Stormfury

Hi there,

Last week, I penned a case for why it’s time to get a lot more serious about geoengineering. Today’s piece expands on that argument and offers a taxonomy of 13+ geoengineering approaches (many are categories) for which humanity should not just do R&D, but should advance scalability work. 5,000 words below (on the dot, sorry).

Many thanks to Keep Cool friend Kiran Kling for offering suggestions on this one. 

♡ If you find this work valuable, you can support it here. I put a lot of time into it. ♡

DEEP DIVE

I’m writing more about adaptation, including geoengineering, now. As much as data centers and load growth are the big stories hogging headlines right now, alongside nuclear fission to provide more clean electrons, my bet is on a lot of attention flowing to geoengineering in 2025. I don’t have a source or a long list of arguments to make to support my hypothesis. I’m reading tea leaves. That said, adaptation is more of a necessity now than ever, well, 50 years ago, we had time to mitigate climate change more meaningfully. Now, we may not.

As we’ll explore, more warming is coming. If you think the climate is getting weird now, sorry, relief isn’t coming soon. Can the world limit warming to, say 2°C without geoengineering? Not unless efforts to mitigate greenhouse gas emissions accelerate dramatically in short order.

Turning the page, geoengineering isn’t new. More than fifty years ago, the U.S. government was doing more cutting-edge geoengineering research than many folks (including myself until recently) may realize. Project Stormfury was a U.S. government-led scientific experiment conducted by the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Navy from 1962 to 1983. The project aimed to weaken hurricanes by seeding their clouds with silver iodide, a substance known to induce cloud formation by causing supercooled water droplets to freeze.

Today, similar technology is being explored by startups, not to wear hurricanes out before they make landfall (at least not yet), but to perform cloud seeding operations to bring extra rain to regions or clients that need it, whether they're drought-stricken areas, farms, places facing wildfires, or other.

I raise the Project Stormfury example for the scope of its aspirations. That the U.S. government invested significant capital and twenty years to see if it could reduce the intensity of hurricanes by disrupting their inner structure speaks to a level of ambition that many think our government now lacks, at least, and perhaps especially, as it pertains to climate mitigation and adaptation. Scientists hypothesized that cloud seeding could expand a hurricane's eyewall, reducing the wind speeds in the core of the hurricane, and actively tested these theories. Planes literally flew into storms’ eyewall.

Several hurricanes were actually seeded, including Hurricane Esther in 1961 and Hurricane Debbie in 1969. There was some evidence that Hurricane Debbie weakened after seeding, but it could not be conclusively attributed to the experiment. As we explored a few weeks ago, attribution is perniciously tricky, whether in experiments related to weather systems or in terms of attributing any one storm to climate change. The uncertainty of the results, i.e., the inability to distinguish the impact of interventions from natural fluctuations, as well as later scientific discoveries that most clouds in hurricanes already contain a lot of ice, led to the project’s abandonment. Further, questions about the ethics of attempting to alter natural weather systems, particularly given the risk of unintended consequences, abounded.

As is often the case, while the Stormfury was discontinued, scientists learned a lot from it, whether regarding hurricane dynamics or cloud seeding. The project also underscored the complexity and unpredictability of weather modification efforts and Earth’s climate systems in general.

Geoengineering, 50 years later (and 250 years later)

This newsletter would be incomplete without explicitly calling out that human society already geoengineers on massive scales. The amount of heat-trapping carbon dioxide (CO₂) and other greenhouse gasses we have pumped into the atmosphere over centuries boggles the mind. While it can seem weird to think about the ‘weight’ of gasses, humans have added trillions of tons of CO₂ into the atmosphere since the Industrial Revolution and coal consumption really kicked into a higher gear ~250 years ago. Much of this persists today—the time CO₂ spends in the atmosphere can range from hundreds of years to thousands. 

For perspective, trillions of tons (approximately 1.5 trillion tons, specifically) is equivalent to roughly 300 billion fully grown African elephants. This figure also ignores the emission of other greenhouse gasses, ranging from methane to nitrous oxide, all of which have stronger warming effects than CO₂, pound for pound (and all of which we should allocate more resources to).

