Atmospheric dust may have hidden the true magnitude of global warming |  Climate crisis

Atmospheric dust may have hidden the true magnitude of global warming | Climate crisis

Atmospheric dust may have hidden the true magnitude of global warming | Climate crisis

Dust rising from desert storms and arid landscapes has helped cool the planet in recent decades, and its presence in the atmosphere may have obscured the true magnitude of global warming caused by fossil fuel emissions.

Atmospheric dust has increased by about 55% since the mid-19th century, an analysis suggests. And that increasing dust may have hidden up to 8% of the warming from carbon emissions.

The analysis by atmospheric scientists and climate researchers in the US and Europe seeks to count the varied, complex ways in which dust has influenced global climate patterns, and concluded that it has generally worked to counter some of the warming effects of greenhouse gases. The study, published in Nature Reviews Earth and Environment, warns that current climate models do not account for the effect of atmospheric dust.

“We’ve been predicting for a long time that we’re headed for a bad spot when it comes to global warming,” said Jasper Kok, an atmospheric physicist who led the study. “What this research shows is that so far we’ve had the emergency brake.”

Scientists estimate that there are about 26 million tons of dust in our atmosphere. Its effects are complicated.

Dust, along with pollution from synthetic particles, can cool the planet in several ways. These mineral particles can reflect sunlight off Earth and dispel cirrus clouds high in the atmosphere that warm the planet. Dust falling into the ocean stimulates 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: snow and ice become darker and cause them to absorb more heat.

But after adding it all up, it seemed clear to the researchers that the dust had an overall cooling effect.

“There are all these different factors that play the role of mineral dust in our atmosphere,” says Gisela Winckler, a climate scientist at the Lamont-Doherty Earth Observatory at Columbia University. “This is the first review of its kind that really brings all these different aspects together.”

While climate models have so far been able to predict global warming with quite a bit of accuracy, Winckler said the review made it clear that these predictions haven’t been particularly good at pinpointing the role of dust.

Limited data from ice cores, marine sediment records and other sources suggest that dust in general had also been increasing since pre-industrial times – due in part to development, agriculture and other human impacts on landscapes. But the amount of dust also seems to be declining since the 1980s.

More data and research are needed to better understand these dust patterns, Winckler said, and better predict how they will change in the coming years.

But as the dust in the atmosphere decreases, the warming effects of greenhouse gases could accelerate.

“We could experience increasingly rapid warming because of this,” Kok said. “And maybe we’re waking up too late to that reality.”



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