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Making sense of “compound” climate impacts in a time of global weirding

Published Jun 20, 2024, 5:45 AM

We are living through the hottest year on record. That’s not news, but growing climate impacts make bigger and bigger news. At 1.3C of warming beyond pre-industrial levels, people are reckoning with a planetary system that’s out of whack. It’s not like the scientists didn’t see worsening impacts coming, but many of them have been surprised by the ferocity with which some have played out. On this week’s episode of Zero, Bloomberg Green’s Akshat Rathi speaks with his colleague Eric Roston, and Texas Tech University professor Katharine Hayhoe explains why we’re all experiencing “global weirding.”

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Zero is a production of Bloomberg Green. Our producer is Mythili Rao. Special thanks this week to Kira Bindrim, Anna Mazarakis and Alicia Clanton. Thoughts or suggestions? Email us at zeropod@bloomberg.net. For more coverage of climate change and solutions, visit https://www.bloomberg.com/green.

Welcome to zero. I am Kshatrati. This week global warming or global weirding. So here in London it's been raining for what feels like months, which is maybe what you think London should be like, but let me tell you this is next level. England has had one of the wettest years since people started keeping track of such things back in eighteen thirty six, and all around the world the weather has been anomalous and disruptive. We are, after all, living through the hottest year there has ever been on record. There's been flooding in Dubai, Haile in Texas, extreme heat in India. In Delhi, where my in laws live, it's been forty four degrees celsius one hundred and eleven fahrenheit this week. I'm sure you can go into some examples of crazy weather where you live. As the summer gets underway in the northern Hemisphere, all of us at Bloomergreen are bracing for new extreme weather events. My colleague Eric Rosston has covered climate change for more than two decades and he's had many, many conversations with climate scientists about the unprecedented times we live in. Today, we're going to bring you a conversation he recently had with Catherine Heho, a climate scientist at Texas Tech University. She focuses on assessing the regional impacts of climate change on people and the environment. We'll hear Eric's conversation with her in a moment, but first I wanted to catch up with him to find out how he is thinking about this moment.

Welcome Eric, Hi, Thanks for having me.

Now, you've been writing about climate change for a long time. How do you convey to somebody now the true weight of all that is happening in the hottest year?

So, in the time that I've been doing this since like two thousand and one, all but one of the years of this century or is one of the hottest years ever. The way you ask the question is sort of overwhelming. It's like, how do you explain the scale of things that are going on? And I think I don't.

You talk to climate scientists often, and you've been doing that for years as part of the job, but they see things getting worse and they understand it better than anybody else because they kind of see it coming and it becomes true. So, in doing these interviews over the years, have you seen a change in their attitude on how they think about climate impacts.

I think you in the last two or three years when one of the big UN climate reports came out, did a column on the evolving language that scientists have used since the nineteen nineties, and scientists are very conservative in the way they speak, and these UN climate reports are the most conservative statements that scientists make about climate change, because not only all the scientists, but two hundred different countries have to agree agree to it. And so if you just look at the top line statements, they evolve from the early nineteen nineties from well we're looking at it, you know, to like a famous mid nineties statement, we can detect a human discernible human impact on the climate, you know, to these days, which to like translate it into conversational speech is it's here, and it's nuts in some ways, it's worse than we thought, and what is anybody doing about it? I think in two thousand and seven they called warming it's unequivocal. This time what's unequivocal was human contribution to the warming, which Catherine Heho, you know, has described as more than one hundred percent. The reason it's possible that we're responsible for more than one hundred percent of warming. Is that we put up all the warming gases, but then some of our pollution has a cooling effect on the atmosphere, so we actually net out a certain amount of our warming, and that's how we're responsible for that much of it.

This is the part that terrifies me. It's humans running an experiment on the planet and we don't really know what will happen. Fortunately, we have climate scientists like Catherine and Haho who can explain what the hell is happening, so let's hear from her.

We often refer to climate change as global warming, but these days I think it's much more appropriate to call it global weirding, because wherever we live, our weather is getting weirder. So think of it like this. We all have a pair of weather dice, and we have a chance of rolling a double six, a heat wave, a storm, a flood, a wildfire, or more at any given time. And if we live in Texas, where I live, we already have three sixes on our dice because Texas naturally gets more extreme weather than any other state. As climate changes, as the ocean and the atmosphere are heating up, it's supercharging our climate system essentially adding more sixes and even nowadays some sevens and even an eight to our dice. Events we've never seen before that are stronger, more deadly, more dangerous than anything we've experienced. And so all around the world we have these weather dice, and we still can roll a one or two or three, but the chances of rolling a six or a seven or an eight eight are increasing year by year the more heat trapping gases we produce. And so when we get a year like we had last year and the year that we're looking at like we're going to have today, when every single time you open your news up there is a new disaster, a killer heat wave in Southeast Asia, record breaking floods in Brazil, biggest wildfire and record in Texas, biggest hurricane season predicted in the North Atlantic this summer, we think what's happening, Well, that's climate change loading the weather dice against us, and again, our future is in our hands. The more carbon pollution we produce, the thicker the blanket we wrap around our planet, the more high numbers are going to start showing up on our dice.

