Solar Geoengineering: Should we go there? LIVE SHOW with David Keith & Ed Whittingham

𝗟𝗶𝘃𝗲 𝗮𝘁 𝗘𝗻𝗲𝗿𝗴𝘆 𝗗𝗶𝘀𝗿𝘂𝗽𝘁𝗼𝗿𝘀: 𝗨𝗡𝗜𝗧𝗘 𝟮𝟬𝟮𝟰 𝘄𝗶𝘁𝗵 𝗗𝗮𝘃𝗶𝗱 𝗞𝗲𝗶𝘁𝗵 & 𝗘𝗱 𝗪𝗵𝗶𝘁𝘁𝗶𝗻𝗴𝗵𝗮𝗺
David and Ed hit the stage at the Energy Disruptors: UNITE 2024 summit in Calgary to discuss solar geoengineering, a major focus of David's academic research. Together, they unpack the technical and non-technical dimensions of solar geoengineering, including global governance and decision making.

(00:45) Start of live show and topic introduction
(04:49) What is Solar Geoengineering?
(30:45) Audience Q & A

𝗔𝗯𝗼𝘂𝘁 𝗬𝗼𝘂𝗿 𝗘𝘃𝗖 𝗖𝗼-𝗛𝗼𝘀𝘁𝘀:
David Keith is Professor and Founding Faculty Director, Climate Systems Engineering Initiative at the University of Chicago. He is the founder of Carbon Engineering and was formerly a professor at Harvard University and the University of Calgary. He splits his time between Canmore and Chicago.

Sara Hastings-Simon studies energy transitions at the intersection of policy, business, and technology. She’s a policy wonk, a physicist turned management consultant, and a professor at the University of Calgary and Director of the Master of Science in Sustainable Energy Development.

Ed Whittingham is a clean energy policy/finance professional specializing in renewable electricity generation and transmission, carbon capture, carbon removal and low carbon transportation. He is a Public Policy Forum fellow and formerly the executive director of the Pembina Institute, a national clean energy think tank.

𝘗𝘳𝘰𝘥𝘶𝘤𝘦𝘥 𝘣𝘺 𝘈𝘮𝘪𝘵 𝘛𝘢𝘯𝘥𝘰𝘯 & 𝘉𝘦𝘴𝘱𝘰𝘬𝘦 𝘗𝘰𝘥𝘤𝘢𝘴𝘵𝘴

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Transcript

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Ed Whittingham: Hi, I'm Ed Whittingham, and you're listening to Energy vs. Climate, the show where my co host, David Keith, Sarah Hastings Simon, and I debate today's climate and energy challenges. On October 1st, David and I hit the stage at the Energy Disruptors Unite 2024 Summit in Calgary. We're there to discuss solar geoengineering, a major focus of David's academic research.

Our goal was to unpack the technical and non technical dimensions of solar geo, including to do with global governance and decision making, before an audience that may really be hearing a conversation about the topic for the first time. We also wanted to generate discussion and debate among the audience, and we did just that.

A reminder that Sara's on medical leave for the time being, so it's just David and me again. Now here's the show. David and I, we spend a good chunk of our careers working on the climate problem. And we're happy that the world has made a lot of progress. 1. 7 percent of global economic output is now being spent on clean energy.

That's the good news, and global emissions may even peak in this decade. The bad news is that resistance to the increasing cost of decarbonization is also increasing, it's on the rise. Public concern around climate as an issue is lower than it's been in the past. The latest Abacus data poll has it at number six on an issue of importance to Canadian government.

and 2030 emissions cut cuts are likely to fall well short of stated pledges. So that's the bad news. And meanwhile, global average temperatures continue to increase. The World Meteorological Association reported in March of this year that 2023 was the hottest year on record with a global average surface temperature near 1.

45 degrees Celsius above pre industrial. And that was the warmest 10 year period. Now let's pivot. The terms climate engineering, solar geoengineering, and solar radiation management all refer to a set of approaches designed to cool the planet or stop the planet from warming. And given that progress to cut emissions may not be as fast as we'd hoped, there is now an increasing amount of interest and attention being paid to these approaches.

Um, yet, of course, the thought of purposely injecting, say, aerosols into the stratosphere as a means to cool the planet is not without controversy, and that's probably understating it. Uh, as many people in this room know, David Keith, uh, you know, my friend and podcast co host, is one of the world's foremost researchers in the field.

So today, we thought at Unite 2024, we'd take advantage of his expertise. To talk about solar geoengineering specifically and bring that to UNITE and bring that to Calgary because I don't think it's a topic that is really discussed much here at all. Now, it seems a bit weird to introduce my co host, but let me just say the brief points.

David is a professor of geophysical sciences at the University of Chicago. He's also the founding faculty director of the Climate Engineering Initiative at University of Chicago. And previously he taught at Harvard. Thank you very At, uh, the University of Calgary here in in Alberta and Carnegie Mellon University.

So as we z, welcome David Keith. Thank 

David Keith: you. Exciting to be here at, uh, I, I, I watching the signs for energy disruptors. It says Disruptors unite. Disruptors unite in the sign behind me, and it feels like there's some kind of oxymoronic vibe there. I wondered about that. Yeah. Yeah. Yeah. What should they want this audience to do?

