Research published in the journal Science Advances indicates that an intervention capable of decreasing or 'blocking' a considerable portion of the solar radiation reaching the Pacific Ocean has the potential to mitigate the severity of future El Niño episodes and their global impacts.
Methodology and Proposal for Solar Geoengineering
Scientists from the University of California in San Diego and the Scripps Institution of Oceanography conducted this study, examining the technique of marine cloud brightening as a possible regional tactic against extreme weather events. This proposal, termed solar geoengineering, aims to increase the reflectivity capacity of clouds over the ocean.
The researchers based their assessments on climate models inspired by a natural event observed after large fires in Australia. El Niño, a natural phenomenon in the tropical Pacific linked to the weakening of trade winds, causes the displacement of ocean heat towards the coast of South America, altering global climate patterns such as droughts, heavy rains, and changes in cyclone activity.
Investigation of Solar Reduction Impact
The team, led by climate scientist Katherine Ricke, investigated whether localized reduction of solar energy in the Pacific could prevent certain El Niño episodes from reaching more severe levels. To achieve this, they utilized marine cloud brightening, a process involving dispersing seawater into the atmosphere to make certain clouds more reflective.
Although the strategy has not yet been tested on a large scale in a real environment, the models found a natural precedent during the Australian bushfire season between 2019 and 2020, which released a lot of smoke into the atmosphere. Previous studies showed that particles from these fires helped trigger a rare sequence of three consecutive La Niña episodes, the opposite of El Niño.
Based on this scenario, scientists created simulations to verify how a similar modification in solar radiation incidence would affect historical El Niño events. The model results indicated that reducing sunlight over the Pacific could decrease the strength of these episodes and soften the associated climatic consequences.
Implications and Expert Warnings
The research does not present geoengineering as a ready-to-implement solution. While geoengineering is often debated as a method to cool the planet and compensate for warming caused by fossil fuels, this new work suggests a more targeted application, focused on specific occurrences of the climate system.
However, experts warn about the risks involved. Andrew Dessler, an atmospheric science professor at the University of Texas A&M, considered the proposal scientifically plausible but emphasized that its execution could provoke political conflicts and unforeseen outcomes. The researchers themselves acknowledge numerous uncertainties before any practical test, as the intentional manipulation of atmospheric processes can generate unanticipated effects.
Katherine Ricke stated that this line of investigation arises from the possibility that humanity may need to seek alternatives if it cannot control pollution from fossil fuels.