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The full conversation from Shift Key, episode three.

This is a transcript of episode three of Shift Key: Is Biden's Climate Law Actually Working?
ROBINSON MEYER: Hi, I'm Rob Meyer. I'm the founding executive editor of Heatmap News and you are listening to Shift Key, a new podcast about climate change and the shift away from fossil fuels from Heatmap. My co-host Jesse Jenkins will join us in a second and we'll get on with the show. But first a word from our sponsor.
[AD BREAK]
MEYER: Hi, I'm Robinson Meyer. I'm the founding executive editor of Heatmap News.
JESSE JENKINS: And I'm Jesse Jenkins, a professor at Princeton University and an expert in energy systems.
MEYER: And you are listening to Shift Key, the new podcast about climate change and the energy transition from Heatmap News. On today's show, we're going to talk about how the IRA, the Inflation Reduction Act, President Joe Biden's big climate law passed in 2022, how it's working, whether it's working. We have new data to shine light on this extremely important question. And we also are going to do as always our upshift and downshift, our thing that gave us hope this week and our thing that maybe has us feeling a little down. So Jesse, ready?
JENKINS: I'm ready. Let's dig in.
MEYER: Let's get into it. In August 2022, President Joe Biden signed the Inflation Reduction Act, the IRA. It's the largest climate law in American history and arguably in global history. And it threw the full financial power of the US federal government behind decarbonization, directing more than $500 billion in grants and tax credits toward replacing old dirty fossil fuel infrastructure with new clean zero carbon technologies. Now, when it passed, modeling, including from the REPEAT Project, which is a collaboration of ZERO Lab at Princeton University, led by my co-host Jesse Jenkins and Evolved Energy Research, a consulting firm, suggested that the law would cut US greenhouse gas emissions 37 to 41% by 2030. And I should say this research when it came out was a big deal. You don't have to take my word for it. The ZERO lab’s work was cited in the Guardian and the New York Times, by the Wall Street Journal, by legislators and by the White House itself.
And it wasn't the only kind of piece of energy modeling that we used to figure out how big a deal the IRA was. There were other reports, one from an organization called the Rhodium Group and another from a nonprofit called Energy Innovation. Now those reports really, I think at the time, helped us understand just how big a deal this law was going to be. We're now just about 18 months after the Inflation Reduction Act has been signed. And that means we're getting to a point where we can see the impact of this legislation. We can start to see whether it's working. And the REPEAT project, in conjunction with the Rhodium Group, MIT and Energy Innovation — all the groups that did this research last time have gone and conducted the first analysis of whether the law is working — our kind of first midstream assessment, 18 months in, of whether the IRA is actually reducing emissions and decarbonizing the economy like we hoped that it would. So that's what we're gonna talk about on the show. The first real analysis of whether Biden's climate law is cutting greenhouse gas emissions, with my co-host Jesse Jenkins, one of the researchers who helped us understand its potential in the first place. So Jesse, I actually want to start by backing up slightly. And before we get into this new data that you have that talks about, you know, whether the law is working, let's start with this: how is the IRA supposed to work?
JENKINS: The IRA is effectively putting clean energy on sale for all Americans. That's how it's supposed to work. It is a set of financial incentives that effectively drop the cost of just about any action you would want to take to help accelerate the clean energy transition by, you know, somewhere in the order of 20 to 50%. So it's a little bit like you know, Black Friday shopping deals or Cyber Monday or whatever your favorite sale is. It’s, you know, using the federal purse to make it easier and a smarter financial decision for households or businesses or utilities or whoever else to just make the greener investment or purchasing decision over the dirtier one.
And it's really quite comprehensive. It involves a set of incentives that cut across really all of the major emitting sectors of the economy. But in particular, all of our modeling from REPEAT Project and our colleagues at Energy innovation and Rhodium Group, indicated that the biggest emissions reductions over the next decade, in particular, would come from the power sector, electricity generation, and the transportation sector, particularly the uptake of electric vehicles.
These are two trends that were already underway before passage of the Inflation Reduction Act. And what we're looking for is evidence that those trends have basically been supercharged by the incentives provided in the act.
MEYER: And luckily my understanding is that those are exactly the two sectors we have new data on today. Is that right?
JENKINS:
That's right. So yeah, this should be a terrifying moment for any modeler — when we get to check our modeling projections against reality. But we did just that. We have data from 2023 now, courtesy of the Clean Investment Monitor Project. If you go to cleaninvestmentmonitor.org, you can check out this data yourself. This is a joint project of the MIT Center for Energy Economic Policy Research and the Rhodium Group. This is led in part by Brian Deese, who is one of the chief economic advisors to President Biden and one of the key architects of the series of laws passed in the last Congress. He was the chair of the National Economic Council and is now an innovation fellow at MIT in helping lead this project.
And what it's doing is, it's basically giving us as close to real time a look at the progress of the clean economy in the United States as I think we can get. It's basically updated every quarter and it's tracking all of the public and private investments in actuality as well as announced projects, that kind of as a leading indicator of what's coming in the future across most of the major sectors that we're talking about here. It's a really helpful data set to gauge our progress. So what we did was we took that data on zero emissions vehicle adoption — so EVs and fuel cell vehicles and plug in hybrids and clean electricity capacity additions — and compared that to what each of our three modeling groups were estimating was likely to happen after passage of the Inflation Reduction Act, and I should add the Bipartisan Infrastructure Law as well, which we were modeling you know back in 2022. So now we have year end 2023 data and the question is, how well are we tracking at least in this first year out from passage of those major laws?
MEYER: I wanna talk in a second about how confident we are that the signal that we're seeing in the data is actually the IRA or the Bipartisan Infrastructure Law, like how confident we are in the Bidenomics signal. But first, let's do the moment of truth. Let's just first get to the data. So in the power sector, what do we see?
JENKINS: What we see in the electricity sector is a new record set for zero carbon electricity generation and storage capacity additions. That's new power plant and battery storage construction. In aggregate, we saw over 32,000 megawatts or 32 gigawatts of new zero carbon generation and storage added to the US grid in 2023. That's about a 32% increase from the rate in 2022. And it edges out a previous record that we saw in 2021 of about 31.6 gigawatts.
So good news is we're setting new record growth rates in total in terms of wind and solar and battery additions. Unfortunately, that does fall on the lower end of what we were projecting in most of the modeling results. We were looking for on average about 46 to 79 gigawatts. So call it, you know, 40 to 80 gigawatts on average of additions in 2023 and 2024. And we fell short of the low end of that range right at 32.3 gigawatts. And so, unless the pace accelerates substantially in 2024, we're probably going to fall a bit behind schedule in terms of capacity additions.
MEYER: And do we have a sense of what's driving that? Because I think that's a very surprising finding, that we're behind schedule in the power sector where I think people feel pretty good generally about the pace of decarbonization or I think where the common wisdom at least is that the pace of decarbonization is like proceeding apace. What's driving this underperformance of the model?
JENKINS: So it's really the difference between solar and wind additions. The solar sector added about 18.4 gigawatts of capacity in 2023. That's up massively from just about 11 gigawatts in 2022. It's about double what we had seen in 2020 which was kind of our reference when we were doing our modeling as we started the REPEAT project in 2021. And so that's looking encouraging and in fact, is running ahead of schedule with the average pace of additions that we saw in REPEAT project results.
Batteries are growing way faster than we expected. And that helps really make the most of those solar capacity additions because solar and batteries are kind of like peanut butter and jelly, they go together quite well. And that's because solar has this nice, regular daily fluctuation, right? From the sun rising and setting. And that pairs really well with batteries, which today in a way lithium ion batteries are best suited for, you know, only a few hours of storage. So they'll charge for three or four hours in the middle of the day when we've got an abundance of sun. And then they'll discharge in the evening to help meet the evening peak of demand when everybody's coming home from work.
The batteries basically helped shift the solar output from the middle of the day to hit that evening peak. And that's, that's really helpful.
Where things are running behind schedule is really in the wind sector, where we only built about half of the peak rate, actually less than half, that we've seen historically in 2023. Additions of wind power in 2023 were only about 6.3 gigawatts, and that's down from nearly 15 gigawatts in each of 2020 and 2021.
So that's a step backwards at a time when we should be smashing new record growth rates across all of these sectors. And that's giving me the biggest concern as we look at in the next couple of years.
MEYER: And that's, I mean, last show we talked about offshore wind and the troubles in offshore wind and how it seems like some big offshore wind projects that we thought might be coming online in the middle of this decade might not be coming online till the end of the decade. But when we talk about wind underperforming in terms of the whole country over the past year, we're really still talking about onshore wind. This is like big turbines in the middle of the Great Plains, not big turbines off the coast of New York, New Jersey, right?
JENKINS: That's right. Yeah, I think I don't think we had any significant offshore wind capacity additions coming in 2024. You know, most of that we were expecting would come in between 2026 and 2030 or 2035. So this is really a story about onshore wind, where if we look at the economics of onshore wind across the country, there's a tremendous number of sites that look very economic given the incentives provided by the Inflation Reduction Act.
And unfortunately, we're just not building out at the pace that would be economically justified. And that is really an indicator that there are a substantial number of other non-economic frictions or barriers to deployment of wind in particular at the pace that we want to see.
MEYER: Before we go on, I just want to make it clear—
JENKINS: Maybe it's worth pausing and unpacking what those incentives look like. But the main one is what's known as a production tax credit that provides a payment of tax credits for every megawatt hour of clean electricity produced over the first 10 years of operations from a new facility. And that credit is worth about $28 per megawatt hour, which is getting pretty close to the average wholesale revenue that you would get just from selling your electricity. So it's basically doubling roughly, or maybe it's an 80% increase, the revenues that a wind or solar facility gets during its first 10 years of operation. And that is a huge boost in terms of the return on investment that people are seeing. And so that is the incentives that the IRA expanded and extended into the long term, you can increase it even further than that, if you meet domestic content requirements or build in so-called energy communities. And so it could be an even larger incentive worth up to 20% more than that if you meet both of those requirements.
MEYER: I was going to say, the back of the envelope number I usually hear is like a 5% increase in interest rates, is like a doubling of project cost. But if you're doubling project revenue, that actually suggests that yes, we're seeing some big non-economic factors hold up offshore wind.
JENKINS: Yeah, so it's definitely true that the increase in interest rates is sucking up some of what would have been the kind of financial tailwinds provided by the Inflation Reduction Act. And that's why I'm eager to see what our new round of modeling results looks like. But the other, I think data point here is that, you know, batteries and solar are also 100% capital investments just like wind. And so interest rates would affect all of them equally in many ways. So there has to be something unique to the wind industry here that's holding the wind sector back while solar and batteries set new growth records. I have my speculation as to what that is, I think it's, you know, three factors and I have no idea, you know what proportion we can assign to each of them.
