Photos of over sea cloud at sunset

Spraying the Bay: A Controversy 


Humans have raised atmospheric carbon emissions by 50% in the last 200 years. In 2023 alone, 38 billion metric tons of carbon dioxide were released. This has devastating consequences for the planet. The pH of the ocean has dropped, and temperatures are steadily rising. Earth’s natural carbon sinks cannot keep up. This is exactly why scientists have been working tirelessly to find solutions to counter the negative impacts of climate change. While there still is no remedy for minimizing the greenhouse gasses already trapped in the atmosphere, researchers at the University of Washington (UW) are looking into a way to reduce climate warming: marine cloud brightening. 

Marine cloud brightening (MCB) relies on the reflectivity of clouds, explained by the Twomey Effect. It states that clouds are most reflective when they are composed of many small droplets. Increasing the reflectivity of clouds would brighten them, which would, hypothetically, increase their reflection of sunlight, reduce the amount of heat absorbed by the atmosphere, and thus lead to cooler temperatures.

Researchers were first inspired to try MCB after viewing satellite images demonstrating that ship emissions often brightened clouds in the lower marine atmosphere. It was a favorable idea to climate scientists, as sea-salt aerosols are one of the most common, naturally existing aerosols in the atmosphere. Additionally, its application would be quite simple. Artificial MCB would be conducted via ships spraying saltwater into areas with low-hanging clouds. Adhering to the Twomey Effect, the addition of these small saltwater particles would heighten the reflectivity of clouds. 

While MCB is a great idea in theory, little is known about its feasibility or its greater border environmental impacts. This is partially why Alemeda residents and city officials were shocked to find out that UW had already commenced their research. Apparently, the scientists had begun testing their Cloud Aerosol Research Instrument (CARI), a device that could measure plumes of aerosols, on the flight deck of the U.S.S Hornet in early April. They had originally planned a 20 week test run, with three sprays occurring per day four times a week–all without the knowledge of the local townsfolk

The people of Alameda only became aware of the project after the NYT published an article about it later that month. City officials immediately called for it to be shut down due to safety concerns. Though the UW research team had confirmed their work wouldn’t pose a threat to the local community very early on, the city called their own investigators, Terraphase Engineering. The company finally concluded their investigation last week, on May 23. They deduced that the experiment posed no measurable health risks and recommended that the City of Alameda provide “consent for the activity to resume.” 

In spite of Terraphase’s findings, the manner in which the MCB research had been  conducted was completely unacceptable. A cornerstone of reputable research is transparency; research means nothing if the public can’t trust the officials behind it. The geoengineers behind the MCB project are doing very important work, but they have tarnished its credibility by taking measures to keep their work private.  

There are times when confidentiality is important to research, but when it’s being conducted in a public setting such as the U.S.S. Hornet Air and Space Museum and involves altering the environment, the community has a right to know about it, even if there are no health risks. The City of Alameda will hold a meeting to determine the fate of the MCB research on June 4. Hopefully, the City can look past the researcher’s mistakes for the sake of the greater good.