What is solar geoengineering?
Solar geoengineering is an umbrella term for numerous approaches dedicated to cooling or simply suppressing the increase in atmospheric and land temperature, by reflecting solar radiation (electromagnetic radiation from the sun) from the earth back into space. Reflecting radiation from the sun would lower the earth’s global temperature, enough to permit the continuous burning of fossil fuels, proceed with current agricultural practices, allow further mining operations, and more. Solar geoengineering – on a planetary scale – would allow for an extended business-as-usual if the right techniques were implemented and an internationally administered board was established to ensure the best geoengineering choices were adopted.

The Union of Concerned Scientists (UCS), however, has little in the way of positive backing for planetary engineering: “[we oppose] the deployment of solar geoengineering because it poses unacceptably high environmental, social, and geopolitical risks.” Other scientific organisations and nonprofits also resist the potential deployment of solar geoengineering. When it comes to climate change, this techno-fix provides the greatest clear-cut divide among experts. Those who believe in a quick solution due to the rapidly declining time frame, and those who believe the risks of such proposals are far too great.
Types of solar geoengineering approaches:
Many solar geoengineering techniques are currently under discussion or have already been tested on a smaller scale. As of 2022, the most mainstream and backed techniques include stratospheric aerosol injection (SAI) and marine cloud brightening (MCB).
Technique | Explanation |
Stratospheric aerosol injection (SAI) | Analysing natural volcanic phenomena, the SAI approach depicts thousands of planes across the globe, releasing billions of aerosol particles (according to NASA, “bright-colored or translucent particles tend to reflect radiation”) into the stratosphere, forming a cooling shield to prevent current solar radiation levels. |
Marine cloud brightening (MCB) | The MCB scheme aims to further whiten the clouds around the globe. Large vessels equipt with machinery both absorbing and filtering seawater would produce sea salt aerosols to be injected into the sky. |
Ocean mirror | As for ocean mirrors, fleets of vessels scattered across the globe would emit billions of microbubbles onto the ocean surface, helping to reduce solar radiation sequestration in the sea. |
Ocean iron fertilisation (OIF) | Among the most controversial, OIF involves sourcing large quantities of iron-ore particles (from shipping docks or mining sites) to be sent out into marine environments that lack iron deposits or nutrients, to fertilise the surrounding ocean. Theoretically stimulating phytoplankton growth – sequestering atmospheric carbon dioxide (Co2). |
Have trials already been conducted?
One trial that nearly went up – quite literally – was a test conducted by a Harvard lead team that aimed at deploying a “high-altitude balloon to lift an instrument package approximately 20 km into the atmosphere.” Once in the atmosphere, the instrument would release between 100 grams to 2 kilograms of sulfate aerosol, predictably spreading 1 kilometre long and 100 meters in diameter. The team claimed that after deployment, “the same balloon [would be used] to measure resulting changes in […] aerosol density, atmospheric chemistry, and light scattering.”
Despite the hype from several people within the scientific community and Harvard itself, the plan was aborted when a group of Swedish environmentalists demanded the project be stopped. According to their letter, “[project SCoPEx] entails risk of catastrophic consequences” and that the adoption of such technology is “dangerous, unpredictable, and unmanageable.” As of 2022, project SCoPEx is yet to go up due to a lack of public engagement.

