Atmospheric dust’s origins aren’t what we’ve assumed, researchers say

• Dust Origins Shakeup: Recent studies challenge the long-standing belief that most global dust comes from North African deserts. Seasonal and hemispherical variations play a key role, and total dust emissions are significantly lower than previously estimated.
• Outdated Models: Existing dust emission models are outdated, based on simplifications that don't align with real-world observations. The assumption that North Africa is the major contributor is now debunked by more accurate satellite data.
• Climate and Health Impact: Atmospheric dust influences climate and human health globally. The discrepancies between old models and satellite observations (up to two orders of magnitude) highlight the urgency of adopting a more accurate model to advance scientific understanding and improve climate change predictions.

Hey there! So, turns out, we might have been a bit off about where all that atmospheric dust is coming from. You know how scientists always thought those windswept deserts in North Africa were the main culprits? Well, new studies are shaking things up.

Two recent papers in JGR Atmospheres and Science of the Total Environment are throwing a curveball into the whole dust situation. Basically, scientists used to think most of the world's dust came from North Africa, but now they're saying it's more of a seasonal and hemispherical thing. And get this, the total amount of dust flying around is way less than we've been thinking.

The researchers are pointing fingers at outdated models that are not keeping up with the real deal on the ground. Back when these dust emission models were born, they didn't have all the cool data sets we have now. They made some pretty basic assumptions, like thinking the Earth's surface is a barren wasteland with no plants, assuming North Africa and the Middle East were dust factories, and imagining there's an endless amount of dry, loose sediment just lying around.

But, surprise surprise, reality is way more complicated. The researchers did their homework using satellite observations from 2001 to 2020, and guess what? The amount of dust being kicked up is way less than what those old models were saying. The main dust sources also change depending on the season, jumping between deserts in East Asia, the Middle East, North Africa, and even the shrub lands in Australia and North America.

Now, why does this matter? Well, atmospheric dust plays a role in both climate and human health. The old model, according to the researchers, was missing the mark by a long shot – like, up to two orders of magnitude kind of miss. Adrian Chappell, the lead author of both studies and a climate change impacts professor at Cardiff University, thinks we've only been getting a fraction of the story.

Using these outdated models could be holding us back from making big strides in science and improving how we predict climate change. The researchers are sounding the alarm, saying it's high time we ditch the old ways and embrace this new, more accurate model for better research in the future.

So, there you have it – the dust in the wind might be blowing from different directions than we thought, and it's time for us to catch up with the times. Who would've guessed, right?

Video from National Geographic shows | When 27M Tons of African Dust falls upon Amazon

Where is atmospheric dust found?

Atmospheric dust is found in the air, especially in arid and dry regions where high-velocity winds can lift small particles of soil, sand, and rock into the atmosphere. These particles can travel long distances and affect the climate and the environment of different regions. For example, Saharan dust can reach the Caribbean and the Amazon basin, and cause changes in temperature, rainfall, and ocean cooling.

What is atmospheric dust made of?

Atmospheric dust is made of various mineral matter and organic compounds, depending on the source and the composition of the surface. Some common components of atmospheric dust are quartz, feldspar, clay minerals, iron oxides, carbonates, gypsum, and organic matter. Some dust particles may also contain pollutants, such as vehicle and industrial exhaust, tire and brake wear, and construction debris.

How much dust is in the atmosphere?

The amount of dust in the atmosphere varies by season, location, and weather conditions, but it is estimated that the global annual average of dust emissions is about 1500 million tons. However, this estimate is much lower than the previous models, which assumed that most of the dust came from North Africa and the Middle East. The new studies show that dust sources shift over the year and across hemispheres, and that other regions, such as East Asia, Australia, and North America, also contribute to dust emissions.