One of the first things that's I think unique about the wind sector is that it was facing the full expiration of that production tax credit that I was mentioning. So prior to passage of the Inflation Reduction Act, which extended this credit for the long term out through into the 2030’s. We've had this on again, off again history with the production tax credit of expirations every few years. It's been around since 1994 but it's not a permanent part of the tax code. And so every few years, it's up for renewal.
But unlike the ITC, the investment tax credit that was supporting solar previously, which was also on a ramp down but was still in place when the IRA passed, the production tax credit had entirely phased out for projects that commenced construction after the end of 2021. At that point, it had been reduced to only 60% of its full value. So if you wanted to get the full value, you had to finish or start construction by the end of 2019.
And I think we can see that in the data, what that did was that pulled forward the project pipeline, the development pipeline, and encouraged everyone if they could to start their construction by the end of 2019 in order to lock in the full value of that production tax credit. And that's why I think we saw record build outs in 2020 and 2021 because everybody was finishing projects that they commenced in 2019 in order to get the full value of the credit.
MEYER: You think the first factor here is like maybe a pipeline problem, so to speak, where a ton of projects started in the pipeline in 2019, they were completed in 2020 or 2021, and now we're in this fallow period where the projects that started after the IRA passed aren't complete yet, so we don't see them showing up.
JENKINS: That's exactly right. So that's the first factor. So if that's an issue, then what we would expect to see is that the project pipeline is large now and that we would see more projects coming in 2024 and 2025 that were started as the IRA was passed.
Now the other factor that's, I think, a little bit more unique to wind is also the impacts of the supply chain disruptions that we saw around COVID, and the increase in labor costs, particularly in Western countries. And that's because the solar sector and batteries are dominated by China and other Asian manufacturing bases. Whereas wind is really still a Western-produced technology, most of the wind manufacturing is in Europe or the United States.
That's partly because these are such big components, wind turbines, missiles and towers and blades are massive. And so there's less advantage of shipping them around the world. You want to build them closer to where you need them. And so we maintain more of a manufacturing base. I think something like two thirds of all of the content of wind turbines built in the US were manufactured here, whereas we only build about 5% of the solar PV modules in the US in terms of their domestic content right now. So I think that's important because what we saw was, you know, a very different pandemic response, right, in Europe and the US versus China where China largely kept its manufacturing going for most of the pandemic. Whereas the US had, you know, these disruptions and Europe had these disruptions from lockdowns.
We had more rapid inflation, you know, labor costs were going up. And so all of that I think hit the wind industry harder than it hit batteries and solar PV. We see that in the real costs of these projects. So for the first time, we saw real cost increases for all of the technologies we're talking about: wind, solar and batteries. But already in 2023 costs are back down for modules, solar PV modules and battery packs, but they're still up for wind. So I think that's an important factor too.
MEYER: It's not only that China kept the factories going, it's that even in the post pandemic moment— I feel like this is such an important aspect of how the global economy is working right now that hasn't been fully understood— the US did a ton of demand support macro-economically. Not electricity demand, but I mean, we sent checks to people, we did expanded employment, we made sure the consumers kept spending. China really did so much less of that. And so China's pathway to growing its economy to the level that it hopes to grow it right now is entirely through expanding exports and trade.
JENKINS: And so no wonder they were pumping the supply side up, right?
MEYER: All their support has gone to the supply side. And then furthermore, there's just like this structural support to the supply side because Chinese consumers are in such poor condition, basically, that they have to export things they make is their only possibility of breaking even and growing the economy.
JENKINS: Yeah, for now, at least. I'm sure we'll come back to talk about China's transition soon. So I would say those two factors are hopefully transitory, right? The sort of supply shocks are fading. The inflation is ebbing and we should be rebuilding the pipeline.
The third factor is the one that keeps me up at night. And that's just that I worry that wind is just much more difficult to site and much more transmission-dependent than solar and batteries are.
And that's kind of a function of the physics of wind power, which is interesting. Wind speeds and solar radiation, you know, kind of vary about proportionally. The best wind sites in the country are about twice as good as the worst wind sites. And that's true for solar too, like the best solar sites in Arizona or New Mexico have about twice the resource quality as you know, Maine or, you know, somewhere else in New England. And that makes sense because the physics of the wind is driven largely by the impacts of the sun heating different parts of the planet differentially and that moves pressure and temperature around and that drives the wind.
The big difference is that solar panels convert sunlight or insulation into electricity kind of proportionally to the resource quality. So a linearly one for one kind of relationship, whereas wind turbines convert wind speeds to wind power at the wind speed cubed. So if you double the wind speed, you get about an 8x increase in the wind power generation. And what that does is it makes wind much more site-dependent than solar, right? If you have a good wind speed site, you're not just a little bit better than a bad wind speed site, you're way better. And so the best, most economic, you know, attractive projects, they have to be where it's really windy.
And that means they don't have as much flexibility about where to build and those windy locations, you know, right up and down the middle of the Great Plains, for example, tend to be a lot further from where most people live. And so they're also much more dependent on transmission to site those projects than solar projects, where you can kind of move around pretty freely across a broad area without really sacrificing much in terms of resource quality. And therefore you can pick a site that's easier to build, that has less local opposition, that happens to be closer to a transmission line. Maybe you lose 3-5% of your, you know, power output by picking that easy-to-develop-site over maybe the best one around. But it's just not that big a difference whereas for wind, it really could make or break a project.
MEYER: Last question, then I want to move on to EVs, because that's so interesting. But how much does solar and batteries need to overperform to make up for this issue we're seeing with wind?
JENKINS: So if wind can't really get back on the same track as it was in 2020 and 2021 where we're building at least 15 gigawatts a year and kind of growing steadily from there, then it's true that solar and batteries are going to have to step up and kind of fill the gap.
And I think there's a chance that could happen if we look at the results kind of extrapolating out a bit further beyond 2023. We in the REPEAT project are estimating about 26 gigawatts a year of solar additions between now and 2026. So 2023 through 2026, and about 15 gigawatts a year of wind. And so if wind can only do eight or seven, you would have to see solar growing at maybe 35 or 40 gigawatts a year.
And that's actually exactly what the US Energy Information Administration is projecting for the solar sector over the next couple of years. They're projecting that in 2024, we'll build about 44 gigawatts of utility scale solar, of both utility and distributed solar, I should say, and about a similar amount in 2025. And so there's a chance that we actually could see solar kind of over-performing and making up for wind being a laggard and that kind of gets us through the next couple of years. But the growth rate just has to keep smashing new records every year from here on out. And I don't think we can really do that if we're dependent only on solar and batteries, we need both wind and solar pulling their weight. And if the wind industry can't pick things back up, I think we're probably gonna fall short of the targets that we were seeing in our modeling.
[AD BREAK]
MEYER: I want to move now to the other sector that your new research looked at, which is EVs, transportation, vehicles. What is happening in the US vehicle sector?
JENKINS: Yeah, this is one where it's funny, you know, you mentioned that I think most people have pretty good vibes about the power sector but maybe there's some warning signs that wind is lagging. I think we've seen a lot of bad vibes on the EV sector as I wrote for Heatmap a while back.
MEYER: It’s nothing but bad vibes right now!
JENKINS: Yeah, it's just all bad vibes. And yet this is the sector that is unequivocally on track, at least compared to our modeling— maybe not compared to Ford or GM’s sales growth projections— but as a sector, compared to our modeling from REPEAT project, as well as Rhodium and Energy Innovation, the EV transition is actually moving at about the pace that we expected. And that's probably likely to be true for the next several years also, not just for 2023.
MEYER: I just wanted to pause and put a pin in this point because it shocked me when I saw the initial report and I think it is so important. In the power sector, I feel like it's mostly good vibes right now. Like people have a sense that the power sector is decarbonizing at roughly the pace we need. That seemingly is not true! In the electric car sector, in EVs, there's a sense that like EVs are in trouble, the transition is in danger, things aren't going well, it's not going as well as the Biden administration wants or thought it would. And in fact, it's going basically at the pace we thought it would happen.
I just think this is such an important, interesting thing because it is completely the opposite of, if you're just reading the paper, it's completely the opposite of what you would think.
JENKINS: Yeah. And maybe this reflects just that our modeling groups were a little bit more conservative than individual car companies were in their sales growth projections. But we look at new technology adoption and we typically apply an S-curve to that adoption where they're growing at double-digit compound annual growth rates at the beginning. But then they hit, usually, a linear phase where they're growing at a pretty steep rate but it's a straight line rather than continuing to bend upwards like an exponential curve. And what that means is that you would expect the annual growth rates, the percentage growth, to be declining even as the absolute sales growth is increasing because you're building on a much bigger base, right? You know, adding 20% to a million vehicles is easier than adding 20% to 5 million vehicles, right?
MEYER: I mean, this is like a version of the Facebook problem, right? Where eventually just enough humans are Facebook users that Facebook has to find other ways to make money. It can't just keep adding new humans every quarter.
JENKINS: Exactly. So we all modeled these uptake rates pretty similarly as this kind of S-curve where we expected growth to be strong. We expected, I think, supply chain constraints on the production side to persist a bit longer than they did in reality. So that's an interesting divergence from at least our kind of underlying thinking at REPEAT. We thought that it would be harder to ramp up manufacturing capacity as quickly as the auto industry has.
MEYER: Huh!
JENKINS: But in general, you know, we are expecting to see what we saw. Actually it’s interesting, in 2023, we actually saw the annual growth rate go up. In 2022, the growth rate for zero-emissions vehicles, and that includes EVs and plug-in hybrids as well as fuel cells (although they’re a rounding error) went up by about 43%, 44% in 2022. And that growth rate accelerated in 2023 to 52%. So despite all the vibes about slowing growth, there's actually no evidence of that, at least on an annual basis. 2023 grew faster in compound annual growth terms, percentage growth terms, than 2022. But we would expect that growth rate to decline. None of our modeling is expecting a 50% annual growth rate from every year. We would hit 100% sales in just a matter of a few years if that were the case.
Instead, we're expecting the growth rate in 2024 to 2026 to be somewhere between 30 and 44% and to fall even further to somewhere between about 15 and 27% from 2027 to 2030. You know, exactly following that S-curve where the annual growth rate is declining as we hit that linear phase.
MEYER: I just want to be clear, this is in the absence of any technology-forcing policy, like new EPA rules that say you have to sell a certain number of EVs per year.
JENKINS: We do include the states that have been following California in adopting the Advanced Clean Cars to standard, which is their requirement that by 2035, 100% of vehicles need to be zero-emissions vehicles, vehicles sold, I should say in 2035 need to be zero-emissions vehicles. And so we had included at the state level, some states like that, there's about a dozen that are following in that direction. That's maybe 30% or so of the overall vehicle market in the US. So it's not inconsequential, but it's not the only thing going on. I think we all expect that 2024 will see a slowdown from 2023. But again, that's in line with what we expected in our modeling.
