A Potential Pain Reliever for Earth: Cloud Brightening
Earth needs help. In Korea, when autumn was supposed to bring in the cool temperature, hitting us with morning breezes, the temperatures of mid-September rose over thirty degrees. The New York Times reports that the monsoon in Nepal has killed at least more than a hundred people. Signs of climate change have been hitting continuously—and although we think we know all of Earth’s symptoms, the pains are coming from the deep ends of Earth.
Central to these discussions of climate change is the role of carbon dioxide (CO₂) as the primary greenhouse gas contributing to global warming. Despite decades of efforts to curb emissions, atmospheric CO₂ levels continue to rise, necessitating innovative solutions that go beyond traditional mitigation strategies. Scientists have brought up a new solution to this climate crisis: Marine cloud brightening. The concept itself was first proposed by the British physicist John Letham in 1990. The process involves spraying tiny aerosol particles into clouds over the ocean to increase their reflectivity. Eventually what they are aiming for is to bounce back more sunlight into outer space. This way, the earth will be cooler, although the effects may be temporary.
Recently, one significant step of improvement occurred in April 2024. Scientists from the University of Washington conducted the first outdoor test of Marine cloud brightening. The Cloud Aerosol Research Instrument (CARI), the medium that generates a sea salt plume for the process of cloud brightening, would spray the particles in the form of a mist and then observe how they would behave in real-world conditions of the atmosphere. The goal of this experiment was to determine whether the machine could produce aerosols —submicron particles about 1/700th the thickness of a human hair— of the right size, which are crucial for brightening clouds effectively. Although the test itself could be considered successful as the machine was able to demonstrate its capabilities, the scientist explained that more research and experimentation are necessary. There may be potential side effects such as changes in the ocean circulation pattern, precipitation, or ecosystem.
Via College of Environment, University of Washington
Due to this, there have been opposing sides to the experiment. Environmental organizations like Greenpeace and Friends of the Earth have advocated for the potential implications, ethically and ecologically. Karen Orenstein, director of the Climate and Energy Justice Program at Friends of the Earth U.S., describes solar geoengineering as “an extraordinarily dangerous distraction” from the urgent need to reduce emissions. She points out that MCB and other solar radiation modification techniques do not address the underlying causes of climate change, such as the buildup of greenhouse gasses in the atmosphere. Instead, they offer only temporary and potentially risky fixes, which could lead to complacency in the fight against climate change. Orenstein’s view reflects a broader concern among environmentalists that pursuing geoengineering may provide a false sense of security, delaying necessary policy changes and technological innovations that are vital for decarbonizing the global economy. Bleaching the clouds may just result in changing patterns of the clouds forcing inevitable repercussions of the new invention. It might be true that instead of searching for geoengineering solutions to mitigate climate change, efforts toward reducing the use of fossil fuels and carbon emissions may be more worthwhile.
However, if the MCB project is successful, Earth may be able to relieve itself from the excruciating heat. As the United States government has been leaning towards the success of this project, they have funded research into various technologies including Marine cloud brightening. Kelly Wanser, who is executive director of SilverLining, a non-profit organization supporting climate invention research, argues that the MCB project may be effective in preventing the worst scenarios of climate change. She states, “MCB is not a silver bullet” but rather a “temporary measure to buy time while society transitions away from fossil fuels.”
At the current stage, although there have been many inventions toward the mitigation of climate change, the discussions have been highly controversial. The long-term effects of the research are also a hot issue among the debaters. Although we are not sure if the MCB project could become a hero in this climate crisis, continuous inventions will hopefully bring positive effects.