Thu September 5, 2013
iSeeChange: The West is Getting Dustier
In late July, a massive dust storm in the Saharan Desert of Africa moved across the Atlantic, making for an interesting start to the hurricane season, or you could say a boring one.
All that dust in the air essentially acted like a shield, fending off the sun and keeping the ocean cooler, which in turn has kept tropical storms from growing into hurricanes. This August is actually on track to be the first without an Atlantic Hurricane since 2002.
Though that’s probably good news to people along the Gulf Coast, dust storms at their origins can be severely destructive. Southeastern Coloradans have been learning that lesson the hard way recently, with an unusually high amount of dust storms hitting an area east of Pueblo this month and all but destroying the wheat industry in that part of the state.
Jason Neff, a Geological Sciences professor at CU-Boulder, says many Coloradans are surprised at the amount of dust storms the state has seen recently. A study he co-authored with Janice Brahney found that the amount of dust in the air across the West has risen dramatically in the past 17 years.
"What we saw was this huge increase - 400 or 500 percent - along the Western Slope of the Rocky Mountains, particularly over Colorado and up into Wyoming," Neff says.
He says that increase is partly due to severe drought plaguing the West, but also stems from complex and interwoven land uses – things like oil and gas extraction, housing development, livestock grazing and even the use of ATVs. When you combine those factors with drought and the right wind conditions, you get much more dust in the air.
Neff says that depending on your perspective, more dust can actually be a good thing – when soils erode and take to the air, they deprive areas of nutrients – but those nutrients can wind up nourishing other areas like mountainous Alpine forests. But that benefit still walks a fine line:
"There are possibilities that if you have too much deposition of nutrients, dust or other things than you really start changing ecosystems in ways that you might not like," he says.
Above all else, Neff says more dust poses a threat to water supplies. When dust lands in the mountains, it makes the snow darker, which causes it to melt sooner. When that happens, rivers come up faster.
"Here in the western US, and in a lot of arid regions, what you're hoping is that the snow stays in the mountains longer," says Neff. "All of us in the cities and all the folks doing agriculture out in the West need that water later in the summer."
Neff cautions that Saharan dust storms aren’t really affected by human activity like those in the American West are, but says both are signs of a more global trend.
"Scientists debate this a little bit, but there is evidence that overall, globally, dust is increasing," he says. "Certainly in deserts that are impacted by humans, and agricultural regions as well like the Eastern Plains, but in general we're seeing more dust simply because we have more people."
As Colorado's growing population and drought conditions continue to put stress on water supplies, studying dust activity may help us better understand how to adapt.
"This is one of those things looking forward that we're going to have to pay attention to as we figure out how to manage water resources in the West," says Neff.