain, the aggregate and individual human behavior, it's unbelievably complicated. But let me ask you on that. So you're a scientist.

You work on models so you know that there are things that we don't know and that there are also unknown unknowns. As far as climate change per se, setting aside human behavior and energy and such. But as far as climate change, how much are unknown knowns and unknown unknowns still out there? Or have you guys really honed in on understanding how the climate works? Well, I guess by definition, an unknown unknown is an unknown, right? But in terms of adding more complexity, we have added more complexity. And that, in a way, that's good because it's a better representation of the totality of the system. But it also makes the models more complicated, that makes them harder to diagnose. It also can make them a little harder to behave correctly

because when you try to calibrate the model based on the historical climate record to make sure your model's accurate, it becomes increasingly difficult to produce as realistic a simulation as we'd like when you add more of these complicated feedbacks in. And so, for instance, clouds have always been a bugaboo is trying to handle those correctly. As we add more complex cloud physics that we know are realistic, it also makes it harder to control these models and their behavior. So it's always a constant struggle among climate modelers to add complexity, but not so much that you change your models to the point where they're no longer trustworthy. Is there one or a half dozen climate modelers on IPCC that are like one ring rules them all? They understand the whole system or is it a bunch of people like you that have a specific expertise that are adding that into the system and no one person understands it all? It's definitely the latter. So when I go to conferences, it's become so interdisciplinary. There are people who's, you know, whose scientific language I can't even understand and they can't understand mine. So you have oceanographers, glaciologists, biologists, chemists, computer scientists, all sorts of people in the climate modeling world. And we talk to each other. We try to understand each other's language, so to speak, but we all are coming at it from a different perspective. And that can be useful because you make sure,

Nobody's forgotten anything, but it can also tend to bog you down compared to the early days of simpler climate models that were essentially just representing the fluid dynamics of the atmosphere and the ocean. Thank you. Okay. Let's get back to the Arctic. So if the Arctic is warming at four times the world average, wouldn't it be possible that even if the Earth eventually stabilizes because of declining fossil carbon burning at one and a half to two degrees Celsius above pre-industrial? Doesn't that imply like five or six degrees Celsius in the Arctic? And wouldn't that be enough to in turn kick off more of those tipping points and feedbacks you mentioned? Yes, it would. And the so-called Arctic amplification of global warming is a very real thing. We've observed it in the last several decades. We know it from the paleo-climate record from the geologic past when times of dinosaurs.

The poles were ice-free, hard to believe. but it was the warmest, the biggest warming region of the world compared with other regions like the tropics. And, of course, in climate models, they've been very consistent that as the earth warms, the Arctic, and eventually the Antarctic warm more too. And so you're right. So the concern is that any sort of tipping point feedbacks, not just the snow and ice albedo feedback that we talked about earlier, but some of the massive ones that are wild cards, like huge carbon loss from permafrostom, or Greenland ice sheet destruction or collapse of one of the Antarctic ice sheets, those kinds of tipping points as we get more and more warming in the globe and amplified in high latitudes,

that's what keep climatologist up at night is worrying about those sorts of wild card scenarios. So let's talk about one of those scenarios. There's a lot of doomsday talk on the Internet on this topic, and many topics, actually. And there's also outright dismissals of climate risk. But one topic in particular that I've heard a lot about, especially recently, is a blue ocean event in the near future. And some people assume that if there is a blue ocean event, that signals runaway climate change due to the lower albedo and absorption of more incoming heat, et cetera.

So first of all, what is a blue ocean event? When is the last time that Earth experienced that? And what do you think about if that happens in the future? What does it imply? Well, by blue ocean event, I assume you mean more ice-free conditions in the Arctic Ocean, for example. Correct. So we transform from white to blue. Yeah.

Yes. So this is the direction we're headed. And in terms of seasonal blue ocean, so summertime ice loss, complete ice loss in the Arctic Ocean, it's likely, based on climate modeling, that that's going to happen as. early as the next few decades. So that wouldn't mean annual, completely blue ocean all winter long, but in the summer for at least a period. And as the climate warms even more, that means more and more months would be blue instead of white as they have been.

