In 2014, dust storms covered the Persian Gulf and the Middle East.
It is a well-known fact that humans have brought great changes to the earth and its atmosphere. But as greenhouse gases accumulate in the atmosphere and the Earth’s average surface temperature rises, a lesser-known phenomenon is occurring.
Earth’s atmosphere has been dusty since before the industrial revolution. And all these additional particles are likely subtly counteracting some of the effects of climate change, cooling the planet a bit. review studies It was published in the journal Nature Reviews Earth & Environment on Tuesday.
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Atmospheric dust effects are not included in nearly all climate studies and projections, according to a new analysis. It means that these models may underestimate the warming associated with human-induced climate change. And less dust in the atmosphere could lead to even faster temperature spikes.
“We want our climate predictions to be as accurate as possible, and this increase in dust contributes up to 8% of greenhouse warming,” said Jasper Koch, senior researcher and atmospheric physicist at the University of California, Los Angeles. It may have obscured the press releaseBy adding dust effects to future climate models, scientists can improve them, he continued. “This is very important, because better forecasts allow us to make better decisions about how to mitigate or adapt to climate change.”
Koch and his collaborators arrived at this 8% figure through a complex mix of models based on a wealth of previously published research.
First, they needed to understand how dust in the atmosphere changed over time. Using computer modeling and existing data from ice core and sediment records, the abundance of large dust particles in the atmosphere is now about 55% higher than in pre-industrial times. I discovered that The reasons behind an increasingly dusty planet are numerous, but researchers say it all comes down to climate change, such as drought, as well as changes in land use, such as increased agriculture and development.
The study authors then had to determine the overall climate impact of the dust.
Dust interacts with the climate in different ways.By scattering and absorbing heat from the sun and the surface of the earth, dust particles both cool or warm the earth. For example, dust can reflect heat from the sun back into space. Alternatively, it can absorb and retain heat radiating from the earth itself. The impact also varies by region. Dust on reflective deserts, ice, and snow promotes warming, while dust on oceans and dark forests contributes to cooling.
The direction and magnitude of dust’s impact on global temperature are further dependent on factors such as particle size, the wavelength of the radiation involved, and the land cover beneath atmospheric dust. Dust can also chemically react with water and other compounds in the atmosphere to transfer heat, and dust particles can alter cloud cycles. Finally, the dust that ends up in the water carries nutrients, thus increasing the productivity of phytoplankton and increasing the amount of carbon dioxide the ocean absorbs, indirectly affecting climate change.
TL;DR: It’s difficult to know exactly how and how much dust in the atmosphere is actually changing the temperature of the Earth. To get the final estimate, Koku and crew calculated the thermal effects of 12 different dust-related parameters—what dust contributed to warming and what contributed to cooling—and added them all together. . They found that the net energy flux was somewhere between “substantial cooling” (-0.7 +/- 0.18 watts/m2) and “slight warming” (+0.3 watts/m2), with a median of I found it to be -0.2 W/sqm. Therefore, the calculated maximum cooling effect is about 8%.
Previous studies have shown how particles and aerosols Pollution could cause planetary coolingFor example, lower temperatures are a well-known side effect. several volcanic eruptionsand the entire subset of geoengineering hinge to that concept. But Tuesday’s review is novel in that it focuses on naturally occurring dust.
Their model is not perfect, and the researchers point out that there are many uncertainties in their calculations. “This is the first review of its kind to really bring all these different aspects together,” said Columbia University climatologist Gisela Winkler, who was not part of the new study. told the GuardianBut despite these uncertainties, “dust is more likely to cool the climate than warm it,” the study says. This is bad news for our understanding of climate change.
“For a long time we’ve been predicting that we’re headed in the wrong direction with regards to greenhouse gas warming,” Kok told The Guardian. means that the emergency brake is on.”
That accidental temperature buffer is not guaranteed to persist forever. Atmospheric dust concentrations have been increasing since before the Industrial Revolution, peaking in the 1980s and then declining. If that decline continues or is intense, warming could catch up with us even more rapidly. record breaking alreadyhot reality.
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