Download Mummies Group C

Mummies: Group C
Why a changing climate could
destroy some of the world's oldest
mummies
By Chris Mooney, Washington Post
03.18.15
A Chinchorro mummy at San Miguel de Azapa Museum in Arica, Chile. Arica is often referred to as the driest place
on Earth, but locals say that the climate is changing, which could be affecting the mummies there. Photo:Courtesy of
Vivien StandenSome seven millennia ago or more, a group of people called the Chinchorro
lived along the coasts of northern Chile and southern Peru. Their lives revolved around
fishing from the rich Pacific waters, even as a uniquely arid desert — the Atacama —
lay inland behind them.
The Chinchorro were unique in many ways, but perhaps most of all in their burial
practices. Several thousands of years before the Egyptians, they were mummifying their
dead — creating the oldest known mummies on Earth — and doing so in a truly equal
fashion. "Whereas the Egyptians considered only kings and other exalted citizens
worthy of mummification, the Chinchorro accorded everyone in the community,
regardless of age or status, this sacred rite," wrote Bernardo Arriaza, an expert on the
mummies, which were first discovered in the Atacama desert in 1917.
Since then, hundreds of mummies have been unearthed, with more still in the ground
being uncovered regularly. But lately, there's been a problem. The specimens — more
than 100 are held at a museum of the Universidad de Tarapacá in Arica, Chile — have
started to degrade. "The tissue change is reflected in the appearance of dark and bright
spots," Marcela Sepulveda, an archaeologist at the Universidad de Tarapacá, explained
by email.
Indoors, the change has been slow, but outdoors, mummies are being discovered
already damaged, Sepulveda said. "When you excavate mummies you can see that
degradation is already there," she said. And the suspected reason? A changing climate.
Arica is often referred to as the driest place on Earth — but locals say that's changing.
According to Sepulveda, the city has seen increases in precipitation and humidity of
late. "Everybody say(s) that here," she averred. Indeed, weather historian Christopher
Burt wrote about Arica in 2013, noting that despite its famous reputation for dryness,
weather records from 1971 to 2000 suggest that lately it has been somewhat wetter
than usual.
This may not be a change that can be definitively pinned on global climate change
caused by humans, cautioned Ralph Mitchell, a Harvard microbiologist who teamed up
with the Chilean researchers to figure out what was ailing the mummies. But it's a
change nonetheless. "Our colleagues in northern Chile say it's terribly obvious that the
place is foggy a lot more than it ever was," Mitchell said.
Mitchell noted that many of the mummies, found in the 1980s, had no problems until 10
years ago, "when they started to deteriorate." The sequence itself suggests a climatic
factor may be behind what's happening.
So Mitchell and two Harvard colleagues collaborated with Sepulveda and one of her
colleagues to try to figure out what was going on — whether indeed, climatic changes
were the reason for mummy decay — and what that would mean for better preserving
these unique, ancient objects. Their hypothesis was that, in effect, more airborne
moisture had enabled bacteria to start to chow down on the ancient relics.
So they studied samples of mummy skin and dried pig skin, in various conditions,
examining which microbes were living on and in the skin. The result, said Mitchell, was
the finding that what he calls bacterial "opportunists" were taking advantage of a more
humid environment to "use the skin as a nutrient and start to break it down." These
were common skin bacteria, among others, which had been enabled by a particular set
of environmental conditions.
The research has not been published yet, but the findings were publicized by Harvard
on Monday. Mitchell, who is also a visiting professor in the environmental health
department in the George Washington University School of Public Health, has worked
on preserving many historical materials, ranging from ancient book manuscripts to the
Apollo spacesuits.
The saga of the Chinchorro mummies illustrates just how vulnerable many irreplaceable
cultural artifacts and world heritage sites may be to a changing climate (human caused
or otherwise). It's something that the UNESCO World Heritage Center has been
attentive to for some time; a 2007 report from the U.N. agency noted that "the impacts
of climate change are affecting many World Heritage properties and are likely to affect
many more, both natural and cultural, in the years ahead."
The U.S. Agency for International Development is also concerned about how climate
change can affect world heritage sites — and it highlights an example that on a physical
level sounds similar to what appears to be happening in Arica. "Buildings in the rare
medieval city of Leh in Ladakh, India, were constructed in a high altitude desert
environment and are ill suited to current increases in precipitation," it notes.
Several years back, Archaeology magazine listed yet another related example, noting
that the frozen burial mounds of Scythian warlords (called "kurgans"), preserved in
permafrost near Siberia, can be destabilized by Arctic thawing. In this case, it was ice,
rather than desert, that had preserved remains intact for a magnificently long time — but
a change in climate can once again mean an irreplaceable loss of artifacts and ruins.
Harvard's Mitchell, meanwhile, said he suspects another possible climate heritage
victim: outdoor marble statuary. "Historic marbles in the outdoor environment are at risk
from climate change," he said.
So while we may not know exactly what's happening in Arica, Chile — or whether it
should be attributed to human-caused global warming — the fact is that damage to
historical artifacts and world heritage sites is an expected consequence of climate
change in general. And how could it be otherwise? Many of these sites have been
remarkably preserved precisely because of the fact that they have been climatically
unperturbed.
Alter that, and, along with many other consequences, the world could lose some of its
history.