What's actually really interesting, at least from the REPEAT side, is that hybrids, both plug-in hybrids and just regular hybrid electrics, are far outselling our projections from our modeling.
MEYER: The IRA has incentives for some plug-in hybrid vehicles, but it has no incentives for regular hybrid vehicles. Is that right?
JENKINS: That's right. Yeah, that's right. And that's kind of what we expected was that basically hybrids would kind of give way to EVs, and that seems to be not what we're seeing. We're seeing that actually, they're kind of additive, particularly hybrids. Where last year, I think we mentioned this on an earlier show, we sold about as many hybrid electric vehicles as we did battery electric vehicles about 1.1 or 1.2 million of each of them, and that is way higher than what we expected. I think we only expected about a 1 or 2% sale share, which is about where we were in 2019.
And instead hybrid electric vehicles have just grown right alongside EV growth, and that's encouraging from an emissions perspective because those hybrids are emitting about 40% less per mile traveled, probably, than an equivalent sized internal combustion car.
MEYER: They're also going to then go have a long life as a used car, continuing to reduce emissions.
JENKINS: So from a climate perspective, every internal combustion engine vehicle that's sold that's a hybrid instead of a regular one, that's a win.
MEYER: It is funny because I feel like on the one hand, this is surprising. And on the other hand, I can think of multiple new car consumers, like in my life, friends I know, who were buying a new car in the past two years and were EV-curious, they looked at EVs. They kind of quickly decided there were none in their price range or there were none that needed exactly what they needed them to do. And so then they bought a hybrid.
Why did they buy a hybrid? Well, because they wanted to buy an EV, and they couldn't find one they liked. So they bought a hybrid because they felt like that was on the path of the transition, which is not really a rational consumer behavior as I think you would expect from a model. But on the other hand, kind of makes sense from a certain flavor of like, “Oh, well, I wanna help with this, but I can't buy an EV yet, so I'm gonna buy a hybrid.”
JENKINS: Yeah, I mean that was my mental model too because I think that's how you think about it. If you're segmenting the market, there's a certain amount of consumer who cares about the environment, they care about the cost of fueling their vehicle or both. And so they're looking at a hybrid versus a plug-in hybrid versus an EV, and they're going to fall in that range. And our expectation was that the large incentives provided for EVs would basically shift the consumer from a hybrid to the EV. But it looks like either that's not what's happening or there's a larger market out there for EVs than even we anticipated, and it's just that right now that market is still being split between hybrids and EVs.
But there's basically twice as many consumers interested in one of those than we thought, right? Because we sold about 2.2 million hybrids and battery electric vehicles, you know, whereas we were only expecting, you know, a few 100,000 hybrids and then around that many EVs. So, you know, there's a million extra consumers out there that we didn't think would be there in the market in 2023. And again, my thinking was, look, a plug-in hybrid vehicle is always going to be more expensive than a battery electric or an internal combustion car because it's just, both drivetrains crammed into the same vehicle.
MEYER: Right.
JENKINS: It's got a pretty big battery, not as big as an EV, but it's a pretty good size one. It has to keep the internal combustion drivetrain and add the electric motors, you know, and so it's gonna be relative. It's always gonna be a cost premium over an internal combustion car. Whereas a battery electric vehicle, they're getting cheaper and cheaper every year and there's gonna be a point before too long where even the upfront cost is lower. I think the cost of ownership is already at parity, but you're gonna go to the dealership and it's just gonna be cheaper to get in a battery electric car than a internal combustion car because they're simpler to build and they have less parts and batteries are the biggest chunk of the cost and batteries keep getting cheaper year after year.
MEYER: Yeah, there's this argument you hear from Toyota executives, which I've always taken as like 70% cope. Where they say, “Oh, well, actually, you know, plug-in hybrids and regular hybrids make more sense because as long as lithium and these minerals we need for the batteries are scarce, you get more emissions reductions per ton of lithium or per ounce of lithium or per ounce of cobalt, whatever, than you do with, with a plug-in hybrid or a regular hybrid than you would with a pure battery electric vehicle. Do you think that a plug-in hybrid is this range anxiety security blanket where you're able to do a lot of your trips plug-in but, whenever you need—
JENKINS: It depends on the size of the battery. Yeah, in some ways, the plug-in hybrid is the ideal vehicle, right? If you had, you know, a 40 or 30 mile range, that covers most people's daily commute, the all year around town, driving to pick up the kids at soccer, school or whatever. And then when you need to go on a road trip, you've got your gasoline engine and you can go for as long as you want. So in some ways, it's kind of the ideal American car if you didn't think about charging infrastructure.
But of course, as we build out the charging infrastructure and as batteries get cheaper, you know, BEVS get cheaper. I think it will make sense for more and more people to just get rid of the gas part and you don't need the range extender. You know, we are a single car household. We have one EV only and our second car is an e-bike, for riding around town. You know, we put 20,000 miles on our car since we bought it in November of 2022. And we've been on many road trips and we had maybe one or two charging experiences that were suboptimal.
MEYER: [laughs]
JENKINS: But like that is such a small part of my overall driving experience on those 20,000 miles. Most of them, I just wake up in the morning and my car is full with 280 miles, 290 miles of range. That's like enough for a week. And I never have to go to the gas station! The convenience of that so outweighs the one or two frustrating experiences in a long distance trip every year, that I think most people, once they're in a battery electric vehicle, they don't miss the gas at all. We've seen actually in recent consumer reports, trends that consumers who have bought EVs are far more likely to buy a second EV than to go back to internal combustion cars.
Toyota's argument about lithium, I think is intellectually correct, I should say, if you think that lithium is in finite supply. But go look at lithium prices on the market right now. They're in freefall. We are not lithium constrained, right? So, I don't know, it's a good, nice ex post justification for Toyota’s strategy. But basically what Toyota did was they bet big on fuel cell vehicles and they've lost massively. So they're trying to recoup their position by doubling down on the one area where they do have advantage, and that's in hybrids and plug-in hybrids.
MEYER: How would you look at this big— is Paris any good or not? Yes or no, is the IRA working?
JENKINS: I would say yes, I think that we're still within the cone of growth for these sectors that we projected. So I don't think there's any evidence that we're off, you know, way off base yet. Emissions did fall in 2023 as the economy expanded for the first time since the pandemic hit, it’s lower than what we projected in our modeling. So, you know, again, it's early. We should have mentioned this much earlier on, but it's hard to know— I think you alluded this actually in your setup— how much signal there is here from the IRA.
MEYER: Yeah.
JENKINS: Because we spent most of the last 18 months writing tax credit guidance and setting up new grant programs and issuing RFPs and reviewing those and most of the money hasn't actually gotten out the door yet. And so, whatever we're seeing now is just sort of like the early stages of influence from these policies and where the real signal is going to show up is in particularly 2025 and 2026 and 2027. When you have time to build a new factory, to install a new wind farm, to expand our charging infrastructure, and really take advantage of the credits and grant programs and others that were enacted by these laws, which are really just starting to get out the door.
MEYER: One more observation, which is, it is crazy that hybrids especially— I don't want to keep going back to this and I feel like again, we're just seeding topics for a future conversation— but it is crazy that hybrids are popping off during a year when gas prices did not go up.
JENKINS: Yeah!
MEYER: Because I feel like in the past, what we've seen is the only years where Americans don't buy more SUVs, let's say, than they did the previous year, is in years like 2007 or 2022, when gas prices spike to really high, you know, previously unprecedented levels. 2023, gas prices went down.
JENKINS: Maybe the memory is still in people's minds, maybe it's the inflation and the cost of living overall is still very salient for people. And so the ability to save some money on your gas bill is still helpful even if gas is not at its peak inflation levels.
I think the other factor is just that the upfront cost of buying a hybrid has fallen so much that for many models, it's just like a total no brainer. I spend a few $100 more and I get a better car that has more power and less fuel consumption. You know, it just makes a ton of sense from an economic perspective.
MEYER: And I was thinking earlier that in some ways, the presence of battery electric vehicles really defangs conventional hybrids because it is no longer the “lib car.” I mean, I don't think that cultural politics are the entire driver here, but the presence of battery electric vehicles as kind of the new “Democrat car” for lack of a more elegant way of phrasing that particular cultural idea. Okay, what I've learned from this is we need to do like 15 more episodes on cars and we need to do another 15 more episodes on China's macroeconomy and green transition.
JENKINS: Alright, we got the next season lined out.
MEYER: Yeah, let's do Upshift and Downshift. But first, let's take a break.
[AD BREAK]
MEYER: Okay, let's do Upshift/Downshift. Jesse, what is your downshift for the week?
JENKINS: So my downshift is one of the things that I think flew under the radar for a lot of people, is that on February 15th, the US Federal Energy Regulatory Commission approved a new pipeline from Texas to Mexico that will export about 2.8 billion cubic feet of natural gas for the purposes of supplying a new liquefied natural gas plant on the Pacific coast of Mexico. You know, we talked in our first episode about the pause that the Biden administration has put on the review of new LNG export terminals in the US.
This is an export pipeline which I think falls under the same criteria of, you know, having to decide whether it's in the public interest or not. And we just approved another 2.8 billion cubic feet of exports. That's like a quarter of all of our LNG exports today! And this is going to go out as a pipeline, not as LNG, right. It'll leave the US in a pipeline but it will then go to the Pacific coast of Mexico where it will supply a new $15 billion LNG terminal that is meant to supply Asian markets, right? So the ability to get the gas to the Pacific Ocean and then go from there to Asia is, you know, quite advantageous relative to the Gulf coast terminals that we're mostly talking about in the US.
So I just thought this was really interesting, I mean, we've had this big debate in our first episode and across the energy sphere about the role of exports in the US economy of natural gas exports, and here's this really massive pipeline that just kind of snuck in under most people's radar. I almost didn't catch it. But you know, big approval last week of a 2.8 billion cubic feet per day gas export pipeline to Mexico. What’s let you down this week?
MEYER: I feel like I'm about to use a downshift that I will have to use sparingly over the next few months. The presidential election, Jesse! I'm not sure you've heard about it, but there's a presidential election in the United States of America in 2024. And it has me down. Ezra Klein published a really interesting audio essay this past week about calling for Biden to step aside and for a Democratic Convention, an open Democratic Convention later this summer to select a candidate. I think he counseled something in that, which I thought was quite wise, which was that it's February and a lot of Democrats are acting very fatalistically about their candidate, and that's kind of absurd.
It's February, it's too late to get on the primary ballot in a lot of states. But there's still many months to go before the presidential election and nothing is written. There’s still a lot of different possibilities that could happen. It’s just that the outcome of the presidential election is not yet secure. However, at this point, I think it is important to say Biden is losing, which from a strictly climate policy lens would be a really bad thing for climate policy.