And are there events that have occurred in the last year, I mean near or far from you that have struck you as particularly novel or concerning.

So because of Texas's geographic location, and because it has high population density and high infrastructure density, it already gets more billion dollar weather in climate disasters than any other state in the country. As I said, Texas already has three sixes on its weather dice. So as climate changes loading the weather dice against us, what do you expect to happen to Texas? We expect it to be the poster child of how extreme weather is affecting us today. And that's exactly what's happening. We are seeing record breaking hurricanes. We are seeing massive increases in extreme precipitation. It's more often to flood than not these days when it rains, we are seeing that. We saw the biggest wildfe on record in January. We are seeing incredible extreme heat. I was just talking about my newsletter the other day. I've lived here for seventeen years, and the last two summers we have all in my family gotten heatstroke, some multiple times, and we've been drinking more. We've been cutting our time outside. I mean, the heat is different. I can feel it, and if you look at the stats, you can tell it's different at the cutting edge of climate science as a field called attribution, where as scientists we can now put a number on how much more likely climate change made a given event or how much worse it made it. So with Hurricane Harvey, for example, which hit Texas in twenty seventeen, we now know not only how much more rain fell because of climate change supersizing that hurricane, we can even draw a map and show which houses flooded that would not have flooded if the same hurricane it happened one hundred years ago, and put a price tag on how much more expensive the damages were. So Hurricane Harvey, even though it happened now over six years ago, was really a game changer in understanding and quantifying the direct impacts of human activities on these extreme events. So since then, World Weather Attribution, led by freddie Otto, has turned into a rapid response unit where you could have the Brazilian floods you know, just the other week, and they've already published the attribution study showing that those specific floods were at least twice as likely due to climate change. But if I had to pick one event so far that has really showed how far off the charts we are. It would be the massive heat wave and associated wildfires that occurred along the western coast of North America from British Columbia down into Washington and Oregon State in the summer of twenty twenty one. It happened in June, and according to attribution studies, it was so far off the tail of the distribution that it was at least one hundred and fifty times more likely. That is a lot of dice waiting. We're talking about. Those dice were weighted to basically balance on the tip of the dice. That heat wave was like throwing two dice and having both of them balanced on the corner, not even falling. That's how rare that event was. And the impacts were stunning, you know, millions of marine creatures literally boiled to death in the ocean. The town of Lytton and British Columbia set the all time I'M high temperature record for Canada one day, the second day, the third day, and then on the fourth day, a wildfire, which of course was exacerbated by the record hot and dry conditions, swept through and burned about ninety five percent of the town down. So that to me is the marker so far, but I know for sure that it won't remain that way. We are going to see events that are even more extreme that pass that likelihood, because again, the more heat trapping gases we produce, the thicker the blanket of carbon pollution we wrap around the planet, the more higher numbers we're going to have on our dice.

And the you know, like the cocktail party contrarian will say, you haven't done an attribution study on all of these things that have happened this year.

Well, we're getting to the point where it's almost possible to do that. So if you go to the World Weather Attribution website, you'll see that they are picking up a lot of events from around the world. And to me personally, the event this past year that stood out the most as a scientist was not one that was on most people's radars. I didn't see a lot of news reports about the drought in Syria in Iran, but when they did the attribution analysis, what they showed is that this drought, which was I think a category four and of five severe drought, would not even have been a drought if it weren't for human induced climate change. It would have been in the low ones, which is just sort of a slightly drier than average, it would not even have classified as a drought. So that was an example where climate change took a small anomaly, a small precipitation deficit, and it turned it into a massive, severe drought in a part of the world that has very you know, a lot of water shortages, a lot of civil and political instability, a lot of poverty, all of which are exacerbated by that water shortfall. So that to me really stood out this past year, and it didn't even make headlines because of all the other headlines that we already have about the other weather disasters happening around the world. A disaster is a function of three things, not just one. First of all, you have to have the hazard itself, the drought, the wildfire, the heat wave, the hurricane or cyclone or typhoon. But then whether it's a disaster or not depends on exposure. So if the hurricane never makes landfall, if it doesn't you know, if it doesn't hit a large city right on the coast with people and infrastructure, it isn't a disaster. And then if it does make landfall, how vulnerable or how prepared are those people. If the same hurricane hits Haiti, the poorest country in the Americas, versus the Carolinas, you know, relative well developed country, it could be the same hurricane, the same strength, with the same rainfall and the same wind speeds, but there could be orders of magnitude difference in the impacts because of the vulnerability of the system. So what that means is there's a lot that we can do to mitigate our impacts on climate to prevent these hazards from getting worse. But there's also a lot we can do right here, right now, especially at the local scale, to reduce our vulnerability, to build resilience, to ensure people are prepared. Our future truly is in our hands, and it's in our hands in multiple ways, at multiple scales. And so that's why climate action includes not just reducing our emissions of heat trapping gases, but also building resilience to the impacts that are already here today.

