A solar geoengineering technology that brighten the clouds to dim the sun may help reduce the impacts of weather events like Super El Niño
By
Society could benefit from using geoengineering as a tool to mitigate the floods, extreme heat and other weather events that a Super El Niño would bring, a new study published by the University of California’s Institute of Oceanography has found. The study, published in the journal Science Advances, was led by researchers Kate Ricke and Jessica Wan, whose previous research found that the smoke-brightened clouds throughout the southeastern Pacific Ocean appeared to play a key role in creating global La Niña-like weather patterns.
Enjoying this article? Check out our related reads…
Using a seasonal forecasting model, researchers proposed a strategy that would involve injecting special aerosols into the Earth’s stratosphere – the second-lowest level of Earth’s atmosphere. This would make clouds over the sea brighter, a process known as marine cloud brightening. Brighter clouds could reflect sunlight back into space, helping cool the surface below.
In the study, the team modelled what would have happened if deliberate marine cloud brightening was deployed in the Southeast Pacific during major El Niños such as 2015 and 1997. The simulation suggested that targeted marine cloud brightening would indeed counter its effects, becoming more effective the earlier in the El Niño event it was introduced. According to the data collected, marine cloud brightening could increase the cooling and drying effects associated with La Niña by more than 40 per cent.
However, there is much controversy around the use of geoengineering to intervene with natural phenomena such as Super El Niños. It is effective at encouraging short-term cooling effects, but fails to address the long-term impacts associated with climate change, such as reducing carbon dioxide in the atmosphere. In addition, cloud brightening would do nothing to address ocean acidification, a process which harms marine ecosystems.
What are the problems of geoengineering to solve this crisis?
Using geoengineering techniques such as cloud brightening could lead to disastrous unintended consequences for the planet, such as unpredictable disruptions to global weather patterns (like deepening droughts in sensitive areas such as the Amazon) and the threat of a dangerous ‘termination shock’ – a spike in global temperatures – if its usage is suddenly interrupted.
Although risky, geoengineering has become a vital area to research, as human efforts are not doing enough to reduce carbon emissions – which remains the source of intensified weather events such as the Super El Niño.
Furthermore, the abrupt introduction of solar geoengineering may not be effective enough to fully remedy changes caused by a warming deep ocean, such as the slowing of the Atlantic Meridional Overturning Current (AMOC), according to a recent study. Other problems caused by a warming deep ocean, including altered weather patterns, sea level rise and weakened currents, would also persist even if geoengineering were utilised.
Researchers say much more study is needed to make an adequate judgement on whether geoengineering such as cloud brightening is worth the risks.
They also said they are not aware of any proposals to test their findings on the 2026 El Niño, but as research efforts develop, governments could consider actual geoengineering schemes in the future.
‘It’s a different way of thinking about geoengineering,’ Ricke said. ‘We need to understand a lot more, but if there is a way to use this in addition to the risk reduction tools to mitigate El Niños, why wouldn’t we consider it?’
