Stratospheric Aerosol Injection: Earth’s Last Chance Dance?
What’s our path as global warming accelerates?
As the planet warms ever faster fueling longer, hotter heat waves, tinder conditions for record-breaking wildfires, and rainstorms that deliver months or even a year’s worth of rain in hours, when do we reach the point of desperation? From the record setting fires of Canada this year (40.77 million acres destroyed, 232,000 forced to flee) and Greece (800,000 acres carbonized in the Evros fire alone in late August and 19,000 evacuated in a single July event), to the killing summer long heatwave in the south and western US, living conditions for people in every part of the world are becoming ever more precarious and deadly. Phoenix alone withered under temperatures reaching 110° F (43.3° C) for a record 55 days this year, with an all-time high of 118° F (47.78° C) on July 15. 194 heat related deaths in the city have been confirmed, with 351 more under investigation.
Evacuations in Greece have continued even as the country’s summer of devastating wildfires finally dwindle. Storm Daniel brought devastating flooding, 25” of precipitation to a wide region around Athens in just 24 hours. Athens's rainfall averages just 16” annually. More sickeningly, Daniel caused the stunning deaths of at least 11,300 Libyans in the Mediterranean port city of Derna, former population 90,000. Over 10,000 are missing and 25 percent of the city was destroyed, as water reached the fourth floor of buildings and entire neighborhoods were washed out to sea. Corpses are floating back to shore by the dozens. We are now daily victims of weather events that would have been impossible just a decade ago. It’s destroying homes, communities and livelihoods, creating mass evacuations and shrinking our inhabitable world.
It’s reasonable to argue we have been experimenting with the Earth’s atmosphere ever since burning the first lump of coal in the earliest days of the industrial revolution. Now that we have wrecked our planet with greed and corruption that fueled the cover-up about the truth of fossil fuels, will we be forced to experiment further in a desperate attempt to save ourselves?
This is an increasingly likely scenario as we fall well short of reducing our carbon and methane emissions. For your consideration, there is a controversial idea in parts of the scientific community, a global climate experiment based on the concept of Solar Radiation Management (SRM), a plan to control global warming by deliberately injecting particles into the atmosphere through Stratospheric Aerosol Injection (SAI). Specifics of this proposed technology can be found in a brief article here.
The Case For Stratospheric Aerosol Injection
During the Covid lockdown, it was observed that the corresponding reduction in smog resulted in clearer skies. The Himalayan Mountains became visible from northern India for the first time in 30 years, and city skylines were freed of haze from Jakarta, to Los Angeles and Paris. However, global warming increased during this time of lower emissions.
It has also been observed that volcanic eruptions cool the planet, as a result of particles in the atmosphere that reflect heat back into outer space. This was observed in the 1991 eruption of Mount Pinatubo in the Philippines, the second-largest volcanic event of the 20th century. Satellites tracked the ash cloud as it traveled several times around the globe. Airborne measurements of sulfur dioxide (SO2) from May 13 to May 28 increased from 500 metric tons to over 5,000 metric tons per day.
It was estimated 17 million tons of SO2 gas were injected into the stratosphere by Pinatubo. An aerosol of tiny sulfate droplets and extremely fine volcanic dust, encircled the globe in about three weeks and reduced solar radiation reaching the Earth’s surface. This layer of haze in the stratosphere which diminished over the next three years caused an average cooling of 0.7 °F (0.4 °C) of Earth’s temperature during 1992 and 1993.
These two events, the Covid lockdown and Mount Pinatubo give solid evidence that aerosols or particulates, we can consider the words interchangeable, cool the planet. Ironically, as air got healthier to breathe during Covid, the reduction of particulates hastened global warming.
These observations (and undoubtably others) explain the thesis for SAI. Those who promote the idea point out we are likely to blow past the IPCC’s critical recommendation of holding warming to 1.5° C (their most recent report here). I agree with that. In fact, it’s becoming likely we will exceed that number this year. It may waver up and down for a few years, but will inevitably exceed 1.5° C permanently, and we already well see the effects of the #ClimateEmergency below that number.