The greenhouse gas emission dynamic represents one of the most large-scale (and brazen) geoengineering efforts imaginable, especially as all of the Earth’s land, oceans, and inhabitants are intimately intertwined with the atmosphere. Our understanding of the full impacts our geoengineering will have, both in the short-term and long-term, is as of yet relatively limited, even as we get better at modeling, measuring, and parsing the many intricacies of the Earth’s climate systems. Plus, we remain deeply ‘committed’ to this centuries-long geoengineering ‘experiment;’ greenhouse gas emissions today are no lower, at a global level, than they were 5 or 10 years ago. Overall, they’re still rising, driven primarily by China and India. Suffice it to say, what will happen to Earth’s climate system is impossible to predict in full. We know it is and will continue to warm and change in other ways. How bad will the results be? Time will tell. Don’t just take it from me—climate scientists readily admit how little we know.

Greenhouse gasses are also not the only driver with which we geoengineer at scale. Land use change is another—only 5% of Earth’s land is relatively ‘untouched.’ Other forms of pollutants beyond emissions are yet another example. I probably don’t need to tell you that scientists and researchers are finding microplastics everywhere (additional reading here). We have little idea what the long-term consequences of that will be. Some likely won’t be fun. More pollution examples abound. Researchers found a beer bottle at the bottom of the Mariana Trench, one of the deepest points on the Earth.

Geoengineering is woven into the fabric of how the world supports a growing, modern society, from continent to continent.

Should we do it in reverse?

All of this raises a core question, namely whether and to what extent we should geoengineer in reverse. Should we proactively reflect more sunlight as the Earth warms? Should we paint all the roofs white? Should we learn how to make extra rain, as some countries and companies are trying to? Should we learn how to oxidize methane in the atmosphere, turning it into CO₂ more quickly, which carries lower warming potential?

You’ll already know my perspective if you read these pages regularly. To put it succinctly, I think we should definitely study most of the possible geoengineering approaches under the proverbial sun. Not because we should necessarily deploy them on large scales willy-nilly. But because:

• We may need to use specific approaches on large scales someday

• We should better understand which approaches work better than others

• We’ll invariably learn a lot more about climate science in the process

My perspective on this is also informed by how much warming is basically unavoidable at this point in the short and medium term otherwise. Because of how long-lived CO₂ is in the atmosphere, even if CO₂ emissions globally were cut by 80% tomorrow (a miracle!), the world would keep warming. Regardless of whether we start moving 5-10x faster on mitigation, we’ll experience more warming for decades to come. Other greenhouse gasses and indirect greenhouse gasses also drive warming and would need to fall in concentration, too. See below for a per-decade visualization of anticipated warming.

Climate change is incredibly complex but how CO₂ ‘works’ in the atmosphere is relatively simple. It’s a long-lived greenhouse gas—as noted, it can linger in the atmosphere for hundreds to thousands of years. More CO₂ emissions on top of existing ones translates to faster and more warming. No net additional CO₂ emissions translates to relatively constant (though still more) warming. Decreasing emissions translates to slowing warming (not cooling). Zero emissions stops warming, but still offers no cooling. (h/t Zeke Hausfather on this.)

Hence why geoengineering efforts—as well as reducing methane emissions, which would reduce warming more quickly as methane is a much shorter lived greenhouse gas—deserve their due. If and when government institutions or universities aren't taking geoengineering work on, I support private sector companies catalyzing action. 

To hammer this point home, I'll reinforce words I already used last week. You can do scalability work and research on a technology without using it. Said differently, you can prepare to deploy a solution at scale without ever actually doing so. This thinking was informed by this tweet.

A fair question to ask is whether private sector companies can do so; the need to make money invariably pushes companies towards deployment versus developing the capacity for deployment without using it. The government, meanwhile, has a track record of developing massively scaled systems without using them. Take, for instance, the U.S.'s post-WWII, multi-trillion dollar nuclear weapon armament. The U.S. has maintained and updated its atomic arsenal for 50+ years without using it outside of strategic deterrance. The U.S. did of course use nuclear weapons during WWII, but the armament discussed here really accelerated later. The U.S. and other major geopolitical players continue to spend boatloads often just to upgrade the vehicles and the personnel needed to deploy a nuclear weapon at a moment's notice, to say nothing of the weapons themselves.

God willing, no nuclear weapon is ever used again. But the point remains—technology we hope never to use gets more funding than most ‘climate’ stuff does.

Finally pre-taxonomy, it’s also worth noting a ‘war’ against warming is (probably) winnable. Arms races aren’t, as Jessica T. Mathews articulated in this recent article:

A taxonomy of geoengineering approaches

So, what the geoengineering options? Here’s a taxonomy of sorts of different geoengineering categories and approaches, all of which deserve more consideration.

