“It’s Dangerous, But Let’s Still Research It: Dr. Michael Mann on ‘Solar Geoengineering'”

‘POTUS’ Podcaster Smerconish’s interview with Dr. Michael E. Mann

FEBRUARY 15TH, 2023 | 20:45 | E412


‘Solar Geoengineering‘ has been brought up recently as a solution to combat climate change. But, what is it, and are its potential rewards worth the risks? Michael gets expertise from leading climate scientist Dr. Michael Mann, Presidential Distinguished Professor and Director, Penn Center for Science, Sustainability & the Media in the Department of Earth & Environmental Science at the University of Pennsylvania. Original air date 15 February 2023.


Announcer: Here’s Michael Smerconish. 

Smerconish:  I had wanted to include a poll question on solar geoengineering in today’s newsletter, but then I thought no one would know what I was talking about—I don’t know what I am talking about.

I read something at CNN that caused me to extend an invitation to a special guest to return to us. Michael Mann will be with us in just a sec, but let me share with you the first three paragraphs of that which I read that will frame this conversation:

“When US start-up Make Sunsets released two weather balloons into the skies above Mexico’s Baja, California peninsula last year, it kicked up a fierce debate about one of the world’s most controversial climate solutions. The plan was for balloons filled with helium and a small amount of sulfur dioxide to float high into the stratosphere. There they would burst, dispersing their load of sun-reflecting sulfur dioxide particles, and cool the earth just a tiny bit. 

“Some dismissed it as a stunt. It’s not clear if any particles were actually released, or even if the balloons made it into the stratosphere. But Make Sunsets’ experiment is significant for crossing the threshold when it comes to a hotly debated climate solution. 

Solar geoengineering to its supporter, solar geoengineering is a fix we cannot ignore. As the world hurdles toward climate disaster for critics, it’s a technology so dangerous, we shouldn’t even research it. 

Dr. Michael Mann is the Presidential Distinguished Professor and Director of the Penn Center for Science Sustainability and the Media at the University of Pennsylvania. He’s the co-founder of RealClimate.org. He’s the author of more than 200 peer reviewed and edited publications, numerous co-ops and commentaries, and five books including Dire Predictions, The Hockey Stick and The Climate Wars, The Madhouse Effect, The Tantrum That Saved the World, and The New Climate War

This is Dr. Michael Man. 

Dr. Mann, thanks so much for coming back to the program. 

So into which of those camps or categories do you fall on the subject of solar geoengineering

Mann: Yeah, thanks, uh, Michael, it’s great to be back with you. And, um, I, I, I’ll give you sort of a hint as to where I stand in, uh, the Madhouse Effect, uh, uh, my book with, uh, Tom Toles Washington Post cartoonist. We had a chapter on geoengineering that was, uh, titled “Geoengineering or What Could Possibly Go Wrong?” <laugh>. Right, you know, it, it really does evoke the principle of unintended consequences. 

Now, of the two positions you cited, um, I would say it’s overly extreme to say we shouldn’t research it at all, because in fact, some of the research that’s, uh, been done, and we need to make a distinction here between, um, you know, theoretical research using numerical climate models and actual field experiments where people might be trying to implement these schemes. 

I think the latter is quite dangerous. But I think the former, uh, using climate models to investigate the possible consequences actually is critical, because if anything, those sorts of experiments, um, climate modelers who have looked at the potential consequences, uh, indeed that that work has demonstrated, uh, some real, uh, potential unintended consequences. If anything, it’s a reason for greater apprehension, uh, uh, about some of these more elaborate schemes. 

And when we talk about geoengineering, there’s a range of sort of geoengineering interventions. Some involve, for example, carbon capture—that’s really relatively safe. It’s trying to get the genie back into the bottle. So it’s hard to do, but it’s trying to solve the problem at its source. 

Whereas, say, solar geoengineering, we’re starting to tinker with sort of aspects of the climate system that we’ve never tinkered with before. We’re changing atmospheric chemistry. We’re not directly dealing with the problem at its source, which is the carbon pollution and increased greenhouse effect. What we’re doing is trying to cover that up by essentially dimming the sun. 

