Controversial trial of technology that could be used to lighten clouds is voted down in California

The Alameda, California, City Council voted early Wednesday to deny scientists permission to proceed with a controversial trial of a technology that could one day be used to lighten clouds.

The project, among the first of its kind, involved spraying salt on the deck of a former aircraft carrier moored at the city’s pier. The scientists behind it planned to test devices that can create and measure aerosol plumes.

In the long term, the research could serve as a step towards a type of climate intervention known as marine cloud brightening. The concept, still largely theoretical, is to make clouds more reflective of sunlight, which would send more heat back into space and help moderate global warming.

No such efforts are underway yet—instead, scientists are designing experiments to investigate how the technology might work. The trial in Alameda would have been part of those efforts, but the City Council voted unanimously against it.

This episode put Alameda officials at the center of a public debate that extends far beyond the city, about the promises and dangers of geoengineering and whether tests of this type of technology should be conducted at all. The council’s decision follows similar actions in other areas, including a state-level ban on geoengineering implemented in Tennessee and the abandonment of a geoengineering project that Harvard scientists sought to deploy in Sweden.

However, the council’s vote was not a denial of the science or the idea of ​​geoengineering, but of the researchers’ approach. The members complained that the project’s leaders were not transparent, that they had not provided enough review by medical professionals about its safety, and that they had started on the wrong foot by first starting to spray saline and asking for permission in after that.

In fact the University of Washington scientists behind the trial had already begun their work – and did not have the data widely publicized in advance – when Alameda city leaders learned more about it from reports in the New York Times and news outlets. another. The researchers were spraying salt water along the deck of the USS Hornet, which is now used as a museum on the Alameda waterfront. Their plan called for spraying three times a day four days a week for 20 weeks.

But after city leaders learned about the project, they quickly shut it down to investigate its safety and vote on its fate.

The idea behind cloud brightening is to increase the number of water droplets within the clouds to increase their reflectivity. If more sunlight were returned to space in that way, overall global warming could be reduced but that would not help other climate problems such as ocean acidification.

Geoengineering research is still a tough public sell despite the worsening effects of climate change, and the events in Alameda show the intense skepticism scientists face about even the most basic experiments.

Much of the discussion by City Council members avoided the larger implications of the project, focusing instead on potential local health risks — including the proximity of the spray to soccer fields and school neighborhoods — and whether project leaders have taken the regulatory steps. appropriate.

Sarah Doherty, a University of Washington professor who manages the cloud brightening research program, faced sharp questioning.

“I want you to tell us exactly what you did to us,” said Council member Trish Herrera Spencer. “I think it’s unfortunate. I think you should be able to tell us what you were sprayed with when you were sprayed, so we all know what we were exposed to.”

Doherty told the council that the sprays had a very low concentration of salt and would have little impact on the environment.

“We are not raising any clouds. We are not changing the weather. We are not changing the climate,” said Doherty.

A consultant employed by the city also told the council that the project was safe and “was not expected to pose an unacceptable risk to the surrounding community.”

Other council members were concerned learning about the project from news reports.

“I don’t like hearing things or getting things from the New York Times. I would rather have an opportunity to review them,” said Council member Malia Vella.

Organizers of the project, including Doherty, said in a statement that they were disappointed with the city’s decision and had begun exploring “other sites.” The group also said it had tried to be “completely open and transparent.”

“All the experts employed confirmed the safety of the sea salt spray involved in the studies,” the scientists wrote. “These supported our own evaluation that this is a safe, accessible way to further research atmospheric aerosols, support environmental goals and promote education and science equity.”

Alameda Mayor Marilyn Ezzy Ashcraft said the city did not need to be at the forefront of such research.

“There are so many competing considerations that we have to apply and I don’t think you’ve made your case,” Ashcraft told Doherty at the council meeting.

Meanwhile, some environmental organizations have opposed the project based on more global concerns.

More than 70 environmental groups issued a statement last month urging Alameda to complete the project. Opponents were concerned that widespread use of geoengineering technology could alter the climate with unintended consequences or reduce the ambition of global efforts to wean off fossil fuels.

“Our real concern with this is that it opens a Pandora’s box,” said Mary Church, geoengineering campaign manager at the Center for International Environmental Law.

Church, speaking before the vote, said her organization was not concerned about immediate impacts in Alameda, but that the project would lay the groundwork for widespread climate manipulation.

“It does nothing to attack the root causes of the crisis,” she said.

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