This is by no means exhaustive. It’s intended to offer an entry point, an overview for additional exploration and (collaborative, open-source?) development.

1. Stratospheric Aerosol Injection (SAI)

• Concept: SAI is a specific form solar radiation management that aims to reflect additional sunlight away from Earth by spraying reflective particles like sulfur dioxide into the stratosphere. The efficacy of aerosols like sulfur dioxide at reflecting sunlight is well documented, whether from volcanic eruptions or emissions from shipping fuels. However, some aerosols like sulfur dioxide are also air pollutants that portend negative health externalities. A key R&D area is whether other particles, including newly synthesized ones, could offer the same sunlight reflectivity benefit sans the environmental and health externalities.

• Potential / certainty of directionality: Offers a way to rapidly reduce global temperatures, though the impact isn’t necessarily sustained as aerosols fall out of the atmosphere quickly, requiring consistent administration for consistent cooling. That said, ‘certainty of directionality’ is high.

• Challenges: There are many potentially significant unintended environmental and geopolitical consequences here. Environmental impacts are especially contingent on the specific particle used to achieve a reflective effect. Geopolitically, if less sunlight reaches Earth, it would invariably benefit certain regions more than others (think in terms of agriculture, for instance). That could yield fights!

• Stage: Early; this is predominantly in the R&D stage, though some companies, like Make Sunsets, are working on small deployments. Investment is tiny.

• Short-term vs. long-term warming: SAI has the potential to offer rapid coolin (think weeks, not years), which is part of why it attracts more attention in the current discourse / proverbial ‘climate.’

2. Direct Air Capture (DAC)

• Concept: Again, this is more of a category, as will be true of many entries in this taxonomy. DAC uses chemical processes to capture CO₂ from ambient air. Captured CO₂ can then be stored underground or upcycled into various applications. There are many unique approaches to DAC, as the types of adsorbents and other chemicals, as well as the machine form factors, energy inputs, and more, can all vary considerably.

• Potential / certainty of directionality: If scaled, DAC could help reduce atmospheric CO₂ levels both before and after CO₂ emissions are curbed. There’s no uncertainty in the potential efficacy; cost and scalability is the question. 

• Challenges: DAC requires a lot of energy; economic viability and storage of CO₂ are probally the mmost significant hurdles here. Today, $100 per ton of CO₂ is a vaulted goal. Even if global CO₂ emissions stopped tomorrow, returning the atmosphere to pre-Industrial Revolution levels of atmospheric CO₂ concentration would cost trillions of dollars at those prices. That said, improvements in the technology itself will likely be met by improvements in availability and reduced cost of clean electricity over time, as well as across other inputs.

• Stage: Of the geoengineering technologies, DAC is relatively advanced insofar as it has attracted a lot of capital, ranging from venture capital to government funding and committed pre-purchase revenue from major corporations. There are also active, working DAC plants in the world, though they’re small-scale in the grand scheme of things. (think 5-10k tons per year). See companies like Climeworks, Carbon Engineering, Heirloom, and many others.

• Short-term vs. long-term warming: DAC is most relevant for long-term warming. As long as CO₂ emissions continue globally, the work being done on DAC today is much more about scalability than it is about actually making an appreciable difference in warming. In the future, if and when the world reaches an emissions equilibrium, DAC could help reduce atmospheric CO₂ levels, reducing warming, though still not quickly, per se.

• More resources: I wrote more on DAC here with Jack Andreason for Keep Cool. Further, just today, Climeworks announced a long-term agreement with Morgan Stanley to remove 40,000 tons of CO₂ from the air, its second largest agreement to date. Probably a mid seven figure deal.

3. Terrestrial CO₂ Removal

• Concept: Again, this is really a category. There are dozens of terrestrially-based carbon removal approaches that aim to remove and store CO₂ from the atmosphere. I could have folded DAC under here too. Others range from planting trees to burying biomass, creating biochar (converting biomass into a stable form of carbon through pyrolysis), soil carbon sequestration, and more. There’s also BECCs, wetland and peatland restoration, mangrove restoration / planting, etc...

• Potential / certainty of directionality: Many natural terrestrial systems readily remove CO₂ from the atmosphere. The efficacy of most of the above-listed solutions is well-proven (although some somewhat more so than others).

