|Glaciologists extract ice cores, analyze them and determine changes in climate over time.|
Once or twice a year Keith Mountain, chair of the Department of Geography and Geosciences at the University of Louisville, and colleagues from the Byrd Polar Research Center at Ohio State University spend months hunting for a disappearing treasure: ice.
They travel to a glacier in the mountains of Bolivia, Peru, China, Antarctica or Tanzania. The conditions can be brutal at elevations as high as 20,000 feet, but what they find might help save the planet.
Glacier ice contains thousands of years of the Earth’s climate history. It also provides clues as to how and why global warming is happening today, Mountain said.
The researchers use a portable drilling system to extract from the glaciers cylindrical ice cores about 13 centimeters in diameter and hundreds of meters long. They cut each core into 1-meter segments, then mark and pack it for later analyses.
Like the rings of trees, these ice cores are time capsules which can span tens of thousands of years.
Through mathematical models and other methods, including preliminary test drillings, the team can determine the amount of ice compression and come up with reliable ways to interpret these ice cores, he explained.
“We can reconstruct atmospheric temperatures and ascertain precipitation rates and how much dust there was in the atmosphere,” Mountain said. “We can find out the chemical composition of the atmosphere. You can pick up things like various nitrates-sea salt, for example-and figure out wind directions and the sources of moisture and how those may have changed over time.”
The team has determined from interpreting the ice records over time that, “yes, climate change is global and real,” he said.
Rising temperatures worldwide and local decreases in precipitation are contributing to the decline of the glaciers — which makes their work a race against time.
“When I started out in this field in the late ’70s I never would have thought that the photographs we took of this big ice sheet in southern Peru would become archival records of something lost,” Mountain said. “We photograph the changes there every year now, and the changes are occurring quickly. It’s retreating on the order of 50 meters a year.”
Ice is retreating not only in Peru, but worldwide. The famed white cap of Mt. Kilimanjaro in Tanzania soon will be no more. At its current rate of melting, he said, it will disappear by about 2015.
Glaciologists are just one scientific sector contributing to the mass of evidence on the reality of global climate change, Mountain said, noting that 95 percent of the scientific community believes that global climate change is happening and that humans are a significant causal factor.
Yet somehow, he said, a 95 to 5 percent ratio becomes a yes-no, either-or vote: “Some are trying to turn this into a debate, but there is no debate.”
In his native Australia where years of drought have led to bush fires and dying cattle, global warming is a real issue, Mountain said. That’s also true in other parts of the world.
“For the people in Peru, as the glaciers melt they are losing their irrigation water for farming. In Tibet, as the glaciers recede streams are evaporating and leaving big salt deposits that make the remaining water undrinkable,” he said.
The jury is no longer out on global warming, Mountain said.
“At some point, the jury has to come back and make a decision. What kind of policies are we going to develop to deal with this?”