With numerous tipping points in motion from the melting of the Greenland and Arctic ice sheets, to the slowing of the Atlantic Meridional Ocean Current (AMOC), the dangers of melting permafrost in the northern boreal forests, and depleted buffer of the Amazon rainforest, it may be that we’re approaching the point of being forced to take radical action. Once one tipping point falls, there could be a cascade, and we won’t know the precise day the first point will have tipped. It’s possible it’s already happened. Proponents of SRM and SAI build their case on these unnerving realities. It is also pointed out that SAI is fairly inexpensive, straightforward to deploy, and could facilitate rapid global cooling.
From PNAS, Proceedings of the National Academy of Sciences, a peer-reviewed multidisciplinary scientific journal:
To possibly grant humanity additional time to sufficiently reduce greenhouse gas emissions, lessen the existing negative impacts of climate change, and avoid transgression of irreversible tipping points, there is renewed interest in developing an international research agenda on solar radiation modification (SRM)—a speculative form of climate change response that has the potential to offset human-induced warming by reflecting a small amount of solar energy back to space before it enters and warms the planetary environment.
The Case Against Stratospheric Aerosol Injection
Tidy computer models can estimate overall planet cooling from injecting particulates into the stratosphere. They can’t however, predict local and regional effects with accuracy. Filling the stratosphere with aerosols whatever the delivery device, balloons, airplanes, or benevolent climate fairies from heaven taking pity on us, elicit huge uncertainties.
Essential questions we must ask about SAI:
Who makes the decision to attempt geoengineering the atmosphere? How do we arrive at an international consensus?
What might the masking effect be? Will temporary cooling lead us to underestimate the greater driving forces of global warming that are fundamental to address? Would this cause us to delay or not address them?
Would the cooling effect of SAI be used as a license to continue burning fossil fuels indefinitely?
Could masking global warming lead to a scenario where cessation of SAI from its perceived success caused a sudden and catastrophic rise of global temperatures?
Could a time lag of perceived benefits and unintended adverse effects halt the program, resulting in a sudden and that catastrophic rise of global temperatures from masking?
How would this climate intervention drive changes in essential Earth system processes?
Would the unknown specific consequences arising from SRM disproportionately impact populations already more harmed by climate change?
Could this path increase crop failures rather than stabilize our threatened agriculture?
If volcanic eruptions happened during SAI, what hazards could that create?
Would future generations be hostage to this technology to stay alive?
What particulates will be chosen, and what could their health consequences be?
Could war, particularly nuclear, become an increased threat from potential unequal benefits and unintended negative outcomes?
Additionally, basic scientific questions about how to distinguish the climate effects of SRM from anomalies driven by the variability of the Earth herself raises more issues. For instance, how will identifying the frequency of extreme hot and cold spells, the severity of drought, the path of the mid-latitude storm tracks, changes in regional temperature and precipitation, the state of Arctic Sea ice, or the strength of tropical modes of variability such as the El Niño Southern Oscillation be measured against natural variability? Sorting out this data poses numerous challenges that could be subject to disagreement. Add the inevitable wildcard of politics and money, the usual maneuvering for world domination, and further distortions outside reasonably debated science seem likely.
SAI is a strategy to release particles into the stratosphere that slow, pause, or reverse global warming. Climate simulations provide evidence that the long-term result of SAI could lead to stabilized global temperatures. However, the regional temperature and precipitation impacts of SAI will likely vary unpredictably. Natural climate variability may mask the short-term perceived effectiveness of SAI as well. While SAI could successfully stabilize mean global temperatures, the perceived effectiveness on regional scales may be overwhelmed by local climate variability in the short term.
Unfortunately, there are dangers associated with stratospheric aerosol injection. This approach may reduce rainfall in some areas of the world. Loss of crops and access to fresh water due to reduced rainfall could lead to starvation and suffering.
People’s relationship — belief or non-belief of climate change is generally dependent on its direct, local effects. I am keenly aware of my good fortune to live in an area of the northeastern US that has largely been spared some of the worst effects of the crisis to date. Local conditions in climate such as continued warming or additional extreme events may cause climate SAI to be perceived as a failure. This could lead to abruptly halting SAI and increase the possibility of even more rapid climate change because of masking effects if the root problem of increasing global warming gasses are not addressed. Perception of failure, real or not, on a regional scale carries global risks.
