Egypt Felled by Famine Even
ancient Egypt’ mighty pyramid builders were powerless in the face of the famine
that helped bring down their civilian around 2180 BC. Now evidence gleaned(搜集)
from mud deposited by the River Nile suggests that a shift in climate thousands
of kilometers to the south was ultimately to blame—and the same or worse could
happen today. The ancient Egyptians depended on the Niles
annual floods to irrigate their crops. But any change in climate that pushed the
African monsoons(季风)southwards out of Ethiopia would have diminished these
floods. Dwindling(逐渐变少)rains in the Ethiopian highlands would
have meant fewer plants to establish the soil. When rain did fall it would have
washed large amounts of soil into the Blue Nile and into Egypt, along with
sediment(沉积物)from the White Nile. The Blue Nile mud has a
different isotope signature(特征) from that of the White Nile. So by analyzing
isotope(同位素；核素) differences in mud deposited in the Nile Delta, Michael Krom of
Leeds University worked out what proportion of sediment came from each branch of
the river. Krom reasons that during periods of drought, the
amount of the Blue Nile mud in the river would be relatively high. He found that
one of these periods, from 4,500 to 4,200 years ago, immediately predates the
fall of the Egypt’s old Kingdom. The weakened waters would have
been catastrophic for the Egyptians. Changes that affect food supply don’t have
to be very large to have a ripple effect in societies, says Bill Ryan of the
Lamont Doherty Earth Observatory(天文台) in New York. Similar
events today could be even more devastating, says team
member Daniel Stanley, a geoarchaeologist(地质考古学家) from the Smithsonian
Institution in Washington, D. C. "Anything humans do to shift the climate belts
would have an even worse effect along the Nile system because the populations
have increased dramatically." The word "devastating" in the last paragraph could be best replaced by
______.
A. frustrating
B. damaging
C. defeating
D. worrying