And I think what has me most worried about this presidential election and, and which I think, I hope that folks listening to this and folks who were very angry at me when I posted the Ezra Klein essay— I don't know whether I agree with it, I'm not gonna take an advice standpoint here— I will say that what has been so noticeable about the campaign so far is the reluctance to use Biden and the reluctance to put Biden out in public. And that the way to dispel public concerns, which seem to be extremely widespread, understandably, about the president's age, are to have the president out there a lot, talking! Showing that he can campaign, showing that he's up to the task, and the fact that that has not happened as much over the past two weeks and the fact that the president is so unavailable— he's done fewer press conferences than both of his predecessors— I think should give a lot of folks who are interested in US politics, even solely because of climate policy, a lot of pause.
Well, let's turn this around, and what's your upshift?
JENKINS: My upshift is from Jeff Stein at the Washington Post who is an economics reporter there and has been doing some really interesting on-the-ground reporting as to the impacts of the Inflation Reduction Act and other incentives in these climate bills on, you know, local economies around the country. And so he spent some time last week in Michigan with the United Association Union of Plumbers and pipefitters in central Michigan. So this is, you know, a union that does plumbing and HVAC technicians and welding and pipe fitting. And what he found is that the demand for union jobs there is just booming, driven largely by two massive new EV battery plants that are under construction in Michigan, driven by the Inflation Reduction Act and the incentives for domestic battery manufacturing that the law provides, that includes both direct subsidies for manufacturing EVs in the US, as well as tying some of the EV tax credits to the sourcing of domestic or North American assembled batteries.
So it’s a straight line from the passage of the Inflation Reduction Act to the employment boom that they're talking about. He noted that typically this union in central Michigan has fewer than 1000 members and that these two plants alone could hire about 500 full time jobs each from their union. So the entire union would be employed building these two battery plants. And clearly that's gonna create new jobs and new opportunities for union work and well-paid family-supporting jobs in Michigan. I think that that story is playing out across the country. That’s hopefully encouraging in the long term for the politics of the clean energy transition because when people see the clean energy transition as something that's fueling their economic future and not just as about avoiding scary future climate outcomes, I think that has a strong amount of durability and a lot of political salience.
MEYER: I am so curious though to see whether these— I mean, unions are now, the federal government has passed a ton of policy that increases demand for union workers, and like a lot of these unions have to grow in a way they have not been asked to grow in a long time. And I'm so curious to see how that happens.
JENKINS: So, what about you, Rob? Do you have something to close us out on and keep us a little bit more positive than that electoral news?
MEYER: There's a really interesting study that came out earlier this month in the Journal Earth's Future by Mallory L. Barnes et al, she's a scholar at Indiana University in Bloomington, that looked at this question that I think has kind of hung over some climate data for a long time, which is when you look at these global maps of temperature rise and how much different parts of the planet have experienced global warming, often the least amount of warming has happened in the Eastern United States. And you'll sometimes even hear this called “a warming hole” that while the rest of the planet seems to be experiencing, you know, varying levels of global warming and especially at the poles, quite extreme levels of global warming, the Eastern US, which of course, is this extremely important area, if you're talking about global climate policy, the Eastern US isn't experiencing as much warming, at least compared to other places in the world.
So what this study found, the study is called “A Century of Reforestation Reduced Anthropogenic Warming in the Eastern United States.” What the study found is that basically in the Southeast US, especially, a lot of land that used to be tillage or farmland has since become reforested. And that reforestation drives local cooling and that has mitigated a lot of the global warming we'd otherwise expect to see, and that’s why recent temperatures have been cooler than we might have expected with global warming. And so the abstract says, “Ground and satellite-based observations showed that Eastern United States forests cool the land service by 1 to 2 °C annually compared to nearby grasslands and crop lands, with the strongest cooling effect during midday in the growing season when cooling is 2 to 5 °C.”
I just found that really fascinating. Of course, it raises lots of adaptation questions like should we be doing more reforestation in other places in order to generate local cooling in those places? Reforestation has, while not a silver bullet by any means, does also have climate benefits as well. You know, carbon cycle benefits. And so I just thought that was such a cool study and while it might not be kind of encouraging in the conventional sense in the same way that maybe yours was, I just found it to be so engrossing. It made me think about processes being connected to each other in ways I maybe hadn't thought about before. I thought it was really cool.
JENKINS: That is really fascinating. Those are not small effects. Those are quite substantial. So that's really quite interesting. I'm glad you shared that. I've heard a lot of conversation about urban forestation as an adaptation measure, right? Adding urban tree canopies does have appreciable impacts on local heat island effects that you see in cities, and that's maybe an important area of adaptation policy. Some of my colleagues here at Princeton are exploring those kinds of dynamics and there's a lot of interest there. But this is interesting. This is almost continental scale effects, right?
MEYER: Exactly.
JENKINS: Across a broad region for reforestation, not just in cities. So, wow, that's, that's really interesting. Thanks for sharing.
MEYER: Well, Jesse, I feel like we have so much here. There's just like 10 different things we could talk about next week. And I know I want to talk about China, I know I want to talk more about electric vehicles, I want to talk about transportation policy, maybe reforestation.
JENKINS: Yeah, there is so much to unpack here on Shift Key. I hope you all join us again next week as we dive in again.
MEYER: Thank you for listening to Shift Key.
[AD BREAK]
MEYER: Shift Key is a production of Heatmap News. The podcast was edited by Jillian Goodman. Our editor in chief is Nico Lauricella, multimedia editing and audio engineering by Jacob Lambert and Nick Woodbury. Our music is by Adam Kromelow. Thanks so much for listening and see you next week.
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On copper prices, nuclear’s jellyfish woes, and Leo DiCaprio’s Chilean NIMBYism
Current conditions: The death toll from Colombia’s earthquake has risen beyond 250 • A severe thunderstorm flipped a car in Columbus, Ohio, as a large system swept across the Midwest • A partial solar eclipse is set to occur the Northeast.

David Crowley, a moderate Democrat and local official in Milwaukee, narrowly defeated Francesca Hong, a leftist state lawmaker and former ramen chef, in the Democratic gubernatorial primary in Wisconsin last night. The race marked one of the most significant tests of Democratic voters’ willingness to elect a member of the ascendant Democratic Socialists of America, now the most popular socialist group in U.S. history. Her campaign promised to make childcare and school lunches free, repeal anti-union laws, and give renters more protections against eviction. She also pitched what she called her “control-alt-delete” plan to eliminate tax credits for data centers and put a statewide moratorium on permits for new artificial intelligence facilities.
Ahead of Tuesday’s primary, the AI developers Vantage, Oracle, and OpenAI announced a $60,000 community investment in Port Washington, which my colleague Jael Holzman described as “the most controversial data center development area in the state.”
Just last week, the Trump administration agreed to pay the energy giant RWE more than $1.2 billion to abandon an offshore wind project, the latest in a series of deals in which taxpayers hand over billions to not receive new sources of clean electricity they badly need. On Tuesday, Senators Alex Padilla, the California Democrat, and Angus King, the independent from Maine, introduced a bill that would give companies that reject Trump’s payouts an expedited route to more development. “The Trump Administration is doing everything it can to kill California’s offshore wind future, handing energy companies billions of taxpayer dollars to walk away from projects that would have powered millions of homes,” Padilla said in a press release. “This bill makes sure their destructive approach doesn’t waste what’s already been invested so we can get these leases back to work, create the jobs Trump killed, and keep energy bills low for working families instead of letting his war on renewables cost Californians even more.”
The bill has one potential flaw, other than the fact that Republicans are unlikely to pass it and President Donald Trump is even less likely to sign it. That, as my colleague Robinson Meyer wrote this week, is that the roughly $4 billion in payouts so far went to projects that were “already dead or dying.” The money spent, in other words, is “for nothing.”
Please read the following two sentences in the tone of the famous scene of Tony Soprano defending Christopher Columbus: In this newsletter, Ea-nāṣir, the Mesopotamian copper merchant from Bronze Age-era Ur whose stone-carved complaints about a subpar metal shipment remain readable millennia later, is a hero. End of story! Why, you might ask? Because we are once again living through an age where copper, the basic building block of all things electric, is in high demand. Copper soared back to within half a cent of its record high Tuesday of nearly $14,000 per metric ton after an outage at a major smelter in Indonesia rattled global prices, Mining.com reported.
The fight over North America’s only major cobalt refinery, meanwhile, is heating up. The mining giant Glencore made a bid for control of Sherritt International, which has taken a beating from U.S. sanctions due to its 50% stake in Moa, a joint venture with the Cuban government. The joint venture’s assets include the Canadian refinery and Moa nickel-cobalt mine in Cuba. The Glencore-backed consortium is up against Gillon Capital, the family office of Ray Washburne, a Republican fundraiser and former Trump official, according to the Financial Times.
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Weeks after Europe’s latest heat wave forced inland nuclear stations to pare down output for lack of cooling water in the continent’s rivers, a “massive influx” of jellyfish has forced France’s EDF to shut down three units at its Gravelines nuclear station and cut power from a fourth. That’s taken at least 3.2 gigawatts of capacity offline, Bloomberg reported, right as temperatures are expected to surpass 104 degrees Fahrenheit in the coming days. The unusually hot temperatures off France’s shores have encouraged jellyfish populations to “bloom,” clogging the pumping stations through which coastal nuclear plants like Gravelines pull in cooling water.
In Egypt, meanwhile, construction crews working on the country’s first nuclear station hit a critical milestone. The containment vessel for the Russian-designed El Dabaa plant’s first unit is nearly completed, according to World Nuclear News.
Digging deep enough into the bedrock around New York City to tap into lava-hot rocks for electricity production is probably still years away, despite the progress that next-generation geothermal companies such as Fervo Energy have recently made. But thermal networks that maintain a steady environment year-round by circulating air at a constant temperature are increasingly popular ways for New Yorkers in private homes outside the city to stay warm in winter and cool in summer. Now the city itself is seeing whether a large-scale version could work for the subway system and municipal buildings. A study is set to begin soon into whether a thermal energy network could be built along subway routes to capture, store, and redirect excess heat that accumulates in the Brooklyn Bridge-City Hall and Chambers Street station complex to municipal buildings above ground. “Radiant cooling technology will absorb heat from the subway platforms and transfer it to geothermal boreholes drilled beneath Chambers Street,” reporter Carlo Cariaga wrote for Think Geo Energy. “This excess heat will then be stored underground until it can be used for supply to nearby municipal buildings during winter.” The contract for the feasibility study is due to be awarded in the fall, with work scheduled to start in early 2027.
“It seems like it’s a good place to test geothermal solutions because it sounds like there is a part of the tracks that isn’t being used, so they don’t have to stop service,” Jack Klein, the citizen researcher who conducted his own gonzo Subway heat study last year, told my colleague Jeva Lange this week.
