Go ahead and alter the atmosphere, no one’s going to stop you — probably

A de facto moratorium on solar geoengineering will stay in place after heated talks at the United Nations Environment Assembly ended in a stalemate. The debate is over whether to let people launch particles into the sky that would reflect sunlight back into space, ostensibly cooling down the planet.

It’s a hotly contested tactic for tackling climate change. Geoengineering does nothing to stop what’s actually causing the problem: greenhouse gas emissions from fossil fuels. And tinkering with the makeup of our planet and its atmosphere in order to reflect solar radiation could lead to unforeseen consequences that scientists are still trying to understand. After all, the climate change we’re already experiencing — in the form of rising seas, extreme weather, and other disasters — can be thought of as the result of unintended geoengineering through greenhouse gas pollution.

Humanity just experienced its hottest year on record, with soaring temperatures in 2023 likely exceeding those in at least the last 100,000 years. And despite being trapped on what is essentially a burning home, planet-heating emissions from our energy use still reached a record high last year. With that in mind, proponents of solar geoengineering research say it’s time to consider even the weirdest options for turning the heat down.

One scrappy startup — really just a couple of guys grilling fungicide and launching the resulting sulfur dioxide gas aboard weather balloons — pissed a lot of people off by forging ahead with its solar geoengineering experiments in Mexico and the US since 2022. The company is essentially trying to mimic the way volcanic eruptions can temporarily cool the planet by releasing sulfur dioxide, which mixes with water in the stratosphere to create a hazy layer of reflective aerosols.

Actual research groups interested in solar geoengineering’s potential have been much more cautious — avoiding real-world tests until they have a better sense of what the pitfalls might be. For now, no one really knows what might happen with large-scale geoengineering projects. It might help cool down the planet; it also might rip open the ozone over Antarctica.

All of that has led to a flurry of attempts to set some parameters for solar geoengineering projects. The startup’s experiments last year were probably too small to make much of an impact. But if a more capable group or government decided to throw caution to the wind and try something similar on a larger scale, it could have consequences for the whole planet.

There’s already a de facto global moratorium on large-scale geoengineering that was agreed on during a 2010 United Nations biodiversity conference. But it’s outdated and the language is vague. It doesn’t apply to small-scale experiments and might be limited to solar geoengineering efforts deemed harmful to biodiversity.

Without tougher international rules to stop rogue experiments, governments could be left playing whack-a-mole with startups that can move their operations from place to place. Mexico said it would bar future experiments after the fungicide-grilling startup’s balloon launches within its borders. The startup just launched more balloons in California the following year.

A United Nations Environment Programme (UNEP) expert panel published a report in 2023 saying that, “With many unknowns and risks, there is a strong need to establish an international scientific review process to identify scenarios, consequences, uncertainties and knowledge gaps.” In June, the European Union called for an international framework for governing geoengineering efforts.

Switzerland came to the UN Environment Assembly in Nairobi, Kenya, this week proposing a plan to establish an expert panel to study the “risks and opportunities” of solar geoengineering, Climate Home News reports. But it was reportedly shot down by a group of African and Pacific Island nations, Mexico, and Colombia.

Opponents saw that proposal as a veiled attempt to legitimize solar geoengineering. Some countries and environmental advocates are pushing for a tougher agreement that would bar solar geoengineering full stop. But that also failed to materialize at the summit in Nairobi this week.

“Solar Radiation Modification (SRM) technologies are dangerous and do not have any role to play in our common future. These technologies cannot tackle the root causes of the climate crisis and would instead enable major polluters to delay the urgent need to phase out fossil fuels,” Mary Church, senior geoengineering campaigner at the Center for International Environmental Law (CIEL), said in a statement yesterday.

After all that back and forth, the 2010 de facto moratorium on geoengineering is still the only international agreement standing between intrepid startups and their plans to try to save — or maybe imperil — the world.