Scientists Discover that Cloud Engineering Can Act as an Effective Painkiller for Global Warming

Cloud engineering may be more effective at cooling the climate than previously thought - and the effect is largely due to increased cloud cover.

Scientists discover that cloud engineering can act as an effective painkiller for global warming
Ship performs sea cloud whitening (MCB) by spraying aerosols into the atmosphere through a turbine installed on the deck (image: Southern Cross University)

The practice of marine cloud brightening (MCB) has attracted a lot of attention in recent years as a possible way to compensate for the effects of global warming caused by humans and gain some time as the global economy decarbonizes.

The MCB works through the controlled spraying of tiny particles (aerosols) in the atmosphere, with the aim of increasing the amount of sunlight reflected by the clouds. Although MCB experiments are already underway in some regions of the world - such as Australia, to protect coral reefs from bleaching - there is still much to be understood about their long-term effects and possible unintentional consequences.

How scientists used a volcano to get answers about the MCB

Using an innovative method, the researchers employed a "natural experiment" taking advantage of the eruption of the Kilauea volcano in Hawaii to study the complex interactions between natural aerosols, clouds and climate. The eruption of the volcano expels aerosols into the atmosphere in the same way as MCB turbines.

Scientists discover that cloud engineering can act as an effective painkiller for global warming
The Kilauea volcano in Hawaii expels aerosols into the atmosphere in the same way as MCB turbines - which allows researchers to use it as a "natural experiment".

Through artificial intelligence and analysis of historical data from satellites and weather stations, the team developed a predictive model that allowed to identify the direct impacts of volcanic aerosols on cloud cover and properties.

The results were surprising, revealing an increase of up to 50% in cloud cover during periods of volcanic activity, resulting in a regional cooling effect of up to -10 Wm-2.

Global heating and cooling are measured in watts per square meter, and a negative value indicates cooling. As a comparison parameter, doubling carbon dioxide in the atmosphere would lead to a warming effect of approximately +3.7 Wm-2 on a global average.

While previous studies focused on the influence of aerosols, this new research revealed that the increase in cloud cover is mainly responsible for the effect, causing 60 to 90% of the cooling.

Scientists discover that cloud engineering can act as an effective painkiller for global warming
MCB turbine bombarding aerosols into the atmosphere. The method is a temporary "analgesic", but does not solve the roots of the problem (image: Southern Cross University)

The main author of the study, Dr. Ying Chen, emphasizes that although the MCB may be useful as a temporary intervention, the method does not address the roots of global warming - which are greenhouse gas emissions.

Therefore, Chen describes the MCB as a temporary "analgesic" for the symptoms of global warming, highlighting that only by reducing carbon emissions and investing in clean and sustainable energy solutions will we be able to cure this disease once and for all.

The University of Birmingham's research is part of a growing global interest in cloud engineering as a possible tool to combat climate change. In the UK, the government recently launched a £10.5 million research program to explore solar radiation management approaches, including the MCB.

Research is also increasing in other parts of the world. In the United States, a team from the University of Washington recently conducted their first outdoor aerosol experiment on a disabled aircraft carrier in Alameda, California.

At the end of the day, these initiatives highlight the importance of continuing to investigate and develop innovative solutions to address global climate challenges.

News reference:
Chen, Y., Haywood, J., Wang, Y. et al. Substantial cooling effect from aerosol-induced increase in tropical marine cloud cover. Nat. Geosci. (2024).