In addition to project SCoPEx, a slightly (but not entirely) successful project of ocean iron fertilisation was conducted back in 2012. A team of 12 led by an entrepreneur named Russ George, headed out to sea in British Columbia to fertilise the surrounding waters with “100 tons of iron sulfate dust.” Vox claimed that the boat was fitted with state-of-the-art oceanic equipment provided by the National Oceanic and Atmospheric Administration (NOAA). George’s plan was to trigger algae blooms which would both invite larger fish populations back into the region, and capture Co2. The Co2 sequester would either be consumed by fish or sink to the ocean floor when the algae decomposed – adding to the already huge oceanic carbon pool.
Following the iron fertilisation, in easter 2013 George stated that his team heard a pounding bang on their research office in Vancouver “and in burst an-11 man Canadian Government SWAT team.” Subsequently, all data collections were taken away and the scientific study was ended. Canadian officials later investigated him for illegal dumping.
What’s the problem with solar geoengineering?
Placing aside the legal and social hurdles currently standing in the way of solar geoengineering trials, the general ideas and projects seem worth at least testing, right? Not quite. If the trials are successful, increased political backing could encourage global considerations: considerations that could have immense implications.
- Ocean acidification
Even though solar geoengineering – whether in the sky, ocean or land – could reduce global temperatures, the continuous burning of fossil fuels would inevitably reduce the ocean pH levels. NOAA claims that increased carbon sequestration in seawater is having a huge impact on both “the ocean and the creatures that live there.” Solar geoengineering not only does nothing in the way of managing ocean acidification from rising Co2 but, if anything, encourages further fossil fuel extraction far into the foreseeable future. - No turning back
If acidifying 71% of the planet isn’t concerning enough, then perhaps this is. No matter what form of solar geoengineering technique we deploy, once we start there is no turning back. Because as soon as we stop spraying or bubbling our environment, all of the artificially suppressed heat would hit the planet in a single event. Naomi Klein explains: “Think of the wicked witches of fairy tales, staying young by drinking ill-gotten magical elixirs, only to decay and wither all at once when the supply is abruptly cut off.” The Washington Post states, “sudden[ly] climate change is even worse than the kind we already know about.” - Deliberate climate injustice: sacrifice zones
Engineering the atmosphere with techniques like SAI could spark a crisis for billions with the reduction in monsoons throughout Asia and Africa. In India alone, the monsoon seasons provide between 70% and 90% of their annual rainfall. Messing with those vital patterns could be catastrophic. Climate Home News adds that monsoon “rains in East Asia would fall by 6%, in South Africa by 5%, in North America by 7%, and in South America by 6%.” Geophysics Research stated bluntly: “[sulfur dioxide injections] would disrupt the Asian and African summer monsoons, reducing precipitation to the food supply for billions of people.” - Crop decline
According to PBS News Hour, a study conducted by a professor and researchers at the University of California revealed solar geoengineering could reduce “global corn yields by an average of 9 percent, and soy, rice and wheat by 5 percent.” Analysing 2 major volcanic eruptions – Mount Pinatubo in 1991 and El Chichón in 1982 – the team found meaningful reductions in crop yields during those years of eruption. Due to the decline in plant photosynthesis potential because of light reflection, it seems evident that atmospheric or ocean engineering could cause both a shrink in crop yields and billions of dollars. - Billions of lives in the hands of a few
Another potential – though avoidable – issue is in regard to the privatisation of such technology. If companies and startups begin investing large amounts of resources and money into developing effective and cheaper means of planetary engineering, it would be relatively difficult for governments to ignore. Once privatised, we risk many unforeseen environmental problems, evident in today’s capitalist economies. Furthermore, once a company is given the tick of approval, there’s the issue of an economic monopoly. It could be said that multiple companies would contribute to solar geoengineering, however, that would require a universal agreement on a single approach. The last thing the planet would need is companies each running their own experiments all over the globe.

Persistent pollution with no global argument to stop it:
As highlighted above, there are major issues both economically, politically and environmentally in regard to solar geoengineering. Just because solar geoengineering technology may be soon available, emission reduction schemes must still be the top priority with a continuous influx of climate policies and initiatives.
Although, depict an engineered planet with no global consequences for burning fossil fuels, eating meat, or investing in the plastic industry, how difficult would it now be to sway public opinion and international policymakers away from common practices?
Despite millions still dying from air pollution, billions of species going extinct due to deforestation, and thousands of low-socio economic towns being subjected to mining and factory farm operations; much of the middle-class that wasn’t exposed to such wouldn’t care (or at least not know how to take action). Already today – in a world where the actions we take do matter – people continue to buy palm oil products, eat roasts and buy plastic bottles of water daily.
Again, imagine a solar geoengineered planet and trying to convince politicians to stop burning so much coal because they are damaging regional Chinese villages, or trying to persuade BP and ExxonMobil to reduce mining because their oil is going into products that turtles mistake for jellyfish.
Change is already difficult enough even with the most present and dominating threat of climate change, take that out of the equation, and any form of transition on the community, business or international level just got a whole lot harder.

Conclusion:
Solar geoengineering promises to be an efficient means of cooling the planet down if plan A – to eliminate anthropogenic wrecking – takes too long. It must be stressed that solar geoengineering should not be an alternative to taking environmental action but, instead, should act as assistance only if we finally find ourselves on truely thin ice.
By focusing on plan A, the world could rig huge environmental, social and economic benefits: preserving species, introducing 4-day work weeks and saving trillions in pollution damages – to list a few. Conversely, if we choose to sit back and let the billionaires deploy solar geoengineering, such schemes will not only permit further Amazon depletion and fossil fuel burning but jeopardise the water and food supply of billions in Asia and Africa.
Technology has – in many cases – dug us into bad situations. Who is to say a privatised, unjust, and dangerously unplanned techno-fix would be any different.