Again, from PNAS:
We found that while global temperature was stabilized, substantial land areas continued to experience warming. For example, in the SAI scenario we explored, up to 55% of the global population experienced rising temperatures over the decade following SAI deployment and large areas exhibited high probability of extremely hot years. These conditions could cause SAI to be perceived as a failure. Countries with the largest economies experienced some of the largest probabilities of this perceived failure.
From Frontiers, another peer-reviewed scientific journal:
Thicker SAI masking extreme warming could create a planetary Sword of Damocles. That is, if SAI were removed but underlying greenhouse gas concentrations not reduced, there would be extreme warming in a very short timeframe. Sufficiently large global shocks could force SAI termination and trigger SAI's latent risk, compounding disasters and catastrophic risks.
Could the risks of large-scale solar geoengineering be worse than the dangers posed by climate change? Many concerns have been expressed over geoengineering the Earth's climate. These tend to centre on solar radiation management (SRM) methods, particularly stratospheric aerosol injection (SAI). These range from fears over negative unintended effects on ecology, political conflict, mitigation deterrence, to ethical objections. Given the breadth of objections, it is quite clear that SAI would be iatrogenic in some way. Like some medical interventions, SAI may have adverse side-effects [sic] and complications. The question is whether it could be worse than the problem it is seeking to remedy: climate change.
I was encouraged to write this article by interaction with people who share my deep concern, perhaps I should say fear, about the #ClimateEmergency on my Twitter replacement, Mastodon. One person strongly advocated for SAI as soon as possible. I can’t dismiss all of his arguments, particularly the idea that at some point even the radical action of SAI will be ineffective, given the growing power of the climate changes we are experiencing. As a non-scientist, I can’t give an opinion about when to deploy this technology. I certainly don’t want to see the situation come to that. I can say with confidence, however, every day brings us closer to taking this risky path, likely filled with unintended, negative, unpredictable consequences.
All around the world, leadership is failing to address the root cause of global warming, the continued reckless burning of fossil fuels. The 28th meeting of the United Nations Climate Change Conference, COP 28 is just a little over a month away, being held in the United Arab Emirates and led by Sultan Ahmed Al Jaber, who is also managing director and group CEO of the Abu Dhabi National Oil Company. I am hardly filled with confidence.
This weekend, a worldwide protest of fossil fuels is taking place. The participants will likely be vilified for trying to protect their futures and those of their children. Some will be arrested and serve time, as laws against public demonstrations are being turned into felonies, particularly anything to do with fossil fuel infrastructure. I encourage you to do everything in your power to support the brave people speaking to power and putting their bodies on the front lines.
We are truly at the make-or-break point for our future on Earth.
I opened a window in my browser to check out bio fiber in the morning, thanks. As to the Dyson sphere, call me a Luddite. Everything we need is here on Earth. We evolved here with her. There will never be a more perfect home for us. The sun won't burn us up for a billion years, so there is really no need if we simply take care of what we have. I mean, does any species last for a billion years? Highly improbable.
Hugging the ones you love and random acts of kindness should always be encouraged.
I, too, am pessimistic about our future. Or perhaps just realistic. 6,000 years of supposed civilization where we continue to hate and kill each other, inventing more effective ways the whole time. At this moment of existential threat posed by climate change, we are still unable to unify. That reality is so awful, that I am certain I don't completely grasp it, even if I know it intellectually.
There's a part of me that thinks it's all quite deliberate.
https://geoffreydeihl.substack.com/p/circumstantial-evidence
I know I’m three years late to the party, but the closest analogy I can come up with for using SAI and continued use of fossil fuels is the equivalent of a diabetic taking metformin while making no lifestyle changes. You treat the symptoms without solving the problem.
The problem is that a buildout of energy infrastructure necessary to move away from fossil fuels requires a huge upfront investment using these carbon based fuels. This is where my analogy fails.