Dust

Humans have contended with dust storms for thousands of years, ever since early civilizations appeared in the Middle East and North Africa. But modern desert dust storms are different from their preindustrial counterparts. Around the world, deserts now increasingly border built structures, including urban dwellings, manufacturing, transportation hubs, sewage treatment and landfills. As a result, desert dust lifts a growing load of airborne pollutants and transports these substances over long distances. This is happening throughout the Global Dust Belt, an arid to semiarid region that stretches from western China through Central Asia, the Middle East and North Africa. Similar storms occur in the U.S. Southwest and central Australia. Global pattern of dust frequency estimated from weather records, 1974-2012. Shao et al., 2013, CC BY-ND To our thinking, modern desert dust storms have been overlooked...

The Salton Sea spreads across a remote valley in California’s lower Colorado Desert, 40 miles (65 kilometers) from the Mexican border. For birds migrating along the Pacific coast, it’s an avian Grand Central Station. In midwinter tens of thousands of snow geese, ducks, pelicans, gulls and other species forage on and around the lake. Hundreds of other species nest there year-round or use it as a rest stop during spring and fall migration. At the dawn of the 20th century, this massive oasis didn’t even exist. It was created in 1905 when Colorado River floodwaters breached an irrigation canal under construction in Southern California and flowed into a basin that had flooded in the past. In earlier years, the sea covered roughly 40 square miles more than its current size of 343 square miles (890 square kilometers). Since then, agricultural runoff from newly formed nearby irrigation districts has sustained it. By midcentury, the sea was considered a regional amenity...