Dust 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 extent of global warming caused by fuel emissions.
Atmospheric dust has increased by 55% since the mid-19th century, according to an analysis. And this increase in dust may have hidden up to 8% of the global warming from carbon emissions.
The analysis, conducted by atmospheric scientists and climatologists in the United States and Europe, attempts to identify the diverse and complex ways in which dust affects global climate patterns, concluding that in general it has somewhat dampened 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 influence of atmospheric dust.
“We’ve long predicted that we’re headed to a bad place when it comes to warming warming,” said Jasper Cooke, a UCLA atmospheric physicist who led the research. “What this research shows is that so far we have activated the emergency brakes.”
Scientists estimate that about 26 million tons of dust are suspended in our atmosphere. Its effects are complex.
Dust, as well as man-made particle pollution, can cool the planet in a number of ways. These metallic particles can reflect sunlight away from Earth and scatter cirrus clouds high in the atmosphere that are warming the planet. Dust that falls into the ocean promotes 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 the snow and ice causing it to absorb more heat.
But after everything was calculated, it seemed clear to the researchers that the dust had an all-around cooling effect.
“There are all these different factors that play the role of metallic dust in our atmosphere,” said Gisela Winkler, climate scientist at Columbia University’s Lamont-Doherty Earth Observatory. “This is the first review of its kind that really brings all these different aspects together.”
Although climate models have so far been able to predict global warming with some accuracy, Winckler said the review made it clear that these predictions have not been able to capture the role of climate particularly well. الغبار.
Limited records from ice samples, marine sediment records, and other sources indicate that dust as a whole has also increased since preindustrial times—due in part to development, agriculture, and other human impacts on the landscape. But the amount of dust also seems to have decreased since the 1980s.
Winkler 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 decreases in the atmosphere, the warming effects of greenhouse gases may accelerate.
“We may start to get warmer faster and faster because of that,” Cook said. “We may have woken up too late to this reality.”
