An anonymous reader quotes a report from The Guardian: Dust that billows up from desert storms and arid landscapes has helped cool the planet for the past several decades, and its presence in the atmosphere may have obscured the true extent of global heating caused by fossil fuel emissions. Atmospheric dust has increased by about 55% since the mid-1800s, an analysis suggests. And that increasing dust may have hidden up to 8% of warming from carbon emissions. The analysis by atmospheric scientists and climate researchers in the US and Europe attempts to tally the varied, complex ways in which dust has affected global climate patterns, concluding that overall, it has worked to somewhat counteract the warming effects of greenhouse gasses. The study, published in Nature Reviews Earth and Environment, warns that current climate models fail to take into account the effect of atmospheric dust.

About 26m tons of dust are suspended in our atmosphere, scientists estimate. Its effects are complicated. Dust, along with synthetic particulate pollution, can cool the planet in several ways. These mineral particles can reflect sunlight away from the Earth and dissipate cirrus clouds high in the atmosphere that warm the planet. Dust that falls into the ocean encourages the growth of phytoplankton — microscopic plants in the ocean — that absorb carbon dioxide and produce oxygen. Dust can also have a warming effect in some cases — darkening snow and ice, and prompting them to absorb more heat. But after they tallied everything up, it seemed clear to researchers that the dust had an overall cooling effect.

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