Archaeologists say climate change is destroying the historical record of the Arctic people. The artefacts being received by the University of Alaska Fairbanks’s Museum of the North are more deteriorated than those unearthed decades ago, curator and professor Josh Reuther told KUAC, and he attributes that to the changing climate.A wooden mask recovered from the Nunalleq archaeological site in western Alaska [Credit: University of Aberdeen]
The problem isn’t just being noticed by academics in museums — archaeologists have seen changes in the field.
“It’s kind of a whole series of problems coming together at the same time to sort of create a perfect storm,” said Max Friesen, a University of Toronto archaeologist working on a dig in Canada’s Northwest Territories.
From left, UA Museum of the North Archaeology Curator Josh Reuther and Kaktovik resident Marie Rexford examine ivory and bone artifacts in the Barter Island collection [Credit: Kelsey Gobroski/UA Museum of the North]
“You have the potential melting of the permafrost, you have sea level rise, you have in some cases changing weather patterns.”
Friesen said he’s alarmed by the rapid deterioration. Until recently, he said, organic artefacts made of materials like wood or animal hides, were abundant around the region because they were preserved by permafrost or silty soils.
“It’s a very rich data base that’s being lost all across the Arctic,” he said.
Near the border with Botswana in the Shashi-Limpopo region lies Mapela, which is now an excavation site. The ruins of what is believed to have been a flourishing urban community for an astoundingly long period of time were first examined in the early 1960s. As a result of political developments in the country, which at that time was known as Rhodesia, the site was later abandoned and forgotten by the archaeologists.A section of Mapela Hill from the north [Credit: PLoS ONE]
Until June 2013, that is. Then, new excavations started under the leadership of Dr Chirikure from the University of Cape Town. Chirikure and his team discovered a large area with massive stone walls, huge piles of fossilised animal excrement, pottery, spinning wheels and thousands of glass beads that testify to thriving trade with other countries, probably India and China. Carbon dating indicates that Mapela was as a flourishing community that existed continuously from the early 8th century until well into the 18th.
'Mapela lies virtually untouched in a rather inaccessible area, and is unique in several respects,' says Per Ditlef Fredriksen, associate professor of archaeology at the University of Oslo. Since June 2014 he has been Dr Chirikure's collaboration partner and head of the research project that will dig deeper into the ecological history of Mapela to find out more about how people and the environment mutually affected each other in the Shashi-Limpopo region.
Mapela is unique, but also one of many
Ecological history studies the complex interplay between people and the environment through the centuries.
The excavation of Mapela is a collaborative project between the universities of Cape Town and Oslo, with funding from the research councils in both countries [Credit: Per Ditlef Fredriksen]
'In other words, the question is not only how people have adapted to climate change; it's also a fact that urban societies generate climate change,' Fredriksen points out.
The forgotten stonewalled site at Mapela Hill will be used as a case study in the project, but this is only one of a number of urban, historical communities that have been discovered in the Shashi-Limpopo region. The more famous ruined cities of Khami and Great Zimbabwe, both on UNESCO's World Heritage List, are also located in this part of Southern Africa.
'We are undertaking excavations in several locations in the area to obtain a better understanding of the development of all these world heritage sites, since the relationship between them remains unclarified.'
More concerned with the common folk
Until now, researchers have been mostly concerned with the elite and the elite culture that has been uncovered in places such as Great Zimbabwe and other well-known historical sites in the region. The common folk, on the other hand, were not deemed to be of equal interest ‒ until now.
A K2 sherd surface collected from the lower summit of Mapela hilltop [Credit: PLoS ONE]
'We wish to learn more about the relationship between the common population and the elite. Part of Mapela's uniqueness is that this site shows traces of all the three elite cultures in the area. The material culture testifies to this fact,' Fredriksen explains.
'Especially the jewellery, but even the fantastically constructed stone walls are extremely rich in symbols. Our findings in Mapela include traces of the stone walls of Khami.'
Using climate data from the start
'Climate and the environment have previously been topics raised in the debate over the urbanisation of Southern Africa. However, this new interdisciplinary project proceeds several steps further in the direction of natural science,' Fredriksen says.
The location of Mapela in relation to other important sites in the region around present-day Zimbabwe [Credit: PLoS ONE]
'We include climate data at an early stage when establishing research questions. Our objective is to obtain a deeper insight into the associations between climate, environment and socioeconomic and political strategies.'
Today, Mapela is located in an underdeveloped and marginal agricultural area, and researchers have assumed that this was an arid region earlier as well, and that Mapela was a regional centre of little importance. New findings, however, indicate the opposite.
