Produced by: Mohsin Shaikh
The UK is funding £50M in real-world experiments to reflect sunlight and cool the Earth—marking its first foray into climate geoengineering.
Scientists will trial Marine Cloud Brightening—spraying sea salt into clouds to make them whiter and more reflective.
Stratospheric Aerosol Injection involves releasing particles high in the sky to bounce sunlight back into space and reduce heat.
Aria’s lead says simulations aren’t enough—small outdoor trials are essential to understanding these theories in practice.
Volcanic eruptions and ship trails have already shown how atmospheric particles can brighten clouds and cool the planet.
Emissions from ships create reflective cloud streaks—proof that even unintentional pollution can cool the Earth.
Another method being studied involves thinning cirrus clouds—those wispy heat-trapping clouds—to let more warmth escape into space.
Planes may cool Earth by tweaking clouds; sulphur from fuel modifies cloud behavior, showing unintentional geoengineering in action.
Critics warn that geoengineering could trigger unknown side effects—and may distract from cutting carbon emissions urgently needed now.