SB'24 San Diego is open for registration. Register early and save!

Product, Service & Design Innovation
A Rogue Startup Thinks It Has a Solution to Climate Change; The Scientific Community Disagrees

Despite a lack of scientific consensus regarding the efficacy and safety of its approach, intrepid startup Make Sunsets is throwing caution to the wind (literally).

Stratospheric Aerosol Injection (SAI) might sound like something out of science fiction, but it's an idea that was introduced by Russian climatologist Mikhail Ivanovich Budyko in 1974: Releasing tiny, reflective particles into the upper atmosphere would theoretically bounce sunlight back into space — essentially creating a planetary sun shade to cool the Earth. It was inspired by cooling effects caused by volcanic eruptions’ ejected particles, spurring the question — could this natural phenomenon be mimicked to cool our planet?

Since then, SAI — along with several other unproven theories around geoengineering our way clear of a climate castrophe — has remained a controversial idea, even as we recognize the need for unconventional solutions to avert catastrophic climate change. Scientists have been studying the effects of SAI for years, trying to navigate through a complicated field of geopolitical debates and possible environmental consequences.

Make Sunsets

Despite the lack of scientific consensus regarding its efficacy, intrepid startup Make Sunsets has thrown caution to the wind (literally). Co-founded by friends Luke Iseman and Andrew Song in 2022, Make Sunsets has been causing a stir amongst scientists for its rather unscientific approach to SAI: The company — based in Box Elder, South Dakota — has begun injecting sulfur dioxide (SO2) into the atmosphere in latex balloons, in an effort to keep planetary temperatures in a livable range long enough for other solutions to develop.

“What we’re doing is not new; it's been in academia since the 1970s. It's well studied — there are tons of research papers out there about this, and loads of modeling has been done too, with people carrying out computer simulations [to answer] ‘what happens if we do XYZ?’” Song, who bonded with serial entrepreneur Iseman back in 2015 over their “shared passion for hardware companies,” told Sustainable Brands® (SB). “But there hasn't been a company that has tried to deploy — so, that is our focus.”

Make Sunsets positions itself as finally taking the needed actions that researchers are too ‘scared’ to do. But scientists are cautious for a reason — meaning, there must be a reason why this radical solution has yet to be deployed.

“I don’t personally know any scientists who think we should be out doing SRM (solar radiation modification) right now or are even advocating for using SRM at any point. We need to know how it would play out in the climate system,” Sarah Doherty — a PhD in Atmospheric Sciences from the University of Washington who has been conducting research on particulate pollution in the atmosphere and how it affects climate, told SB. “The biggest worries with SRM involve how it will alter patterns in the climate system, and how that plays out for different ecosystems. There'll be less warming, yes; but you'll also have changes in precipitation — which could, for example, cause drought over the Amazon, etc. So, you would want to know how to not do that.”

Despite the unknowns, Make Sunsets has forged ahead and launched 28 balloons. Song explained that they source their SO2 from a commercial welding and gas company that sells tanks of it, and measure the amount emitted by weighing the balloon before and after they fill it with SO2 using a “sensitive scale.” Helium is also added, which allows the balloons to float. As they get higher, they expand — eventually bursting and releasing SO2 into the atmosphere. The altitude is confirmed using GPS and a camera; however, readings have been inconsistent.

Make Sunsets’ approach is based on the work of geoengineering expert David Keith, a Harvard University professor and lead researcher for the SCoPEx project — a scientific experiment to advance understanding of stratospheric aerosols that could be relevant to solar geoengineering. The project builds on four decades of SCoPEx research on the environmental chemistry of the ozone layer.

[Keith's hypothesis]( is that “one gram of SO2 offsets the warming effect of one ton of CO2.” This math is the driving force behind Make Sunsets’ balloon deployment, and also the rationale behind the cooling credits which the company now offers — $10 to offset 1 tonne.

“The balloons that we currently use have a capacity of about one kilogram. The weight of $1 is one gram, so the weight offsets the warming effect of one tonne of CO2 for a year,” Song exclaims. “It’s a very simple concept — the hard part is convincing enough people that we should do this.”

While Make Sunsets is moving ahead, many scientists and international bodies seem to agree that solar engineering should be tested and discussed on an international level before being carried out in the field: Mexico recently banned solar geoengineering experiments in the country after the startup carried out two experiments in the northern state of Baja California. Iseman and Song are now deploying their balloons in the US, after apparently receiving an OK from the FAA. However, this is one of many claims by the company that remain unconfirmed.

With a lack of scientific data to support the efficacy and safety of SAI, the scientific community is vocally frustrated with the two entrepreneurs who see it as a magic bullet for slowing climate change. On the flip side, Song says the Make Sunsets team doubts the motives behind the pushback.

“When it comes to scientists, you have to think about where the money is coming from,” he asserted. “The reason why they say we shouldn't do this is because, at the end of the day, their jobs are on the line. If we start deployment, then they can't do research anymore using computer simulations and modeling — we're kind of taking the wind out of their sails if we keep continuing to do this.”

What the scientists say

However, Doherty insists the scientific community merely wants to ensure that every climate risk is considered, the outcome of every approach is known, and that there is an international consensus before any methods of SRM are implemented.

“We need to know how SRM would play out in the climate system; and then other people — decision-makers and society — can decide whether or not to use it,” she says. “Make Sunsets is not doing science — they're not taking measurements; they don't know what altitude the balloons are bursting at; they don't know how much particulate ends up in the stratosphere, if any — or whether if it’s even reflecting sunlight. They're just throwing stuff up there with no appreciable effect.”

Jim Haywood, PhD — a Professor of Atmospheric Physics at the University of Exeter, has been researching climate intervention for over a decade. During that time he led the UK’s Geoengineering Model Intercomparison Project (GeoMIP) which used state-of-the-art climate models to determine what the impacts of climate are in future scenarios, including combatting some of the worst effects of global warming.

Haywood told SB: “What Make Sunsets is doing is not credible and has no backing of the scientific community. Scientists research and take a very cautionary attitude. Making sunsets is entirely the opposite; they’re not scientists — they’re provocateurs.”

He explained the scale at which SO2 needs to be deployed to make a difference. The 1991 eruption of Mount Pinatubo in the Philippines emitted nearly 20 million tons of sulfur dioxide into the stratosphere, which caused global temperatures to drop temporarily (1991 through 1993) by about 1°F (0.5°C). Make Sunsets emit 100-500 grams of SO2 per balloon. Therefore, they would have to deploy billions of balloons to make a difference.

Meanwhile, Make Sunsets continues to attractors investors — including Pioneer Fund, Draper Associates and Boost VC. However, both Doherty and Haywood agree that reducing atmospheric greenhouse gas emissions (GHGs) should be the priority before anyone considers SAI.

“None of the SRM approaches are the answer to climate change. They won't fix the problem,” Doherty stated. “The only way to fix the problem is to reduce greenhouse gas emissions and get concentrations back to safer levels in the atmosphere.”

“The first port of call must be greenhouse gas emission reduction — anyone working in solar radiation modification will say the same,” Haywood asserted. “You won't find many people suggesting that it's time for us to start deploying sulfur dioxide into the stratosphere, because it's just not.”

While SAI may hold potential for mitigating climate change, it also carries many as-yet-unruled-out risks and uncertainties; and proceeding with unproven geoengineering solutions could lead to unforeseen environmental, ecological and geopolitical consequences beyond what we already face.