• Challenges: There is considerable variance by approach, especially with respect to the durability / duration of how long CO₂ remains sequestered. Some are cheaper but offer less durability, while others are more expensive but offer longer / more guaranteed sequestration. As always, cost to scale is a crucial consideration, as is the observable measurability of impact.

• Stage: Various considerably. Some approaches have delivered tens of thousands to hundreds of thousands of tons of CO₂ removal successfully. See CDR.fyi for more. Others haven’t gotten to that point yet.

• Short-term vs. long-term warming: Medium to long-term warming mitigation.

4. Enhanced weathering 

• Concept: This could be a subcategory of other carbon removal categories, but I’ll break it out on its own briefly as it’s getting more attention these days. Minerals like silicate can be spread over land areas to speed up natural chemical reactions that react with atmospheric CO₂ and water to form bicarbonates and other carbon compounds.

• Potential / certainty of directionality: This is a natural process that can sequester CO₂ for millennia. As to how scalable it is with additional human intervention, there’s a lot still to learn, but it has strong potential. 

• Challenges: Crushing and distributing the rock requires significant mining and energy, and quantifying measurable effects here is difficult. Said differently, measuring impact (beyond modeling) is one of the harder challenges.

• Stage: Gaining traction (see here and here, for instance).

• Short-term vs. long-term warming: Medium to long-term warming mitigation.

5. Ocean-based CO₂ Removal

• Concept: Again, this is really a category. In general, ocean-based carbon removal refers to a range of technologies and methods aimed at enhancing the ocean’s ability to absorb and store CO₂. The ocean already acts as one of the world’s largest carbon sinks, but various approaches aim to accelerate or reinvigorate its capacity to remove CO₂ from the atmosphere. These include methods such as ocean alkalinity enhancement, kelp and seaweed farming for carbon sequestration, iron fertilization, seagrass restoration, and more. Two more R&D-stage approaches that I could have folded up into it follow as the next dedicated sections for more color.

• Potential / certainty of directionality: The ocean covers over 70% of the Earth’s surface, making it a vast area to target for carbon removal and sequestration. Enhancing natural processes to absorb and store more CO₂ could play a significant role in mitigating climate change, with benefits beyond warming, as many ocean-based carbon removal techniques could help restore marine ecosystems, protect biodiversity, support food security, and more. That said, depending on the approach, there are questions about certainty of directionality.

• Challenges: Ocean-based carbon removal techniques can also come with ecological risks, such as disrupting marine ecosystems, altering local food chains, and affecting biodiversity. Scalability is also (and always) a question, as is the observability / measurability of impact. Some methods could also create serious unintended consequences for ocean chemistry and local ecosystems.

• Stage: All these techniques are mostly in the research stage, though a few are far enough along to have formed public-private partnerships and launched real-world demonstration projects. The ocean’s complexity makes it a difficult environment for controlled interventions, and as always more research into the long-term impacts and effectiveness of solutions is needed.

• Short-term vs. long-term warming: Medium to long-term warming mitigation.

• More resources: Just today, Microsoft inked a massive deal with ocean carbon dioxide removal company Ebb Carbon for up to 350,000 tonnes of CO₂ delivered over the next decade.

On carbon removal in general, The Carbon Removal Alliance also does great work in general; check out reports they put out including a new one that dropped yesterday.

6. Iron Fertilization: 

• Concept: Iron fertilization involves adding iron to the ocean to stimulate phytoplankton growth. Phytoplankton, the base of the marine food web, photosynthesize and absorb CO₂ from the atmosphere. By adding iron to iron-deficient areas of the ocean, it is theorized that algal blooms could be triggered to absorb large amounts of CO₂. As the phytoplankton die, they could sink to the ocean floor, potentially sequestering carbon for long periods of time.

• Potential / certainty of directionality: In regions where iron is a limiting nutrient, fertilization could enhance carbon sequestration by boosting biological productivity. This method has been proposed as a potentially highly scalable way to remove CO₂ from the atmosphere. That said, many academics and scientists are highly skeptical whether it would work at all, not to mention the externalities.

• Challenges: Iron fertilization is controversial due to the potential for unintended ecological consequences. Large-scale fertilization could disrupt marine ecosystems and alter food webs. It’s also unclear how much of the carbon taken up by phytoplankton would remain sequestered in the deep ocean. Additionally, ocean currents and biological responses to iron enrichment vary, making outcomes hard to predict. 