Disrupt or unite? Yeah. It's like the meeting for the anarchists. The anarchists are all going to meet 

Ed Whittingham: at four o'clock. Don't be late. So, David and I, we're going to have a discussion about solar geoengineering, the technical, the non technical bits, uh, and then we're going to turn to the audience for questions.

We're going to save the last 10 to 15 minutes for audience Q and A. And just a note for everyone that this is being recorded for posterity, that this will drop on the Energy vs. Climate field of, uh, um, Pod. Yes, pod, not field. So, uh, anything you say will be, uh, saved for all time immemorial. Now, I just want to say off the top, so I ran an NGO, the Eminent Student, as an executive director.

With David, we helped convene the first meeting on solar geoengineering, uh, in Canada that we knew of, a serious one, involving governments and NGOs in its day. I'm supportive of research into it, and when I listen to you and others in the field, specifically around stratospheric aerosol injection, I think the technical and economic barriers are surmountable, but that the real challenges lay in the non technical aspects, which we'll get to.

Those are the most prickly ones. But let's start at the beginning. What is solar geoengineering? I 

David Keith: define it only in terms of the other things we can do about climate. So from the way I think about it, there's really four fundamental categories of things humans can do to manage climate risk. Decarbonize the economy, cut emissions, remove carbon from the atmosphere, alter the energy balance of the Earth to reduce some of the consequences of carbon and other gases in the atmosphere, or adaptation.

And I think none of those can really be lumped with another. Of course, there's lots of individual technologies inside and lots of political pathways to get there. I'm not saying we need to do all those things. But I think we need to think in four dimensions. I think you can't throw any of those out of the pie forever.

I think there aren't really any other. Those are the four categories of ways humans can manage climate risk. And I think one way that, I don't think you should lump them together too much, but one thing that unites carbon removal and solar geoengineering is they both deal with the consequences of CO2 emissions that are in the atmosphere.

What cutting emissions does is we have to do, what cutting emissions does is it avoids us putting more CO2 in the atmosphere. But as of course, I assume all of you know, even if we cut emissions to zero tomorrow, we don't stop, well we stop it warming up further, but we don't deal with the warming there is.

In that sense, it's important to realize how different, uh, climate change is from a lot of environmental problems we might be used to. So, air pollution is still a much bigger killer in the world than climate, but air pollutants last in the atmosphere for a few days. So if you really did regulate out all the air pollutants, then the impacts on human health basically go away almost instantly, or the direct impacts.

Climate is just not like that. If we eliminate emissions tomorrow, uh, uh, climate doesn't get any better. And indeed, some aspects like sea level rise would keep getting worse. And so if you want to deal with historical emissions, if you want global temperatures to go down at any point, you have to consider Either carbon removal or solar geoengineering or some combination.

Ed Whittingham: So that's what you mean, because you wrote an op ed in the New York Times, and I think you published it last year, and you said that there are only two ways to cool the planet in this century. One is through carbon removal, and the other would be through another climate engineering thing, like stratospheric aerosol injection or solar geo.

Exactly. 

David Keith: So, Cutting emissions doesn't cool the planet. Cutting emissions stops you warming the planet. Cutting emissions makes, cutting emissions makes the planet warm more slowly than it otherwise would have. But at no point will cutting emissions actually bring temperatures down. To bring temperatures down, you have to do either a carbon removal or solar geo.

Ed Whittingham: Yeah, so I just want to hammer that point home because I think it's a really important one. We might be successful in getting to net zero in our lifetimes. It 2050, which is sort of the rough global target. That's That, what you're saying, may just crystallize a level of warming that is dangerous, where a lot of bad things happen, and just getting to net zero doesn't bring that temperature down.

David Keith: Correct. I want to inject my view about 2050. Um, I personally think the chance of getting to net zero by 2050 is really low, and I'm not sure it's meaningfully a global target. I agree, it's something that some governments say, but I There's dynamics in politics where, as we all understand, governments have reasons to say things for some constituents that they don't mean.

If you measure by actual actions, if you look at the flow of actions and rules on the ground, I don't think the world is on target for, for net zero by 2050. And I'm not actually sure net zero by 2050 would be a ethically sound choice at this point, because there are real trade offs. There are, you know, still, you know, 700 million people without access to electricity, they're a complicated trade off.

I think getting that to around 2070 feels a lot more believable and kind of like a reasonable choice to me. 

Ed Whittingham: Yeah, and just on the global disparity, for us, if I, if I turn on a 40 watt bulb in my house and leave it on for an hour, it costs me less than half a cent. 860 people still lack access to, uh, reliable access to, uh, electricity.

And generally you want to charge a phone, it costs something similar to that, it costs half a cent. Then in many places you're walking down, going to a store, and you're paying 25 cents or 200 times what we pay. So there's great disparity, and thank you for bringing that up. But let's now talk about the technical dimensions of solar geoengineering.

Or specifically within that stream, stratospheric aerosol injection. So you're talking about putting sulfates into the stratosphere as a way of Sir, to put it crudely, is there refracting sunlight or yeah, how do you do that in a way when you do that? Is it on a hemispheric basis? You put it up into the atmosphere.

It goes across the hemisphere. Can you do it in a localized way? Like how does that work? 