So the first time that that happens in a couple decades maybe, then at first it's just a seasonal. But while it's seasonal, that itself would be a positive feedback, which would accelerate warming around the earth because of the incoming heat absorption. Right. And it's not binary. It's not like all of a sudden once we have one that has complete ice loss. It would have massively different effects than the year before that was nearly complete ice loss in the summer. But that is true. So it would have these, you know, broader consequences. The last time we think that the world and the Arctic was really significantly warmer than today unless ice cover with seasonal ice-free, potentially ice-free conditions,

was the last interglacial period, which peaked 125,000 years ago. So over 100,000 years it's been since we're looking at some of the changes in the Arctic that we're expecting in the near future. To put that in perspective, that kind of warming that we had 125,000 years ago was enough to raise global sea levels six to nine meters. So that's about 20 to 30 feet compared to today. we're worried about potentially one meter of sea level rise in the future. Haven't we in the last 25,000 years, the sea levels risen over 400 feet? So the low level of the ice sheets, or low levels of sea level, rather, during the peak of the last ice age, the last glacial maximum, about 20,000 years ago, sea levels were about 120 meters lower, or about 360 feet lower than they are today.

It's a huge drop. I mean, enough to connect Russia with Alaska, for example. So since then, in rapid fashion, during the last 10,000 years or so, or 20,000 years, there were these massive increases in the rate of sea level rise. Over time, those got slower and slower, as most of the ice sheets had melted. And so over the last 6,000 years, the sea levels haven't changed dramatically. But during, oh, maybe 15,000, 10,000 years ago, we had some of these meltwater pulse events where he had these huge levels of sea level increase. But one of the concerns about sea level rise is that not only does it have huge consequences because people around the world disproportionately live on coastlines, but it has such a long-term

effect. So even if we could get carbon emissions under control and get temperatures moderated through policy changes and other actions, sea levels would continue to rise. And so this is going to be a problem with us not just for years or decades, but even centuries because there's such a big time lag in the response of sea level to climate warming. So what about the mechanics of situations that are really difficult to model because they lie outside, observe parameters or system states? I'm not aware of any published literature, but what might change with a permanent seasonal blue ocean in the Arctic when the heat loss in the winter from the ocean to the atmosphere overcompensates?

Heat gain in the summer from a lower albedo, heating the atmosphere, disturbing the jet stream. What would happen if the center of cold in the Arctic, which is right now like at the North Pole is no longer the North Pole but moves to the Greenland ice sheet, which would be at that point the remaining cold mass? Would the jet stream like tilt significantly more? You walk us through such a change or do I have that all wrong? from first principles? Is that being considered at all? Yeah, so these kinds of scenarios are what we can test in climate models.

And for instance, people have done quite a bit of climate modeling of the last interglacial period in part to study that very question. And so we know at that time there was a lot less sea ice, at least in the summer. Greenland was also, the Greenland ice sheet was also largely contracted. But we can look at those kinds of climate scenarios or climate periods where we might lose enough sea ice to shift toward the cold core being around Greenland and look at how the climate model thinks the jet stream would behave. So one thing to consider is that it wouldn't necessarily mean a fundamental transformation of atmospheric circulation. Right now we have two

major jet streams. One's called the polar jet stream that's located farther north, you know, 40 to 60 degrees latitude, and the other being the subtropical jet stream that's located around 20 or 30 degrees latitude. No matter what the climate, we're going to have both of those jet streams, but their location, their speed, how wavy they are. Those are all sorts of things that can and probably would change with climate change, either colder or warmer, or even these drastic kinds of climates that you're describing in which Greenland becomes the core cold pole, and we no longer have extensive ice cover in the Arctic Ocean. So getting back to the seasonal ice-free Arctic,

Do you think that that it's possible that could happen? And then 10 years after that, we have the same season. We have ice in the Arctic again. Or is it a tipping point of no return? Yeah, that's a good question. People have studied this. And that's something also that's pretty amenable to addressing with climate models. And it looks like in the case of sea ice loss that it's not irreversible.

So if we did start to lose ice cover seasonally, if we found a way to cool the climate, the ice would come back. And so that's encouraging. When it comes to things like the loss of ice sheets like Greenland or the East Antarctic ice sheet or West Antarctic ice sheet, that's a different story because that's a much slower process. And there are various other feedbacks that would probably prevent or largely thwart the ice sheets from returning anytime in the near future. So sea ice is a faster responding part of the climate system and probably it's not part of a tipping point mechanism the way some of the other components could be. That makes sense.

