A visualization from space of the “Godzilla” dust storm on June 18, 2020, when desert dust traveled from the Sahara to North America. A UCLA study now finds that atmospheric dust has declined by 10% since 2003.
Image Credit: NASA Scientific Visualization Studio
Scientific Frontline: Extended "At a Glance" Summary: Atmospheric Dust Decline
The Core Concept: The total volume of desert dust circulating within Earth's atmosphere has decreased by approximately ten percent between 2003 and 2023.
Key Distinction/Mechanism: Atmospheric dust generally exerts a slight cooling effect on the global climate; therefore, its measurable reduction removes a portion of this mitigating influence, potentially exacerbating the warming trends driven by anthropogenic climate change.
Origin/History: Following an increase during the twentieth century that peaked in the 1980s, recent satellite and ground-based observations demonstrate a definitive decline beginning in the early twenty-first century.
Major Frameworks/Components:
- Data Integration: The study synthesized satellite observations, ground-based atmospheric measurements, and complex atmospheric modeling to quantify the ten percent reduction.
- Source Geography: The majority of the global dust burden originates in the Northern Hemisphere, specifically from major arid regions like the Sahara in North Africa and the Gobi Desert in Asia.
- Secondary Sources: A smaller but notable contribution arises from desiccated lake beds, often driven by human water diversion, such as the Salton Sea, Owens Valley, the Great Salt Lake, and the Aral Sea.
- Systemic Impacts: Beyond temperature modulation, circulating dust is a critical mechanism for depositing essential minerals and nutrients into terrestrial ecosystems and oceans, while also affecting air quality and the albedo of snow and ice.
Branch of Science: Atmospheric Science, Climatology, Earth Science.
Future Application: Improving predictive climate modeling by incorporating accurate dust variability, leading to more refined forecasts regarding both global temperature trajectories and regional ecosystem health.
Why It Matters: Understanding the dynamics of atmospheric dust is crucial for accurately assessing the pace of human-caused climate change, as the loss of this natural cooling agent means warming may occur more rapidly than previously modeled, while simultaneously disrupting nutrient cycles in oceans and on land.
A video shows the drop in atmospheric dust levels across North Africa, Asia, and the globe from 2003 to 2023.
Video Credit: Courtesy of UCLA
Atmospheric desert dust has long swirled around the globe, but a new UCLA study presents the strongest evidence yet that global dust is mysteriously decreasing.
Because atmospheric dust overall has a slight cooling effect on the climate, the researchers say its decrease may have contributed modestly to recent climate warming.
The study, which combined satellite observations, ground-based measurements, and atmospheric models, found that the amount of dust in Earth’s atmosphere decreased by about 10% from 2003 to 2023.
Most of the atmospheric dust originates in the Northern Hemisphere, with major desert regions such as the Sahara in North Africa and the deserts of Asia, including the Gobi, contributing much of the global dust burden.
The causes of the recent decline, however, remain unclear, according to the study.
“This is the strongest evidence to date that Earth’s atmosphere became less dusty in the early twenty-first century,” said lead author Ashok Gupta, who conducted much of the analysis as a researcher and assistant project scientist in the UCLA Department of Atmospheric and Oceanic Sciences. He is now a staff scientist at Vanderbilt University.
Study coauthor Jasper Kok, a UCLA atmospheric scientist and principal investigator on the project, noted that the recent dust decrease marks a change from much of the twentieth century, during which atmospheric dust increased before peaking in the 1980s for reasons scientists are still exploring.
“Because of atmospheric dust’s slight overall cooling effect on the climate, the decline in dust that we’re seeing now likely contributed modestly to the warming seen from human-caused climate change,” Kok said.
“The decline in dust has other potential effects on ecosystems, air quality, and the atmosphere,” Kok said. “Dust circulating through the atmosphere plays an important role in depositing nutrients and minerals into oceans and on land. It also contributes to air pollution and decreases the reflectivity of snow and ice.”
Even with the decline since the 1980s, dust levels are still elevated compared to preindustrial times, Kok noted. In addition to deserts like the Sahara and the Gobi, some of the dust today comes from drying lakebeds where agriculture and other needs led humans to reroute water, such as at the Salton Sea and Owens Valley in California, Utah’s Great Salt Lake, and the Aral Sea on the border of Kazakhstan and Uzbekistan, he said.
Gupta is now investigating what is driving the decline in atmospheric dust through ongoing research at Vanderbilt, in collaboration with UCLA.
“We are working to determine how much of the global dust decline can be attributed to changing surface winds and other environmental factors, and what those changes could mean for atmospheric dust in a future climate,” Gupta said.
Published in journal: Science Advances
Title: A global decline in atmospheric dust during the 21st century
Authors: Ashok Kumar Gupta, Jasper F. Kok, Vassilis Amiridis, Antonis Gkikas, Konstantinos Rizos, Emmanouil Proestakis, Stavros-Andreas Logothetis, Eleni Marinou, and Carlos Pérez García-Pando
Source/Credit: University of California, Los Angeles | Alison Hewitt
Edited by: Scientific Frontline
Reference Number: as091626_01