A society against all odds
Mapela must have been larger than the known locality of Mapungubwe, where the elite is thought to have lived. Perhaps even the climate was quite different in earlier times.
Khami (shown here) is already on the World Heritage List. There is a lot to support the inclusion of Mapela, too [Credit: UNESCO]
'Was Mapela a community that existed against all odds?'
'That is an extremely interesting question. After all, Mapela continued to exist for centuries, while other communities, such as Mapungubwe, perished. Why? This is one of the questions we will attempt to answer.'
'Could this project provide new knowledge about the ways in which societies have adapted to climate change?'
'It's very complex, but hopefully we will be able to contribute to this,' says Fredriksen. He refers to the achievements of the University of Cape Town in the field of climate research.
'We are in this project to learn from the South Africans, and we have a lot to learn from them,' he concludes.
For more information see: Zimbabwe Culture before Mapungubwe: New Evidence from Mapela Hill, South-Western Zimbabwe. PLoS ONE (2014)
Author: Mari Kildahl | Source: University of Oslo [May 30, 2015]
Climate change is threatening archaeological sites in N.W.T.'s Mackenzie Delta, says University of Toronto professor Max Friesen.Pingos in N.W.T.'s Mackenzie Delta are unmistakeable evidence of permafrost activity in the soil. University of Toronto professor Max Friesen says thawing permafrost due to climate change is endangering archaeological sites in the area [Credit: Karen McColl]
He says thawing permafrost is endangering sites and artifacts dating back thousands of years.
"Instead of having the archaeological remains and the houses and whatnot being stable, they're actually eroding out of the cliff face," he said.
"As you walk along the beach, you can actually see all the artifacts, animal bones, and even pieces of houses that are slumping down the slope and will eventually wash out into the ocean."
Friesen says researchers need to act quickly and prioritize which sites should be excavated before their contents are destroyed.
For thousands of years, the mummies lay buried beneath the sands of the Atacama Desert, a volcanically active region along the northern Chilean coast with virtually no rainfall.The Chinchorro mummies at the University of Tarapaca's museum in Arica, Chile, date back as far as 5000 BC and are among archaeology’s most enigmatic objects [Credit: Chris Kraul]
When the first ones were discovered 100 years ago, archaeologists marvelled at the ancient relics, some of them foetuses, their little bodies amazingly intact.
But now the mummies, which are believed to be the oldest on earth, are melting. Mariela Santos, curator at the University of Tarapaca museum, noticed a few years ago that the desiccated skins of a dozen of the mummies were decomposing and turning into a mysterious black ooze.
"I knew the situation was critical and that we'd have to ask specialists for help," said Santos, whose museum stores and displays the so-called Chinchorro mummies, which date back as far as 5000 BC and are among archaeology's most enigmatic objects.
Within weeks, university staff members had contacted Harvard scientist Ralph Mitchell, an Ireland native who specialises in finding out why relics are falling apart. A bacteria sleuth of sorts, Mitchell has taken on assignments that included identifying a mysterious microflora breaking down Apollo spacesuits at Washington's National Air and Space Museum, analysing dark spots on the walls of King Tut's tomb and studying the deterioration of the Lascaux cave paintings in France.
Mitchell launched an investigation of the mummies' deterioration and this year issued a startling declaration: The objects are the victims of climate change. He concluded that the germs doing the damage are common microorganisms that, thanks to higher humidity in northern Chile over the last 10 years, have morphed into voracious consumers of collagen, the main component of mummified skin.
Mitchell believes that the case of the disintegrating Chinchorro mummies should sound a warning to museums everywhere.
"How broad a phenomenon this is, we don't really know. The Arica case is the first example I know of deterioration caused by climate change," Mitchell said. "But there is no reason to think it is not damaging heritage materials everywhere. It's affecting everything else."
Conservation of the fragile mummies has been a constant concern of researchers and curators since German researcher Max Uhle's archaeological expedition to Arica ended in 1919. Named after the nearby beach district where Uhle uncovered them, the Chinchorro mummies - about 120 of which are at the museum - are considered special for many reasons in addition to their age.
The community that made them was at the early hunter-gatherer stage of social evolution, compared with more advanced mummy-making civilisations such as the Egyptians, who had progressed to agriculture and trade, said Bernardo Arriaza, a professor at the University of Tarapaca's Institute of Advanced Research.
