In 2014, a dust storm covered the Persian Gulf and the Middle East.
It’s no secret that humans are making major changes to Earth and its atmosphere. But a less well-known phenomenon is occurring as greenhouse gases build up in the air and our planet’s average surface temperature rises.
Earth’s atmosphere has become dustier since the pre-industrial era. And all these additional particles are likely subtly removing some of the effects of climate change – cooling the planet a bit. and review studies It was published Tuesday in the journal Nature Reviews Earth & Environment.
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The effects of atmospheric dust are absent from nearly all climate research and forecasts, according to the new analysis. This means that these models may underestimate the warming associated with human-induced climate change. And if the atmosphere becomes less dusty, we could experience even faster temperature rises.
“We want climate predictions to be as accurate as possible, and this dust increase could mask up to 8% of greenhouse warming,” said Jasper Kok, an atmospheric physicist and study researcher at the University of California, Los Angeles. and press release. He added that scientists could improve future climate models by adding the effects of dust. “This is crucial because better forecasts can make better decisions about how to mitigate or adapt to climate change.”
Coke and its co-investigators achieved this 8% number through a complex combination of models based on numerous previously published studies.
First, they needed to understand how atmospheric dust changed over time. Using computer modeling and existing data from ice cores and sediment records, they found that the amount of large dust particles in the atmosphere has increased by about 55% today compared to the pre-industrial era. The reasons behind our increasingly pollinated Earth are many, but climate changes such as drought, as well as land use changes such as increased agriculture and development, according to researchers.
Next, the study authors needed to determine the overall climate effects of this dust.
Dust interacts with the climate in many different ways. Dust particles radiate and absorb heat from the Sun and Earth’s surface. Both cool and warm the planet. For example, dust can reflect heat from the Sun back into space. Or it could absorb and retain heat radiated from the Earth itself. The effects also vary by region: dust on reflective deserts, ice and snow increases warming, while dust on oceans and dark forests causes cooling.
The direction and magnitude of dust’s impact on global temperature also depend on factors such as particle size, wavelength of relevant radiation, and land cover beneath atmospheric dust. Dust can also chemically react with water and other compounds in the atmosphere, dissipating heat, and dust particles can change cloud cycles. Finally, the dust that eventually settles into the water carries with it nutrients and thus can increase phytoplankton productivity and increase the amount of carbon dioxide our oceans absorb – indirectly affecting climate change.
TL;DR: It’s hard to fully understand how and how much dust in the atmosphere really changes global temperature. To arrive at their final estimates, Kok and his team calculated the heat effects of 12 different dust-related parameters (some where dust increases warming and some contributes to cooling) and put them all together. Net energy flow is somewhere between “significant cooling” (-0.7 +/- 0.18 Watts per square metre) and “mild warming” (+0.3 Watts per square metre) averaged -0.2 W/square metre. they found it. Therefore, the calculated maximum cooling effect is approximately 8%.
Past research has documented how particles and aerosols are. pollution can cause planet to cool. For example, lower temperatures are a well-known side effect. some volcanic eruptionsand a complete subset geoengineering hinges on this concept. But Tuesday’s review is new as it focuses on naturally occurring dust.
Their models aren’t perfect, and the researchers note that there is a lot of uncertainty in their calculations—largely because they were some of the first scientists to try such predictions. “This is the first review of its kind that really brings all these different aspects together,” said Gisela Winckler, a climatologist at Columbia University who was not part of the new research. told the Guardian. But despite all this uncertainty, the study says, “dust is more likely to cool the climate than to warm it,” which is bad news for our understanding of climate change.
“We’ve known for a long time that we’re headed for a bad place when it comes to greenhouse warming,” Kok told the Guardian. “What this research shows is that we’ve already applied the emergency brake.”
This incidental temperature buffer may not stay in place forever. Although atmospheric dust concentrations have increased since the pre-industrial era, they peaked in the 1980s and have declined since then. If this decline continues or worsens, warming could catch up with us much more quickly; already broke the recordhot reality.
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