If you’ve ever prayed for a big, juicy raincloud to appear in the sky to dampen parched drought-ridden earth, or even sought the welcome shade of a passing cumulus cloud under the blazing sun, you’ll know just how important clouds are to life on our planet.

But beyond shade and rainfall, these fluffy-looking formations of water and ice droplets hold a very important role.

Clouds are vital in our fight against climate change.

This is because clouds reflect radiation and light back into space, allowing the Earth’s surface to stay cool.

They also act as a kind of absorbent blanket around the earth, absorbing radiation from our own planet and radiating it back down. This can be vital for keeping us warm, but if too many greenhouse gases are present in our atmosphere, these – along with our radiation – can become trapped under the cloud cover, resulting in the planet becoming warmer.

Some of the planet’s most important areas of cloud cover are the band that stretch around the equator, and in the jet streams. This is because of the way that air circulates around the planet’s various latitudes: temperature differences between cold and warm air, when they meet, causes a difference in pressure.

This pressure difference causes the various cycles of air and wind around our planet to push clouds towards the equatorial cloud belt and the subtropical and polar jet streams, resulting in a greater number of storms in these areas.

At the equator, a low pressure band called the Inter Tropical Convergence Zone (more commonly referred to as the ITCZ) is a band of low pressure at the place where the North and South Hemispheres meet, and their weather systems push back against one another. This is the location of the band of clouds that have, for as long as our atmosphere has existed, stretched around the breadth of our planet.

Though these are the areas in which clouds are most prolific, they of course occur across the planet, as the sun causes water to evaporate, and it cools and condenses in the sky to form clouds.

In a vital leap forward in the fight against climate change, a team of geophysicists and climate scientists have made a discovery.

By examining data from NASA’s Terra satellite, the climate experts have discovered that over the last 35 years, our planet’s cloud cover has changed.

Firstly, cloud formations are moving. Not only have the bands of clouds stretching around the equator become more narrow, the storms that are prevalent in the mid latitude jet streams have moved closer to the North and South poles, meaning that the space in which they are able to form and grow has got smaller, hampering the planet’s overall cloud cover.

In a paper recently published in the academic journal Climate Dynamics and presented at a conference of the American Geophysical Union, the scientists explained how this change has taken place in the mid latitudes over time:

“In the midlatitude zones, a strong contraction of the storm-cloud regions produces cloud radiative warming, which is counteracted by an increase in cloud radiative cooling in the low cloud cover region, resulting in a net midlatitude cloud radiative warming.”

Meanwhile, in the tropics, the situation is equally problematic, as the scientists go on to explain:

“In the tropics, the contraction of the ITCZ produces a net cloud radiative warming, which is aided by an increase in cloud radiative warming in the low cloud cover region. This results in tropical cloud radiative warming. The results indicate that changes in large-scale dynamical processes, primarily midlatitude storm shifts and ITCZ narrowing, produce contraction of the world’s storm-cloud zones and constitute the primary contributor to the recent increase in cloud radiative warming.”

Why is all this happening?

Two words: climate change.

Though the scientists are still searching for the full explanation, it seems key that humans have affected the planet’s atmosphere to such an extent that even natural processes like cloud formation have changed.

While the calculated figure – a reduction of about 1.5% every decade – sounds small, it is huge in climatic terms.

This is because of the seriousness of the cycle that the planet seems now to be in: the climate crisis has caused fewer clouds to form, an the formation of fewer clouds leads to increased global warming.

It’s a loop that shows no sign of an end point, as Bjorn Stephens – a climate scientist at the Max Planck Institute for Meteorology – explained the in an interview with the journal Science:

“If you calculate these trends, it’s massive. This would indicate a cloud feedback that’s off the charts.”

This shift is detrimental to the planet for two key reasons.

Firstly, we need clouds in order to block harmful radiation from space.

But perhaps even more importantly, they are vital for providing the rain that nourishes our crops and the shade that stops our entire planet from sizzling.

The news that clouds are on the decline is another dire warning about the state of the climate crisis.

If you thought that was interesting, you might like to read about why we should be worried about the leak in the bottom of the ocean.