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Fertile and fragile, desert surface a war casualty
By David J. Craig
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Farouk El-Baz Photo by Kalman Zabarsky |
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From the toxic black mist spewing from burning Iraqi oil wells to the
threat of biological and chemical attacks, environmental disasters from
the war in Iraq will probably hinge on the tactics employed by Saddam
Hussein and his henchmen.
But according to renowned geologist and CAS
Research Professor Farouk El-Baz, television images of military vehicles
churning up suffocating
dust clouds in southern Iraq illustrate a less widely acknowledged environmental
threat — the erosion of the desert’s delicate surface. What may
appear to be a barren landscape is, in fact, a fragile ecosystem that
relies on the stabilizing effects of an extremely thin layer of gravel
blanketing large sections of the desert. Known to geologists as “desert
pavement,” the gravel has protected underlying soil from the effects
of wind for thousands of years, as well as helped trap water and sustain
plant life on about 23 percent of the desert surface. But it’s
no match for a tank.
“
The desert surface could have been put together by a master craftsman,” says
El-Baz, who directs BU’s Center for Remote Sensing and is an expert
on the origin and evolution of arid landforms. “The pebbles, which
are between the size of a pea and a peanut, are spread very evenly, so
the surface is just one grain thick. Yet it holds down the soil, which
is actually quite fertile.”
The earth is fertile, he explains,
because between 5,000 and 11,000 years ago much of what is now Middle
Eastern desert was lush land with many
rivers and lakes. And where once there were riverbeds and lakebeds, pebbles
were deposited that now form desert pavement. Almost all of present-day
Kuwait and much of southern Iraq and southern Iran, in fact, were once
a huge river delta, El-Baz says, and are currently covered by gravel.
And
when the pebbles are disturbed today, the wind picks up the exposed fine
grains underneath and “blows them around forever, either in
the form of sand dunes, which move around the land slowly, or as sandstorms
that move in and out of the region according to the season,” he
says. “The dunes cover farms, and they block roads and airports.
They wreak total havoc.”
The sandstorms have serious ramifications
for human health: Middle Eastern countries have higher than average rates
of respiratory diseases, partially
attributable to sand, scientists say, and the dust deposited in lungs
has been shown to cause cancer. “When you’re in a sandstorm,
the sand and dust gets in absolutely everything,” says El-Baz,
who was born in Zagazig, Egypt, in 1938 and lived in the country’s
Nile Delta region before coming to the United States in the late 1950s. “You
can be wearing a handkerchief tight around your face and when you take
it off to blow your nose, out comes sand. If you’re using a pen,
fine sand gets inside it.”
El-Baz says that large military convoys
traveling in the desert add “an
enormous amount” of dust and dirt to sandstorms. In a 1991 study
he conducted for the Kuwaiti government on the environmental effects
of the first Gulf War, he and fellow researchers at the Center for Remote
Sensing mapped surface areas directly damaged by military operations
— including vehicle traffic and the digging of trenches — and
those that had new dunes caused by military activity. They estimated
that nearly
30 percent of the Kuwaiti desert was affected in some way. Their findings
were based on time-lapse satellite images of the nation’s surface:
patches of disturbed desert reflect more light than areas covered by
desert pavement, because after thousands of years in direct sunlight,
surface pebbles react chemically in a way that allows them to absorb
more light.
Subsequently, the Kuwaiti government took several steps recommended
by El-Baz to help restore the land’s stability — including
pouring fresh gravel on large areas of disturbed desert. “Another
thing that helps is leveling off land where trenches have been dug or
mounds
of dirt piled up,” he says, “because the wind will act on
those areas more than on the flat areas.”
It is evident that studying
the desert strikes a deep personal chord with El-Baz, who has worked
tirelessly since September 11 to bridge the
gap between Muslims and non-Muslims. Possibly his most important contribution
to geology is his theory, established in the 1970s, that deserts are
not formed by man’s neglect of land but by long-term natural cycles.
“
There has been a great deal of misunderstanding about desertification,” he
says. He currently is using remote sensing technology to locate groundwater
in the Middle East. “Between 1968 and 1973, when there was drought
and misery in North Africa, the belief among experts worldwide was that
the people there had misused and ruined the land. But we now know that
the desert shrinks and expands in response to major variations in rainfall,
which are related to major variations in the amount of energy the earth
receives from the sun.”
The last thing the current dry cycle needs,
however, is the destructiveness of military activity. “The effects
of the war on the desert will be very long-lasting,” El-Baz says. “When
a sand dune forms, it continues to blow around as long as there is wind.” And
when the sandstorms blow out of Iraq to the south this summer, they will
be
larger than last year. “And then they will blow in again; these
things go on forever.”
4
April 2003
Boston University
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