David Keith: So, very quickly, there are a bunch of different ways that, theoretically, you could do solar geoengineering, from huge space shields to marine cloud brightening, but the only way that is technically a development project, without any research, you actually understand how you could do it, is to put sulfide There's a way in which, a kind of brutal way, there's no question you could go and build the hardware to do that now.

And what you would do is put air, put sulfuric acid precursor gases, so two H two s or something in the atmosphere at somewhere between maybe 15 to 20 kilometers altitude, depending on the latitude. And yes, it doesn't stay in one place. It naturally wants to mix at least on a hemispheric basis. And so a key thing we say is that if, if one wanted to do this, I think in a way that was.

You want to do it in a way that was hemispherically balanced. You want to do about the same amount across the hemispheres so you don't shift the inner trouble conversion zone the area of, of heavy rainfall and, and dry land. 

Ed Whittingham: So can you speak quickly and, and you want that radiative forcing to be roughly even?

And if it's uneven, are then you shifting the climate benefits versus climate dis benefits equation? Like, for instance, is there a way that you could do this, and obviously unintentionally, where you've got localized benefits over here, let's say the Western Hemisphere. But then, in the Eastern Hemisphere, then you've got dis benefits.

And so one side of the world is, is winning and one side of the world is losing. So, 

David Keith: western and eastern, the answer is a clear no. Atmosphere flows around with the, the jet stream and the circulation going the other way. Yeah. Atmosphere flows east to west pretty quickly. So there's no version of this allows you to do east versus west.

But north versus south is more isolated. And the two hemispheres are really quite isolated, north, northern versus southern. Yeah. So it is possible, technically, to do it in just one hemisphere and not the other. 

Ed Whittingham: Okay, then just also on the technical side, well, let's talk a little bit about the state of research and the knowns versus the unknowns.

So, what do we know now, based on, maybe you could start, like, what is the total spend on research going into solar geoengineering relative to? Other forms of climate mitigation and then roughly what do we know now and what are the big unknowns? So 

David Keith: I think that's a crucial question. A crucial question is should you folks, should decision makers and citizens trust and the thing that I or other people like me are saying, I think in thinking about that, you need to think what makes you trust or not trust different areas of science.

I don't have a magic answer, but I think, I think general rules are I trust science more if it's been going on for a long time. If it's, uh, pretty global, that it's not just all in one place, and if there isn't a big commercial interest, those are kind of factors that lead me to trust. So, if there's some, like, amazing thing that maybe got published in Nature that shows how some totally new drug can cure cancer, but, um, you know, it was just published last year, and the people have patents on it, I'm, you know, I'm excited that it got into Nature, but I'm not gonna believe it that much.

But things that have been around for a very long time, like our knowledge of climate science. Uh, that are very distributed over, yeah, both over time and space. And whether it's not big commercial interests, I have a lot of faith in. And so I think in thinking about solar geoengineering, on the one hand, the total research spend is, you know, uh, 50 million a year, 30 million a year.

It's hard to measure. It's that kind of number. It depends on whether you're measuring explicit money or people in government science labs working on it, even though they don't have a grant of that order. And, uh, there's, you know, a thousand papers that have been published, but maybe the median age of those papers is just sort of, you know, Five years, or eight years, a lot have happened new.

So if I just tell you that, and much of the papers are dominated by a small group of people, whom I'm one. So with all those factors, I think you should say this isn't very trustworthy. But I think it actually is trustworthy. And the reason it's trustworthy is that this really is not rightly thought about as a new piece of science and technology.

It's really just applying stuff that we know from Atmospheric and environmental science and some that we've known for a very long time. So to get a little nerdy for you, but I think it really matters and kind of you forming opinions about where you should trust any of this. So I can tell you that all climate models, when you actually put in hemispherically balanced, moderate solar geoengineering, they show amazing results.

Every single model. They show that any variable you, that, that, that are the big variables we care about. Extreme temperatures, extreme precipitations, water availability. We see that those are. Pushed back towards the pre industrial, the changes were reduced to centrally everywhere. But again, you might think, why would you believe it?

Here's one little factoid that you may think about. The first review article. on stratospheric sulfates was published in 1961. It's very old thing. And because sulfur is such an environmental killer, we have an enormous number of papers studying sulfur in the atmosphere going back literally to the 1880s.

I mean, the first power plant with a sulfur scrubber was upstream of London in the 18, I forget, 1880s or nineties. I mean, this is not a new thing. So it's that deep body of science. It means that I think in many ways the uncertainties are not as big as we used to portray them. 

Ed Whittingham: And just going back to the trustworthiness question, because it's a very interesting one.

Roughly, how many researchers would you say today are working globally on solar geoengineering? 

David Keith: It's really hard to measure. If you're talking people who are working full time on it, I don't know, hundreds? But if you're talking people who touch it, it's much larger, because almost any climate center now has somebody thinking about it.

It's changing very fast. Yeah. And there's probably Big chunk of new, both government money and private money, philanthropic money coming in this year. There's also, some of you may not know, there's some kind of high level assessments. So the UNEP, the United Nations Environment Program, published a very short, readable summary called One Atmosphere last year that made a very clear and, I think, pretty positive story about how this could be useful, also how it is definitely risky.

