This is an excerpt written by Michael Tennesen in the May 2010 issue of Discover magazine:

“What Greg Okin [a professor of geography at the University of California at Los Angeles] experienced was just one gust in a gathering storm. Blowing dust and brownout conditions on January 19, 2009, created a chain reaction of fatal crashes on I-70 in eastern Colorado. In July a massive dust cloud descended on Iraq, forcing the police to wear masks while directing traffic through the strangely dark streets of Baghdad. In september one of Australia’s worst dust storms in 70 years clogged the skies over Sydney with 5 million tons of particles, causing international flights to be diverted and prompting a spike in emergency calls from people who were having trouble breathing. And such disruptions can take on global dimension. Satellite images show storms in northern Africa blowing particles all the way to the Amazon Basin. Plumes from northern China can reach Hawaii and California. A 2002 dust storm from the Gobi Desert tracked east across the Pacific Ocean, past the United States, and out into the Atlantic.

The problem has been building for a long time. Wars, oil and gas exploration, agriculture, cattle production, and general development have broken up soil surfaces around the world. Drought, rising temperatures, and a shift in some regions from grasslands to scrublands have accelerated the problem in the past 10 to 15 years. In the United States, the loss of grasslands and other natural shields that hold arid soils in place is particularly pronounced in New Mexico, Arizona, and Nevada, where dust production has increased by orders of magnitude over the past several decades. And dust begets more dust: It reduces the reflectance of the winter snowpack and increases the absorption of sunlight, causing snow to melt sooner. Five times as much dust now falls on the snowpack in the Colorado Rockies as when the area was first heavily settled in the mid-19th century.”