Earth Day Connections: NASA Study Predicts Less Saharan Dust in Future Winds
In June 2020, a “Godzilla” dust plume travelled from the Sahara, the planet’s largest, hottest desert, across the Atlantic ocean to North America. While this eye-catching plume made headlines, NASA scientists, using a combination of satellite data and computer models, predict that Africa’s annual dust plumes will actually shrink to a 20,000-year minimum over the next century as a result of climate change and ocean warming.
The Sahara Desert is 3,600,000 square miles (9,200,000 square kilometers) of arid land stretched across the northern half of Africa, coming in just slightly smaller in size than the continental United States. Upwards of 60 million tons of its nutrient-laden mineral dust are lifted into the atmosphere each year, creating a massive layer of hot, dusty air that winds carry across the Atlantic to deliver those nutrients to the ocean and vegetation in South America and the Caribbean.
Recent NASA research outlines the domino-like connections between factors beyond the desert’s borders and the development of dust plumes. These start with temperature differences between the North and South Atlantic, which then impact the region’s consistent east to west winds as well as a tropical band of relatively high rainfall located near the Equator, both of which impact the annual dust plumes. Supported by NASA’s Modeling, Analysis, and Prediction (MAP) Program, and Radiation Sciences Program, the scientists used their new understanding of these relationships to forecast a more substantial reduction in dust activity than previous studies had predicted based on anticipated climate warming.
Every year millions of tons of dust from the Sahara Desert are swirled up into the atmosphere by easterly trade winds and carried across the Atlantic. The plumes can make their way from the African continent as far as the Amazon rainforest, where they fertilize plant life.
Credits: NASA's Goddard Space Flight Center.
A Dusty Past
“From ground observations and satellite observations, we see African dust variability,” said Tianle Yuan, atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. “In fact, it can change quite a bit, from month to month, day to day, year to year, even decade to decade.”
Recent dust estimates are derived from data collected by NASA satellite missions, including Terra, Aqua, and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), a joint mission between NASA and the French space agency, Centre National d'Etudes Spatiales.