In 2022, extreme heatwaves, drought, and devastating floods affected millions of lives and cost billions to economies around the world. While the past eight years are on track to be the warmest on record, tell-tale signs and impacts of climate change became even more concerning this year—as glaciers took a heavy toll and sea levels rose by nearly ten millimetres since January 2020 to a new record high.

In February, the 2022 Winter Olympics in Beijing was the first of the renowned events to rely completely on artificial snow. At the time, several reports predicted that the winter games would be unviable at 20 out of 21 former host venues by the year 2100 if global warming continues on the trajectory of the preceding two decades.

Fuelled by ever-rising greenhouse gas concentrations and accumulated heat, nations initially deployed initiatives to reduce emissions of carbon dioxide (CO2) and methane by replacing fossil fuels with clean energy. With new laws taxing cow and sheep burps, the measures are certainly underway but it’s not happening fast enough to keep up with the horrors of an overheating Earth.

As a result, scientists are now considering a controversial idea that includes shooting undisclosed dollars worth of particles into the stratosphere to dim the sun and hopefully cool our home planet. Welcome to the outlandish world of solar geoengineering, a scheme that is considered to be the last resort for tackling the climate crisis.

Solar geoengineering, or solar radiation modification (SRM), involves spraying highly-reflective particles of a material like sulphur into the upper atmosphere to form fine aerosols. While sulphur dioxide is the most commonly discussed candidate, aluminium, calcium carbonate, and diamond dust have also been proposed. Theoretically, these tiny particles would bounce sunlight back to outer space and limit climate change.

The idea behind the scheme is to essentially mimic the effect of a volcanic eruption—like Mount Pinatubo in 1991, which cooled the planet by about half a degree Celsius for several months. If we decide to solar geoengineer the Earth, it will reportedly be the second most expansive project that humans have ever undertaken.

That being said, everyone studying solar geoengineering seems to agree on the fact that it’s a terrible idea.

For starters, the wider consequences of solar geoengineering are still poorly understood, making it a potentially risky approach to tackling global warming. Although scientific evidence suggests that it would “likely produce a substantial, rapid cooling effect worldwide” and “could also reduce the rate of sea-level rise, sea-ice loss, heatwaves, extreme weather, and climate change-associated anomalies in the water cycle,” the real question is: what else would it do?

As reported by The New Yorker, solar geoengineering could, at least temporarily, turn the sky hazy or milky. It could also alter the quality of the light plants use for photosynthesis, damage the ozone layer, and kick off extreme weather in unexpected locations around the world. An increase in local reservoirs could even allow for diseases like malaria to spread. Then comes the whole conversation surrounding its political ramifications.

According to the Harvard Environmental Law Review, the direct cost of solar geoengineering the Earth—including the collection of the precursor materials for aerosols, putting them into the sky, monitoring, and so on—would be as low as several billion dollars a year. In short, any country with a dedicated air force could probably pull the scheme off by deploying planes in the upper atmosphere.

“Imagine if India started pumping sulphur into the atmosphere only to see a huge drought hit Pakistan: two nuclear powers, already at odds, with one convinced the other is harming its people,” The New Yorker noted. “Or maybe it’s China—driven by a series of summers like the one it just endured—that starts down this road, and it’s India that suddenly faces unrelenting floods. These two nations also share a militarised border, and a series of overlapping international alliances.”

According to Frank Biermann, a political scientist at Utrecht University, no existing governance system can decide on a move like solar geoengineering. “You’d have to take decisions on duration, on the degree—and if there are conflicts—‘we want a little more here, a little less here’—all these need adjudication,” the expert told the publication, adding that the UN Security Council would be a problematic governing body in this case.

“Anything can be blocked by the veto of five of the most polluting countries. Some kind of governance by the major powers? You’d need the agreement of the US, Russia, China, India, and there’s no chance of that. The small countries? The people who want this talk about consultation, but not co-decision.” Ultimately, Biermann believes that governance has to come first before implementing initiatives that have unchecked global effects. On these terms, it’s worth noting that idea may not ever get off the ground as it would require everyone to sign off on it.

“If you don’t know what to do with such technology, don’t develop it,” Biermann concluded.

In 2021, Harvard scientists planned a preliminary solar geoengineering test in Sweden—which was shut down almost immediately, with activist groups writing a letter that even Greta Thunberg signed. The following year, more than 60 policy experts and scientists wrote an open letter stating that the technology could be potentially dangerous and should be banned by governments.

“Solar geoengineering deployment cannot be governed globally in a fair, inclusive, and effective manner,” the letter read. “We therefore call for immediate political action from governments, the United Nations and other actors to prevent the normalisation of solar geoengineering as a climate policy option.”

Despite such opposition however, in October 2022, the White House announced a five-year research plan to assess the feasibility of solar geoengineering—thereby pushing the idea out of the realm of science fiction. “Sunlight reflection has the potential to safeguard the livelihoods of billions of people, and it’s a sign of the White House’s leadership that they’re advancing the research so that any future decisions can be rooted in science not geopolitical brinkmanship,” Chris Sacca, founder of the climate tech investment fund Lowercarbon Capital, told CNBC at the time.

Meanwhile, Anote Tong, former president of Kiribati—a small island nation that has already been greatly affected by the rise of sea levels—told The New Yorker that solar geoengineering is a “prime example of our arrogance in our capacity to shape nature to our whims with technology. It should not be the answer to a disaster which we have caused and now seek to remedy.”

Yet, Tong added: “Geoengineering as a possible solution to this catastrophe will definitely become the only option of last resort if we as a global community continue on the path we have been going. There will be a point when it has to be either geoengineering or total destruction.”