Um, there's also, in a kind of global sense, this isn't just run by any, again, don't trust it if it's run, don't trust if it's run by UChicago, right? Don't trust if it's run by any one thing. There's a, the World Meteorological Organization, which is, you know, maybe the, one of the very oldest international orgs of any kind, way previous to the UN.

It has a thing called the World Climate Research Program, which is very international, and, you know, even through the Cold War, that was international research. That thing has a, a limited number of so called lighthouse programs that push on new areas of research. There's now a major one on climate engineering and then again, none of that that I just mentioned, that and the UNAP report that shows the way this is all much more kind of real than it was five years ago.

Ed Whittingham: Yeah, and, and as I said off the top, I, for one, am supportive of expanded research into solar geoengineering, climate engineering generally, and as a way of. And increase that scientific base of knowledge and increase the number of researchers too, so that it's less susceptible to group think. Yeah. And that group think I assume can creep into those climate models too.

For 

David Keith: sure, and so, to me, I'm actually been pushing kinda the internal of the solar geo community, saying that we're kinda getting bored of just running the same model experiment, I don't think we're learning much. I think. The community has to be more serious about looking about what the high consequence, low probability kind of tails of the distribution are.

A lot of the papers you see published on SolarGeo are saying, Oh, this other result was wrong by 30%. But if it's 30 percent all about finding ways that we dramatically reduce climate risks, those of you out there won't really care. The big question is, is it wrong? Is there some giant thing we're missing?

Is there some gotcha that means you do this and you don't get the, what we expect? And I think we need a much better effort to look for those gotchas. And I personally, I'll say this, I wouldn't vote. to really begin deployment until, I don't think we actually need a lot in the way of new science. We need a much more critical look at the science we have.

With teams of scientists whose job it is to find problems. 

Ed Whittingham: And just to be clear, I trust you personally. I've been climbing with you, you've been repelling me. I trusted you, I didn't fall off the wall. I even squeezed into your tiny little climbing shoes when we did that. But let's talk about this strange notion of fighting pollution with pollution.

So as you say, you talked about sulfuric acid, and it's been well documented from industrial plants like coal plants. It affects, it creates respiratory illness, it kills people, so we're talking about, intentionally, Right. So, um, sulfuric acid or sulfates into the, into the stratosphere, so then there's gotta be a good cost benefit ratio to that.

That's right. And, and what do we know about that cost benefit ratio? 

David Keith: I think the answer is we increasingly know a lot. So for putting sulfur in the stratosphere, again, we have this giant body of research about the impacts of sulfur aerosols on human health. So we can actually calculate that if you put, uh, say this kind of million and a half tons a year of sulfur in the atmosphere, it should cool the earth some.

A little more than half a degree C, you can calculate what the direct health impacts would be. And that is what the added mortality burden would be. And it's about 7, 000 a year with quite wide error bars, but that's the kind of number we're talking about for that amount. That's for one degree C of cooling.

And that's no joke. That's actual 7, 000 added, added sulfur mortality. Of course, the total sulfur mortality now is more like 5 million. But then what you want to do is compare that to how many, uh, how much mortality will be reduced By the cooling effect, and so we now have really quite good epidemiology that shows what the impacts of cooling the world are.

It's the flip side of what the impacts of heating the world are in terms of people dying from heat stress. And so using really the kind of state of the art of these epidemiological models, we're now able to compare those two things. And again, you know, me and some people are comparing them, but it's not like we've done all the work underneath.

It's under, work done underneath, it's by huge groups of people. And that comparison shows that for one degree C of cooling late this century, you'd have this sort of. 7, 000 ish with big error bars added deaths from sulfur air pollution and 1 or 2, 000 added deaths from the effect of ozone depletion.

Those are not jokes. And then you'd have something like half a million reduction in deaths from heat. And so that ratio is more than 10 to 1. And the reduction in deaths from heat is heavily concentrated in the poorer and developing parts of the world who need it the most. And that to me is the ethical case, not necessarily for doing this, but for taking it seriously.

Ed Whittingham: Yep. I said off the top from what I understand, and we're getting to it, that the technical challenges and the economic challenges are surmountable, the governance and decision making challenges are very prickly. So we've talked about the technical challenges, let's just talk very quickly about economics.

If you're to put a million and a half tons per year of sulfur, sulfuric stratosphere, what's the rough order of 

David Keith: cost? A few billion dollars, certainly under 10 billion a year. So the costs are basically zero compared to the other costs. I mean, the cost of climate damages, the monetized cost of climate damages, mid or late century, are well over a trillion a year, well over 1 percent of GDP.

And the costs of decarbonization are also well over a trillion dollars a year. So something that's less than 10 billion is, I think the big lesson here is that cost is not the issue. The issue is about trust and power and decision making. How confident different groups of humans are this is really a good idea or not.

Yeah. What they do, but it's not really about them. 

Ed Whittingham: Yeah, the cost is on the order of the food and beverage bill for Unite 2024. It's, you know, No, well, for the hot chocolate, by the way. I don't think we're getting our share. I've just 

David Keith: got water here. 

Ed Whittingham: Can I get a stage runner for hot chocolate, please? Yeah, bring it up.

Yeah. Yeah. Okay, well let's get to those non technical dimensions, the prickly bits. So first off, you'd mentioned before, like, cooling the planet by a degree. So, how do we agree on an objective? Are we actually cooling the planet? Are we stopping the planet from warming? So a little bit of, like, what's the objective and how do you, how do you get consensus on that objective?

