Cloud engineering, specifically the practice of marine cloud brightening (MCB), has been found to be more effective for climate cooling than previously thought. A study published in Nature Geoscience by researchers at the University of Birmingham revealed that MCB primarily works by increasing cloud cover, accounting for 60-90% of the cooling effect. Previous models focused on the ability of aerosol injection to brighten clouds and reflect sunlight back into space. This practice has gained attention as a way to offset the effects of global warming while transitioning to a decarbonized economy. Experiments with MCB are currently being conducted in Australia to reduce bleaching on the Great Barrier Reef.
The research team created a “natural experiment” to study the interactions between aerosols, clouds, and climate during the effusive eruption of Kilauea volcano in Hawaii. By using machine learning and historic data, they developed a predictor to show how clouds would behave during non-volcanic periods, enabling them to identify the impacts caused directly by volcanic aerosols. They found that cloud cover increased by up to 50% during volcanic activity, resulting in a regional cooling effect of up to -10 W m-2. Global heating and cooling are measured in watts per square meter, with a negative figure indicating cooling. For comparison, doubling CO2 would lead to a warming effect of +3.7 W m-2 on a global average.
Collaborating with institutions such as the Met Office, the Universities of Edinburgh, Reading, and Leeds, ETH Zurich, and NASA, the researchers highlighted the potential of MCB as a climate intervention. Lead author Dr. Ying Chen emphasized that while MCB could be useful, it does not address the root causes of global warming from human-produced greenhouse gases. It should be viewed as a temporary measure, akin to a painkiller, and efforts should continue to understand the impacts of aerosols on clouds, assess global risks, and work towards decarbonizing human activities. The research coincides with a growing interest in cloud engineering globally, with initiatives such as the UK’s £10.5m research program on solar radiation management and the US’s ARIA focusing on climate and weather management technologies.
The study’s findings suggest that MCB has the potential to be a more effective climate intervention than previously believed. By increasing cloud cover, MCB contributes significantly to the cooling effect, demonstrating a promising strategy for combating global warming. However, there are still uncertainties and challenges associated with MCB, including the variability in cloud responses to aerosols and the need for further research to understand and mitigate potential risks. Continued research is essential to improve our understanding of aerosols’ impacts on clouds, evaluate global implications, and develop sustainable solutions for climate change mitigation.
The use of machine learning and historical data in the research allowed for a comprehensive analysis of the impacts of aerosols on cloud cover and climate. By leveraging data from the Kilauea volcano eruption, the researchers were able to quantify the cooling effect of increased cloud cover resulting from aerosol interaction. This innovative approach provides valuable insights into the potential of cloud engineering technologies like MCB to address climate change challenges and highlights the importance of interdisciplinary collaborations in advancing climate solutions.
Overall, the study sheds light on the effectiveness of cloud engineering, particularly marine cloud brightening, as a viable climate intervention strategy. While MCB shows promise in cooling the climate by increasing cloud cover, it should be viewed as a complement to broader efforts to address greenhouse gas emissions and decarbonize human activities. Research initiatives like the one conducted by the University of Birmingham and its collaborators contribute valuable knowledge to the field of climate science and provide a foundation for future developments in cloud engineering and climate intervention technologies.
