Saharan dust events to be less frequent but more severe as climate change intensifies
The Earth is a system of smaller systems, and changes in one part of the world can majorly impact another. One such example is the Saharan Air Layer and the plumes of dust that travel on global wind currents.
Last month, one of these giant plumes of dust from the Sahara desert in Africa made its way across the Atlantic and to the Caribbean. The dust cloud, visible from space, blotted out the sun in the US Virgin Islands for almost a week. The air quality index skyrocketed as visibility decreased significantly. These Saharan dust events are fairly common, and usually occur in late spring and early fall when the wind from the northwest Atlantic picks up dust from the Sahara and kicks it into the trade winds where it is carried west across the Ocean.
As alarming as these giant plumes of dust may seem, they actually have surprising benefits that have shaped ecologies in South America and the Caribbean for thousands of years. The dust is very rich in nutrients and minerals, and the movement and settling of that dust mineralize the soil in the Caribbean. This mineralization accounts for some of the lush vegetation and thick tropical forests that are characteristic of these regions. The nutrient-rich soils benefit agricultural production in the Caribbean as well.
Saharan dust events disrupt the formation of hurricanes. The hot, dry masses of air and the subsequent wind shear from the dust clouds can prevent tropical storms and choke existing ones. According to a recent Nasa study, as climate change intensifies, disruptions in the normal global wind patterns and ocean currents will affect the frequency and intensity of these Saharan dust events. Researchers claim that,
“[There will be] at least a 30% reduction in Saharan dust activity from current levels over the next 20 to 50 years, and a continued decline beyond that.”
However, when the events do occur, it is predicted that they will be much more intense and carry a larger volume of dust than in the past. While the improvement in annual air quality benefits people in the Caribbean, the long-term effects on ecological health are unknown and will be closely monitored.