Earth-cooling research to be piloted by Imperial aerospace engineers

UK is funding multiple new climate cooling projects that could avoid the worst effects of climate change

Aircraft emissions influence climate change through their effects on high-altitude cirrus clouds, which insulate the planet like a blanket.

Imperial College London researchers have been awarded £3.6 million from the UK’s Advanced Research and Invention Agency (ARIA) to understand why existing atmospheric particles (such as desert sand or airplane soot) appear to reduce the warming effect of cirrus, and investigate whether this effect might one day be used to cool the planet.

Operating in UK airspace, this project aims to gather vital real-world data on these natural cirrus cloud processes and how they are already being affected by the presence of aircraft engine soot.

This project is just one part of a programme that the UK government is hoping could give humanity extra time to reduce the carbon emissions from industry, transport, farming and manufacturing, that are changing our climate and exacerbating extreme weather events around the world.

Dr Sebastian Eastham, Senior Lecturer in Sustainable Aviation in Imperial’s Department of Aeronautics, who leads the project, said:

“With this funding from ARIA, we want to study the effect that aircraft have on climate warming through their inadvertent modification of cirrus clouds. We then want to understand if careful, deliberate application might eventually provide a safe, short-term and predictable way to cool our planet; to avert the worst of global heating – with its associated cost to lives, jobs and homes.

“We will look for evidence that aircraft-emitted soot causes the same reduction, first studying satellite data and then using dedicated flights to measure the effect of aircraft engine soot on cirrus. Confirmation would point to a possible climate cooling mechanism already in effect – albeit inadvertently – that could be used to achieve further cooling in the future.”

Climate change could cause global temperatures to increase by several degrees by the end of the century, which could lead to climate tipping points – abrupt changes in the Earth system that, if crossed, could have devastating and essentially irreversible consequences. Scientists don’t know when a tipping point might happen, or how long it would take to feel the effects if it did; significant uncertainties remain regarding the probability and potential impacts of any given tipping point.

ARIA’s Exploring Climate Cooling programme will explore more than one potential climate cooling approach in order to be comprehensive and to allow a range of potential options to be explored thoroughly and objectively. 

Successful outcomes from this programme include assessing the feasibility and risks of these approaches, as well as setting the standard for how research in this field can be conducted responsibly and inclusively. 

Dr Eastham said: “The transparency, external oversight and ethical governance central to ARIA make it ideal for this problem, ensuring that the smallest possible intervention is used to answer core scientific questions without introducing any unnecessary risk. We have built in stopping points where oversight committees can review activity, verify it is safe and within scope, and decide whether the project proceeds.”

This project brings together researchers from Imperial College London – including Dr Marc Stettler from the Department of Civil and Environmental Engineering and Dr Ed Gryspeerdt from the Department of Physics – alongside the University of Leeds, the University of Vienna, and RIKEN.

The team will combine computer modelling, satellite data analysis, and dedicated research flights to directly measure how atmospheric particles, including aircraft engine soot, affect cirrus cloud properties. Their work will provide crucial real-world data to refine climate models and inform future strategies for climate intervention, always with rigorous oversight and a commitment to responsible research.

This award is part of ARIA’s £56.8 million “Exploring Climate Cooling” programme, which supports 21 interdisciplinary teams investigating whether any climate cooling approaches could be feasible, scalable, and safe, with a strong emphasis on transparency, public engagement, and ethical governance.

Footnote

*This project is subject to final contract negotiation.