David Keith: So, big news flash, which I expect you know, I expect you all know, humans don't get consensus on anything. Okay. And that's just not the way we roll as a species. I'm not sure I would want to live in a species that did everything by consensus, but in any case, hominids, this hominid class does not. And I think there's ways in which we've done things better or worse as a society.

Obviously global governance feels a lot less good now than it did 10 years ago or 20 years ago. But there's also ways in which humans have collaborated pretty imperfectly on not having nuclear wars or not destroying the ozone layer, Global diseases in ways that are surprisingly effective despite having no consensus.

And I think, uh, consensus is not the right thing to hope for. Uh, uh, I think what you can hope for is a reasonably stable political outcome that actually provides a good outcome for most people, and not just humans. I also think that, uh, Humans aren't the only entities that matter here. I care about the natural world other than humans.

Um, but, but I think consensus is really to be blind, a kind of absurd thing to talk about. I think what we need to do is some way talk about a middle ground. It's common in conversations about this is sort of some people who say we can't do solar, because we'll never get global agreement about it. But of course we never got global agreement about the internet or.

mRNA vaccines, which could also be weaponized or AI being released to the internet

David Keith: and another point of view is it'll all be done by one, you know, billionaire rogue. It just doesn't. I think there's also deep reasons why that's not the way it's going to happen. I think in practice, if it happens, it happens with a Small coalition of countries and you get to start to think about what that coalition is, what holds it together, who the opponents are.

That's the kind of reality of how this happens. 

Ed Whittingham: Yeah. So, it's similar to unintended consequences, I say consensus. The unintended consequences We can say there will certainly be unintended consequences, were you to start doing that, for sure, like a hundred percent. But there are also unintended consequences from letting CO2 concentrations get to 450 parts per million, right?

Yes. In both cases. Exactly, it's a risk risk. It's, it's, it's, you've got to try to evaluate those relative unintended consequences. But I do want to go back. So you said it's unlikely that a rogue state or a rogue billionaire would initiate that. Would initiate, like, the first sort of significant deployment.

Um, but, but why? So let's say you're India. We had Kim Stanley Robbins talk. I understand. Stranger than fiction, like, what if India has 20 million people dying from a heat event? And says, we're just going to do this ourselves. Totally 

David Keith: get it. So Kim Stanley Robinson did his homework. So it's not just fiction imitating science or science imitating fiction.

Kim went to a bunch of meetings about solar geoengineering and heard people talk about India or Stan, as he's called, not Kim. Um, I don't know. Um, I spent a week in India about exactly one year ago, where there were actually amazing number of pretty senior people talking about this. Some of whom were talking about deployment in ways where I'm not sure they knew what they were saying.

I think, though, in a, in a kind of purely rational sense, if you imagine yourself as a leader in India and Indonesia or somewhere like that, even if you're fundamentally self interested, you know, the real politic is you think about what other countries are going to do in response, and if choice A is to do it purely unilaterally, and choice B is to gather a few other countries and make a deal that you'll announce stuff together and do it, You're going to know that case B is going to be much more stable, and so you're going to be much more likely to do case B, and so that's where I think a purely unilateral action is not very likely.

Ed Whittingham: Yeah, and there, there is recourse available to other state actors where, say, a state to move unilaterally. 

David Keith: So, so my sense is that to be a stable coalition, it needs to have some major players from the global south, because, because they're the ones most at risk. They're the ones who can kind of have the moral authority to do stuff.

Uh, countries like India have the technical ability to do it. And then, you know, hopefully some Western democracies, but who the heck knows? Mm hmm. I mean, I think the biggest thing to say is, I'm talking like I know, I'm very involved in these conversations, but I have no idea what's going to happen politically.

I don't think anybody does. I think there's some very overheated, overconfident claims about how solar geoengineering will play out. Right now I can say opinions are changing quickly. The only thing I think, believe really strongly and with confidence is we ought to have a much more serious research program to know more.

And we need better mechanisms of international assessment, uh, to kind of pull the science together so that people like me aren't the ones talking to you in a way so there's much more credible assessments like an IPCC special report or a bunch of different mechanisms that would provide better credible answers that summarize the science.

Ed Whittingham: And do we need a moratorium on deployment for the time being? Like with some, some, some enforcement capabilities behind it? Yes, 

David Keith: I think we need some kind of Soft moratorium. is what the exit conditions are, but yeah, Ted Parson, you know, I'm friendly with, and I proposed an early one 10 years ago or so. I think something where a bunch of countries essentially proclaim what they would do in the case of, proclaim their resistance to unilateral action and say something about what do to block unilateral action and say something about the conditions they need In terms of, uh, science and assessment to make decisions, I think a thing like that would be very helpful.

Okay, 

Ed Whittingham: uh, just giving the audience a heads up, uh, I'll, we'll turn to Q& A in probably about three minutes, and I think we'll have 15 minutes for Q& A. How do you know when to start? You could say right now, with the warming that people have experienced, some of it's anecdotal, some of it, you know, people are saying, hey, you know, it's, it's a warming world, and the World Meteorological Organization reported 1.