Here's a dumb question. You are known on your website and everything as an Arctic specialist. When you say that, does that also include Antarctica or not? A bit of yes and no. So most of my studies have been in the Arctic, but I also have studied the Antarctic. And the nice thing about using global climate models is that you can look anywhere in the world. And obviously, the Arctic and the Antarctic share certain similarities, but there are also some important differences. So one of the things people always point out is that Antarctica is a landmass surrounded by ocean, and the Arctic is an ocean surrounded by landmass.

So the North Pole is right in the middle of the Arctic Ocean, whereas the South Pole is right on the Antarctic ice sheet. So there are some fundamental differences between the two, and it's largely because the Antarctic has that gigantic mass of ice that it is slower to respond to climate change than is the Arctic. So one of the reasons why we hear so much about the Arctic and Arctic amplification and so forth compared to Antarctic amplification is because the Arctic really is responding more quickly, more dramatically, at least in the near term, than Antarctica. But that said, those positive feedbacks can and likely will kick in eventually in Antarctica, and that will provide even more oomph to the warming when that happens. I'm going to ask you some personal questions at the end of this interview. But for now, I'm just curious, if we just stick to climate change, not human systems or our economy or our culture, anything like that, of the things that you research, what thing keeps you up at night? What aspect of the climate system or the

feedbacks that you've been discussing are you most worried about? A lot of what I hear about ice sheet loss concerns me a great deal, partly because I don't think we fully understand it. When you look at the uncertainty bars in the IPCC report, they're very large around sea level. Traditionally, the IPCC has made projections on the very conservative side about how much sea level will rise in the future. But others have pointed out that it's entirely possible that we're going to see much larger sea level increases in the future, in the near term even in the next century than the IPCC has warned us about. And then, like I said before, long-term sea level is something that's not going to just stop, even if we can get temperatures stabilized. That'll continue long into the future.

And because so many people live along coastlines, it's so expensive to move, there's all sorts of problems, societal problems that come from sea level increase. That is something that concerns me a great deal. Personally, and of course I'm not a climate scientist, but of all the impacts, sea level rise is one of the ones I'm least worried about with respect to the oceans. There's acidification, there's the change in the thermal haline circulation and the amok, you know, overfishing the impact. of food webs on cetaceans and other things, I worry about those things more than sea level rise because they seem to me kind of not permanent but semi-permanent. And we can always move inland a century from now. I'm not belittling sea level rise, but to me, that just doesn't strike my emotions such

as some of the other things I mentioned. Well, and some of the things you mentioned are more immediate, you know, overfishing. That's something, you know, very immediate. ocean acidification, again, a long-term problem, kind of an invisible problem compared to sea level rise, but it's still very much there. And if we have time to talk about geoengineering solutions, one of the criticisms that's been made of that is that some of these schemes that have been proposed might be able to help curtail the rise in temperature, but they would do nothing to reduce the problem of ocean acidification because they don't find ways to reduce the carbon

in the atmosphere that's ultimately acidifying the oceans. We are a problem-solving species. And when we isolate the problem instead of looking at the system, we end up pushing the problem elsewhere. And yeah, let's talk about geoengineering. Will we reach a point as a culture where the impacts on climate and what's coming ahead are so obvious that policymakers around the world will have to take drastic steps? What do you think about that eventuality and what are some of the geoengineering things that are being discussed that you find at least plausible or possible? Yeah, so I think the key word that you use there was culture.

Whose culture? Whose country? Who's making the decision? Who has the power? You know, all of these things are up for grabs right now. I think it's an incredibly thorny legal question that we've not even scratched the surface on. There are geoengineering schemes that are relevant. relatively inexpensive. The one that's been proposed the most is pumping sulfate aerosols

high into the atmosphere, sort of recreating an artificially creating a major volcano. So when we get major volcanoes, the nature naturally spews a lot of carbon into the atmosphere, sulfate aerosols high into the atmosphere, and that creates kind of an umbrella that blocks some sunlight. And so temporarily for a year or two, the climate cools a bit, and then it rebounds, but those sorts of geoengineering schemes have been shown to be relatively inexpensive, which means that someone or some country could do it in terms of the cost of it. But that raises the big question. Who has the authority? Who has the power? What if there are unintended consequences, which they almost certainly would be, how do we navigate this legally, not ethically too, but legally