And what the model experiments show is if you do that, you don’t actually get back the climate that you started with. You might be able to prevent the average temperature of the planet from increasing. But the patterns, the pattern of greenhouse warming and the pattern of the geoengineering _induced cooling,_ they don’t look the same. They’re not mirror opposites. And so when you put one on top of the other, some regions could actually warm even faster. Greenland could warm faster. We could induce melt of the Greenland ice sheet even sooner at the expense of, say, cooling some other region elsewhere on the planet. 

So we really do have to be very careful as we sort of move headlong into the consideration of implementation of these schemes. The modeling work, if anything, um, has been, uh, has really given us a reason, a reason for greater caution. 

Smerconish: In a broad sense. Are we talking about whether we should impact or control the weather? 

Mann: Yeah, it’s, you know, I would say it’s even deeper than that. There’s a hubris <laugh> that comes with the idea that we can control the weather, um, in, in the sense that we are tinkering with a system we don’t understand, uh, completely. You could argue that that’s the, that’s the, the, the fundamental problem in the first place. 

We’re tinkering with the earth system by increasing the concentration of carbon dioxide from fossil fuel burning faster than we’ve ever seen in in Earth’s history, and we don’t know how it’s gonna respond. So we’re already tinkering with the, the, the system. 

But geoengineering, solar, geoengineering, the idea there is, well, let’s tinker with it some more in the hope that somehow we almost magically offset, you know, the, you know, the first, uh, intervention that we engaged in. And I’ll, again, I’ll draw from the Madhouse Effect. We begin the chapter with, um, this, uh, you know, the, the lyrics to this song we all learned when we were growing up. I’m sure you remember it. I’m sure many of your listeners remember it, Michael, there was an old lady who swallowed a fly <laugh>. 

Um, you know, then she swallowed the frog to, to, to deal with the fly. And in the end, it wasn’t the fly that killed her, it was the horse that she ended up swallowing as she went to larger and larger and larger creatures. Um, that’s sort of, uh, in a sense, a, um, you know, that’s a metaphor really for geoengineering. 

Smerconish: Dr. Mann, what happened as it relates to this conversation at Mount Pinatubo in the Philippines in 1991? 

Mann: Yeah, so there was a, a big, uh, volcanic eruption. Uh, one of the largest on record, uh, is a tropical eruption. If you have a large tropical eruption, then, uh, and it, and it’s explosive enough, then it will send particles reflective sulfur dioxide, um, in, in, in particles that we can call aerosols that form from them into the stratosphere. And, uh, it will spread out around basically the entire planet. So we get this layer up in the stratosphere, you know, 10, what, 10 miles up in the atmosphere where jets fly.  Um, we get this layer of reflective sulfur dioxide particles, sulfur, sulfur aerosols that reflect some of the sun back to space. And climate modelers did a calculation. 

Uh, James Hansen and NASA Goddard Institute for Space Studies back in the late 19 and the early 1990s, rather, famously did an experiment with a pretty primitive climate model where he made a prediction of the cooling that would happen from Pinatubo, and he pretty much got it right on. 

Um, you know, it a, a little less than a degree Fahrenheit, uh, cooling of the planet in, in the several years that followed until those particulates sort of fall out of the atmosphere and the effect disappears. And so what we’re talking about, and we can measure the impacts, we saw that some places suffered severe droughts, uh, some places warmed, other places cooled. Um, so we changed the climate. 

That was a natural experiment, um, that showed what happens when you inject this stuff into the stratosphere. What we’re talking about doing would basically be equivalent to, to, to an artificial Mount Pinatubo eruption every three years. 

We would have to do this every three years to offset the warming effect of the carbon pollution we’ve already generated. Um, and again, uh, that, you know, there would be all sorts of potential unintended consequences. 

It could dry out the continents by slowing down the hydrological cycle, and we would be addicted to it, right? It’s like methadone, once you start doing this as a way to offset the increasing concentration of carbon pollution in the atmosphere, you’re, you’re sort of, you’re, you’re addicted to it.  You can’t stop doing it because if you do, then you will realize all of that warming that had been hidden by this series of interventions, 

Smerconish: And I guess along the way, you would provide a disincentive for carbon polluters to change their ways. That’s really the big fear at the same time. True?

