As a scholar researching clouds, I have spent much of my time trying to understand the economy of the sky. Not the weather reports showing scudding rainclouds, but the deeper logic of cloud movements, their distributions and densities and the way they intervene in light, regulate temperatures and choreograph heat flows across our restless planet.
Recently, I have been noticing something strange: skies that feel hollowed out, clouds that look like they have lost their conviction. I think of them as ghost clouds. Not quite absent, but not fully there. These wispy formations drift unmoored from the systems that once gave them coherence. Too thin to reflect sunlight, too fragmented to produce rain, too sluggish to stir up wind, they give the illusion of a cloud without its function.
We think of clouds as insubstantial. But they matter far beyond their weight or tangibility. In dry Western Australia where I live, rain-bringing clouds are eagerly anticipated. But the winter storms which bring most rain to the south-west are being pushed south, depositing vital fresh water into the oceans. More and more days pass under a hard, endless blue – beautiful, but also brutal in its vacancy.
Worldwide, cloud patterns are now changing in concerning ways. Scientists have found the expanse of Earth’s highly reflective clouds is steadily shrinking. With less heat reflected, the Earth is now trapping more heat than expected.
A quiet crisis above
When there are fewer and fewer clouds, it doesn’t make headlines as floods or fires do. Their absence is quiet, cumulative and very worrying.
To be clear, clouds aren’t going to disappear. They may increase in some areas. But the belts of shiny white clouds we need most are declining between 1.5 and 3% per decade.
These clouds are the best at reflecting sunlight back to space, especially in the sunniest parts of the world close to the equator. By contrast, broken grey clouds reflect less heat, while less light hits polar regions, giving polar clouds less to reflect.
Clouds are often thought of as an ambient backdrop to climate action. But we’re now learning this is a fundamental oversight. Clouds aren’t décor – they’re dynamic, distributed and deeply consequential infrastructure able to cool the planet and shape the rainfall patterns seeding life below. These masses of tiny water droplets or ice crystals represent climate protection accessible to all, regardless of nation, wealth or politics.
On average, clouds cover two-thirds of the Earth’s surface, clustering over the oceans. Of all solar radiation reflected back to space, clouds are responsible for about 70%.
Clouds mediate extremes, soften sunlight, ferry moisture and form invisible feedback loops sustaining a stable climate.
Earth’s expanse of white, reflective clouds is shrinking decade after decade.
Bernd Dittrich/Unsplash, CC BY-NC-ND
When loss is invisible
If clouds become rarer or leave, it’s not just a loss to the climate system.