as well. I have no idea how we're going to cope with this if people try to engage in these geoengineering schemes on a large scale. Some of my speculation and some of my Earth Day talks and it may border on science fiction, but I can see the energetic economic logic of it is that we continue to grow our economy, which is measured by GDP, but GDP only cares about the gross energy, not the net. So if we're throwing more money into drilling shale oil, all that extra cost goes to the drillers and the pumpers and the frackers. So it grows our gross GDP. But that energy and money have to come from somewhere else in the economy. And I can envision that 30, 50 years from now, we're spending a lot of our energy to get energy that we need. And we're also spending a lot of our energy to mitigate the damage to the environment, which, means that outside of those two sources of energy, there's a lot left, less left for hospitals

and ballet and fancy restaurants and air travel, et cetera. But it almost seems like we're going to have to somehow globally think of geoengineering strategies at some point. I'm friends with the people who run Vesta, which is an organization looking at crushed Olivine Rock, that they put on beaches. It's like green sand and then the ocean comes and pulls it in and the waves churn it and it absorbs CO2 and sequesters in and it sinks to the bottom of the ocean. I don't know how scalable that is. I think the energetics of it actually look favorable.

But like you said, the legal frameworks of how such a thing would meaningful scale are beyond our current ability. Right. Yeah. Other people have proposed brightening. sea ice or brightening snow cover to try to reflect solar energy. There's all sorts of things that one could do, but who has the authority to actually do it? And you need to have some way to evaluate whether it's effective and what any kind of side effects are. So, and I mean this as a compliment.

So far on this call, you are speaking almost as if it were a peer review conversation. Perfect science, uncertainty facts. But I know you as a person, and I know. you are very emotionally invested in the environment and that you care deeply about these things, how do you manage as a human phase shifting between being an impartial scientist compiling and describing data and being a human with emotions and anxiety and ethics and a family? Yeah, I get that question a lot more and more, in fact, as this problem becomes more apparent. It is critical. I mean, one thing to say up front is that all.

scientists are human first and scientists second and my obviously I'm no exception so I'm I'm emotionally alarmed when I hear these new stories pretty much every day about some new impact or discovery about the climate system and climate change so there is that on the other hand day to day I am focused on on my job trying to meet deadlines get a paper out get a proposal finished that sort of thing and so I necessarily have to put blinders on and have to kind of put some of that, the worries aside, at least temporarily. Not unlike a surgeon who better not be worried thinking every step of the way, how he or she has this person's life in their hands,

because you wouldn't want them to be broadening their mindset too much for that reason, too. But you're right, you know, it is hard. It's increasingly difficult, I would say, to separate some of the emotional concerns from the science. And then, you know, broad-scale ethics, I just think you know, here we are as a human species and we have the potential to really alter the normal course of the planet in terms of our climate system. And that's something that humans haven't had in the past like we have now. And I feel honestly like we're really failing. And so there is that sort of really deep sense that, wow, you know, we as a species are really screwing things up. And there's going to be long-term consequences and we are definitely not rising to the challenge and time is running out.

I know you know this, but climate change is only one of many other human-induced, human-impacted environmental crises like biodiversity, population decline of animals, insects, fish, etc., endocrine disrupting chemicals, habitat loss, all those things. Are climate experts as siloed as many other disciplines in the academy or are climate scientists by definition look at complex issues that interrelate? Are they more systems aware, would you think? I would say that climate scientists have become more systems aware over the years. When I started in this, it was less of a policy topic.

It was more of a science, pure science topic. I would say that people were narrower, but it becomes very much apparent as time goes on, how you have to look at the entire system, including economics, your specialty, politics. That's a huge one. We saw how difficult it is to get any kind of climate bill passed. So you really have to take all these things into consideration. And nobody's an expert on all of it. And as you were asking before about, you know, how interdisciplinary this is, you have to have experts from all these different areas and try to find a way to speak a common language to make progress on this really, really complex problem. So while you have the microphone, literally, what would you wish more people would ask about Arctic dynamics? How and on what questions, what instrumentation like remote sensing field expeditions, would you like more of future research focused on?