• Stage: Early-stage research; some small-scale field trials have been conducted, not all with any authorization. A lone actor once went rogue and deployed iron to oceans in Alaska, which upset a lot of people, though it did possibly yield some ecosystem benefits, such as a boon to the local salmon population.

• Short-term vs. long-term warming: Medium to long-term.

7. Ocean Upwelling

• Concept: Ocean upwelling involves using mechanical pumps to bring nutrient-rich deep ocean water to the surface, encouraging the growth of phytoplankton and algal blooms that absorb atmospheric CO₂ through photosynthesis. Unlike ocean fertilization, this method doesn't introduce external substances.

• Potential / certainty of directionality: This approach could boost marine ecosystems and increase biological carbon storage in the ocean. The potential benefits also include strengthening local food chains, benefiting fisheries, and enhancing oceanic CO₂ sequestration on a large scale by stimulating phytoplankton, which can act as a carbon sink—less well-proven certainty of directionality.

• Challenges: Large-scale implementation could disrupt marine ecosystems, altering nutrient cycles and affecting biodiversity in unpredictable ways. Potential consequences include localized oxygen depletion (hypoxia) and ocean acidification, which would negatively impact marine life and potentially counteract other efforts, like ocean alkalinity enhancement. Additionally, as with other geoengineering techniques, there are concerns about the long-term impacts on global ocean circulation patterns and climate systems.

• Stage: Still in the conceptual and experimental stages. Small pilot projects have been discussed, but technical, ecological, and governance hurdles remain.

• Short-term vs. long-term warming: Medium to long-term.

8. Atmospheric methane removal

• Concept: Atmospheric methane removal focuses on technologies and processes that aim to break down methane (CH₄) in the atmosphere faster than it does naturally. While other methods focus on terrestrial applications, like soil oxidation enhancements, R&D for atmospheric removal focuses on the use of methane-oxidizing catalysts or photocatalytic reactions to convert methane into CO₂ or water. As a note, methane typically oxidizes in the atmosphere and turns into CO₂ anyway (roughly 90% of methane is naturally ‘removed’ from the atmosphere this way, with the rest removed by soils or tree bark).

• Potential / certainty of directionality: Methane removal could help reduce short-term warming quickly, slowing climate change while longer-term CO₂ reduction strategies take effect. It also offers the opportunity to target methane emissions from natural sources, like wetlands, as well as anthropogenic sources, such as agriculture and coal mines, for which scaling mitigative solutions has proved difficult. The certainty of directionality is unclear, though I do want to emphasize the certainty of directionality with respect to methane emissions reductions in general is very clear. Methane decays very quickly in the atmosphere, meaning large emissions reductions drive warming reductions very quickly as atmospheric concentrations would fall fast.

• Challenges: Removing methane from the atmosphere is difficult because it exists in much lower concentrations than CO₂ (~1.9 ppm versus ~420 ppm CO₂). This makes everything related to removal approaches harder. Most methane removal technologies are in the early stages of development, given uncertainty about their scalability, cost-effectiveness, environmental side effects, and whether they work at all.

• Stage: Early-stage research and experimental demonstrations. Though some techniques show promise in laboratory settings or small field trials, larger-scale methane removal is a ways off. This field is probably 5-10 years behind CO₂ removal but deserves a lot more attention.

• Short-term vs. long-term warming: All else equal, atmospheric methane removal is a much faster approach than carbon removal to address short-term warming.

• More resources: See more from Spark Climate, for instance.

9. Albedo Enhancement

• Concept: Increasing the reflectivity (albedo) of Earth's surface to reflect more sunlight and reduce warming. As with many other sections here, this is really a category. You can enhance albedo by literally painting things white, by adding other reflective materials in urban areas, increasing the reflectivity of desert surfaces, or more.

• Potential / certainty of directionality: I think of this more as a localized cooling solution for urban areas, e.g., helping mitigate the urban heat island effect. That said, we may get to a point where people pay more attention to preserving ice in polar regions for similar reasons they try to conserve forests today (the reflectivity of ice provides a quantifiable warming mitigation effect with high certainty of directionality.)

• Challenges: Global effects are likely to be limited as large-scale deployment would be extremely expensive. From an urban planning perspective, however, this category already gets attention from urban planners and the like, though it should get even more attention.

• Stage: Well understood; used locally.

• Short-term vs. long-term warming: Short-term, as close to instant as it gets.

