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  • From: "TradingPostPaul" <tradingpost@riseup.net>
  • To: livingontheland@lists.ibiblio.org
  • Subject: [Livingontheland] Drought becoming norm, experts say
  • Date: Sun, 08 Oct 2006 15:36:05 -0600


http://www.azcentral.com/arizonarepublic/local/articles/0930b3blog0930.htm
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Drought becoming norm, experts say
Sept. 30, 2006 12:00 AM

Everything you think you know about water in the West is about to change.

Scratch that. It's changing now.

The drought that's squeezing Arizona and the Colorado River? It could be
the new normal. The warming temperatures that seem to start earlier and
linger later? A shift in climate that already has stolen runoff in some
parts of the Northwest.

Scientists met in Colorado last week for a conference on drought and water
scarcity and there was no missing the theme of change in their messages,
swathed as they were at times in dense, geologic research papers.

" . . . the natural snow pack reservoir is getting smaller and smaller,"
said Richard Palmer, who teaches water resource management at the
University of Washington. "In the winter of 2005, we had the smallest snow
pack on record. That's a real wake-up call for us that something is
changing."

An Australian scientist urged Americans to treat drought as constant rather
than an emergency: In her country, "drought is no longer considered a
disaster," said Linda Botterill, who teaches at the Australian National
University in Canberra. "We have one of the most variable climates on
earth. We really don't have a 'normal' climate. Therefore it's absurd to
treat every drought as an emergency."

Changing ideas about climate and rain and water are nothing new in the arid
West. It hasn't been that long ago - the middle of the 19th century - that
respected leaders subscribed to a theory called "rain follows the plow."
The theory gained prominence as homesteaders began moving into the Great
Plains and the edge of the West and found that they couldn't rely on rain
to water their crops.

Leaders of the time, fearful of the economic effects of a stalled
expansion, convinced farmers that if they would only plow their fields and
plant crops, the rain would follow. They found scientists who swore that
plowing field would release moisture into the air and create rain; some
even suggested the vibrations from all the building and digging and
tromping around would drum up storms.

The whole scheme is widely blamed for early dry farming failures.

As late as the early 1900s, leaders of the seven Colorado River states
apportioned water based on what turned out to be some of the wettest years
in centuries. The river is now overallocated.

Botterill and others say we should consider drought the baseline condition
here and the wet years part of the dramatic variability in climate.

"Drought is always out there," said Donald Wilhite of the National Drought
Mitigation Center in Lincoln, Neb. "It's always affecting some part of the
country." Reacting to droughts is far more expensive than planning for
them, he said. Climate change and growth will only worsen our plight if we
don't shift our thinking.

In other words, the drought we're surviving now in Arizona might flatten us
in 30 or 40 years, when climate change has cut into runoff and our
population has doubled again.

Evidence is accumulating that warming temperatures will affect mountain
snows in the West, reducing runoff into reservoirs. Several studies suggest
the Colorado River could shrink by 30 percent or more over the next
half-century.

Warmer conditions eat away on several fronts: Less snow falls, resulting in
less runoff. Rain falls at the wrong times of year, when reservoirs can't
contain it. Warmer temperatures increase demand for water sooner in the
season, tightening the supply further.

In studies of the Seattle and Portland areas, the UW's Palmer estimated
that the amount of water available in the high-demand months will decrease
6 percent a year, 24 percent by 2040. Some of the water that arrives as
rain in the winter will seep into the aquifers for pumping later, but it
changes the equation in an area so reliant on runoff.



Reach McKinnon at shaun.mckinnon@arizonarepublic.com; read his water blog
Tuesdays and Thursdays at mckinnonblog.azcentral.com.







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