ADVERTISEMENT

Aerosol pollution generated by humans cools the climate more than previously thought, new research has found.

The effect of fine particles on cloud properties may be masking the true extent of global warming, according to the study led by the University of Eastern Finland and the Finnish Meteorological Institute.

The authors say the findings will help improve the ability of scientific models to predict the future impact of climate change and global warming induced by greenhouse gas emissions.

Aerosols have ‘partly counteracted greenhouse gas warming’

Aerosols are tiny floating particles in the air which are often not or barely visible to the human eye. They can come from natural sources such as volcanoes or sea spray but also from human-caused sources such as the burning of fossil fuels, industrial emissions or even cooking.

The new study found that the formation and properties of low-altitude clouds are highly sensitive to changes in atmospheric concentrations of these tiny particles.

The discovery may provide a better understanding of how much aerosol pollution from human activity has slowed down climate warming caused by greenhouse gases.

The research, published in the journal Nature Geoscience, examined long-term measurements collected at Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS) monitoring stations in Svalbard and Finland.

The characteristics of clouds can vary a lot over time, meaning scientists had to take long-term measurements to accurately determine how aerosols could be influencing them.

They found that cloud properties are more strongly affected by changes in aerosol levels than previously believed.

“Emissions of anthropogenic fine particles have cooled the climate by modifying cloud properties and have thus partly counteracted greenhouse gas-induced climate warming,” says Professor Annele Virtanen from the University of Eastern Finland.

“Based on these results, this cooling effect is at the upper end of previous estimates based on satellite data.”

Findings will help develop more accurate climate models to predict warming

The study also evaluated the ability of climate models to accurately describe the relationship between cloud properties and aerosol concentrations.

By making a comparison with real world observations, scientists found problems with how key processes are represented in the models.

The study also identified significant variations between different models when it came to predicted interactions between aerosols and clouds.

“These findings will help us develop more accurate climate models to predict future climate change,” says research professor Sami Romakkaniemi from the Finnish Meteorological Institute.

ADVERTISEMENT

Romakkeniemi adds that these models play a “key role” in assessing what impact different future emissions scenarios could have on climate change.