45C about pre industrial. How At what point do you say, we need to do this? We talked a bit about the how, like UN or consensus driven or semi consensus. Is it at 2C above pre industrial? Is it 2. 5? Is it 3C? Like, when do you flip the 

David Keith: switch? So, I think the biggest thing to say is that there's, there's, We is too easy a word in climate because we kind of implies that we can all agree and the hard part of course is that there is no we, but there's a whole bunch of individuals and different, some of them aren't born yet and, uh, uh, Oliver Morton, uh, uh, from the economist wrote one of the most thoughtful books on this topic called The Planet, uh, Remade.

He has a very nice paragraph about how he avoided the use of the word we because it applies this kind of easy assumption about agreement. You know, there are a lot of, there are now quite a lot of thoughtful people who think that we should have already started. Okay. Solar geoengineering, and I'm pretty close to that, but not quite there, but I have a few conditions.

Uh, and there are people who really seem to believe we should never ever do it under any circumstances, and I think, I think, I think for myself that the balance of evidence is that if you start it very slowly, the risks are really low, and you learn a lot and get some small benefits. it. So I think an important thing to say is, if you think about starting and it's hitting a big red button and starting it, so you suddenly try and cool the world actually cool the world down.

I think that would almost certainly be a bad idea under basically any circumstance. But if you think starting means very incrementally being to add more sulfur to stratosphere, inching up towards the background level of stratosphere and monitoring as you go, where where you're still a factor of 10 or more below what a big volcano does, I think that is By many measures, objectively, in physical risk, a very low risk thing, and we learn a lot from it.

And I basically would be in favor of such a thing. But I do think the key thing is to get some more trusted assessments really quickly, like years. 

Ed Whittingham: So, last question to you, then we'll open it up to the audience. And I do a lot of work in carbon removal these days, I get this question all the time. Isn't this just the latest panacea, latest, greatest panacea put forward by industries, specifically the oil and gas industry?

To avoid actually reducing emissions. Now, I don't want to be clear, the oil and gas industry is not behind what you're talking about by the research. But how do you deal with that moral hazard question? Because some would look at it and say, great, problem solved. 

David Keith: So, I think you gotta partly deal with it head on.

Realize there's absolutely part of that that's real. That you can, self interest is a powerful motivator. So I expect, That some people in big oil companies or fossil influenced nations will seek to over claim about solar geoengineering, say how it just does solve the problem and it really does mean we don't need to cut emissions.

I think we should expect that to happen because that's how self interest works. And I think those of us who believe we ought to cut emissions and eventually do carbon removal and maybe do solar geoengineering in the interim need to find how to address that head on. But we need to admit that that that push to moral hazard is real.

I don't think there's any way to kind of magically legislate it away. I do think the research community can be clear that it's not associating itself with the fossil fuel industry, but I don't think that magically solves the problem. Um, I think you can think about ways to couple together, um, nations that have a vote in some future treaty or regime around solar geoengineering.

So you get more of a vote if you're cutting emissions strongly and Particularly, actually, this colleague Ted Parson has thought a little bit about how that could actually work in a treaty or, we're not making treaties so much these days, but some kind of regime, international regime, could couple together strong emissions cuts and actions.

It's no magic answer, but it's the right question. 

Ed Whittingham: That sounds a better preferential system than J. D. Vance giving extra votes to parents. Because they're Oh, and the vice presidential debate's tonight. It'll be scintillating. Great edutainment. Okay, thanks. Let's, let's go to the audience. We have 14 minutes and 7 seconds for audience Q& A.

Question: Hey guys, um, Thank you so much for introducing me to Kim Stanley Robinson. First off, I loved, uh, I love Ministry for the Future, so it's awesome. And I feel like we're living in it at this very moment. Um, but for Canada, we have an issue with permafrost melting. And when we speak often about geoengineering, we're talking about sometimes albedo, looking at the ground rather than the stratosphere.

Um, worrying about sulfur emissions into the atmosphere and then having a big permafrost melt turning it all over as a big soup. So, would you mind speaking a little bit about geoengineering with it having to do with albedo and ground? 

David Keith: Well, I mean, the way that we most know how to deal with albedo melt is sulfuric acid in the stratosphere.

That's the thing that we're, have the only thing that there's really high confidence, even the IPCC says so, that you could. And it would reduce temperatures, and it would reduce melt. And, and, you can see that that's a significant contributor to uncertainty about future warming in, in lots of work, including work that Damien, uh, Matthews, uh, uh, Canadian Climate Scientist and I published a long time ago.

Here's the interesting thing. People often think about, um, the ways that the presence of the knowledge of solar geoengineering, or the actual implementation of it, might encourage humans to emit more, to be clear. That's this kind of moral hazard connection, but fundamentally, they're separate tracks.

Emissions is its own problem. Emissions, no matter whether solar geoengineering is there or not, emissions hurts our grandkids. Emissions puts a risk on the future, period. And we need to push emissions down towards zero. Solar geoengineering has its own set of risks, but it's ultimately an independent thing.

In thinking about that connection, people often think that solar geoengineering doesn't, does or doesn't directly do anything to carbon. Here's a thing to think about. If you imagine two worlds with exactly the same anthropogenic, industrial emissions of carbon, One world has significant solar geo and the other doesn't.

