California City Leaders End Cloud Lighting Test, Ignore Staff

Elected leaders in Alameda, California, voted early Wednesday morning to ban scientists from testing a device that could one day be used to artificially cool the planet, overriding a decision by city staff that determined the experiment posed no danger.

Despite assurances from experts that the experiment was safe for people and the environment, residents of the small city of 76,000 expressed the kind of fear that swirls around the idea of ​​intervening in natural systems to temporarily alleviate global warming.

The test involved spraying tiny particles of sea salt over the flight deck of a decommissioned aircraft carrier, the USS Hornet, docked in Alameda in San Francisco Bay. Versions of that device could eventually be used to spray the material into the sky, brightening clouds so they reflect more sunlight away from Earth. Scientists say that could help cool the planet and combat the effects of global warming.

As humans continue to burn fossil fuels and pump ever-increasing amounts of carbon dioxide into the atmosphere, the goal of keeping global warming at a relatively safe level, 1.5 degrees Celsius compared to pre-industrial times, is disappearing. This has brought the idea of ​​deliberate intervention in climate systems closer to reality.

Universities, foundations, private investors and the federal government have begun funding a variety of projects, ranging from pulling carbon dioxide out of the atmosphere to adding iron to the ocean in an effort to store carbon dioxide on the seafloor.

The Alameda experiment did not involve glowing clouds; it merely tested the way sea salt particles emitted from a spray device behave under different atmospheric conditions. It took researchers years to design and build the sprayer, and the experiment was expected to last months or even years and cost about $1 million a year.

But during a council meeting Tuesday that lasted past midnight, Alameda’s five elected council members, none of whom are scientists, said they were still not sure whether the experiment on the deck of the USS Hornet was harmless.

“I don’t think it’s appropriate for our community to have to bear that risk,” said Councilwoman Trish Herrera Spencer. “I don’t think this is the right place.”

Mayor Marilyn Ezzy Ashcraft echoed those sentiments. “I don’t have a great desire to be a leader,” she said. “I just feel like this isn’t the right time.”

The testing, conducted by researchers at the University of Washington, began on April 2. The city temporarily halted them after officials said they needed more time to assess potential effects on human health or the environment. Two weeks ago, Alameda published a report from the city manager, which found no risk whatsoever.

“The chemical components of the saltwater solution (which is similar to seawater) that is sprayed occur naturally in the environment,” the report said. The staff advised the city council to allow the experiment to proceed, possibly with additional safety measures such as monitors to measure air quality at the test site.

Sarah J. Doherty, director of the Marine Cloud Brightening Program at the University of Washington, which is conducting the experiment, said in a statement that she and her team are “disappointed by the city of Alameda’s decision.”

Dr. Doherty said her team was “exploring alternative sites” for the study. But she noted that the city’s own findings showed no risk from the experiment, and urged the city to reconsider its decision.

The question of whether the experiment should continue went beyond the local impact of the salt particles and into whether climate interventions such as cloud brightening should be implemented at all.

Some environmentalists oppose research into so-called climate intervention, also known as solar geoengineering. They argue that such technology risks unintended consequences and also diverts money and attention from efforts to reduce the use of fossil fuels, the burning of which is the underlying cause of climate change.

Opponents expressed concern that the tests in Alameda could bring society closer to large-scale deployment of such technology.

“While this is a local decision, it has far-reaching implications,” Gary Hughes of the environmental group Hands Off Mother Earth Alliance said at the meeting. “There is a global dynamic of climate justice at stake.”

In a statement after the vote, Mary Church, geoengineering campaign director for the Center for International Environmental Law, an advocacy group based in Washington, D.C., supported the city’s decision.

“The rejection rightly reflects the gravity of what is at stake for both local and global communities,” said Ms Church, whose organization wants countries to pledge not to use climate interventions.

Not everyone who spoke at the meeting, which included comments both in person and online, opposed the research.

A youth climate leader in Honduras urged the council to approve the project, saying the University of Washington had expertise that could help his country and others hardest hit by climate change.