Dorothea Lange | Library Of Congress
Submitted by theadminx on Tue, 11/27/2012 - 22:22
November 27, 2012 by Melissa Gaskill, Scientific
American
A cool October broke a 16-month streak of above average
temperatures across the Lower 48, but temperatures
are projected
to remain above normal across most of the western half
of the country in the coming months.
In addition, the latest climate change projections put
future temperature
gains on the high side of various models.
As of November 6, 59.5 percent of the contiguous U.S. was
experiencing persistent drought conditions that are most
severe in the Great Plains — North and South Dakota,
Nebraska, Kansas, Oklahoma, Texas, Montana, Wyoming and Colorado
— where drought is expected to persist
or intensify in the foreseeable future.
On October 17–18 those drought conditions combined with high
winds to create a large dust
storm across Colorado, Nebraska, Kansas, Oklahoma and
Wyoming, closing major highways.
To Katharine Hayhoe, professor and director of the Climate
Science Center at Texas Tech University in Lubbock, this heralds
big changes for agriculture on the Great Plains. "In a nutshell,"
Hayhoe says, "we're seeing major shifts in places and times we
can plant, the types of crops we can grow and the pests and
diseases we're dealing with.
"If you talk to seed companies, the U.S. Department of
Agriculture (USDA) and even farmers, they tell you we can modify
our way out of this, that we can overcome all these problems with
technology. There's no question we can adapt to some of the
change, but whether we can adapt to all of it is a very open
question."
In the 1930s Dust Bowl a land speculator– and
government-encouraged plowing frenzy removed windbreaks and
grasslands that stabilized soil. The dry, windy weather that
followed created one of the worst man-made ecological disasters
ever. Powerful windsscoured
bare soil from the ground and carried it long
distances. Farms
failed across Colorado, Kansas, Oklahoma and
Texas.
This October's dust storm, which followed preparation of fields
for fall planting, could be the first act of an encore
performance. "If the drought holds on for two or three more
years, as droughts have in the past, we will have Dust Bowl
conditions in the farm ng belt," says Craig Cox, an agriculture
and natural resources expert with the Environmental Working
Group, a nonprofit using public information to protect public
health and the environment.
"It could be in a sense an invisible Dust Bowl—not like the big
storms before, but withered crops, dry streams and other
disasters that accompanied the Dust Bowl. Wind erosion is
tremendously damaging and hard to control. A lot of practices
that control wind erosion require growing things, and if those
weren't in place when the drought hit, it's almost impossible to
put them in place now."
Since the 1940s agriculture on the semiarid southern Great Plains
— Colorado, Kansas, Oklahoma and Texas — has relied on
irrigation. On the high plains of Texas, tens of thousands of
wells pumping from the 10-million-year-old Ogallala Aquifer have
depleted it by 50 percent. Given variation in its depth and the
difficulty of pumping at low water levels,
most of the remaining
reservoir will likely be useless for irrigation within
about 30 years.
At the same time, climate change has brought less rain as well as
hotter temperatures that increase evaporation — forcing farmers
to use even more water for irrigation. "We have agriculture
systems in semiarid areas," Hayhoe says. "We built these
vulnerabilities into the system and climate change is the final
straw that may break the camel's back."
Agriculture on the southern plains isn't necessarily doomed,
though, Hayhoe stresses. "There are techniques being developed
already, such as dry-land farming, rotating crops and using waste
as biofuel that will keep the economy going." Actions also can be
taken at the local level to reduce the vulnerability of
agriculture, she says, including using energy more efficiently
and developing sounder management and development policies.
Other adaptations include switching to more heat-tolerant breeds
of livestock and even away from cattle altogether, says Wayne
Polley, research ecologist at the USDA's Grassland, Soil
and Water Research
Laboratory. "Major changes in agricultural land use will mean
changes in our eating habits and our family budgets as
well."
"There are absolutely things farmers could do to deal with
climate change," Cox says. "This is not a technical problem.
There is a whole suite of practices that would make farming
systems more resilient and able to stand up to climate change.
Yet instead of making farming more resilient to the challenges,
current government agricultural policy actually takes us in the
opposite direction."
Ending mandates for corn ethanol and once again tying crop
insurance to land conservation would help reduce erosion and
drainage of wetlands on farmland, he says, reducing the risk of
returning Dust Bowl conditions.
The good news, Hayhoe adds, is that whatever happens, the land
will still be here. "In the southern Great Plains we may have a
major shift to dry-land crops. We may have to shift when we
plant. But we have the option of trying different things — as
opposed to, say, Bangladesh, where cropland is being lost to
sea-level rise.
"We can save ourselves by wise planning," she says. "But a lot of
change has been hampered because people don't want to do anything
that has a 'climate change' label on it, and also because
industrial, large-scale systems are resistant to changes because
changes are expensive. But that's true only in the short term.
Not doing anything will be way more expensive in the long term.
Business as usual is not going to be a viable option 30 years
from now, or even sooner."
Fifty miles south of Hayhoe's Texas Tech office, agricultural
fields line an arrow-straight highway. On a dry, windy day, in
circular fields created by wheeled irrigation contraptions that
spin from a well in the center, water sprays onto new autumn
crops.
Enormous bales of recently harvested cotton stacked up at nearby
gins render bits of the snowy fluff to the wind, which catch the
grass along the road's edge to gather into miniature drifts. As
temperatures rise and the aquifer levels fall, these iconic
images of high plains agriculture may be blown away with the
dust.
http://www.businessinsider.com/climate-change-to-cause-dust-bowl-2012-11