So the world with solar geo has lower temperatures at the end of the century. In a world with lower temperatures, the carbon cycle feedbacks, including permafrost loss, but also the ocean ones, are lower. So a world with solar geoengineering, there's actually less carbon in the atmosphere at the end of the century than a world without it.

And it's quite a bit less. Like, it's the equivalent, if you do quite a bit of solar geoengineering, of, like, eliminating U. S. emissions for the century. So there is some carbon benefit to solar geo. 

Question: Thanks. And I do enjoy your podcast. I'm a regular subscriber. Thanks so much guys. Great to see you in the flush, but I have a conundrum.

Well, first of all, my first conundrum is I'm 80 years old. Second conundrum is I've got a memory. And that memory is of pollution of the atmosphere with sulfur from coal fired generating plants. I've also worked on coal fired plants as well. That was a big problem. Sulfur laden coal, especially in the eastern seaboard.

Pollution of lakes, killing of fish, vegetation, getting into the ocean, and now we're talking about adding sulfuric acid into the atmosphere. Help me understand. Totally get it. I think 

David Keith: some numbers will really help. So, absolutely get it. But because of all that history, which you just said, which I already mentioned, that's why we know so much about sulfur in the atmosphere.

Completely agreed. But the numbers matter. At the peak of global industrial sulfur emissions in the, around 19, in the seventies, emissions were over a hundred million tons a year. S and sulfur and over 70, I'm mixing up SO2 and S units, over 70 million tons a year in sulfur units. And they're now down well under 50.

It's actually a little hard to get the exact number because of pollution control is driven by the all the concerns you said. Um, and what we're talking about doing if you want to cool the earth late in the century by say, I think half a degree, which to me is more credible, maybe taking us down from, you know, two and a half to two or something like that.

Um, that would take, if you did it carefully under 2 million tons a year. So it would be, Uh, A few percent of what we were putting in before, and it's globally distributed, whereas at least for acid rain and also for air pollution, the concentration matters. Acid rain is very much a problem of local concentration.

So we use all the same environmental science that was used to find out about both air pollution and acid rain and other impacts of sulfur. And we're applying all that. And we find that if you're putting a few million tons a year in the stratosphere, it does all come down. It comes down evenly. You just don't see environmental problems that are very big.

They're not zero. That's the number I told you before about additional mortality But they're objectively pretty small compared to the benefits if we're doing the science, right? 

Ed Whittingham: There's a paradoxical thing to David You could just talk about it quickly is that the current sulfuric acid emissions the world has said it's 50 million tons No, it's actually providing a cooling effect Like, what would happen if we eliminated all those emissions today?

David Keith: So if we eliminated all human greenhouse gas and air pollution emissions today, the world would, answer for yourself first, warm up or cool down in 10 years? The answer is the world would warm up. Because right now we've got the, all the long lived greenhouse gases are a warming thing, but they're partly masked by the aerosol cooling.

And the aerosol cooling is short lived, but if we instantly eliminated both, what you'd actually see is a little bit, a little warming blip as you revealed. Took away the cooling effect of aerosols. Um, and so that gives you a sense that these, that, that, that. That again, this idea of humans, human aerosol changing the climate is not news.

I mean, why did it not warm up very much in the 60s and 70s and then warming started in the 80s, mostly because of aerosol pollution was masking the CO2 driven warming. 

Question: David and Ed, um, if you could inject something into the atmosphere that would in fact reduce um, the warming effect. Um, how permanent is this likely to be?

I mean, if we, if we just shoot something up into the air today, is it gonna last to tomorrow, next century? Is it just gonna reduce the blip for a short period of time? What's the permanence? 

David Keith: The lifetime in the stratosphere of aerosols is about two years. And from my perspective, that's actually kind of a, a, a, a, that is just a fact, but it's kind of a good number in a sense that it means you can adjust the amount up and down.

But it also means that if like the thing putting it in broke, it does not like the aerosols suddenly go out. You could have six months, you can fix it. Um, so the, anyway, the answer is about two years, so you can ramp it up and ramp it down slowly in principle. And one thing that kind of gets it, maybe that question in the last one, So, you might say, why are we talking about the stratosphere and not the lower atmosphere?

Because I kept talking about sulfur pollution in the lower atmosphere. Sulfur in the lower atmosphere lasts about a week, where sulfur in the upper atmosphere lasts about a year. So, 50 to 1 ratio. And sulfur that comes down is rained out, so it's about 20 times less air pollution damage than local sulfur.

The combination of that 20 times 50 means that the ratio of cooling benefit is To, um, air pollution harm and measuring a human mortality is a thousand to one. So putting a kilogram of sulfur in the stratosphere is, has a thousand more times more cooling per air pollution harm than does emitting sulfur with our current distribution of sulfur sources.

Ed Whittingham: Can you contrast that lifetime with CO2? So let's say we get to net zero by 2050. And it's 450 parts per million, let's say. How long would it take through non interventionist means, just through the natural carbon cycles, for that CO2 concentration to dissipate? 

David Keith: The short answer on policy relevant timescale is forever.

So the, the, the warming commitment, which isn't quite the same as the CO2 commitment, but it's one that matters, is, is many thousands of years. 

Question: The half life of CO2 in the atmosphere is 43 years. And I'm not going to make it to 43 years, so you guys, uh, watch for it. So, that, that's actually 

David Keith: false. There's several different lives.

