Since the future of humanity may be at stake as we face global warming, Hominid Highlights will feature occasional news dispatches on this topic.

Climate on the Rocks

By Eli Kintisch
ScienceNOW Daily News
17 February 2006

SAN FRANCISCO, CALIFORNIA--The most detailed analysis yet of the largest body of ice in the world's tropics shows the 5000-year-old glacier in danger of disappearing in five years. Glaciologist Lonnie Thompson, who presented the findings here yesterday at the annual meeting of the American Association for the Advancement of Science (which publishes ScienceNOW), says his study of the vanishing Quelccaya Ice Cap in Peru provides frightening new evidence of accelerating glacier loss, which he says could be a "canary in the coal mine" for intense global climate change.

The fate of glaciers is crucial because their ice is highly sensitive to global climate change, Thompson says. In addition, millions of people around the world are dependent on water from glaciers or live in their shadows, making an accurate assessment of their fate important to prepare for the possibility of deadly droughts or floods as the ice melts.

Thompson collected the cores of the Qori Kalis glacier--part of the Quelccaya Ice Cap--in 2003, revisiting a site he'd first drilled to bedrock in 1983. In that year, his team used a solar-powered drill to collect ice samples, which they brought back to U.S. labs as melted water. The samples revealed a remarkable sensitivity of climatic fluctuations going back 5000 years. More recently, the team used generators to drill, and special trucks kept the ice frozen for shipping back to Ohio State University in Columbus, where Thompson performed some twenty chemical tests, including isotopic and organic analyses that were not possible in 1983.

The analysis showed accelerating melting, with liquid water having disturbed the top thirty meters of the frozen core, erasing the seasonal patterns of the two decades of the record. "This condition hasn't been seen in the whole history of the sheet," Thompson says, underscoring how unique the last decade of warming has been. The record shows that a few degrees in air temperature rise, accelerated by solar radiation in the thin atmosphere, has overcome steady precipitation that otherwise might have preserved the glaciers. "All things being equal, those glaciers should be growing," he says.

Thompson's work has a kind of rescue aspect to it, as the 80-meter-long record could be gone in five years, taking with it important insights into the vanishing history of the ice. "When I am long gone, this will be the holy grail of tropical glaciology," says Thompson. Although historical studies on the Qori cores have yet to be published, Thompson says initial analyses confirm some interesting historical events, including the 1345 Black Death record and the 1790 monsoon failure that lasted 20 years. Both show up as elevated levels of organic compounds.

Climatologist Henry Diaz of the U.S. National Oceanic and Atmospheric Administration says the vital record, kept in cold storage indefinitely at Oregon State University in Corvalis, will give clues about glaciers for generations as paleoclimatologists continually refine their analytical methods. "It's like having an archeological record," he says. Now Diaz says that glaciers such as Qori Kalis and ice caps on Mt. Kilamajaro and North American peaks suggest the world's climate could be "entering a period of inflationary warming ... very warm conditions, sustained year after year."