Switzerland proposes first UN expert group on solar geoengineering

A draft resolution aimed at creating a space for discussion on sun dimming technologies will be debated at the summit of the UN’s environment body this month

Solar geoengineering UN Switzerland

Solar radiation modification aims to mask the effect of climate change by reflecting more sunlight back into space. Photo: maxime raynal


Switzerland wants to advance global talks on whether controversial solar geoengineering techniques should be used to compensate for climate change by cooling down the earth.

It is proposing to create the first United Nations expert group to “examine risks and opportunities” of solar radiation management (SRM), a suite of largely untested technologies aimed at dimming the sun.

The panel would be made up of experts appointed by member states of the UN’s environment programme (Unep) and representatives of international scientific bodies, according to a draft resolution submitted by Switzerland and seen by Climate Home.

Governments will negotiate and vote on the proposal at Unep’s meeting due to start at the end of February in Nairobi, Kenya. It has been formally endorsed by Senegal, Georgia, Monaco and Guinea.

A Swiss government spokesperson told Climate Home that SRM is “a new topic on the political agenda” and Switzerland is “committed to ensuring that states are informed about these technologies, in particular about possible risks and cross-border effects”.

Split scientific opinions

Solar geoengineering is a deeply contested topic and scientists are divided over whether it should be explored at all as a potential solution.

Ines Camilloni, a climatology professor at the University of Buenos Aires, welcomed Switzerland’s proposal, saying the UN “is in a good position to facilitate equitable, transparent, and inclusive discussions”.

“There is an urgent need to continue researching the benefits and risks of SRM to guide decisions around research activities and deployment”, she told Climate Home.

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But Carl-Friedrich Schleussner, head of climate science at Climate Analytics, says he is concerned about that prospect.

“The risk of such an initiative is that it elevates SRM as a real solution and contributes to the normalisation of something that is still very premature and hypothetical from a scientific perspective”, he added. “You need to be careful about unintended consequences and consider the risks of opening a Pandora’s box”.

An open letter signed by more than 400 scientists in 2022 called for an international “non-use agreement” on solar geoengineering. It also said United Nations bodies, including Unep, “are all incapable of guaranteeing equitable and effective multilateral control over the deployment of solar geoengineering technologies at planetary scale”.

Poorly understood risks

Long touted as a futuristic climate hack, solar geoengineering has risen in prominence in recent years as the prospect  of curbing emissions enough to limit global warming to 1.5C has faded.

The technologies aim to reduce the amount of sunlight reaching the planet’s surface. This could be achieved by pumping aerosols into the high atmosphere or by whitening clouds.

Its supporters say it could be a relatively cheap and fast way to counter extreme heat. But it would only temporarily reduce the impact of rising emissions, without tackling the root causes.

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The regional effects of manipulating the weather are hard to predict and large uncertainties over wider climate, social and economic implications remain.

Solar geoengineering could “introduce a widespread range of new risks to people and ecosystems, which are not well-understood”, the IPCC’s scientists said in their latest assessment of climate science.

Its critics argue that putting the SRM option on the table undermines existing climate policies and relieves pressure on polluters to reduce emissions as quickly as possible. There are also questions about how long this technology would be needed and what happens after it is stopped.

Space for discussion

In its proposal to the Unep assembly, Switzerland acknowledges the “potential global risks and adverse impacts”.

The 25-people-strong group would first be tasked with writing a comprehensive scientific report on solar geoengineering.

But the main goal would be to establish “a space for an informed discussion” about research on the potential use of SRM, giving the possibility for future decisions on how that should be governed, according to an accompanying technical note seen by Climate Home.

It is not the first time Switzerland brings a resolution on solar geoengineering to the Unep summit. In 2019, its attempt to get countries to agree to the development of a governance framework failed as a result of opposition from Donald Trump’s USA and Saudi Arabia – who didn’t want restrictions on geoengineering.

Calls for more research

Last year, Unep produced an “independent expert review” of the subject, concluding that “far more research” is needed “before any consideration for potential deployment” of SRM.

A Unep spokesperson said the exact characteristics of the group proposed by Switzerland would need to be negotiated at the upcoming summit. But, if approved, it would differ from any previous panel “because it would have a clear mandate from member states” with experts directly appointed by them.

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Ines Camilloni was one of the authors of last year’s UNEP report. She says “managing the risks of climate change requires a portfolio of policy responses”, of which mitigation and adaptation would be the most important and urgent.

But she added that “SRM has been proposed as a complementary approach” and more research is needed to weigh its benefits and risks against the impact of adverse climate scenarios.

A panel of leaders called the Overshoot Commission also recommended last year that governments expand research into solar geoengineering while placing a moratorium on large-scale experiments outdoors. 

A rogue SRM experiment conducted by a US startup in Mexico led the Mexican government to announce a ban on solar geoengineering in January 2023.

‘Precautionary approach’

Mary Church, a campaigner at the CEnter for International Environmental Law, says “it’s hard to see what could be gained from establishing an expert group under Unep”.

“There’s a real risk that such a group could undermine the existing regulatory framework and inadvertently provide legitimacy for solar geoengineering technology development and experimentation”.

Countries should instead “take a precautionary approach, commit to non-use, and prioritise a fast, fair and funded phase out of fossil fuels”, she added.

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