10. Ocean Albedo Enhancement

• Concept: Similar to general albedo enhancement, a variety of techniques aim to increase the reflectivity of the ocean's surface to reflect more sunlight back into space, reducing warming and ocean heat absorption. One proposed method involves using microbubbles or other reflective materials on the ocean's surface.

• Potential / certainty of directionality: Enhancing the ocean's albedo could help reduce regional or global temperatures. It could also help mitigate other products of warmer oceans, such as more intense hurricanes, though the certainty of directionality here is quite limited.

• Challenges: Large-scale deployment could interfere with marine ecosystems, meaning it would also run into significant permitting hurdles and skepticism from environmental and conservation-oriented groups. Additionally, maintaining the albedo effect over time and on a global scale would be costly. As always, the consequences on weather patterns won't be fully understood.

• Stage: Quite early.

• Short-term vs. long-term warming: Short-term.

11. Marine cloud brightening:

• Concept: Marine Cloud Brightening (MCB) is another form of solar radiation management that aims to increase the reflectivity of marine clouds by injecting seawater or other aerosols into the atmosphere to increase the number of water droplets in clouds, making them brighter and more reflective of sunlight.

• Potential / certainty of directionality: MCB could cool specific regions of the planet by increasing cloud cover over oceans, potentially reducing the intensity of hurricanes, heatwaves, and other extreme weather exacerbated by climate change. It could offer a more localized / targeted approach compared to other radiation management methods. The certainty of directionality is very much unproven here—lot more work to do.

• Challenges: The long-term effects of MCB on global and regional weather patterns, ecosystems, and ocean health are poorly understood. There are concerns that it could disrupt precipitation patterns and marine life. As always, geopolitical considerations could get murky quickly, too, if scaled significantly.

• Stage: Early research and small-scale experiments have been conducted and more extensive pilot programs are proposed. Overall, this one’s quite early, though.

• Short-term vs. long-term warming: Short-term.

• More reading: See here and here.

12. Cloud seeding

• Concept: Cloud seeding is a weather modification technique that involves dispersing substances like silver iodide, potassium iodide, or sodium chloride into clouds to encourage the formation of ice crystals or raindrops. This process aims to enhance precipitation, either as rainfall or snow. The substances are typically delivered via aircraft or ground-based generators.

• Potential / certainty of directionality: Cloud seeding has been used in many regions to try to help alleviate drought, increase water supply, and enhance snowpack in mountainous areas for water management (or skiing). Think of it as a way to artificially influence weather to benefit agriculture, reservoir replenishment, and water security in arid regions. Certainty of directionality is quite circumstantial; parsing what rain is truly additional can be challenging. That said, this has been studied for decades.

• Challenges: There are uncertainties around how effective cloud seeding is in consistently enhancing precipitation, as natural variability in weather patterns makes it hard to distinguish seeded effects from normal weather variability. Additionally, there are ethical and geopolitical concerns, as altering weather patterns in one region can have unintended consequences for neighboring areas.

• Stage: Cloud seeding has been used operationally for decades in various countries (the U.S., China, and the UAE) and is in the practical application stage, though its efficacy requires more research. Rainmaker is a startup to watch.

• Short-term vs. long-term warming: Other (making more rain!).

13. Space-based stuff!!

• Concept: This involves placing reflective objects in space to reduce the amount of sunlight reaching the Earth. Ideas include large mirrors or deploying a cloud of small reflective particles into orbit. Giant space mirrors!!! & other ideas I’m sure.

• Potential / certainty of directionality: Could provide global cooling without direct intervention in Earth's atmosphere and has a high certainty of directionality. It's just really damn expensive to put things into space at scale.

• Challenges: Extremely expensive and technologically challenging. It also raises concerns about unintended effects on the Earth's climate system.

• Stage: Theoretical, more or less.

• Short-term vs. long-term warming: Short-term

The net-net

To reiterate, what we don’t know about Earth’s climate system far outweighs the amount that we do know. Hence, the fact that we don’t know what the second and third order impacts of some geoengineering approaches might be doesn’t mean we shouldn’t evaluate their potential utility. Rather, we should endeavor to understand them better and learn how to deploy them at larger scale. We might be glad we did, if and when the need becomes dire. None of that suggests we deploy them at today.

If you've made it this far, thanks for reading. If you find this work valuable, you can support it here. I put a lot of time into it. Also, if I missed anything you’re working on or interested in geoengineering wise, LMK. Happy to make this a collaborative effort to grow the taxonomy and to open source it.

— Nick