The distribution of clouds across the world is changing in a way predicted by climate change models, satellite images confirm.
A paper published in the journal Nature on Tuesday examines how the large-scale patterns of clouds have changed over the decades.
The satellite data had been used in previous studies, but the researchers behind this paper say the datasets have been corrected by removing artefacts - while it means the data can't be used for global averages of cloud change, it still works for examining distribution.
The resulting observations link a rise in greenhouse gas concentrations to the changing cloud distribution. The paper found storm tracks, narrow areas where storms travel across the world, are changing from near the centre of the globe to the poles.
All over the world clouds are rising higher.
"As cloud tops rise, their greenhouse effect becomes stronger," the researchers say.
And subtropical zones are losing cloud cover, with an expansion in subtropical dry zones noted.
"Both of these cloud changes have a warming effect on climate."
They're all changes predicted by earlier modelling.
The trends are different from modelling where no external influences, such as a rise in concentrations of greenhouse gases attributed to humans, are accounted for.
Because of this, the study attributes the changes mostly to the increase in carbon emissions and other greenhouse gases such as carbon dioxide and nitrous oxide, and the distribution of volcanic aerosols decreasing.
Clouds reduce the amount of heat lost to space by reflecting back sunlight, which affects the planet's energy levels considerably.
"We expect that increasing greenhouse gases will cause these cloud trends to continue in the future, unless offset by unpredictable large volcanic eruptions," the study says.