02 March 2023 |

Trial balloons for geoengineering


When I wrote a short newsletter titled “What geoengineering is good?” six weeks ago, I didn’t imagine the discourse around that question would accelerate as much as it has since.

Fast forward to now. The conversation around geoengineering, particularly solar radiation management (‘SRM’), has shifted to the forefront much more quickly than I anticipated:

  1. The startup Make Sunset is actively planning tests to release sulfur dioxide into the atmosphere in the U.S. via helium weather balloons. The firm recently debuted its efforts in Mexico (much to the chagrin of the Mexican government). 
  2. Researchers in the U.K. also launched a geoengineering test flight last fall, though it managed to skirt media attention until now.
  3. Gernot Wagner – a staple of climate tech conversations – recently penned a piece in the Washington Post arguing that we need to at least research and study SRM more.
  4. First-of-their-kind test flights are being conducted in the U.S. to gather baseline data to research solar geoengineering.
  5. George Soros and other prominent high-net-worth individuals are starting to throw their weight behind SRM

Solar radiation management refers to a variety of things. Most of the above list of updates refers to the intentional release of chemicals into the air to reflect the sun’s rays. This can be done by weather balloon or by plane. But it also already happens all the time, whether from burning fossil fuels or aerosol emissions from ships

Many other things also already reflect solar radiation to keep the planet cooler. Snowpacks in the arctic are one example. Snow has a high ‘albedo effect,’ referring to its reflectivity. And aerosols and particulates from pollution also counteract warming. By some estimates, absent sulfur dioxide emissions over the past centuries, the Earth would be 0.5° to 1.5° C hotter!

In short, humanity and nature alike already contribute actively to solar radiation management. It’s just all been an inadvertent byproduct of business as usual in humanity’s case (and one that, to be sure, has other more negative consequences). If we cleaned up our act and stopped geoengineering by putting aerosols and particulate matter into the air, it might accelerate global warming even further. 

Which feeds back into the SRM question. Should we be exploring ways to keep aerosols and particulates in the air, in some areas, to reflect the sun’s rays? 

Dirt cheap… maybe

The fact that solar radiation management has already helped keep global warming at bay emboldens some of its proponents. Another factor emboldening companies and would-be investors in SRM is its cost. By some estimates, SRM could drive 1°C of global cooling for as little as $10B. That’s an oversimplification, sure, but the order of magnitude is important. 

In contrast, it costs $500+ to remove one tonne of CO2 from the atmosphere with currently available direct air capture methods. To remove 1 billion tonnes – still only one week’s worth of global greenhouse gas emissions – you’re looking at a tab totaling $500B.

Of course, other externalities and costs from performing global solar radiation management would likely eclipse the purely financial price of spraying sulfur dioxide into the air. The Earth’s climate is one of the most complex systems imaginable; alter it significantly (as we have been with greenhouse gasses), and you have no idea what might happen. 

And it’d be hard to predict where the climate would change most. Some folks, like Soros, would like to see efforts focused in areas like the Arctic. But there’s no telling how localized that would keep its impact. 

If you get an average of 1°C of global cooling from SRM, you could see more extreme swings in different local environments. That could irreparably harm industries like agriculture in unforeseen ways, whether by shifting local rainfall patterns or mega-systems like the Indian summer monsoon. Another study of one potential SRM application found that it could drive significant cooling in the Antarctic (desirable), but could cause dryness in the Amazon (not so desirable). 

In sum, similar to climate change itself, there’s no way to know what the ‘all-in’ cost of solar radiation management would be. Which makes it incredibly risky at really any serious scale.

Zooming out, we’re still a ways (decades, maybe only years?) away from a point where companies are conducting serious solar radiation management, whether by weather balloon, plane, or other mechanisms. You’d need entirely new regulatory frameworks to facilitate that, and, as we’re seeing with the carbon removal industry, that’s no small feat.

A weather balloon sans sulfur dioxide (via Shutterstock)

We’re going trial ballooning 

Many other folks have written about geoengineering and solar radiation management this week. I enjoyed many of those articles and found them informative. Especially Dr. Volts podcast. The important content questions and considerations include:

  • What are the most critical areas of research, e.g., ones that underpin geoengineering theories but that would be beneficial to study for other applications? E.g., how readily are aerosols already impacting the climate?
  • There’s a worthwhile argument about moral hazard, too. Even if you could find surefire ways to cool the globe, wouldn’t that derail decarbonization efforts?
  • Given both of the above, how to scale (and fund) geoengineering research responsibly.

But I’m ultimately more interested in the context of all this than the content. For now.

The recent explosion of articles and press surrounding solar radiation management is the context. It is its own important form of trial balloon, where ‘trial balloons’ refer to media intended to gauge reaction to ideas, proposals, or policies. 

Entities like Central Banks use these all the time. When George Soros gets up at a conference and talks about why he’s interested in SRM, or when the Washington Post publishes an article on why we should be studying it, and these things happen concurrently, I perk up as someone who moonlights as a media analyst, not just as a climate analyst. 

Trial balloons in media, academia, and on speaking circuits pave the path for trial balloons in the atmosphere. One day you wake up and there’s a bit more conversation about something like SRM. Fast forward three years, and suddenly, it’s in the mainstream, much in the same way carbon removal is a hot topic now but wasn’t five years ago. 

Nor does the public reaction to trial balloons even matter that much. Most people’s reaction to solar radiation management seems to run along the lines of “that’s crazy and irresponsible.” Especially when you ask environmental scientists

What matters is that trial balloons cement things in conversation and cultural consciousness. No one’s seeding solar radiation management businesses with capital yet. But, institutions and influential people are seeding it as the ‘current thing.’ 

The net-net

Here’s a hot take. By 2030, companies and governments will be spraying solar radiating chemicals into the air on purpose. Perhaps not en masse, but they’ll build capacity for larger deployments while suggesting they’re saving that for when it’s “absolutely necessary.” 

This won’t all look like sulfur dioxide. There are other techniques for SRM (shoutout to the space mirror crowd). Nor will it even be all about SRM. As heated debate over SRM persists, it will make other geoengineering efforts – whether carbon removal, genetic engineering of crops or microorganisms, or other things I haven’t seen – more palatable in comparison.