Leonardo DiCaprio has long been a major donor to environmental causes. But rarely has the actor taken as clear a stance against green development if it comes at any ecological cost as this. On Tuesday, Bloomberg reported that the Oscar winner had told his nearly 60 million Instagram followers that fewer than 1,000 Pehuenche spiny-chest frogs remain in the wild, and that construction of the proposed Chile-Argentina transmission line threatens the amphibians’ habitat. “Conservationists are not asking for the transmission project to be stopped,” the celebrity wrote in the post over the weekend. “They are asking for it to be built where it does not put a Critically Endangered species at even greater risk.”
Rob checks in on this season’s supercharged ocean temperatures with climate researcher Zeke Hausfather.
Every few years, the Pacific Ocean’s surface waters become especially warm near the equator, a climatic phenomenon known as El Niño.
El Niño is a normal part of the climate system, but even in a normal year, it can trigger extreme weather around the world. Forecasters are worried that the current El Niño — which just began a few weeks ago — is going to be anything but normal. Models suggest that we could soon see the hottest El Niño ever measured, with unpredictable and catastrophic effects for ecosystems and societies around the world.
What does that mean? And why does this El Niño look so bad? On this episode of Shift Key, Rob is joined by Zeke Hausfather, a climate research lead at Stripe and a research scientist at Berkeley Earth. They discuss what forecast models are saying about this El Niño, why it gives us a glance at the future, and whether climate change itself is accelerating.
Shift Key is hosted by Robinson Meyer, the founding executive editor of Heatmap News.
Subscribe to “Shift Key” and find this episode on Apple Podcasts, Spotify, Amazon, or wherever you get your podcasts.
You can also add the show’s RSS feed to your podcast app to follow us directly.
Here is an excerpt from their conversation:
Robinson Meyer: How much, at this point, are we in an El Niño that is record-breaking? Like, how much do we see in observations, physical observations of the ocean or the atmosphere and the rest of the climate system, and how much do we think from the models that it is going to get even hotter?
Zeke Hausfather: So the way that we track the strength of an El Niño — there’s a few different ways to track it. But the most common one is from this particular region of the tropical Pacific called the Niño 3.4 region, which is sort of like about a third of the way into the Pacific off the coast of Chile, right around the equator. And that’s where this tongue of warm water forms during El Niño events. That’s sort of the characteristic signal of El Niños. And temperatures in that region, as of today, are at 2.8 degrees centigrade above normal, normal meaning the average of the last 30 years. So it’s sort of a sliding window that tries to remove some of the human-caused warming.
Robinson Meyer: Are we comparing temperatures from that region to another region? Or they’re just in that region two or more degrees above normal?
Zeke Hausfather: So it’s a good question. The traditional way that El Niño has been defined is to just compare that region to itself, but with a 30-year moving average applied to remove the effects of human-caused warming. There is another metric that was introduced by NOAA last year called the Relative El Niño Index, which is a variant where you sort of subtract out the average over the tropical ocean as a whole from that region, so you’re looking at the difference between that region and the rest of the tropics.
There’s pros and cons of that approach. Arguably, it removes the human warming signal a bit better, but it also can overly penalize really strong El Niño events that reach outside of that region because they start warming the whole tropics. So anyway, the details are technical, but the point on the observations is that we’re already seeing a very strong event occurring there today. You know, temperatures as of today, when we’re recording, August 10, are 2.8C above normal. To put that in perspective, the strongest ever anomalies we’ve recorded, at least daily in the satellite record since the 1980 or so, were in 2015, 2016, and those were about 3.1 degrees above normal. And so as of today, by itself, it would be the third strongest El Niño signal ever recorded in that region.
But what’s different is that El Niño almost always peaks near the end of the year. So if you look at all the El Niño events on record, there’s been one or two that have peaked in October, but the vast majority peak in November or December, and a couple as late as January. It’s a very persistent pattern of these events. And so the fact that it’s only the beginning of August now and we’re already at this extremely high level, we’re essentially running two to three months ahead of any other El Niño on record in terms of how quickly it’s developing, which is one of the reasons why we’re increasingly convinced that this is going to be a record-setting event. It’s going to blow any event we’ve seen previously out of the water. And if you look at the latest models that came out this morning, actually, it’s good timing. They’re predicting a peak of around 4C in the Niño 3.4 region, which will be, you know, more than a degree above the previous record and could end up being the strongest El Niño in 500 or 1,000 years. We don’t have great proxy estimates going back, but, it certainly is something well outside of anything we’ve seen since records began in 1850.
Robinson Meyer: The swimmer Katie Ledecky swims a race sometimes in the Olympics and she’ll be out swimming and then behind her there’s a computer-generated line which is the current world record, and she’s way out in front of the current world record, and you’re watching her and then she does she turns around in the pool and then the world record is behind her. That is the current El Niño. This is the Katie Ledecky-style El Niño.
You can find a full transcript of the episode here.
Mentioned:
NOAA’s El Niño page and the relative El Niño index
An Assessment of Earth's Climate Sensitivity Using Multiple Lines of Evidence, the 2020 paper where Zeke was a coauthor
Zeke’s blog post on AI emissions: The real energy use of agentic AI
John Bistline’s post on AI emissions at Watershed
Heatmap’s coverage of AI emissions: A New Guesstimate for Corporate AI Emissions
This episode of Shift Key is sponsored by ...
Discover the Yale Clean and Equitable Energy Development online certificate program at the Yale Center for Business and the Environment. In this fully online, 5-month program, you’ll learn from leading experts, develop practical skills, and grow a powerful network. Visit cbey.yale.edu to learn more and apply.
Music for Shift Key is by Adam Kromelow.
This transcript has been automatically generated.
Subscribe to “Shift Key” and find this episode on Apple Podcasts, Spotify, Amazon, or wherever you get your podcasts.
You can also add the show’s RSS feed to your podcast app to follow us directly.
Robinson Meyer:
Hello, it’s Wednesday, August 12, and the Pacific Ocean is officially in El Niño. According to the National Oceanic and Atmospheric Administration, sea surface temperatures in the key region of the Pacific are now above average, and the agency expects they’ll remain that way through early spring 2027. Now, even a normal El Niño can be a big deal. They can cause very wet winters in California, huge rainfall events in South America, and droughts or even famines in parts of Africa and Asia.
Robinson Meyer:
But if you’ve been paying attention, you know that this El Niño seems like it’s not going to be normal. It seems like it will be a super El Niño. Forecasters are now warning we could see the largest El Niño in years or decades, if not in a century or more. The last time we had a super El Niño event in 2015 and 2016, it caused almost $4 trillion in global economic damages. This one now seems like it could be even bigger. So I wanted to learn more about what might be coming down the pike, why we think this El Niño, even though it hasn’t happened yet, or has only just begun, could be so big and what it could all mean. And we have a great guest. Zeke Hausfather is a climate research lead at Stripe and a research scientist at Berkeley Earth. He’s also an IPCC author. He’s a climate scientist with a strong interest in observational temperature records, climate modeling, mitigation and emission scenarios, and carbon removal. He’s kind of working on all sides of the climate problem at the same time, which is why I always enjoy talking to him. And I can’t believe we’ve never had him on Shift Key before. On this show, we talk about why we think this El Niño will be so big, why it will be a kind of preview of sorts of the climate of the 2030s, and whether climate change now seems to be accelerating and getting worse. I’m Robinson Meyer, the founding executive editor of Heatmap News, and it’s all coming up on Shift Key. Zeke Hausfather, welcome to Shift Key.
Zeke Hausfather:
Thanks, Rob. Great to be on.
Robinson Meyer:
One reason I always enjoy talking to you is because you’re at this nexus of, let’s say, climate science and the physical systems and physical processes that happen in the world and mitigation and carbon removal and decarbonization and the various processes we need to master to tackle climate change. You’ve been tracking recently a particularly worrying set of developments around this year’s El Niño. And I think over the past few weeks, it’s gone from something watching you write and share what the models are saying, what we can know about the coming El Niño, has gone from making me think that it was, oh, that’s kind of interesting to, wow, this is a massive story that’s unfolding in front of us that’s going to shape this. Not only the next year of how we talk about weather and climate, but really the coming year of global events. So I want to just start by asking you, what do we know about this year’s coming Monster El Niño, as it has recently been described? And how has it developed over the past few weeks and months?
Zeke Hausfather:
Yeah, so it’s funny you call it a Monster El Niño. We’ve traditionally said super El Niño but this is going to be so far beyond a super El Niño if the models are right that we sort of need a new term for it i prefer monster to godzilla El Niño which is the other one thrown around but in terms of this year’s El Niño so we knew an El Niño was coming by late 2025 but we didn’t know how strong and so there’s a set of different dynamical models this year some of them are actual climate models some of them are you know more simple sort of adapted weather models But there’s about 14 or so different groups around the world that publish these sort of dynamical models of El Niño behavior. And so we knew that there was something in the pipeline. But at least initially, you know, circa January, February, it looked like it would be a pretty moderate event, you know, something maybe akin to... What we saw in 2010 may be enough by itself to drive a record warm year. And we’ll talk about the relationship later between El Niño and global temperatures, but not something that would be record setting by any stretch of the imagination. But by April or so of this year, we really started getting a big shift in the models. Back then, they showed something that could potentially tie 2015-2016 as the strongest El Niño event on record. Actually tie both 2015-2016 and the sort of storied El Niño of 1877-1878,
Zeke Hausfather:
Which is a particularly disastrous event in the early part of the record. But with every month that has come since, the models have been projecting higher and higher and higher estimates for this El Niño event. And the observations have been consistently overshooting what the models previously had projected. So, it’s not just the models that are going up, the observations are also skyrocketing and leaving the previous model projections in the dust. And there’s this thing in El Niño forecasting called the spring predictability barrier, which essentially is the fact that we’re just not very accurate at predicting El Niño during the spring. And so for a while there, everyone was kind of debating, like, is this another, you know, because there have been some historical cases where particularly individual models have gotten things really wrong in the spring. They’ve said the super strong El Niño event is coming, and it never came for one reason or another. The westerly wind bursts didn’t happen, or there’s changing patterns of circulation that led to the El Niño not developing. But now we’re well out of the spring predictability barrier, right? And we’ve seen observations already go into record territories. In fact, as of today, we are currently in the third strongest El Niño event ever recorded, maybe fourth if you go back to the 1800s.
Robinson Meyer:
Well, this actually gets to a key follow-up, which is how much at this point are we in an El Niño that is record-breaking? Like how much do we see in observations, physical observations of the ocean or the atmosphere and the rest of the climate system? And how much do we think from the models that it is going to get even hotter?
Zeke Hausfather:
So the way that we track the strength of an El Niño, there’s a few different ways to track it. But the most common one is from this particular region of the tropical Pacific called the Nino 3.4 region, which is sort of like about a third of the way into the Pacific off the coast of Chile, right around the equator. And that’s where this sort of tongue of warm water forms during El Niño events. That’s sort of the characteristic signal of El Niños. And temperatures in that region, as of today, are at 2.8 degrees centigrade above normal, normal meaning the average of the last 30 years. So it’s sort of a sliding window that tries to remove some of the human-caused warming.
