Sep 14, 2023 · 46m · catalyst
Stopping geoengineering, by accident
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gold bands on the timeline = statements, start to end. Hover to read, click to jump. CC turns on captions
Host Shayle Kann and climate scientist Dr. Dan Visioni discuss how international maritime clean fuel regulations inadvertently halted a decades-long solar geoengineering experiment, unmasking regional warming in the North Atlantic and providing crucial insights for future climate intervention governance.
How this conversation actually went
Every chapter scored 0–10 on four independent dynamics. Hover any point for the reasoning behind the score. Shayle holds 17.1% of the talking time here. How this is scored →
Shayle as informed peer 5.4 Guest teaching 6.3 Guest disagreement 1.4 Shayle pushing back 1.4
speaking balance: gold is Shayle, purple is the guest (3 minute bins)
Sharpest disagreement ▶ 37:40 Dan critiques climate scientists dismissing regional effects
Dan pushes back against mainstream climate scientists who dismiss shipping emissions impacts without conducting thorough detection and attribution research.
Hardest push from Shayle ▶ 39:32 Shayle probes stagnation in geoengineeringShayle challenges the field's trajectory by asking if real-world research has stalled due to regulatory paralysis and political controversy.
Biggest teaching moment ▶ 16:25 Pinatubo stratospheric forcing vs human tropospheric emissionsDan details how 15 megatons of volcanic sulfur in the stratosphere caused cooling equal to 120 megatons of industrial surface emissions due to differing atmospheric lifetimes.
Shayle holds their own ▶ 26:48 Shayle extrapolates 10x warming trajectory from sulfur phaseoutShayle demonstrates strong technical understanding by projecting how removing the remaining 90% of global industrial sulfate emissions could compound regional and global heating.
the scores for every segment, with the reasoning behind each
| Chapter | Topic | Shayle as informed peer | Guest teaching | Guest disagreement | Shayle pushing back | Why |
|---|---|---|---|---|---|---|
| Latitude Media Rebranding and Upcoming Climate Events | 0 | 0 | 0 | 0 | Executive editor Stephen Lacey delivers a solo promotional monologue announcing the Latitude Media rebrand and upcoming conferences. | |
| Episode Teaser: The Unintended Geoengineering Experiment | 5 | 6 | 1 | 1 | Shayle frames the episode around the unintended geoengineering experiment of shipping emissions, while Dan outlines cloud condensation nuclei theory. | |
| Why the North Atlantic Is Uniquely Susceptible | 6 | 7 | 1 | 1 | Dan explains why marine stratocumulus clouds over low-albedo oceans are uniquely susceptible to droplet sizing and brightening, with Shayle synthesizing the key takeaways. | |
| Comparing Shipping Emissions to Volcanic Eruptions | 6 | 8 | 1 | 1 | Shayle introduces the volcanic aerosol comparison, prompting Dan to explain the contrast between short-lived tropospheric sulfur and stratospheric persistence from Mount Pinatubo. | |
| The 2020 IMO Rule and Quantifying Radiative Forcing | 6 | 8 | 2 | 2 | Dan provides granular figures on the IMO sulfur rule reduction and CERES satellite radiative forcing measurements, noting how natural variability complicates simple temperature attribution. | |
| Sponsor Break: Bloom Energy, Engie, and EnergyHub | 7 | 7 | 2 | 2 | Shayle pushes on the unintended trade-offs of air quality regulations and asks whether cleaning the remaining 90% of emissions could have a tenfold warming effect, leading Dan to discuss aerosol masking. | |
| Lessons from Shipping for Deliberate Solar Geoengineering | 7 | 7 | 2 | 2 | The dialogue explores deliberate solar geoengineering and how unintentional shipping cutbacks define safe thresholds for future outdoor experiments. | |
| The Current State of Global Geoengineering Governance | 6 | 7 | 2 | 2 | Shayle questions whether the geoengineering field is stagnating, and Dan counters by pointing out growing international governance discussions and arguing against premature physical experiments. |
Statements from this episode (12)
Visioni: Smaller cloud droplets create brighter, more reflective clouds
“If you have more cloud nuclei, so particles that allow this coagulation, this condensation to happen, the more nuclei you have, the more this water vapor that condenses is distributed across more nuclei, and so you have smaller water droplets. And the optical …”
Visioni: Decades of literature showed shipping emissions brightened ocean clouds
“There was a very strong suggestion in the literature for decades about the fact that shipping, ah, was making clouds brighter. Burning from shipping was making clouds brighter, especially over the North Atlantic and in general over the oceans.”
Visioni: North Atlantic clouds were the perfect target for aerosol brightening
“The ones in the North Atlantic, the clouds in the North Atlantic, tended to be the perfect target where these aerosols would reduce the size, and there were a lot of them. There were a lot of shipping tracks.”
Visioni: Mount Pinatubo injected 10 to 20 megatons of stratospheric sulfate
“Pinatubo happened in 1991. It released anywhere between 10 and 20 teragrams. That's megatons. So that's a million of tons of sulfate in the stratosphere. We called that a big number, but it just released it once, and it had an effect for a couple of years, and…”
Visioni: IPCC estimates surface aerosols masked 0.3 to 0.4°C of warming
“Right now, the IPCC estimates that aerosol emissions from the surface have probably hidden a small fraction of the overall global warming, probably 0.3 to 0.4 Celsius. Whereas Pinatubo itself, just by that outburst of that tiny fraction of sulfate compared to …”
Visioni: IMO 2020 cut shipping sulfate emissions by 7-8 megatons
“But so we, the estimate for now is that there was probably a reduction of around seven to eight megatons of sulfate emitted less from shipping. That's 10% of the overall emissions right now of sulfate from the whole world, from anthropogenic emissions.”
Visioni: IMO 2020 sulfur cuts added roughly 0.05°C of global warming
“There's a few course estimates that, just based on Earth's sensitivity, say, suggested, says probably Alf, a 10th of a degree overall of increased warming.”
Visioni: Halting all human emissions immediately would cause near-term global warming
“We know that if today, if tomorrow morning there were no more anthropogenic emission of anything at all in the world, The main impact that we would see in the first decade, it would be a warming, because this aerosol effect that is masking part of the warming …”
Visioni: Global bodies like White House and UN published geoengineering reports
“In the last year, there's been a lot of advances in bringing the conversation around geoengineering to a more global public, right? There's been plenty of reports from very influential places. The White House has had a report, the OSTP, the Office of Science, …”
Visioni: Unintended shipping aerosol drop reveals safe threshold for geoengineering experiments
“This example of the shipping regulation should really be Can really tell us a lot about this, right? So, because we're, we are claiming that this effect is maybe there, but it's small, and a lot of climate scientists are sort of saying already, in a way, befor…”
Visioni: Planet-altering geoengineering deployment is extremely unlikely in next decade
“Whatever happens, we're not doing, we're not going to change the planet in the next decade. There, we just, there's no upside. There's, it's extremely unlikely.”
Visioni: Geoengineering research should rely on modeling over small-scale experiments
“When it comes to the kind of discussion that we need to be having right now, I am a bit skeptical about how much small-scale experiments could move the needle. Whereas, I think that once we're going to go to the point where we've sort of gotten enough people o…”