The United States joined Saudi Arabia to derail a U.N. resolution that sought to improve the world’s understanding of potential efforts to lace the sky with sunlight-reflecting aerosols or use carbon-catching fans.

The two countries were joined by Brazil in blocking the resolution at the U.N. Environment Assembly conference in Nairobi, Kenya, earlier this week. The measure asked the world’s decisionmaking body on the environment to commission a report outlining research and planning related to carbon dioxide removal and solar radiation management. Those controversial efforts are still in the planning stage and are not operational.

Switzerland and nine other nations originally asked the U.N. Environment Programme for guidance on possible future governance options and analysis of the implications of geoengineering, but they agreed to substantially reduce the scope of their resolution in hopes that the United States, Saudi Arabia and Brazil would allow it to move forward. The final version, which failed to gain consensus Wednesday, would have asked UNEP only to provide a compilation by next year of current scientific research on geoengineering and U.N. bodies that have adopted resolutions regarding it.

The proponents wished to see UNEA become the institutional home for geoengineering within the U.N. structure. But sources said the United States in particular insisted that questions about geoengineering be left to the Intergovernmental Panel on Climate Change, a scientific body with a narrow focus on global warming. Geoengineering will be a key part of the IPCC’s upcoming Sixth Assessment Report to be published in 2021 and 2022, and sources say the U.S. negotiators refused to agree to any other study or assessment that would be published before it.

The United States’ focus on the IPCC raised eyebrows. Both the United States and Saudi Arabia angered parties at the U.N. climate talks in Katowice, Poland, in December by questioning IPCC’s work. The two countries joined Russia to block a popular proposal to “welcome” last year’s landmark IPCC report that said the world must act aggressively to counteract climate change within 12 years. The special report said that failing to do so would result in catastrophic effects.

In Nairobi, atmospheric chemist and State Department official Farhan Akhtar led negotiations for the United States on the geoengineering resolution last week. The State Department didn’t provide comment for this story.

Environmentalists expressed disappointment.

“There’s definitely a lot of frustration on the part of those countries that have fought for the resolution in the last two weeks and have tried to improve it and find consensus,” said Linda Schneider, a senior program officer with Heinrich-Böll-Stiftung.

Besides Switzerland, the motion was backed by Burkina Faso, Micronesia, Georgia, Liechtenstein, Mali, Mexico, Montenegro, New Zealand, Niger and Senegal. Other parties, including some European nations and Bolivia, argued for even stronger language for using caution in approaching geoengineering. None of them opposed the final resolution.

The final version of the measure included a lengthy preamble that expressed concern about the “potential transboundary risks and adverse impacts of carbon dioxide removal and solar radiation management on the environment and sustainable development.” It also emphasized the importance of “applying the precautionary principle” when fiddling with the world’s thermostat.

Daniel Bodansky, a professor of law at Arizona State University and an expert on international climate agreements, criticized the resolution for painting direct air capture of carbon dioxide and solar radiation management with the same brush.

“I can understand fears about the latter,” he said. “But I find it much more difficult to understand objections to the former. Lumping them together as ‘geoengineering’ makes no sense to me, since they don’t pose similar risks.”

Some experts suggest that there could be unwanted side effects from infusing the atmosphere with aerosols, like more severe weather.

While Bodansky said there are potential risks associated with solar radiation management, or SRM, he noted that the proposed resolution didn’t balance those with the dangers of runaway climate change.

“It seems to me inconsistent to say, on the one hand, that global warming is the biggest problem that humanity faces, and then go on to say, on the other hand, but we shouldn’t even do research on SRM because it may pose risks,” he said. “Either climate change is the biggest problem we face or it’s not. And if it is, then it’s all hands on deck.”

Bodansky also argued that the IPCC was the appropriate body to explore issues of geoengineering. Last year’s special report found that there are no possible pathways to maintain the threshold of 1.5 degrees Celsius of warming that don’t include large-scale carbon dioxide removal. The report also noted possible governance challenges.

The Swiss resolution’s preamble recognizes the IPCC’s work on the issue and the U.N. Framework Convention on Climate Change’s authority over climate mitigation and adaptation. The Convention on Biological Diversity and the London Convention on the prevention of marine dumping have also weighed in on geoengineering in the past.

But Schneider of Heinrich-Böll-Stiftung said the U.N. Environment Assembly’s broad purview made it the ideal forum to oversee future geoengineering experiments or governance issues.

Questions of artificially altering the world’s climate are “much broader than just a climate discussion and involve impacts on the environment on ecosystems on human rights and democracy,” she said. “From our perspective, it would have been really good to also anchor that discussion in UNEA and the environment program, to make sure that we would get a broader perspective on the impacts.”

The list of Switzerland’s co-sponsors shows that climate-vulnerable countries want broader oversight of geoengineering, too. Countries with small governments lack the personnel to sift through numerous reports, and they stand to suffer if the practices result in unintended consequences. Micronesia, late during last year’s meeting of the Montreal Protocol, proposed language calling for an assessment of possible impacts on the stratospheric ozone layer from geoengineering after an advisory panel warned that SRM could harm it. It wasn’t adopted, but the country plans to offer a similar proposal at this year’s conference.

Janos Pasztor, executive director of the Carnegie Climate Geoengineering Governance Initiative, said carbon capture and SRM would ultimately need to be treated separately when it came to global governance issues.

Mitigation means reducing emissions, and direct carbon removal will likely become a larger part of nations’ goals under the Paris Agreement, he said.

“When it comes to solar radiation management, that’s where the challenge is. There’s no home,” said Pasztor, who is a former U.N. official.

Climate advocates and progressive countries also worry that the existance of tools to cool the atmosphere could blunt interest in climate mitigation and adaptation, and lengthen global reliance on fossil fuels. But they acknowledge the need to start a conversation about it.

“I think governance is an incredibly vital component of geoengineering,” said Shuchi Talati of the Union of Concerned Scientists. “Even if you’re opposed to geoengineering, you need a governance mechanism to be able to enforce that. So international conversations will absolutely be necessary.”

Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at