Robinson Meyer:
Are we comparing temperatures from that region to another region, or they’re just in that region two or more degrees above normal?
Zeke Hausfather:
So it’s a good question. The traditional way that El Niño has been defined is to just compare that region to itself, but with a sort of 30-year moving average applied to remove the effects of human-caused warming. There is another metric that was introduced by NOAA last year called the relative El Niño index, which is a variant where you sort of subtract out the average over the tropical ocean as a whole from that region. So you’re sort of looking at the difference between that region and the rest of the tropics. There’s pros and cons of that approach. Arguably, it removes the human warming signal a bit better, but it also can overly penalize really strong El Niño events. That reach outside of that region because they start warming the whole tropics. So anyway, the details are technical, but the point on the observations is that we’re already seeing a very strong event occurring there today. You know, temperatures as of today, when we’re recording, August 10, are 2.8C above normal. To put that in perspective, the strongest ever anomalies we’ve recorded, at least daily in the satellite record since the 1980 or so, were in 2015, 2016 …
Zeke Hausfather:
And those were about 3.1 degrees above normal. And so as of today, by itself, it would be the third strongest El Niño signal ever recorded in that region. But what’s different is that El Niño almost always peaks near the end of the year. So if you look at all the El Niño events on record, you know, there’s been one or two that have peaked in October, but the vast majority peak in November or December and a couple as late as January. You know, it’s a very persistent pattern of these events. And so the fact that it’s only the beginning of August now and we’re already at this extremely high level, we’re essentially running two to three months ahead of any other El Niño on record in terms of how quickly it’s developing. Which is one of the reasons why we’re increasingly convinced that this is going to be a record setting event. It’s going to blow, you know, any event we’ve seen previously out of the water. And if you look at the latest models that came out this morning, actually, it’s good timing. They’re predicting a peak of around 4C in the Niño 3.4 region, which will be, you know, more than a degree above the previous record and could end up being the strongest El Niño in, you know, 500 or a thousand years. We don’t have great proxy estimates going back, but, you know, it certainly is something well outside of anything we’ve seen since records began in 1850.
Robinson Meyer:
The swimmer Katie Ledecky swims a race sometimes in the Olympics and she’ll be out swimming and then behind her there’s like a there’s a computer generated line which is the current world record and she’s way out in front of the current world record and you’re watching her and then she does she turns around in the pool and then the world record is behind her that is the current El Niño this is the Katie Ledecky style El Niño. This seems like as good a juncture as any to ask what physically is an El Niño? We talk about it as an event. We talk about it as a kind of phenomenon that can develop within the global climate system. I think people know that it has to do with the temperature of the Pacific, but what actually is physically happening on the planet when an El Niño occurs?
Zeke Hausfather:
So El Niño is a natural phenomenon. There is arguably some contribution of climate change to El Niño intensity and frequency, but it’s a topic that’s pretty heavily debated and we can talk about that in more detail later. But El Niño itself happens every three to seven years. It’s got a sister event called La Nina, which is essentially the inverse of it, which is unusually cold temperatures in the tropical Pacific instead of warm temperatures. And El Niño is driven by a combination of wind and currents. You have what we call westerly wind bursts that are changing the ocean mixing behavior in the Pacific. And so during an El Niño event, effectively the ocean takes up less heat, and so the atmosphere ends up being warmer, or the ocean even releases some heat. During La Niña, which is the inverse, the ocean, the deeper ocean, I should say, takes up more heat, And so the surface is cool. And so interestingly enough, during strong El Niño events, you tend to have a smaller increase or even in some extreme cases, a loss of ocean heat content, whereas the surface temperatures where we all live end up being much warmer. And so, you know, this isn’t necessarily something that is being caused by humans, but it’s happening on top of human driven warming. And a lot of the year to year variability in global temperatures, which many folks are familiar with looking at, are driven by the sort of El Niño-La Niña cycle.
Robinson Meyer:
What is driving this shift within the model? If the models believe that it’s going to be very warm, then it seems like there are probably signals within the physical system that are pushing them to believe the sea surface will get even hotter than it is right now. And so what are those signals that they seem to be responding to as we understand them?
Zeke Hausfather:
So there’s a couple factors going on here, right? One is, as I mentioned earlier, observations are persistently running above what previous model runs predicted. So observations themselves of the El Niño region sea surface temperatures are persistently running above. Driving projections for a strong event. But we are not just measuring sea surface temperatures. We are also measuring meteorological conditions that are favorable to the sort of westerly wind bursts that drive growing El Niño strength. And we’re modeling and observing what’s happening in the ocean below the surface. And so there we see this sort of pulse of warm water coming from the Western Pacific into the Eastern Pacific and moving up toward the surface. And that warm water is quite warm. You know, some regions are nine degrees centigrade above normal in sort of the deeper ocean temperatures. And that’ll emerge at the surface off the coast of Chile and then spread out across the El Niño tongue into the sort of eastern and central Pacific in the tropics. And so just seeing this warm water moving under the surface toward the El Niño region gives us a little sneak peek to, you know, what’s going to emerge in the next few weeks.
Robinson Meyer:
Because when you see the satellite imagery. That’s thermal coated of an El Niño, it looks like this big tongue of warm, I mean, you just called it the El Niño tongue, but it looks like this big, you know, stalactite of warm water is jutting out into the ocean, and then fading into the kind of baseline temperature mix. But it looks like this big warm tongue that I guess is aligned with the equator or just below the equator or?
Zeke Hausfather:
It’s right around the equator. Yeah. And I think tongue is generally the term that’s and used by folks. But under the surface, the sort of opposite is happening, right? So at the surface, it’s spreading out from the coast of Chile to the west. But under the surface, you have water moving eastward, like warm water in the deeper ocean. And then that’s coming up at the surface in Chile and then spreading westward. And so it’s almost a circulation you could think of it as.
Robinson Meyer:
Let’s bracket out what this El Niño might mean. But what does an El Niño generally mean for the rest of the world. I realize it has lots of these local effects, but one thing I’ve observed, and even reading about El Niño and covering El Niño, is it seems to be both understood as maybe the biggest annual variable in the climate system. And that means it’s both strongly described and also there’s a lack of specificity sometimes about what exactly it will do or what a large El Niño means as opposed to a small El Niño.
Zeke Hausfather:
So what we can most directly say is what’s happening in the tropical Pacific. You know, we’re measuring the sea surface temperatures. There’s that tongue that is very visible. It stands like a sore thumb in any global temperature map during an El Niño event. But when you shift temperatures in the ocean, in the tropical Pacific, it has a whole bunch of teleconnections to the rest of the planetary climate. It’s going to move the jet stream around, it’s going to lead to changing precipitation patterns. And again, some of these are more deterministic than others.
Zeke Hausfather:
It increases the odds of things. It doesn’t necessarily always cause things. But the things that we do tend to see most often associated with El Niño events are or in the El Niño tongue itself,
Zeke Hausfather:
And directly around it, things get a lot wetter. So coastal Peru and Ecuador see a huge amount of rainfall, the Horn of Africa. There’s a few other areas that tend to get quite a bit wetter. But, and in some ways more importantly, the area around that tongue to the north and the south of it and to the west of it get a lot drier. And this is probably the single biggest and most problematic impact of El Niño is its effects on rainfall in those regions. So places like Indonesia and Southeast Asia, India, Southern Africa, Northern Amazon, Eastern Australia, they all tend to get quite a bit drier during El Niño events. And if you look at some of the bigger El Niño related catastrophes in history, like the,
Zeke Hausfather:
You know, mass deaths following the 1877-1878 El Niño event, when depending on what study you look at, somewhere between, you know, three and 50 million people died, that was largely due to crop failure associated with drought in those regions. So that’s the one I’d be most worried about. But, you know, there are also a bunch of other effects. So the western U.S. famously gets wetter during El Niño years. We tend to have mudslides here in California. Route 1 is probably going to get washed away more than usual. You know, we tend to have a bit warmer temperatures in the northern parts of the U.S. and northwest Canada. You know, the oceans as a whole get warmer. One thing that we’ve started seeing during El Niño events starting in 1997, 1987-1988 is these sort of globally widespread coral bleaching events. So the first time this was observed was in 97-98 during that El Niño event. And it’s since then become sort of a common occurrence every time we have a strong El Niño and even some summers when we don’t because the oceans have
Senator Martin Heinrich:
Gotten so hot.
Zeke Hausfather:
And so certainly this year, that’s something that a lot of people are concerned about in the winter in the tropics. There’s also a bunch of different effects on storms associated with changes in wind shear and circulation patterns. A very strong El Niño event will suppress Atlantic hurricanes. It’s one of the reasons that our forecast for Atlantic hurricanes has been cut in half already and might be cut significantly further. But it does tend to lead to more cyclones in the eastern Pacific. So cyclones that might hit Japan or Hawaii or China are going to become more common this year. And then globally, it tends to warm the climate as a whole. So a strong El Niño event tends to be associated with a boost in global temperatures of up to 0.4C for four or five months, and for the year as a whole of around 0.2C. Though this event, because it’s so unprecedented, might push it much further than that. There’s also a bit of a lag in time between when El Niño peaks in the tropical Pacific and when the global temperature effects have felt of about three to five months. So that’s one of the reasons why, even though El Niño is going to peak this year, it’s next year, 2027, that’s likely to be the record shattering one in terms of global temperatures. And that’s a pattern that we persistently see in, you know, 1997 was warm and 1998 was record shattering. 2015 was warm and 2016 was record shattering. It’s the year after El Niño peaks that we really see this big boost in temperatures.
Robinson Meyer:
And that’s because basically we’ve added all this anthropogenic CO2 to the atmosphere. We already know the Earth is kind of out of temperature balance where there’s more heat captured in the atmospheric system than there would be in a kind of a thermostatic way. And normally how that’s dealt with is that heat gets dumped into the ocean and water goes down to the ocean, the ocean acts as a kind of planetary sink for heat from the atmosphere. Exactly. And if the ocean everywhere is unusually warm, but also if the world’s largest ocean is really, really warm at its warmest point, with heat radiating outward from there into the rest of the marine system, then it stops absorbing heat.
Zeke Hausfather:
If the ocean is absorbing less heat, which is sort of the major effect of El Niño, or even releasing heat in some extreme cases, that’s going to lead to a much hotter atmosphere. And so if we didn’t have El Niño and La Nina, almost every year would set a new record in a warming world. It would be monotonic, as we say. The line would just go up. But because we have El Niño and La Nina on top of that, some years are a bit cooler, some years are a bit warmer. And so you can even think of it as like a sine wave driven by El Niño and La Nina cycles on top of an upward line.
