A new study in Nature Geoscience finds that dust deposition increased 500% in the last two centuries above the average levels of the last 5,000 years. The authors (including Jonathan Overpeck at UA) conclude the higher dust levels are due to expansion of livestock grazing in the early 20th century as settlers moved west across the continent.
[right: Phoenix dust storm, 8-07, aboutphoenix.com]
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