In 2025, the UK’s Exploring Climate Cooling Programme funded 22 scientific projects to explore innovative climate intervention methods designed to cool the planet and slow the onset of critical climate changes. These initiatives span atmospheric, oceanic, and space-based approaches, each aimed at building foundational knowledge and testing feasibility. Here are some of the key projects.

Image: New Scientist

Re-Thickening Arctic Sea Ice

• The University of Cambridge

This project investigates whether deliberately thickening Arctic sea ice during winter could help slow summer melt, reduce regional warming, and limit further ice loss. The approach involves pumping seawater from beneath the ice and spreading it on the surface, where freezing temperatures rapidly form thicker ice layers.

Controlled, small-scale experiments will take place in Canada over three winter seasons, from 2025-26 to 2027-28.

Cirrus Modification

• The Imperial College London

High-altitude cirrus clouds contribute to overall warming, yet predicting and modelling their formation remains challenging, creating a key uncertainty in climate projections. A major factor in this uncertainty is the limited knowledge of ice nucleating particles, tiny atmospheric particles on which cirrus clouds form.

The team aims to deepen our fundamental understanding of cirrus cloud formation, generating essential baseline knowledge to assess whether deliberately thinning these clouds could ever provide a safe and reliable way to cool the climate.

Increasing Cloud Reflectivity Using Seawater Sprays

• The Southern Cross University

This project focuses on Marine Cloud Brightening (MCB), a technique designed to cool specific regions by increasing cloud reflectivity through seawater sprays. Building on previous small-scale outdoor experiments conducted with local communities around Australia’s Great Barrier Reef, the team aims to deepen understanding of the atmospheric and microphysical processes involved and assess whether MCB could work safely and effectively in real-world conditions.

Space-Based Solar Reflectors

• The University of Glasgow

Highly speculative technologies, such as space-based solar reflectors, require careful early-stage evaluation. This project examines the technical feasibility of using space-based approaches to cool the Earth.

Conducted as a desk-based study, it explores the initial engineering steps and challenges of a hypothetical small-scale mission to test a space-based sunlight reflector, providing a conceptual understanding of the requirements for such an intervention.

Cloud Brightening with Electric Charge

• The University of Reading

This project explores the use of controlled electric charges to influence water droplets in fogs and clouds as an alternative to seawater spraying. The research aims to determine whether carefully managed electrical charges could provide a safe and effective way to increase cloud reflectivity.

Natural Materials for Stratospheric Aerosol Injection

• The University of Cambridge

Stratospheric Aerosol Injection (SAI) is a widely discussed potential method for cooling the climate, but commonly proposed materials, such as sulfates, pose significant risks, including ozone depletion and toxicity. Determining whether safer, alternative materials could be feasible and effective for SAI remains a critical unanswered question. The project will conduct fundamental research to investigate the properties and behavior of innovative, non-toxic, non-sulfate materials under carefully controlled conditions.

The programme emphasizes that these are exploratory studies, not deployment initiatives. The primary aim is to generate critical scientific data to inform future climate strategies.

Learn more about The UK's Exploring Climate Cooling Programme on its official website.