Well, one thing that I think has been understudied is the, how the Arctic is going to change in the summer. Most studies have looked at how the Arctic is going to change in the winter, because that's when you get the biggest signal in terms of temperature change and, you know, changes that potentially changes in the jet stream and so on. So a lot of energy and attention has been focused on that, understandably. But I'm concerned about what's going to happen in the summer as we lose snow cover on land.

We don't talk about that as much as losing ice cover in the ocean. And what that is going to mean in terms of extra heating on land, changes in agriculture, forests, and even changes in the atmospheric circulation. Last summer, there was big news because northern Siberia hit 100 degrees for the first time ever recorded. And it's an interesting and important threshold, but obviously we wouldn't expect things to stop there. But when you think about how an area that this north of the Arctic Circle hitting over 100 degrees, That really does give you pause. And so I think that in terms of something that I wish people ask more about, I would say it's how Arctic summer conditions will change.

So I'm going to put you on the spot here. You can just wear your personal citizen hat here and speculate as opposed to your climate scientist hat. But if you had to guess of where things eventually equilibriates out as far as temperature above pre-industrial time, Do you have a middle of Professor Vavris' internal mental distribution on that? Or is that something you don't even speculate on? I only speculate as far as the climate model endpoints go. Typically, we use 2100. Your 2100 is sort of the endpoint.

Somewhat misleading. It's not like climate change is going to stop in 2100. It is misleading. It's like as if the climate doesn't stop changing then, right? Exactly. Exactly. Yeah. So I have my sort of, you know,

mental distribution about where we go through then, but beyond then, it's almost like all bets are off because we don't know what kind of societal actions will be taken or not taken this century. For sure, but where, let's just say 2100, where is your own distribution there? I generally, I don't see a reason to steer away from the standard IPCC estimates, which haven't really changed dramatically over many, many years. You know, doubling a CO2 around a 3 degree Celsius type of warming, obviously it fluctuates depending on which model and newer estimates about emissions. But I try not to get too fixated on that because that is always a moving target.

To me, the most important thing is that even the low-end estimates of where we're heading into the future put us far beyond anything we've been in the historic past. And so if we start nitpicking on exactly what numbers are, I think we lose sight of the the big picture, which is that we're moving into a new era in terms of anthropogenic climate change and what humans and other ecosystems are going to be experiencing. So I told someone at a dinner party last week when I was in Europe that this year will be on balance, the coolest year, the rest of our lives. And mathematically, that seems totally logical to me, given the trends and given the models.

But emotionally, that sounded like an outlandish statement. Do you have any comment on that? Well, yeah, it is an extreme statement, but it could well be true. Just like every year, we're only going to see higher and higher carbon levels, right? CO2 has been going up and up every single year. There's no reason to think it's not going to be higher next year than this year. But even if we stopped burning fossil carbon this year, even if we stopped, there's an enormous amount of warming built in because of price.

CO2. Yeah, exactly. We talk about the extra heating and the pipeline, even if we were to shut off the carbon emissions now, that that would continue into the future. And that's why this is such a, what do they call it, a wicked problem because it's, you know, carbon dioxide, methane are invisible. They have such long time lags. So even if we take action now, we don't see the effects until many years later.

Politicians are elected on two to four to six year terms. They're not elected on 100 year terms. So it's almost like everything is conspiring to create this massive knot of a societal crisis to try to figure out. Yeah. And things that are good for climate are going to be bad for the economy generally, except for the easy things like contraptions, like carbon capture and sequestration, or let's build more solar panels because solar uses less carbon than coal or gas, which is true, but we're really not using less oil and gas. We're adding the renewable energy to the total pie of human energy.

I'm sure you know this, but you overlay a chart of CO2 with all the convening of party parties, climate change international conferences. There's pretty much one-for-one correlation. All those meetings have not changed the trajectory. Right, right. Well, one example is China. They're getting kudos in some respects for their expansion of renewable. energy, but at the same time, they're growing so fast that they're also expanding their fossil

fuel use. So, which way do you look at it? So it can be both. Exactly. So, Steve, do you have any suggestions for how people living in advanced economies, most people listening to this podcast, can prepare themselves in their communities, either for the warming that's already in place or for some of the economic transitions that you and I have discussed in the past. Do you have any recommendations?