Uh, there's, there's both geochemical equilibration with the deep ocean, and there's surface equilibration, so there's both actually a shorter half life. A bunch of the half life is with the ocean mixed layer, which actually just goes in a year and a bit. And then there's this much longer time scale. There, there isn't a single exponential.

We often fit it with three exponentials, one of which is, uh, around a 50 year exponential, and then there's a 300 year one. So, that, that is just not 

Ed Whittingham: what the science says. Thanks. I'd love to do a little instant poll, because David and I were talking on the way in just around Canada. Because Canada is pretty much, apart from great Canadian researchers, like, you know, uh, leading Canadian researchers like, uh, David and, uh, Ted Parsons, who are Canadians, Uh, and there's one And one more, 

David Keith: by a funny, weird coincidence, Three of the authors who are probably the most cited on climate engineering all grew up in Ottawa at the same time, but we went to different high schools.

So me and David Martin and Ted all actually Ted's 10 years older, but we all grew up in Ottawa. 

Ed Whittingham: Yeah. Gosh, had you met then, and you started a band, you know, you can, it would have been a crappy band. It would have been a good 

Ed Whittingham: Yeah. Yeah. Um, but so the pool, Canada is, As a federal government MIA, when it comes to any kind of serious research into solar geoengineering and David and I, we had Jonathan Wilkinson as a minister on the show and David put that question to him and there could be an update there soon.

As Canadians here, and you can just do this through a simple raising of hand, who would be supportive of the federal government spending money and let's say it's on the order of, you know, single digit millions to join the global research effort into solar geoengineering. Would you be supportive of that?

So I'm looking at it and I think it's roughly three quarters supportive. Let's 

David Keith: see the opposite. Let's see. Oppose it strongly or oppose it. Yeah. Okay. So one thing that's really interesting is there's this perception that there's this huge pushback against research and there's some very articulate, impressive climate scientists like rapier Humbert, who I really love, who just thinks that I'm.

It's just a terrible human, and we absolutely shouldn't, shouldn't do this research. And when I took a job at UChicago, where I used to live, he like emailed people saying it sold out. So there are people like Ray, and Susan Solomon is one of the absolute greats who helped discover the ozone hole, and really believes we shouldn't be doing it.

But we did a poll like this, there was a point more than a decade ago, in Europe, where Ken Caldera and I were on stage for a European Geophysical Union meeting, actually a much bigger hall than this, And some BBC announcer was hosting it. There were a couple other people on stage and he had a snap poll kind of like that, but this is in Europe.

And more than 10 years ago on research on solar geo, he had a four categories of like strongly supportive and opposed. And I expected in front of Europe that like almost everybody be opposed. No. Almost everybody was in favor, even then, ten years ago, but somehow it just didn't happen. 

Ed Whittingham: Yeah, and so going back ten years, it will be ten years come this December, when you and I collaborated in running that first workshop in Canada.

This is ten years ago when energy versus climate was a mere twinkle in our eyes. You know, maybe that collaboration was, you know, an early ancestor to climate change. to, uh, Energy vs. Climate, and at the time, I had to pretty much beg and plead the heads of other environmental groups just to send, say, a junior analyst to show up for what was a day long workshop.

Didn't want to know, didn't want to think about it. And now, we have Environmental Defense Fund, which is one of the largest environmental groups in the U. S., which has undertaken a major research program into it. We don't have the Canadian counterpart yet. 

David Keith: But I guess a question for you, Ed, actually, turn the, turn the tables for a second.

And so, yeah, Environmental Defense. He is actually now as a real solar geoengineering research program, like they'll raise 10 or 20 million dollars and they have a program of governance research and they're actually the fund research. So, my thinking is that might be like the first penguin off the ice flow and more NGOs will follow.

But, Ed, you're the NGO expert more than me. How do you, how important do you see that EDF decision to do this as, how much do you think it'll resonate? 

Ed Whittingham: Well, I think it was important and it turned out to be prescient because in the paper, the white paper that we wrote following that workshop, we said, one of the major signs of Some degree of acceptance of at least having the conversation and to be clear the conversation was only about expanded research Yeah, only about that one of the signs would be a major NGO Undertaking a research program starting a research program on it little did we know at the time that we would have to wait 10 years But here we are.

So, it is purely anecdotal, but based on the 75 percent of the hands that we saw go up, I think it's a very different conversation, a very different space today than it was 10 years ago. And I think part of that is that, and whether it's actually grounded in science or not, it could be anecdotal, but people are feeling like the world is warming and that things are getting dire.

That's, that's my anecdotal sense. Oh, thank you. Thanks. We're out of time, folks. Um, enjoy the rest of Unite 2024. Thanks for lending us your ears. Thanks for listening to Energy vs. Climate. The show is created by David Keith, Sara Hastings-Simon, and me, Ed Whittingham, and produced by Emmett Tandon with help from Crystal Hickey.

Our title and show music is The Wind Up by Brian Lipps. This season of Energy vs. Climate is produced with support from the University of Calgary's Office of the Vice President, Research, and the University's Global Research Initiative. Further support comes from the Trottier Family Foundation, the North Family Foundation, the Palmer Family Foundation, and our generous listeners.

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