"Chinchorro mummies were not restricted to the dead of the top classes. This community was very democratic," said Arriaza, who for 30 years has led archaeological digs on the 500-mile stretch of Chilean coastline where most of the mummies have been found.
Archaeologist Bernardo Arriaza with a magnified image of a 7,000-year-old head louse found in the hair of a Chinchorro mummy in Arica, Chile [Credit: Chris Kraul]
Arriaza spends some of his days at a dig on a cliff overlooking Arica. A score of partially unearthed mummies, possibly of the same family, cover a sloping area about 50 feet across. It's one of many sites that construction has revealed, in this case digging for a pipeline.
Vivien Standen, an anthropology professor at Tarapaca and co-author with Arriaza of dozens of papers on the Chinchorro mummies, said they are also unusual in that they include human foetuses.
"That's a very special facet, the empathy that it demonstrates, especially compared with modern times where foetuses are simply abandoned," Standen said.
Volcanic pollution of drinking water evident in the presence of arsenic in the mummies' tissue may hold the key to why the community began mummifying its dead.
"Arsenic poisoning can lead to a high rate of miscarriages, and infant mortality and the sorrow over these deaths may have led this community to start preserving the little bodies," Arriaza said. "Mummification could have started with the foetuses and grown to include adults. The oldest mummies we have found are of children."
Chinchorro mummies have survived into modern times only because of the arid conditions of the Atacama Desert, said Marcela Sepulveda, the university archaeologist who made the initial contact with Harvard's Mitchell.
Sepulveda said it was possible that other groups in Latin America were doing the same thing, "but what is unusual here is that thanks to the climate, the mummies have been conserved."
Arriaza and Sepulveda both direct laboratories with high-powered electron microscopes dedicated to the analysis of materials found on and around the mummies. Continued decomposition of the mummies jeopardises their research, they said.
"Just raising them from the ground introduces the challenge of not breaking them," said Santos, the museum curator. "But over the last several years, the higher humidity - and how to deal with it - has presented a whole new challenge."
After months of growing cultures of microorganisms collected from the skins of the decomposing Chinchorro mummies and comparing their DNA with known bacteria, Mitchell identified the transgressors as everyday germs "probably present in all of us" that suddenly became opportunistic.
"It was a two-year project to identify and grow them and then putting them back on the skin to show what was breaking down," said Mitchell, a professor emeritus who donated his time to the Chileans.
Mitchell had used the same painstaking process to identify the bug causing stains on the walls of King Tut's tomb in Egypt, and to conclude that the germs weren't introduced after the tomb was discovered in 1922 but probably were on the walls of the crypt when the boy king was entombed about 1300 BC.
Similarly, Mitchell used microbial analysis to investigate the erosion of Maya monuments at Chichen Itza at the request of the Mexican government. He found that the application of a polymer coating, far from protecting the ancient carvings and buildings as intended, was actually abetting the destructive microorganisms that were causing the stone work to crumble.
He also has an ongoing project at the USS Arizona monument at Pearl Harbor, where bacteria that thrive in the oil leaking from the battleship's fuel tanks are accelerating the disintegration of the sunken World War II vessel.
Mitchell began specializing in microbial damage to cultural relics in the mid-1990s, when the Italian government invited him to look at widespread damage to centuries-old frescoes at churches and palaces.
He identified Italy's main problem as industrial pollution, and thus came to the sad conclusion he has arrived at several times since: Isolating the problem doesn't always lead to a practical solution.
Mitchell seems more optimistic in his work with the Chilean mummies. Over the next two years, he and the faculty at the University of Tarapaca will be working on possible solutions to the deterioration. He thinks humidity and temperature control offer the best chance of stabilizing the relics.
Mitchell and the archaeologists feel a sense of urgency: The Chilean government has budgeted $56 million for a new museum scheduled to open in 2020 to house the mummies, and everyone wants the right climate controls built in to the new structure to safeguard the relics.
"The next phase of the project is to look at how you protect the mummies and at possible physical and chemical solutions to the problem, which we don't have yet," Mitchell said. He and the Chileans will experiment with different combinations of humidity and temperature to determine an optimal ambience.
Optimally, each mummy will be encased in its own glass cubicle in the new museum and have its own "microclimate," Arriaza said. But the irony is not lost on him and his fellow archaeologists that mummies that survived millenniums in the ground are proving fragile in the face of changing conditions of modern times.
"I'm not optimistic we can save them," said Standen, the anthropology professor. "From the moment they are taken out of the ground, they start deteriorating."
Author: Chris Kraul | Source: LA Times [May 08, 2015]
