Alameda halts cloud brightening tests
The city of Alameda has ordered the University of Washington to halt a controversial marine cloud brightening experiment on the decommissioned aircraft carrier Hornet, citing health and environmental safety concerns.
In a May 4 Facebook post, city of Alameda officials wrote that the experiment “was taking place without the City’s knowledge on the deck of the USS Hornet.” Research began on April 2, and the Chronicle documented a demonstration of the experiments. The study, the first of its kind nationally, is intended to slow global warming by reflecting sunlight back to space.
“Upon learning of the spraying experiment, the city instructed the USS Hornet and the University of Washington to halt the experiment on the grounds that it was in violation of the city’s lease with the USS Hornet,” the city of Alameda wrote in its Facebook post.
The Alameda Post first reported the news.
The University of Washington Marine Cloud Brightening Research Program wrote in an email that the city of Alameda was “informed of the plans for the atmospheric science educational exhibit in advance,” at the USS Hornet Sea, Air and Space Museum.
“Following news articles in early April, City officials were made more closely aware of the research studies taking place and requested a more detailed review. Prior to the City’s posting, our team had already agreed to pause our studies for a period while they undertook this review,” the researchers wrote.
The city of Alameda said it had hired a consulting firm to independently assess whether the microscopic chemical compounds pose a respiratory hazard to humans or animals.
“At this time, there is no indication that the spray from the previous experiments presented a threat to human health or the environment,” the city of Alameda wrote.
Kelly Wanser, the project’s senior adviser, told the Chronicle in April that aerosol emissions from the experiment were within regulatory thresholds for air quality. Wanser said the team alerted local air quality authorities as a precaution.
“The findings from the evaluation will be provided to the public, and shared with the city council for consideration in June,” the city said in its statement. It wasn’t immediately clear what the council would vote on in June, and whether or when the research could resume, pending the results of the health assessment.
At the time of publication, the city of Alameda had not responded to a request for comment.
The Coastal Atmospheric Aerosol Research and Engagement facility aboard the Hornet is led by scientists at the University of Washington, along with SRI International, Silver Lining and other institutions. The field research, in its initial stages, was originally planned to last through summer, with the goal of artificially replicating naturally occurring sea spray, similar to what occurs at the beach when waves break. Scientists told the Chronicle that the spray is composed of water and pressurized microscopic salt particles.
Tiny sea salt aerosols act as the seed for water vapor particles in marine clouds that hang along the California coast and in the Bay Area. Hypothetically, increasing the concentration of small sea salt particles in a cloud could reflect more sunlight back to space. This local or regional cooling could offset some effects of climate change as anthropogenic carbon dioxide levels continue to rise to dangerous levels.
The researchers had said they eventually hoped to scale up their research in a different location, somewhere off the California coast. Scientists involved in the Alameda study said the work is small scale and would not alter weather patterns in the East Bay.
“We continue to appreciate our engagement with the community on the nature of this type of research study, which we do not consider an experiment, as it is not designed to impact clouds, the environment or climate. We appreciate the City’s care regarding this effort and support their approach fully.”