Mann: Yeah, that’s exactly right. Michael. This is one of my greatest concerns there. There are really two kinds of concerns. One is just about the potential impacts it would have if we do this, and that’s what we’ve been talking about here. 

But then there’s sort of the moral hazard, as we call it. If we hold this out there as sort of a get outta jail free card, uh, then, you know, it’s, it becomes an excuse for continued business as usual. And indeed, it’s not a surprise to me that former, uh, CEO, uh, of ExxonMobil world’s largest, uh, publicly traded fossil fuel company, Rex Tillerson once famously said, you know, that, uh, yes, we, we, we should do something about climate change. It’s an engineering problem. 

Basically, he was articulating the case for geoengineering. And it’s understandable if we can hold out this sort of techno fix, um, and say, look, we can implement this down the road. We can solve the problem down the road. It just becomes an excuse for polluters to continue to extract, um, and sell and, and ultimately burn, uh, these fossil fuels that are creating this problem in the first place. 

Smerconish: Dr. Michael Mann is the presidential distinguished professor and director of the Penn Center for Science Sustainability and the media at the University of Pennsylvania. 

[Advertisements and announcements]

Smerconish: Dr. Mann, I have balloons and UFOs on the brain. So as I’ve been listening to you, it made me think of air rights and airspace and the big question, who decides? So, okay, you’re making a logical argument here as to the answer to the question of what could possibly go wrong, a lot of things, but who’s to say that scientists somewhere around the globe don’t decide to take this on themselves? 

Mann: Yeah, that’s exactly right. This is one of the concerns, and there are people here at Penn actually who are sort of studying, um, the governance issues, uh, behind geoengineering. If nothing else, we do need to establish some governance here because of the danger that some rogue actor, even if we sort of collectively decide, we don’t want to go down this road, what as you allude to, is to prevent some rogue actor, um, say, you know, a country like Pakistan or India that is already suffering severe consequences, uh, from the warming that they’ve experienced. What’s to prevent them from unilaterally, um, engaging in geoengineering

And then the question becomes, who gets to set the thermostat? I can tell you, in my home, there’s just three of us, my wife, my daughter, and me, we have enough trouble deciding where, uh, we want the thermostat to set. Imagine 8-billion people competing to determine where we set the thermostat, that that is a slippery slope that we’re going down. If we, if, if we, you know, um, really start to consider engaging in geoengineering. 

Smerconish: So, uh, I’m, another of my naive questions: Is anyone, uh, I’ll just express it as stupidly as I’m thinking it, making it rain now. I mean, there’s drought in different, different parts of the world brought on by climate change. Is anyone seeking to do something about it in lines with the geoengineering that you and I are discussing? I mean, in a very isolated instance, not with an eye toward reducing planetary temperature, but rather, and we gotta water the crops and we can make it happen. 

Mann: Yeah, and you know, we saw this in, in the United States. We’ve seen this, um, it’s cloud seeding, uh, right. You know, there are out west, you know, farmers are suffering drought. Uh, there’s some science there that suggests that cloud seeding could work to some extent. Um, but then the question, it’s exactly the same governance question, who, if one, you know, set of farmers in, you know, one part of the west, um, starts cloud seeding to try to get as much, uh, rainfall they can out of the clouds, then that’s, you know, precipitation, that’s moisture that potentially isn’t available to other farmers who live farther down wind from them. 

And so it, it, it, it’s the same sort of, it’s a microcosm, right, for, um, geoengineering because instead of talking about different farmers in different parts of the state who are fighting to determine who gets the rainfall, we’re talking about different, uh, state actors, different nations around the world competing to determine, um, you know, what sort of climate we get. And it’s not just how warm it is, it’s what sort of atmospheric circulation and ocean currents and where there’s rainfall and where there’s drought. 

You know, we don’t even know the full impact that these sorts of geoengineering interventions could have, how it could change all of those regional patterns. And so again, the principle of unintended consequences really reigned supreme. 

Again, back to the, the title of our geoengineering chapter. Um, you know, what could possibly go wrong? The answer is everything lots. We, we have 8-billion people dependent on the stability of our climate today. 

