Climate Change, Nature

Saharan Dust is Part of the Global Climate and Ecosystem

The desert wind called Calima carries sand from the Sahara Desert across the ocean and into the atmosphere, as seen here on the Canary Islands.
The desert wind called Calima carries sand from the Sahara Desert across the ocean and into the atmosphere, as seen here on the Canary Islands. Photo: Frerk Meyer | FlickrCC.

The Sahara Desert generates more dust than any other desert in the world, and that dust impacts the globe in a number of ways. A lot of it ends up in the ocean, where it introduces nutrients that otherwise might not get there, and some of those same nutrients end up falling over land as well. The dust also blocks or reflects sunlight, which can impact the formation of clouds and hurricanes.

By exploring data collected over the last century, scientists have been able to track what kinds of impact the dust has had in the past. They found that events like El Niño, the North Atlantic Oscillation, rainfall in the Sahel region of Africa, the Sahara Low Heat, and even the Intertropical Convergence Zone, can all impact how much dust is generated, where it moves, and how quickly.

The strength of a Saharan wind called the Harmattan, which blows across the massifs of North Africa, is particularly important to the process. The various other processes and events work to change the intensity of the Harmattan, which in turn determines how the dust works out each year.

Using the data they had, the researchers figured out what was happening as far back as 1850, and then they looked to the future to try and predict how things will work out over the rest of the century. What they found is that there will be a decrease in dust generation, although they aren’t entirely sure yet what that means for the rest of the world.

On the one hand, it could have some unseen benefit for humans, but that might come at the cost of reduced nutrients in soil and ocean. Maybe more of the dust will stay in Africa and help enrich arable lands there.

It could also result in a general warming of the tropical North Atlantic, which might be more suitable for hurricanes and could have a very different impact.

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