University of Tartu Associate Professor in Climate Physics Velle Toll has been awarded a prestigious European Research Council (ERC) Consolidator Grant to determine just how much human-made air pollution particles help cool the Earth’s climate.
The five-year, nearly two-million-euro project aims to close a critical gap in scientists’ understanding of how aerosols counteract global warming.
While the warming effect of greenhouse gases emitted by burning fossil fuels is well established, their cooling counterpart – air pollution particles – remains far less understood. These aerosols act as cloud condensation nuclei, altering cloud properties and ultimately producing a cooling influence on the planet. Exactly how strong that influence is, however, has long puzzled climate researchers.
According to Toll, this uncertainty has important real-world consequences. Reducing air pollution is essential for public health, but it can also accelerate global warming by removing particles that currently mask some of the warming caused by greenhouse gases.
He said: ‘It is necessary to close this gap in our current knowledge. If we get confirmation that the cooling effect of air pollution particles on the climate is greater than previously thought, it would mean that the Earth’s climate is more sensitive to anthropogenic greenhouse gases than we currently know. Therefore, reducing the emissions of air pollution particles speeds up global warming, and each tonne of greenhouse gases released into the atmosphere warms the climate more than we now assume.’
One of the main reasons aerosol-related cooling remains poorly quantified is the difficulty of separating the effects of pollution from natural weather variability. Toll’s earlier work helped break this barrier by comparing the properties of clouds near large industrial sources with nearby unpolluted clouds.
By analysing hundreds of polluted cloud regions near factories, Toll’s team demonstrated a pathway to isolating aerosol effects with far greater confidence. The ERC-funded project will scale this approach massively by combining machine learning, wind-spread modelling and global satellite observations.
The team will use public datasets detailing industrial activity and ship movements to simulate how air pollution disperses. Millions of cloud cases will then be examined to determine whether past estimates underestimated the cooling influence of aerosols – an answer with major implications for future climate projections.
The project, ‘Tracking Polluted Clouds: the Plausibility of a Strong Aerosol Cooling Effect on Earth’s Climate,’ was selected from 3,121 proposals in the latest ERC Consolidator Grant competition. A total of 349 projects from 25 countries received funding.
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