Not everything that counts can be counted.
Our daily lives are surrounded by billions of unwelcome aliens that constantly engulf us, and yet we know next to nothing about them. They are technically the product of aeolian (wind-driven) processes, and are called “dust.”
Dust is everywhere – sprinkled onto our food, inhaled into our lungs, caked on car bodies and vegetation – and sometimes they obliterate the horizon when drought or fires create enormous clouds of particles. The cost of dust is enormous – everything from car washes, to asthma medication, to expensive construction that attempts to seal buildings, to irrigation systems minimizing loss of topsoil.
During the 1930s, the Great Plains experienced one of America’s most severe environmental catastrophes. With the Dust Bowl, accelerated agricultural cultivation combined with a dry spell led to significant increases in wind erosion, and an estimated 800 million metric tons of topsoil simply blew away. The loss of topsoil is expensive, and from that several-year event, approximately 222 million acres of farmland were degraded.
When dust enters the air column, it may travel many miles, ending up as a nuisance on your computer screen, causing respiratory illnesses, infiltrating delicate machinery or valuable artwork, or passively falling into lakes and oceans, degrading water quality. In California, off-road recreational vehicles rose from almost none in 1960 to 10 million user-days in 2006, generating more than 2.5 metric tons of dust per year. Such increased land uses by humans accelerates the production of dust, which in turn has expensive consequences.
Scientists now recognize that dust not only costs billions of dollars per year in damage to technology, health, water quality and agriculture, but it also creates uncertainty in climate-change models. At the small scale of individual plants, photosynthesis is reduced when sunlight can’t reach leaf surfaces through a coat of dust. On a larger scale, dust storms reflect heat away from land; when dust settles on snow and ice, its darker coloration accelerates melting rates. These opposing forces have the potential to alter local climate, as well as to affect larger-scale trends of ecosystem health.
In the not-too-distant future, monitoring dust emissions may become a profession. In the same way that we determine speed limits, monitor food ingredients and require airport security, a new breed of engineer may need to calculate dust movements and limit excessive deployment of particles into the air column.
Dust-related catastrophes are accelerating – along with their cost to both human and planetary health.
Meg Lowman, an N.C. State University professor and forest canopy expert, directs the N.C. Museum of Natural Sciences’ Nature Research Center. Online: www.canopymeg.com.