Robinson Meyer:
You referenced the 1877-1878 event. You referenced that this could be the biggest El Niño in 500 or 1,000 years. How do we know about El Niño events before the satellite record begins in let’s say around 1980 or even before I think modern 1877, 1878 is within the realm of modern temperature reconstructions where we take land records and put them together and some ocean records and put them together and then simulate the Earth’s climate and get a decent sense of what was happening in the climate system. But how do we know about these historical events?
Zeke Hausfather:
Yeah. So there’s, for a record like 1877, 1878, there’s sort of two ways we know about it. One is that we did have a decent amount of ocean measurements that far back. And so at least on trade routes, the sailing ships were throwing buckets over the side of the ship and pulling them up with a rope and sticking a thermometer in them. So we have some measurements in the El Niño region during that event. Not very many. So there still is a pretty big uncertainty there. But we also have a reasonable estimate of global temperatures. And so you can sort of back out to an extent the strength of an El Niño from its effect on global temperatures as well. And then when you go before 1850, we don’t really have any observations. I mean, there’s some land observations, but there’s not much in the way of ocean observations. And so there you’re relying on some individual proxy measurements like corals that can tell you something about temperature at a particular time. And you’re also looking at these overall global temperature reconstructions and trying to back out the strength of an El Niño event based on, you know, how spiky global temperature is. But certainly the further you go back, the lower the resolution those things are. So like 500 years, we can probably get at least a fuzzy picture.
Zeke Hausfather:
You know, a thousand years, you’re starting to push it just because it’s hard to pick up an event that’s only a year in duration in those proxy records that might have a resolution of 10 years or 15 years. And then obviously, if you push, well, before 1,000 years, you know, you’re starting to get into the realm of a single proxy observation is going to tell you something about 50 or 100 year average. And at that point, El Niño is just going to wash out. So it does limit the extent to which we can say something about the El Niño record.
Robinson Meyer:
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Robinson Meyer:
It’s interesting because to me the 2015-2016 event was right around the same time i started covering climate change and i think it actually marked a big moment in climate discourse if i’m allowed to historicize off the top of my head about these things december 2015 which is i really right as that El Niño event was peaking was the same month the paris agreement was signed obama had just issued and was about to fight in the courts for greenhouse gas regulations on power plants under the Clean Air Act. Then, of course, we had the 2016 election, of which a large amount of the content was about climate change. And I think an underrated amount of that election was about climate policy. And then we had the first Trump administration, during which climate became a more and more salient topic politically. And so 2015, 2016, that El Niño, the earth has had most of the warmest years on record have actually happened since that El Niño. That is still the decisive event to me. And I still remember, for instance, those mass coral bleaching events of the 2015-2016 period.
Robinson Meyer:
What do we know, if anything, about El Niño now that we didn’t know 10 years ago during that event? Or what do we know about El Niño’s relationship to climate change, if anything, that we didn’t know for the 2015-2016 event?
Zeke Hausfather:
Before I answer that, I’ll answer another related question, which I think is like why these sort of events have such salience in the public discourse. And I think, you know, part of that is that climate is a slow and gradual problem and our politics are not designed around slow and gradual problems. And so when we do have these acute events, which El Niño on top of global warming represents, you know, it’s a big spike upward. It gives us a sneak peek of, you know, what the new normal global temperature condition is going to be in a decade or so. You know, it tends to focus the attention. And so I think it is important for us to use that to the extent we can, because it is a little sneak peek of what’s coming soon. But in terms of the question you asked around what we know in addition about El Niño and climate, so there certainly have been a number of papers suggesting that climate change could be making strong El Niño events more common. There’s some physical mechanisms that have been proposed, but it isn’t something that shows up particularly robustly in our climate models today. And there are a number of scientists who also argue that there’s those physical reasons that have been proposed are not super strong. So I’d put this in the same category as the debates around like wavy jet stream from global warming and its effects on cold air outbreaks, for example.
Robinson Meyer:
And the way we jet stream, just for listeners, is the idea that climate change is making those extreme cold snaps that we have had recently in North American winters where it’s suddenly negative 10 for a day or two more common because the jet stream is less stable and it dips down, allowing the so-called polar vortex to dip down over more populous parts of North America than where it normally lives.
Zeke Hausfather:
I’d put both of those ideas in this category of very active scientific debate, like the jury is out. And so hopefully in another decade, we’ll have a stronger answer in both of them and more modeling and observations. But I don’t think we can say today that there’s particularly strong evidence that climate change is going to make El Niño’s stronger outside, of course, of, you know, the background warming, just making the impacts of everything worse.
Robinson Meyer:
Right. It’s so funny. I mean, it’s one of those classic climate science discussions where it would be great to know it would be an interesting answer that we’d learn about the Earth climate system. But it wouldn’t really, I don’t know that it would have policy relevance as maybe it would. I mean, maybe we’ll learn about key El Niño mechanisms that could come important later. But the key takeaway of climate science is and remains that we should, you know, reduce anthropogenic greenhouse gas emissions as fast as we possibly can while avoiding overall harms to humanity.
Zeke Hausfather:
And the climate impacts of human emissions are just so much bigger over time than the climate impacts of El Niño, right? You know, a strong El Niño event will add about 0.2 degrees centigrade to global temperatures for a year. You know, human emissions are adding that every eight years. So every eight years, we’re adding a permanent Super El Niño worth of heat to the climate system, which just helps put things in perspective. Or 1998, which at the time was a record-shattering year, would be an exceptionally cool year if it occurred this year.
Robinson Meyer:
Given the monotonic increases of human greenhouse gas emissions every year, at least so far, what does this El Niño event mean for global temperature rise? You’ve been involved in a debate with the, I would say, storied NASA, former NASA climate scientist Jim Hansen, about whether 2026 will be the hottest year ever. Maybe fill us in on that, but generally, what does this event mean for global temperature?
Zeke Hausfather:
Yeah. So El Niño provides a temporary boost in global temperatures. We know how it’s happened historically. It’s a little harder to predict this year because we’re so far out of sample. You know, if the models are right, we end up with a peak at 4C, which is more than a degree above anything we’ve ever seen before. We don’t have analogs to draw on. But if we assume the world is linear, which we get in trouble for sometimes, we would expect a boost in global temperatures in 2027 of, you know, 0.25, maybe even up to 0.3C. And so at least my latest estimate is that this year, 2026, will be pretty neck and neck with 2024. Probably still going to be the second warmest, but, you know, maybe a 40% chance it’s the warmest, 60% chance it’s the second warmest. So getting closer and closer to a coin toss. Next year, 2027, though, is going to shatter records. So the warmest year we’ve had to date was 2024, and that was about 1.5 degrees, 1.5, 2 or so above pre-industrial levels across the average of six different data sets that the scientists have put together. 2027 in those same data sets, given what the models expect El Niño to do, would end up around 1.7 degrees C.
Zeke Hausfather:
So even compared to the previous El Niño event, which was a big boost, you know, this event is going to shatter records. And so the air bars are still pretty big on that, in part because, you know, the models have a wide range of projections. If it ends up being an El Niño that only breaks a record by a small margin instead of shattering it, the global temperature response is going to be smaller. But under any of the El Niño forecasts, 2027 is going to be a record warm year. I think the last time I checked, there was about a 95% chance it sets a new record.
Robinson Meyer:
One of the multi-year running conversations in climate science, and I would say among climate analysts as well, is that this year, as you said, temperatures will be on average about 1.5C warmer than their pre-industrial average. I believe last year we were over 1.5C as well, or very close. And one way I’ve tried to be rigorous as this has happened in the climate system is to say, look, like just because you have one year, you know, of course, at this point, about eight or nine years ago, the IPCC came out with its 1.5C report, which basically said the effects of climate change at making the planet a degree and a half warmer than their pre-industrial average will be more severe than we thought will be bad. Well, it’s a thing that’s worth avoiding. One thing I’ve been carefully rigorous about is like a single year where the global average temperature is more than 1.5C above pre-industrial average doesn’t actually mean we’ve cleared this sort of conceptual 1.5C threshold. I mean, to be clear, we are definitely going to clear the 1.5C threshold, but the first year you do it is not when you actually clear that threshold. You need several years of data above 1.5C to bring the five or 10-year moving average above 1.5. It seems like with this big El Niño, though,
Robinson Meyer:
We are going to have warm temperatures. We’re going to really push that moving average a fair amount and at least could temporarily get the threshold to be pretty close. I realize it’s hard to predict more than beyond 2027. We don’t know what 2028. We could have a big La Nina in 2028 and it could push temperatures back down below 1.5C. But maybe to tie this into another conversation. I think for the past four years or five years at this point, really since the pandemic, global warming has appeared to accelerate. And there’s been this question about whether it was caused by reductions in particulate pollution or whether it’s some other process that’s being revealed as human emissions continue to drive it. I guess the other takeaway from this big El Niño event is like that acceleration is going to continue given that we’re going to be above 1.5C this year and we could be above 1.6 or 1.7 next year.
Zeke Hausfather:
Certainly, our estimates of when the world is going to cross 1.5C have been moving closer and closer to present. One of the challenges, I think there is broad agreement now that global warming is accelerating. In fact, I went out on a bit of a limb in 2023 and published a piece in the New York Times arguing that it was accelerating back when the evidence was much more mixed than it is right now. I think the debate is less today about is it accelerating and more about exactly how much and how quickly it is accelerating. And how much of that acceleration is being driven directly by human emissions, the combination of greenhouse gases that warm the planet and cutting emissions of aerosols, sulfur dioxide in particular, that have masked a portion of historical warming. And how much of it is being driven by feedbacks to the warming process, which in many ways are the more worrying factor, right? You know, is cloud changes that we’re observing, you know, all being driven by cutting air pollution and sulfur and shipping fuel and Chinese particulates from their coal plants? Or is that change in cloud behavior and clouds being less reflective a response to the warming itself? Because it turns out that the biggest driver of how sensitive climate models are to our emissions, this factor we call climate sensitivity, essentially how much warming you get if you double CO2.
Zeke Hausfather:
The biggest determinant of that in climate models is how clouds respond in a warming world. So if the cloud feedback is strong, if clouds become less reflective, if there’s less low-lying clouds, potentially more high clouds in a warming world, then you get a lot more warming for the same amount of CO2. And so we can’t say for sure today, what mix of factors we’re seeing. But I think a lot of us are really concerned that we might be seeing an emergence of a stronger cloud feedback, which would, all things being equal, tend to imply a higher climate sensitivity.
