Tuesday, July 28, 2015

Melting Mummies Are on Thin Ice, Thanks to Climate Change

The world’s greatest archeologist may not be human, but it is human-made. Global warming, the explorer in question, has melted glaciers that have preserved and hidden many past lives. From a celebrity mummy to graveyards of fish-lizards, ancient remnants have begun to spill out of the disappearing ice—faster, even, than researchers can recover them. And as the artifacts emerge, so has the science. The fledgling field of glacial archaeology seeks to find and recover these relics before the glaciers disappear, a time that may come all too soon. “It’s a race against time,” says Albert Hafner, director of the Institute of Archeological Science at the University of Bern in Switzerland.

The formation of a fieldbark containers, medicinal plants and a hat, Ötzi drew the world’s attention to the notion of an archaeology rooted in ice.

Spurred by the promise of other such discoveries, the field of glacial archeology took root in several locations across the globe. Researchers in Norway, Canada and Alaska pored over the silent, rock-strewn tundra in search of spearheads, skulls and any trace of human life. They discussed the immediacy of their work in conferences and symposiums, says James Dixon, a professor of anthropology at the University of New Mexico. Along with Hafner, Dixon serves as an editor of the Journal of Glacial Archeology, in 2014. Thus investigators began to take the first steps in this race against time.

But Dixon’s initial proposals received no more money than they did respect. The field confounded funding agencies. “I would get reviews back saying ‘This is the most ridiculous thing we’ve ever heard of. People never lived on ice!’” he says. Although people never lived on ice (with the rare exception of the Inuit people who live above the Arctic circle), Dixon says, people died on ice all the time. Glaciers and ice fields have long functioned as theaters of war and spirituality. Often the only way to move between the mountains, ancient pathways still host 21st-century travelers. Ötzi himself emerged away from a path still trod by tourists today.

Out of the ice

Unlike glaciers, ice patches stand perfectly still. So anything that ends up on the patch—pollen, animal dung, human tools and even the humans themselves—will succumb to successive seasons of snowfall until it is entirely encased in ice. Each summer’s melt compresses the material like a layer cake of archaeological information. The patches, kept cool by underlying permafrost, should theoretically last thousands of years. But in reality they are melting. Already in Alaska ice patches have entirely disappeared, Lee says.

These soon-to-be-thawed regions around the world promise to bestow on archaeologists a range of discoveries. The Alps contain some of the earliest evidence of prehistoric human habitation and South American ice holds relics of sacred rituals. Meanwhile North American ice patches give way to ancestral material that can be tied to the heritage of extant indigenous populations. In his ice patch study in Yellowstone National Park Dixon has partnered with local tribes to offer the people a window into their past. And all regions’ artifacts extend beyond archaeology. Ice yields valuable paleobotanical insight via items like bison bones and petrified birch, according to Lee. In Chile scientists discovered under a melting glacier.

But once exposed, an artifact’s days are numbered. Investigators have about a year to recover an object before it is too late, Lee says. Each day an object blisters under the sun degrades the value of information returned. Researchers may still recognize items exposed for longer, say, a decade after exposure. But those isolated years render them useless—what Lee calls “an artifact only a mother could love.”

Faced with this decay in a gargantuan expanse of glaciers, archaeologists must trek wisely. With some success, researchers have attempted to design data models in geographic information systems to identify specific features in glaciers more likely to hold artifacts. But accounting for the huge surface area, along with a slew of factors like megafauna distribution, elevation, slope and precipitation, makes these models expensive and time-consuming, Dixon says. Scientists have dabbled in various other detection tools, including aerial reconnaissance, satellite imagery and helicopter surveys. But once on-site, the researchers must simply walk, eyes peeled for what may be exposed. These surveys can only take place late in the summer, during the thaw. Summers, Lee says, that will only grow longer.

Warming up to climate change?

For now, global warming holds the key to understanding human ancestors recent and prehistoric, according to Lee. Glacial archaeology boasts a spectacular record of finds that would not have been possible without glacial retreat. “Without climate change, it’s not clear to me that Ötzi would have been uncovered,” Lee says, adding that the melt has already confirmed a long-lived human presence in alpine areas of North America. Hafner even attributes the very foundation of glacial archaeology to Earth’s rising temperatures.

But the future aftermath of the melt will mean incalculable losses to scientists’ understanding of the past. People mistakenly perceive global warming as beneficial to archaeology, Dixon says. “For every artifact we find, we’re losing thousands. And we’re never going to be able to replace this data,” he adds. “As long as they’re frozen in ice, they’re preserved for the future.”

Climate change has not taken kindly to mummies already unearthed. In a museum in Chile the world’s oldest man-made mummies — dating as far back as 5050 B.C.—have begun to disintegrate into black ooze. Harvard researchers traced this rapid decomposition to rising humidity levels in Chile, where the museum is located.

Few have recognized the immediate need to preserve glaciers, which are crucial scientifically, economically and socially. Only Argentina has made a lasting foray into the politics of ice, to save glaciers from destruction by industrial development.

Thus, glacial archeologists find themselves at the start of an unprecedented but ephemeral run of discovery. “Now is the time to organize expeditions,” Hafner says. “We have 20—maybe 30—years, and then we will be finished.” The necessary funding, however, may never come. General archaeology already draws on such a small endowment that researchers struggle to ground in science a method that consists, more or less, of walking out in the snow to see what you can find. The future of glacial archaeology, Dixon says, depends on funding, logistics and the number of researchers in the field. So researchers continue to work against the clock, writing proposals and treading on ice that grows thinner each day.

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