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Dust’s Dirty Little Secrets

Desert Dust

If the house seems dustier than it used to be, it may not be a reflection on your housekeeping skills. The amount of dust in the Earth’s atmosphere has doubled over the last century, according to a new study by Natalie Mahowald, associate professor of earth and atmospheric sciences, and the dramatic increase is influencing climate and ecology around the world. Soil particles in the atmosphere limit the amount of solar radiation that reaches the Earth, a factor that could mask the warming effects of increasing atmospheric carbon dioxide and influence clouds and precipitation. Dust can also affect the oceans, as it is a major source of iron, which is vital for plankton and other organisms that draw carbon out of the atmosphere.

Mahowald found that regional changes in temperature and precipitation caused a global reduction in terrestrial carbon uptake of 6 parts per million (ppm) over the 20th century, and that dust deposited in oceans increased carbon uptake from the atmosphere by 6 percent, or 4 ppm, over the same period. The study highlights the important role of natural aerosols’ impacts on climate change, Mahowald says.