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Desert Diary
Fossils/Wet or Dry


As we look more closely at climatic change in light of global warming, we're beginning to appreciate how subtle some processes work. We've long known that climatic changes can affect whether the Rio Grande cuts deeper into its bed or begins to fill up the valley with sediment. Some of this we can attribute directly to changes in precipitation upstream, increasing or decreasing the ability of the river to carry sediment. Now we're beginning to realize that some of this may be reliant on the amount of sediment being made available to the river—and that this, in turn, may be dependent on vegetative cover. And what does the amount of vegetation depend on in the arid Southwest? Precipitation!

Traditionally, we have tended to think that more available moisture means more erosion. Now we recognize that diminished rainfall and snow cover also may result in increased erosion, with fewer plants to hold the soil in place. We're in the awkward position of trying to figure out when more sediment means more precipitation and when it means less!
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Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.


Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.