Zeke Hausfather:
But in terms of when we’re going to pass 1.5 degrees, unfortunately, the Paris Agreement didn’t actually define what they meant by 1.5 degrees, which has caused a lot of challenges after that. And then the IPCC decided to fill in the gap. And they said, OK, we’ll define 1.5 degrees as the midpoint of a 20-year period. So 20 years is long enough that El Niño and La Nina effects will cancel each other out, and you’ll just have the human warming, the long-term effects in there. The problem with that, of course, is that means you won’t know when you’ve passed 1.5 degrees until 10 years after the fact, which is not the most useful definition. So there’s a big paper in the works that myself and like 40 other people are co-authors of that hopefully is going to come out later this summer or fall that is trying to actually answer this question and say, how do we as a community figure out a way to define when we’ve crossed 1.5 degrees that doesn’t require waiting 10 years in the future to know? There’s still a bunch of different options you could choose and different methods and ways to combine observations and models or statistical smoothing or linear or exponential projections. Anyway, there’s a million different approaches one could take. The approach we took in this paper was essentially say, okay, which of these methods got previous periods right? Like when we passed one degree or when we passed 0.5 degrees, how resilient are they to like volcanic eruptions or weird El Niños or these other sort of things. But I do think the world is probably going to firmly pass 1.5 degrees by about 2028 or so, you know, it’s coming up pretty darn quickly.
Robinson Meyer:
I’ve always felt like we needed a number that was not just how much warmer is it than average. We need a kind of global warming index number, like a climate changey index that can spit out one number that says how much worse are things right now. The issue is that once you start thinking about what such an index would look like, you realize that you basically just want the global temperature average and also that it’s basically going to go up all the time. And so it doesn’t really have a useful function, except You know, when Europe is having a giant heat wave, you could be like, oh, it’s especially climate changey right now.
Zeke Hausfather:
We do have this human-induced warming estimate that we publish every year in the sort of climate change indicators report that Pierce Foster leads. And I think this year is about 1.4 degrees of pre-industrial levels was our
Zeke Hausfather:
best estimate for 2025, which is, you know, pretty darn close to 1.5.
Robinson Meyer:
We’re talking about this question of climate sensitivity, which is how responsive is the climate system when one doubles atmospheric CO2? CO2. And in many ways, it’s one of the core questions in climate science. And for a long time, we kind of had a distribution for it. We knew what the range of climate sensitivity might be, but we hadn’t made a lot of progress in cutting off the tails. You were a co-author on a 2020 paper that cut off the extreme low end and extreme high end estimates using a number of different lines of evidence. Given what we’ve seen since 2020, where there’s been this seeming acceleration in global warming, does that affect the conclusions of that work at all? Are you more worried that we’re on the high end or that there are more extreme high end possibilities within the climate system that maybe weren’t countenanced by how that paper was run? Or are we just landing, I believe that paper was found that climate sensitivity was somewhere between 2.6 and 3.9 Celsius, are we like pointing more toward the 3.9 side than the 2.6 side, given what we’ve seen over the past few years?
Zeke Hausfather:
So we rounded those numbers a bit in terms of what ended up in the IPCC sixth assessment report. But the IPCC report said that the likely range of climate sensitivity and likely in the IPCC’s parlance means there’s a roughly two-thirds chance it’s in that range was between 2.5 and 4C per doubling CO2. And the very likely range, the 90th percentile range, which I find more useful, to be honest, because a lot of things happen outside of a two thirds chance is somewhere between 2C and 5C if we double CO2. And that’s a pretty big range, right? A lot of stuff can happen between 2C and 5C, but...
Zeke Hausfather:
You know, we are doing an updated report, hopefully in time for the IPCC 7th assessment report that’s going to incorporate all of the evidence that’s come out since 2020, because, you know, it is a big question in climate science. And there’s been a lot of work that has come out in the last six years on this topic. And, you know, I don’t want to spill the beans early, so to speak, in terms of what we’re going to find. But I will say that there’s sort of two countervailing factors, one supporting higher sensitivity and one constraining it a bit. So the thing supporting higher climate sensitivity is what we’re seeing with earth energy imbalance. So this measurement we get from satellites of how much heat is being trapped in the climate system, which is something that’s a fairly new instrument. You know, we don’t have a super long record of it, but it is in some ways the most important measure because it is capturing the sum of the whole climate system. Now, it has shown values that are a bit on the high side of what most climate models expect. And so is an indication that climate sensitivity might be on the higher end, but it is also one satellite and a relatively short record. And so there’s reasons not to just use that as the only bit of information we have. The other thing that we have is the paleoclimate records. So the Earth’s more distant past, particularly the last ice age,
Zeke Hausfather:
The Pliocene, the Eocene, these sort of periods in the Earth’s more distant past that we have measurements of both carbon dioxide and greenhouse gas concentrations, but also of temperatures from proxy records. And those tend to suggest that climate sensitivity is not much above 5 degrees C. You know, if you have a really sensitive model, for example, it’s going to run away to snowball earth if it tries to simulate the last ice age. And there’s been a lot of work by that community to use things like pattern effects and sort of how the continents and ice sheets and everything were different in that period than they are today to try to infer what the relationship in that period means for climate sensitivity today. And I think that has not necessarily been pointing toward very high climate sensitivity. But that said, 5C warming for doubling CO2 is still very much in the range of possibilities. And so there’s been a bit of a heated debate between myself and Jim Hansen and a number of other folks in the community about this topic. And Hansen’s been arguing that climate sensitivity is probably close to 5C. And the rest of us have been saying that it could be. But across all the lines of evidence we have, we don’t necessarily think that it’s more likely to be 5C than 3C, right? I personally wouldn’t be surprised if at the end of the day, in the next IPCC report, we move the best estimate up to closer to 3.5 degrees C for doubling of CO2 from three. But it’s early days, and that’s not my chapter, so I don’t get to decide that.
Robinson Meyer:
Well, speaking of emissions, you recently published a blog post on the emissions intensity of using AI. And I appreciated it for a number of reasons, including the fact that you drew on this John Bistline paper, who’s a researcher at Watershed, trying to estimate the emissions intensity of AI, which was in turn covered by my colleague, Emily Panacorvo. So always great to see heat map in the mix. But your general takeaway from this paper and also from your own estimates was that AI, probably at this point, given how we use it, is much more emissions intensive than maybe early estimates or is somewhat more emissions intensive than early estimates and you were able to put some error bars around how we should think about electricity use associated with both chatbot ai and then also agentic and cloud code style ai and describe a little bit what you think the discourse is missing right now around those topics and why you think speaking of estimates coming in on the high end why some of the more popular estimates around the emissions intensity of AI may underestimate its emissions.
Zeke Hausfather:
So when you’re looking at AI energy use, there’s sort of top-down and bottom-up approaches you can take. I think the top-down numbers are broadly right, and those are the ones that give like, I don’t know, 15% of U.S. electricity use by 2030 going to AI data centers on the high end. I’m not arguing that estimates like those are too low. What this piece was more about is, what is the impact of me as an individual using AI tools? And there, the numbers that were published last year in 2025 by folks like Google or by OpenAI are not very realistic to the way people are actually using AI today. So these numbers that were published in 2025 were that AI per prompt, and by prompt, they mean typing something in a chat GPT text box and hitting enter and getting a response without a reasoning model, important distinction. So just one shot. But those take about 0.3 watts of energy, which really isn’t much, right? At 0.3 watts, you could do many, many, many thousands or tens of thousands of AI prompts and still have much lower impact than, you know. Running your air conditioner in the afternoon or, you know, driving to work.
Robinson Meyer:
That’s less than how a light bulb used to be. So if you didn’t feel bad about adding a single new lamp to your home, then you shouldn’t feel bad, so to speak, about using AI under that estimate. Yeah.
Zeke Hausfather:
But the problem, of course, is that some people are still using AI that way, but increasingly AI is being used in an agentic form. And that more means that you give AI a set of instructions or a goal to achieve. And then AI goes off and does many, many, many, things to try to achieve that goal. AI agents are, at least in the corporate world and the software engineering and scientific world, the vast majority of AI use today. And those agents make both much more complicated calls than the prompts would suggest and many, many more calls. And so when you look at the actual energy use of these AI agents, it’s something on the order of 600 times larger per prompt than the traditional, like, type something in a chat box and got to get an immediate response. And so that does end up adding up. I actually looked at two months of my own AI use because I had local logs of all of the numbers there.
Robinson Meyer:
When you say local AI use, these are calls you’re making locally to ChatGPT or Claude that you’ve retained a record for but the ai is still being run on an external device you don’t have a power meter hooked up to your desktop
Zeke Hausfather:
Yeah my desktop is using next to nothing this is some data center spinning up to process the call i made on my local cloud code but i found that on average i was using about three kilowatt hours a day for my agentic energy use which is the equivalent of running two refrigerators so that’s not nothing in big days when i was really doing some complicated like geospatial analysis or big data crunching exercise, I was using upwards of 10 kilowatt-hours per day. So maybe a third of the typical US household energy is just going to AI agents. And if you annualize that over the entire year, you end up with numbers that they’re not crazy. So for an entire year, my estimate is that my agentic AI energy use is about 1.1 megawatt-hours. If you convert that to CO2, again, using sort of a roughly average grid intensity, It’s about 370 kilograms of CO2. So that’s roughly half of a transcontinental flight. So again, it’s not enormous in terms of my overall emissions, but it’s also not trivial, like some of these initial estimates that came out last year would suggest.
Robinson Meyer:
Carbon emissions with average U.S. grid intensity or with the likely kind of it’s all coming from gas that...
Zeke Hausfather:
All coming from gas and average U.S. grid intensity are not that far apart at the moment.
Robinson Meyer:
Yes.
Zeke Hausfather:
Yeah. So this is using a bit of location-based analysis, but it’s pretty close to the all-gas assumption now. Where I’ve gotten some criticism there is people who said, well, if you account for the fact that these AI companies are buying RECs to cover their data center energy use by building clean energy elsewhere, even if it’s not directly powering the data center, then the number is probably lower. Which, you know, might be fair if they actually disclosed what those numbers would be, I would be happy to use them. But unfortunately, at the moment, AI companies are really not telling us much about the actual energy use of their products. And so we’re having to infer all this with very indirect methods. One of the main takeaways from this piece should be a plea for AI companies to be more transparent and actually tell us how much energy their systems are using.
Robinson Meyer:
I think this is very striking, particularly by Anthropic, which I think has published absolutely no estimates per token of its emissions intensity or energy use, even though it’s the quote unquote kind of good AI company. We just are kind of completely in the dark about what Claude uses. And in fact, we know that Anthropic is contracted with one of the Colossus data centers built by XAI, which is one of the worst offenders in terms of particularly emissions-intensive generation.
Robinson Meyer:
We’re going to have to leave it there. As El Niño continues to develop, maybe we’ll have you back to talk about just how bad it is. Zeke Hausfather, thank you so much for joining us on Shift Key.
Zeke Hausfather:
Thanks, Rob. It was a great conversation.
Robinson Meyer:
And that will do it for us this week, but we’ll be back next week with a new episode of ShiftKey. Until then, Shift Key is a production of Heatmap News. Our editors are Jillian Goodman and Nico Lauricella. Multimedia editing and audio engineering is by Jacob Lambert and by Nick Woodbury. Our music’s by Adam Kromelow. Thanks so much for listening. We’ll see you next week.