Argument has raged for decades over what doomed
the ancient Maya civilization and spurred its people to abandon
their awe-inspiring temples and pyramids in the rainforests of
Mexico and Central America. Warfare, disease, social unrest and over-
farming have all been cited as potential factors in the decline of a
culture that was scientifically and culturally advanced for 750
years.
A new study bolsters the theory that large-scale climate change
was responsible for the society's demise - and also argues that
changes in global weather patterns were also responsible for their
rapid rise.
Using data from a 13,500-year-old stalagmite taken from the floor
of a recently discovered cave in Belize, scientists said they were
able to assemble a precise record of rainfall for the region going
back 2,000 years.
The ancient cave spire was created by rainwater as it leaked from
the ceiling of Yok Balum cave and deposited dissolved minerals in a
growing mass on its floor, drip by drip. By examining the ratio of
atomic isotopes along the length of the stalagmite, researchers said
they were able to determine when portions of it formed, and how much
rainwater fell during each six-month period.
What they discovered was a period of abundant rainfall during the
early days of the civilization, followed eventually by drought. The
results were published in Friday's edition of the journal Science.
"Unusually high amounts of rainfall favored an increase in food
production and an explosion in the population" beginning around 440
A.D., said study leader Douglas J. Kennett, an anthropologist at
Penn State University. "This led to the proliferation of cities like
Tikal, Copan and Caracol across the Maya lowlands."
By 700 A.D., that wet weather gave way to "general drying trend
that lasted four centuries and was punctuated by a series of major
droughts," he said. "That triggered a decline in agricultural
productivity and contributed to societal fragmentation and political
collapse. ... Maya kings lost their power and influence"
Researchers said the severe drought the Maya experienced was akin
to the one that devastated Mexico in the 16th century, bringing crop
failure, famine and death. Kennett said those same circumstances
likely visited the Maya during their classic period, from 250 A.D.
to 1000 A.D.
Although the study adds valuable detail to the ancient climate
record, other Maya researchers said it was unlikely to end debate on
the issue.
Boston University archaeologist William Saturno said he remained
unconvinced that climate change was the primary driver of the
civilization's collapse.
The worst period of drought detailed in the report was in Belize
and came 100 to 300 years after the time the Maya in that region
stopped inscribing major monuments and essentially "went dark" as a
culture, Saturno said. He called it a mistake to believe that
drought in one region affected all areas of Maya civilization, which
also covered portions of what is now Southern Mexico, Guatemala, El
Salvador and Honduras.
Saturno said he believed the growing popularity of the climate
change theory was based on worries about modern-day global warming.
"Oftentimes, we're looking at ancient societies as an analogue to
our own," he said. "We want to drive home the point: If we destroy
the environment, we'll reach a point where we can't recover."
The authors of the study wrote that the prolonged drying trend
triggered balkanization and fueled brutal warfare. Saturno said he
doubted it led to war, but it could well have undermined the Maya
leadership.
