Thursday, April 26, 2012

Cyanobacteria, Dust, Running Out of Water... and the Stars

The first non-native American see to the Grand Canyon was an Army Lieutenant named John Ives. He dismissed the canyon and the Colorado River as worthless in his 1958 report. To give him some credit, he came from the Eastern US, where he was more used to trees and green vegetation. Apparently he couldn't look past the dry desert to see the larger vision that John Wesley Powell registered just 12 years later. Powell went on to become the first Director of the US Geological Survey.

The Colorado River once emptied to the Sea of Cortez. It does not do so today - and will almost certainly never reach the sea again. It currently provides water to 25 million people - about 24.9 million people than it did in Powell's day - and irrigates 2.5 million acres of farmland. The desert crust in all directions around its most obvious and iconic part in northern Arizona is made up of cyanobacteria and lichen. This crust in the past served to anchor the desert floor from the winds... but is dying due to increasing global temperatures and growing land-use. The native grasses that share the desert floor have proven to be very intolerant of climate warming, and are dying - and being replaced by invasive grasses.

The dying off of the native desert bio-surface is apparently related to alteration of water and nitrogen cycles from the steadily elevated temperatures. This has an interesting dual consequence. First, the invasive grasses are more susceptible to drought - and thus become a fire hazard. Second, the loss of the cyanobacteria and lichen means an increase in dust. Who would even notice this? Scientists have - and have recorded a net increase in dust blown up into the atmosphere.

This may not seem significant, but dust falls on snow, which then absorbs more heat, leading to an earlier snow melt... up to 50 days earlier in some regions. The net result is that more water stored in the snowpack is now lost to soil water loss - and evapo-transpiration because plants now germinate earlier.

Where is this going? The net reduction of water available due to the dustier conditions is calculated to be about 5%. That seems like something I could deal with by watering my yard one time less per month, right? But in fact it doesn't work that simply: that water loss is 1.5 times the annual allotment to Los Angeles, and TWICE the annual allotment to Las Vegas. As the old saying goes, a dollar here and a dollar there eventually adds up to real money.

This tells me that I might not want to make a long-term investment in property in the southwestern U.S., nor in southern California. Already in southern California an iterative cycle of drought, followed by wildfires, followed by floods is well underway. My son no longer wants to hike the San Gabriel mountains near his home in Tujunga, California - the mountains are black today. They burned up several years ago in a massive fire started by a meth-lab, which came within meters of taking out the Mount Wilson Observatory.

Everything is connected. If we discount it, we do so at our peril.


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