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Climate models are an invaluable tool for predicting the trajectory of the climate crisis, but we need them to be as accurate as possible if we are to model everything from its pace, its consequences, to its tipping points.
Now, it seems like we need to tweak some numbers on the true dust from Earth’s atmosphere, a property that plays a vital role in climate systems.
Comparing data from dozens of observations in the air around the world, a new study found that our planet’s atmosphere contains around 17 million metric tons of coarse dust (which is larger than fine dust). This is four times more than simulated in current climate models.
That’s roughly the mass of all the people in the United States together, and if that’s really what’s happening here, we have to re-calculate a lot.
This small, invisible matter tends to heat the atmosphere much like greenhouse gases, yet in six widely used global atmospheric simulations, most of that thick dust seems to be missing.
“When we compare our results with what current climate models predict, we find a drastic difference,” says ocean and atmospheric scientist Jasper Kok of the University of California, Los Angeles.
“The latest generation climate models represent just 4 million metric tons, but our results showed more than four times that amount.”
If they are right, that means that these simulations are not incorporating enough dust. And this could have a big impact on many of Earth’s systems, from the amount of carbon dioxide absorbed in the ocean to the volume of rain that falls, for example, in the tropics.
If more dust is transported into the atmosphere and falls further into the ocean, it could cause major changes in clouds, precipitation and weather.
Between Earth and the Sun, these thick particles copy incoming radiation from above and below. This can cause changes in atmospheric circulation, which can lead to phenomena such as hurricanes, which, incidentally, have increased in frequency and severity with climate change.
Furthermore, adding these new dust numbers to current climate models, the authors say, increases the likelihood that fine and coarse particles contribute to global warming, from the atmosphere above to the oceans below.
“Models have been an invaluable tool for scientists,” says UCLA atmospheric and ocean scientist Adeyemi Adebiyi, “but when they miss most of the coarse dust in the atmosphere, they underestimate the impact that this type of dust has on critical issues. of the life”. on Earth, from precipitation to cloud cover, ocean ecosystems and global temperature. “
For example, the researchers say that when there is dust around, the air tends to act more turbulently, keeping it in the atmosphere for longer, allowing them to travel further than many models give them credit.
In fact, in 2018, researchers discovered that large dust particles raised in the Sahara can travel in global winds to the Caribbean, 3,500 kilometers (2,000 miles) away. Measuring 0.45 millimeters in diameter, these pieces of dust were nearly 50 times larger than previously believed to be able to carry global winds.
(Climate.gov)
That surprising idea is supported by this new research, albeit less directly.
“Since there are more coarse dust particles in the atmosphere, it also suggests that they have a longer lifespan than simulated in global models,” the authors write.
And yet, today, many models have all this thick dust that falls from the atmosphere too fast.
“To adequately represent the impact of dust as a whole on Earth’s system, climate models must include precise treatment of coarse dust in the atmosphere,” says Adebiyi.
Our climate models are constantly updating as we learn more about our planet, and this is just one aspect that seems to need a makeover. With the new information available, we will be better equipped to determine the future of Earth.
The study was published in Scientific advances.
