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Atmospheric dust can hide the true extent of global warming | climate crisis

Dust from desert storms and arid landscapes has helped cool the planet over the past few decades, and its presence in the atmosphere may be masking the true extent of global warming caused by fossil fuel emissions.

The analysis shows that atmospheric dust has increased by about 55% since the mid-1800s. And increased dust could mask up to 8% of warming from carbon emissions.

Analyzes by atmospheric scientists and climate researchers in the United States and Europe attempt to account for the various, complex ways in which dust affects global climate patterns and conclude that, overall, it has somewhat counteracted the warming effects of greenhouse gases. The study, published in Nature Reviews Earth and Environment, warns that current climate models do not take into account the effects of atmospheric dust.

“We’ve been predicting for a long time that we’re headed for a bad place when it comes to greenhouse warming,” said Jasper Kok, an atmospheric physicist at UCLA who led the study. “This study shows that by now we have put the emergency brake on.”

According to scientists’ calculations, there are about 26 million tons of dust in our atmosphere. Its effects are complex.

Dust, along with synthetic particulate pollution, can cool the planet in several ways. These mineral particles can reflect sunlight away from Earth and scatter cirrus clouds high in the planet’s warming atmosphere. Dust falling 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 causing them to absorb more heat.

But after they calculated everything, it became clear to the researchers that the dust had an overall cooling effect.

“There are all these different factors in our atmosphere that play the role of mineral dusts,” said Gisela Winckler. climate scientist at Columbia University’s Lamont-Doherty Earth Observatory. “This is the first review that brings all these different aspects together.”

Although climate models have so far been able to predict global warming with some accuracy, Winckler said the study clearly shows that these predictions do not identify the role of dust particularly well.

Limited records from ice cores, marine sediment records, and other sources suggest that total dust has also increased since preindustrial times—in part because of development, agriculture, and other human impacts on landscapes. However, the amount of dust has also started to decrease since the 1980s.

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

But if dust in the atmosphere decreases, the warming effects of greenhouse gases may accelerate.

“That’s why we can start warming faster and faster,” Kok said. “And maybe we’re waking up to this reality too late.”

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