Smerconish: I mean, what I’m taking away from you is that Mother Earth has struck a balance, and we should all be loathed to tinker with it. We’ve already tinkered with it through our carbon emissions, but to try and tinker further might exacerbate the problem. 

Mann: Yeah. You may have seen the headline just the other day. Um, some scientists talking about, uh, sending basically an object to collide with the moon, to to to a break off part of the moon to generate particles that would reflect some of the sun back. Uh, so it doesn’t strike, uh, it doesn’t warm the earth as much. 

Um, I mean, it’s almost, you know, uh, it, it it’s life imitating art. Uh, if you or you know, your, your listeners, some of them may have seen the movie Don’t Look up.  It was really a metaphor, um, for the, the climate crisis. 

And one of the sub metaphors in that film was the dangers of just that sort of, um, geoengineering where we start, we, we adopt the hubris that we can actually, um, start to play planetary engineering projects with other celestial bodies, asteroids, etc. It’s a road , a dangerous road we don’t want to go down.

Smerconish: Well, that was an excellent briefing, and I’;m really much obliged.  Thank you so much for it.

Mann: Thank you, Michael. Always a pleasure to talk with you. 

Posted in Uncategorized | Leave a comment

#CoolTheArctic presentation to ThirdAct! Vermont

Posted in Uncategorized | Leave a comment

Humanity’s Urgent Moral Imperative: Returning the Planet to a Proven Safe State

Abstract – two pages – (download the PDF at Planetary Restoration Action Group (Information)

This is the concluding paragraph … download the pdf to read the entire paper.

8. Conclusions

The ultimate goal of our endeavours is planetary restoration: returning the Earth System to a healthy state for human posterity – a state which is guaranteed safe, sustainable, biodiverse and productive. Such a healthy state can only be guaranteed if it is close to pre-industrial norms. But planetary restoration will be impossible without reversing the most dangerous trends, which are apparent in the Arctic.

The problem we set ourselves was to find plausible methods for addressing the major crises emerging as a result of an accelerated Arctic meltdown. These crises could potentially manifest as abrupt and catastrophic climate change, sea level rise and multi-megaton methane release. The necessary action to quash these crises turns out to be nothing less than a refreezing of the Arctic: offsetting the heating that has resulted from lost albedo; cooling the Atlantic and Pacific water which continues to inject heat into the Arctic; restoring the sea ice whose retreat has boosted methane emissions; halting the ice mass loss from the Greenland Ice Sheet. We recommend a judicious combination of albedo enhancement, radiative cooling and physical constraint. But albedo enhancement using stratospheric and/or tropospheric aerosols turns out to be absolutely essential to provide the necessary basic cooling power if we have done our engineering assessment correctly. These techniques are commonly referred to as Solar Radiation Management (SRM).

With so much at stake, every effort has to be made to ensure a successful stabilisation of the Arctic situation. This is a huge operation which will require, for a decent chance of success: multinational collaboration; brilliant management; detailed planning; independent evaluations; multiple skills and expertise; and careful use of the resources available, since they could be a limiting factor for some techniques.

Parallel development of alternative technologies should be encouraged and parallel deployment allowed where there is no interference. For example, different MCB techniques could be applied in different areas of the ocean at the same time as SAI is deployed in the stratosphere.

However our assessment of the engineering techniques shows a wealth of expertise and ingenuity for tackling the problems. It suggests that there is a good chance of overall success if given proper backing for development and deployment, with appropriate systems for safety, monitoring and continuous evaluation.

But public opinion is heavily against SRM. Here are the predominant arguments against SRM:

• SRM is intrinsically dangerous. However, the proposed SRM methods are all based on naturally occurring processes which cool the planet’s surface without adverse side-effects. Additionally, much research has gone into identifying possible risks; and top modellers say that these risks can be circumvented or mitigated by appropriate careful application and monitoring.

• SRM is dangerous because, when stopped, the temperature will rebound – this is known as the termination problem. However, we urge that the levels of greenhouse gases in the atmosphere are reduced in parallel with the application of SRM, so that no such rebound is possible. SRM can be regarded as a stop-gap in this sense.