Well, some of these are win-win strategies. We can look for low-hanging fruit, things that in terms of adaptation, that will have benefits in the short term, and will have climatic benefits as well. For instance, urban tree cover is one that's a really low-hanging fruit, so to speak. That's one that trees are a natural air conditioner. We know it's an environmental justice issue, places that tend to be poorer, inner city locations, neighborhoods that have a lot worse urban heat islands, lacking parks, vegetation, gardens. Having more trees in cities, for example, would be beneficial in terms of carbon drawdown.

It would also be beneficial in the immediate term, whether you have a warming climate or not, summers are hot, and then it would have a long-term benefit in terms of a natural air conditioner, kind of green infrastructure. So I would say that seeking those kinds of benefits that have dual purposes are ones to seek out. And a lot of experts have pointed out which ones are the easiest to implement in the near term and the cheapest. And so there's some good advice out there already to follow. So you're a teacher. Let me ask you two questions about that.

Do you teach various climate? What is the class you're going to teach this fall? Are you teaching a climate change class? Well, I mainly do full-time research, but I do advise. I mentor students and I give a lot of educational talks to the public and so forth. So I do wear an educator's hat for sure. And what specific recommendations do you have for young humans who become aware of all this? Well, boy, there's so much to learn, right?

In some ways, it's really the young people who are teaching us because when you look at surveys time and again, it's the young people who are taking this climate issue a lot more seriously, even to the point where they often cross political party affiliations in terms of their positions on climate change. And so I'm really inspired. One of the things that does give me hope is that young people are taking this seriously, compared with middle-aged folks like me and older people, and they're going to be around a lot longer, and they're going to experience a lot more climate change than I will. And so it does give me hope to think that the folks coming up who are younger and are going to have

assumed positions of power in the coming years are ones who are taking this issue to heart and more willing to take action on it. So what do you care most about in the world, Professor Vavris? Well, I care about a lot of things, obviously, aside from climate, I would say what's on my mind lately is peace. The fact that we're, you know, the war in Europe is very troubling. And I would say a lot of justice issues in the last couple of years, obviously since the George Floyd tragedy, we're thinking more and more about social justice, environmental justice and so forth. A lot of these things are issues that were swept under the rug for many, many years, and they're coming to light now.

And so these are things that are close to my heart, and some of them are tied together with climate change, like environmental justice. Well, I'm thinking about that more and more. As climate warms and events in the world get worse, including wet bulb problems in very high, Humid places, high temperature, humid places, places without air conditioning. The concept of climate justice is going to become almost undeniable because a lot of the global South never burned any fossil fuels. And yet they're going to bear the brunt of a lot of the impacts.

And it just seems like a huge ethical, you know, quandary in coming decades, yes? Yeah. Oh, absolutely. And so the heat that you're mentioning is one great example. Another one is a sea level rise that is affecting and making it more difficult to live in low Pacific island states. And their contribution to the problem is next to nothing. I study the Arctic and coastal erosion in the Arctic has become a huge problem to the point that some villages in Alaska have had to relocate because there's so much erosion along their coast during storms as the climate warms.

And yet they too contributed next to nothing to the problem. So for a lot of us, depending on where you live, we start to see climate change as, oh, you know, it's hotter this summer or, you know, maybe a discomfort or I have to run my air conditioner more, different things like that. But it's not an existential threat to most of us at this point, whereas for some people, it already is. And it's going to become more so. And when it happens to people who have contributed less, you're next to nothing to the carbon emissions, it makes you realize just how unjust it is. Yeah, and, you know, I'm stuck in model land and reading Western news feeds. And last week I was at a polycrisis conference in Europe and I spoke quite a bit with a Muslim woman from Djibouti. And she was telling me that the knights are getting so warm in her village where she's from that the animals are struggling.

Not the lions and elephants, but like the oxen and animals they use for their food. and it's starting to become an issue with some of the animals. So this is something we don't really think about here when we're doing a podcast in Wisconsin. But these things are starting to happen around the world more and more. Right. And you alluded to the wet bulb temperature. So if listeners aren't familiar with that, that refers to the combination of heat and humidity getting so high that it becomes physiologically impossible to cool through sweating.