After the break, Eric and Catherine discuss something called compound events weather events that stack up on top of each other with no one effects. By the way, if you've been enjoying this episode, please take a moment to rate and review the show on Apple Podcasts or Spotify. It really helps other listeners find it.

You know, I was thinking about conversations I had a long time ago, fifteen years ago maybe, and a colleague saying, you know, I think ten years from now is going to be really interesting because you know, the signal is going to come out of the noise. And I've only been realizing recently that like compound events is how we're actually is how this is actually going to go down. Compound events, which is something today nobody's heard of, is actually in three to ten years going to be how we define climate change. And so this is long. This is a long preamble to saying like when I was talking to my colleague ten or fifteen years ago, I felt like I knew what the narrative was going to be, and that narrative has largely come true because the science was largely correct. But like with the rise of compound events, I don't understand what the narrative is anymore, right, Am I just not reading the right things? Or is there just more uncertainty about what the next phase looks like.

So nearly eight years ago, Bob Copp and I wrote a chapter for the fourth US National Climate Assessment on potential surprises. We talked about tipping points in the climate system, we talked about impacts that we know that we don't know, and we talked about the risk of compound events, and we showed that as these weather dice are getting loaded against us, we do expect compound events to increase. Where either the definition for compound events is either you have sequential events in the same place. So for example, in California, you could have a terrible wildfire season that destroys a lot of the vegetation, and then it could be followed by very severe and strong atmospheric river that with no roots to anchor the slopes and heavy rainfall falling, the risk of landslides is much greater than it would have been if you only had the wildfire or you only had the atmospheric river by itself. So that's the first type of compound event, where they occur sequentially in the same place. But then the second type of compound event is where you have events that occur at the same time in different parts of the same region or the same country. So take the United States for example, or take all of North America, there's only so many firefighters. And it turns out that from Alaska through Canada to the United States, there is a well established practice of based on when the wildfire season starts and ends in each different place, crews of firefighters move around the continent to be in different places depending on when the season. Traditionally used to be well. Now, unfortunately the season is extended, it's much longer, and they have many more fires burning greater area in much of those places, and so there aren't enough firefighters to go around anymore. We just don't have the resources. You could say, the same resources about FEMA or the National Guard. And where this is really coming home to roost in terms of compound events is in insurance. So insurance companies have been tracking this for a long time and they've gotten to the point where there are some areas in the United States that have such high risk of compound events occurring sequentially or within the same state, that they're pulling out of areas in California, in Texas, in Florida, in Louisiana, or in other places. They're just jacking the prices through the roof to the point where somebody who owns like a normal home, you know, with a couple of young toddlers, their insurance could go from two thousand year to five thousand a year in just one year. And if people can't get insurance, then they can't get a mortgage because a mortgage requires you to have insurance. So we are seeing the insurance industry respond to these compound events, but we aren't really seeing anyone else respond at scale. And what that's going to require is it's going to require massively more resources to cope with the same types of disasters, whether it's floods, hurricanes, heat waves, droughts, or wildfires, because if you have many of them occurring at the same time, you can't just have these teams that you send out to help. You have to have a lot more people, and that means it's a lot more expensive, right. And then also we have compound events on the global supply chain, and so we can have, you know, the impact of a flood that knocks out a chip producer in Southeast Asia that can have repercussions on the availabilities of computers in North America. Our world is so interconnected, not just physically but economically and socially that these impacts, and we haven't even talked about refugee crises and migration, climate migration, they can have all of these cascador and knock on effects that I think we're only just beginning to understand.

That was Eric Rosston speaking with Catherine Haho. It's such a treat to listen to a sign to speak so eloquently, and she always brings these amazing examples. Now before we go, Eric, there's a question that vis climate reporters get asked often, which is, given how much you know about climate change, much you have to read about climate impacts all around the world, are you optimistic? And I hate that question.

I hate that question, but I.

Also understand why we get asked that question. Of course, do you have a pet answer?

My answer is, first of all, pessimist don't say they're pessimists, they say they're realists. But also the conversation presupposes that you're an observer. It's like this thing is happening before you. What do you think is going to happen? Like, if you're an optimist, do you think it's going to get better? If you're a pessimist, do you think it's going to get worse? But what I want to know is not if you're an optimist or a pessimist, what are you doing about it? You know what is within your power, and among the things that are within your power, what are you doing about it?

Thank you, Eric, Thanks so much for having me. Thank you for listening to Zero. If you liked this episode, please take a moment to rate and review the show on Apple or Spotify. Share this episode with a friend or with the Texan. You can get in touch at Zero pod at Bloomberg dot Net. Zero's producer is Mithy li Rao. Bloomberg's head of podcast is Sage Bauman and head of Talk is Brendan Newnan. Our team music is composed by Wonderly Special thanks to Key up in the Room, Annamazarakis and Alisia Clinton. I am Akshatrati back so