Researchers are exploring a controversial solar geoengineering proposal that could potentially mitigate the impacts of a forecasted strong El Niño season. The plan, detailed in a study published in the journal Science Advances, suggests injecting particles into clouds to make them brighter, thereby reflecting solar radiation back into space and cooling the Earth's surface.
The National Oceanic and Atmospheric Administration's Climate Prediction Center has indicated an 81% chance of a "very strong" El Niño by December. Such an event is characterized by unusually warm surface temperatures in the Pacific Ocean and can lead to extreme weather, including droughts, heavy rainfall, and heatwaves, with potential global economic costs in the trillions of dollars.
While some attribute the exacerbation of El Niño's effects to climate change, the World Meteorological Association states there is no evidence that climate change increases the frequency or intensity of El Niño events. Regardless, scientists are examining potential mitigation strategies.
The proposed method, termed "marine cloud brightening," would involve deploying aerosols into the stratosphere. Researchers hypothesize that this approach could offer a more targeted response to natural climate variations like El Niño, as opposed to the continuous, long-term response required for greenhouse gas reduction.
The study built upon previous research that observed how bushfire smoke aerosols over the Pacific caused clouds to brighten and reflect solar radiation. The UC San Diego researchers simulated the deployment of such a sun-blocking method in the Southeast Pacific during the major El Niños of 1997 and 2015, finding it could increase cooling and drying effects by up to 40%.
However, the concept of geoengineering faces significant criticism. Some climate scientists argue that such proposals could distract from the essential goal of reducing carbon emissions. Concerns also exist regarding the potential for unforeseen negative side effects. Andrew Dessler, a professor of atmospheric science at Texas A&M University who was not involved in the research, cautioned that models are imperfect and there is a risk of creating a worse problem than the one being addressed.
There are currently no concrete plans to test this solar dimming method on the impending El Niño. Nonetheless, lead researcher Kate Ricke emphasizes the importance of considering all potential solutions in the face of looming climate threats.