Sweating depends on evaporation. And it works well when you have enough dry. air to evaporate the sweat. But if it gets so hot and so humid that that process no longer works effectively, that can lead to some places being absolutely uninhabitable. And you just can't live. It's not even a matter of being outside and toughing it out, drinking enough water. You just can't make it there. And there have been some instances in recent years when we've crossed that threshold at which humans can no longer be effective in cooling themselves through sweating. And as those areas expand become more frequent, that is obviously a huge human health concern.

And it'll mostly happen in the hotter regions, especially the Middle East. That seems to be ground zero right now for that kind of episode. Thank you. That was very clear. And I think I also read recently that forgetting about the temperature change from climate, that the research has shown that the wet bulb temperature that's tolerable is actually lower than was previously thought, meaning that more people will be at risk in coming decades with a similar temperature increase.

So, yeah. And we already know heat is the number one weather-related killer, at least in this country. So there's no reason to think that that won't continue as we get warmer and warmer. So what are you most hopeful about? What in your life, in your world, in seeing what's happening in society? What gives you hope, Steve? Well, I mentioned young people. That gives me hope, not just because they're interesting and enthusiastic and have a new way of looking at things compared to jaded older people like my generation, but also because they are taking this more seriously. So that gives me hope. It also gives me hope to study history. You look back at history and there have been a lot of crises, societal crises, when it looked like all hope was lost. My parents grew up in the Depression and World War II, and they tell me about times when it just looks so.

bleak like, you know, what was going on in Europe with Nazis, fascism, like England was going to fall there for a while in 1940. People didn't have enough to eat. The depression seemed like it was going to go on forever. There was no way out. And yet, we found a way to combat that and get over it. And so that does give me hope that even though I think that the climate crisis is a different animal in terms of how encompassing it is and what a wicked problem it is, it's still a human-made problem. And therefore, it has human-made solutions. They are easy and they can seem politically intractable, but they are problems that we've created and that we can solve. It's different than if we had a deadly asteroid coming at us like the dinosaurs were facing when there was really nothing that could be done. So speaking of solutions or responses, if you were benevolent dictator and there was no personal recourse to your decision, what is one thing you would personally do to improve?

human and planetary futures. I don't even know how to answer that question. I guess the first thing I would do is resign as dictator. Even a benevolent. I would abdicate. But I think what we need to do, and this isn't like an original thought, we need to figuratively turn down the temperature right now. I think that in terms of finding solutions, we are so politically polarized right now that we can hardly stand to be in the same room with each other. Social media doesn't help this problem. I think it's made it worse, adding fuel to the fire.

But, you know, we can't even have civil conversations with our neighbors and with people of different, say, political viewpoints. And I think that's extremely troubling. You know, a lot of what we're hearing about right now, political instability, questions about how sustainable our democracy is, after all the questions that certain people have hurled about the integrity of our elections. I find this terribly troubling because this is really getting at the core. This isn't like, well, you have a different view on tax policy than I do, so we'll find some compromise. This is really getting at the core of our quality of life. And so if I could find a way to turn down the temperature in especially political discourse, I would try to do that. So merging your two thoughts there before you abdicated, you would turn off the Internet. And that might solve that.

Did you see the movie, don't look up? I didn't see it, but I've heard a lot of people say that I should see it. And, of course, it has a strong parallel to the climate crisis. I thought it was excellent. It was so creative. It just implicitly showed how difficult the social overlay of these natural resource environmental problems are that we can't even talk about them because people are expecting to hear happy stories because they don't have agency to, to, to, to, to, to, to, you know, to. deal with this. So I do recommend you watch it. Thank you so much for spending your time today. Is there any closing thoughts, advice, wisdom for our listeners, Steve?

Well, I was going to close with the statement that climate change is a human cause crisis and so it has human solutions. But I've already said that, so I won't close with that. But I'll thank you for your excellent questions, Nate. As always, you've pushed me to try to understand the system better and more broadly. And I appreciate that. And I know our listeners today will get a lot out of it as a result. Thanks to your insights and your creative questions. I'll give you a holler next time I'm in Madison, my friend. Thank you for your time and be well. Thanks, you too. Take care, Nate. If you enjoyed or learned from this episode of the Great Simplification, please subscribe to us on your favorite podcast platform and visit the great simplification.com

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