• SRM is morally wrong, because it allows polluters to continue polluting – it is a “get out of gaol free” card. This is the so-called “moral hazard” argument. However, reducing emissions is not going to save the Arctic, and saving the Arctic is not going to affect emissions; so that does not seem to be a valid argument.

• It would be morally wrong to rely on SRM when it is politically unacceptable, and so the world should prepare for what will happen without SRM – e.g. a metre of more of sea level rise this century. However the starting point should be what is possible from engineering considerations and what has to be avoided. If SRM is necessary to avoid passing points of no return leading to inevitable catastrophe, then this fact has to be faced by the international community. One such catastrophe would be the sudden destabilisation of major Greenland glaciers, with avalanches of kilometre-size chunks of ice leading to tsunamis and abrupt sea-level rise – complete disintegration of the Greenland Ice Sheet would produce 6-7 metres of sea level rise.

• SRM threatens biodiversity. However the opposite is true. For example refreezing the Arctic will help to preserve wildlife such as polar bears.

Although one could restrict SRM to application in the Arctic only, in order to avoid some of this criticism and acrimony, we have found that more globally applied SRM will almost certainly be necessary for refreezing the Arctic. On closer examination, global SRM could have huge benefits besides refreezing the Arctic, especially as regards sea level rise and reducing flood events.

• Countries like Bangladesh and mega-cities like Calcutta and Shanghai which lie on huge river deltas are already suffering heavily from a combination of sea level rise produced by ocean expansion and tidal surges produced by storms. Both sea level and storm intensity have risen due to global warming; global SRM would reverse these two trends.

• Over a billion people at mid and low latitude rely on meltwater from glaciers and their lives and livelihoods are threatened by glacier retreat. SRM applied at these latitudes would help to save these glaciers and prevent disastrous water shortages.

A basic requirement for planetary restoration will be SRM to reduce the global mean temperature below 0.5C, halt glacier retreat worldwide, and reduce intensity of tropical storms.

Complete planetary restoration, including a halt to sea level rise, is a realistic prospect to benefit future generations by returning the planet to a proven safe state.

Link to the 33 page PDF paper

Posted in Uncategorized | Tagged , | Leave a comment

Follow-up email to California Governor Gavin Newsom’s COP26 delegation

Posted in Uncategorized | Tagged , , , | Leave a comment

My email to California Governor Gavin Newsom’s COP26 delegation

Posted in Uncategorized | Tagged , , | Leave a comment

Tell World Leaders at COP26 to Unite Now On a Climate Restoration Action Plan!


Posted in Uncategorized | Tagged , , , , | Leave a comment


COP26: October 31-November 12, 2021page1image28826176


Posted in Uncategorized | Tagged , , , | Leave a comment

Sir David King – Climate repair: Three things we must do now to stabilise the planet

The Conversation – August 12, 2021

Posted in Uncategorized | Tagged , , | Leave a comment

Letter to the Editor: Response to David Keith’s Opinion

Reference to original New York Times October 1 Opinion

The following letter is in response to the Opinion posted a few days ago.

Dear Editor,

If you can remember “Houston, we have a problem,” it is time to start shouting “Mother Earth, we have a conundrum!” We have several do or die remedies for our predicament, but politicians, scientists and activists emphasize only one: decarbonization that relies on energy efficiency and renewable energy. 

Unfortunately, difficult realities and decisions confront us.  Geoengineering and removal of carbon from the atmosphere are suggested to be both mutually exclusive and complementary emergency remedies in David Keith’s October 1 NY Times Opinion.  I agree with the latter: i.e., both are necessary.

Some fear a “milky-white sky” while humanity’s very existence hangs in the balance if we don’t face what has become obvious, that an interim emergency tourniquet or CPR-type intervention is needed to avert our demise until long term prescriptions take effect to restore a vibrant healthy Mother Earth.

Reducing emissions and removing legacy emissions will not rescue us from the climate emergency.  The transition to climate stability will not be completed for at least several decades without geoengineering. 


Posted in Uncategorized | Tagged | Leave a comment

What’s the Least Bad Way to Cool the Planet – True/False answers

Posted in Uncategorized | Tagged , | Leave a comment