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Ice Core Team in Greenland
Photo Courtesy: Ellen Mosley-Thompson
A team drills for ice cores at Crawford Point in Greenland in May 2007. They took seven cores to establish a melt history over the last three centuries to help determine if the current rate of change is outside natural variability. Pictured, from left, are Vladimir Mikhalenko, Lijia Wei, Ellen Mosley-Thompson, Natalie Kehrwald and Victor Zagorodnov.


Nature versus nurture

In a way, some scientists note, the loss of something like the Wilkins Ice Shelf is really just a chip of paint flaking off a wall in terms of its size compared to the whole of Antarctica. East Antarctica, which holds more ice than Greenland and West Antarctica combined, still seems relatively invulnerable.

Ken Jezek, a geophysicist with BPRC whose work involves satellite mapping of the polar regions, notes that our ability to track modern changes in polar ice caps has been largely possible thanks to remote sensing. The satellite observations only date back a few decades.

The question becomes, he says, “Is this a recent phenomenon or a phenomenon that’s been going on for a while but we’re just now able to observe it. … That seems to me to be a bit of an open issue.”

In fact, we are in what scientists call the interglacial period, an interval of warmer global temperatures that separates glacial periods. About 20,000 years ago, the world’s ice sheets and glaciers had reached their largest extent, referred to as the last glacial maximum. On the whole, glaciers and ice sheets have been shrinking for several thousand years.

The debate today is no longer whether or not the world is heating up like a car with a busted radiator. The global engine is overheating, but are we behind the wheel or just sitting in the back seat, along for the ride? The latest IPCC report, and many scientists, say the evidence indicates the former.

“I think the anthropogenic input is real,” Jezek says, but adds that he doesn’t know if human activity is entirely to blame. He notes, for example, that geothermal heat below the bedrock on top of which ice sheets sit may be partly responsible for speeding some glaciers — like holding a lighter under a bowl of ice cream.

Scientists who disagree with the IPCC assessment for rising temperatures say global warming and its associated climatic changes may be part of a natural cycle, increased solar activity or cosmic rays.

Ellen Mosley-Thompson, a professor in OSU’s Department of Geography and a member of BPRC’s ice core paleoclimatology group, says that opposition to human-induced climate change often simplifies the equation, leaving out complexities such as feedbacks in the system. For example, sea ice reflects sunlight, but as it disappears, the exposed ocean surface is darker so it absorbs more solar energy (heat), melting more sea ice, which allows the ocean to absorb more heat, and so forth.

The message from the contrarians, as Mosley-Thompson refers to climate skeptics, is that the problem of global warming and climate change is not much of a problem at all.

“Everyone wants that message,” Mosley-Thompson says. “I’d love for that message to be true. My daughter comes over to our house and says, ‘Please don’t start talking about climate change because I always leave here so depressed.’”

The dust storm

For Thompson, the questions of prediction and blame seem secondary to the one about how the world will respond to the climate changes that few deny are taking place. He tells the story of Hugh Bennett, a pioneer in soil conservation from the early 20th century, to illustrate his point.

The story goes something like this: Drought coupled with decades of intensive farming caused severe soil erosion, which led to the Dust Bowl period of the 1930s, when dust storms caused extensive damage to prairie lands. Bennett was in Washington, D.C. on a fine April day in 1935, urging the U.S. Congress to pass a law to help conserve the nation’s soil.

On the day of his speech, a dust storm rolled over the nation’s capitol to add a dramatic exclamation point to his argument. (History tells us Bennett was warned of the approaching storm, and timed his speech for its arrival.) Shortly after, Congress passed the Soil Conservation Act, which allowed the government to pay farmers to reduce production to conserve the soil.

The world may be waiting for a modern version of that dust storm before it acts against climate change, Thompson said.

“Most of what I see of human nature is that we don’t like to do anything until we have to, until there’s absolutely no other choice, your back’s against the wall, and then we’re pretty good,” he says. “I do wonder what it’s going to take to get everybody on the same page.”

Mosley-Thompson says she feels many people are finally coming together on the problems. “I’ve been at this business for almost three decades,” she says. “I would say the tide has turned tremendously in the last few years. Although we still have a long way to go, at least nearly everyone is talking about climate change.”

And despite what might seem like a doomsday scenario — reinforced almost daily by reports of ice shelf collapses, shrinking summer sea ice in the Arctic, melting permafrost and vanishing species — scientists are amazingly still hopeful.

“I’m absolutely convinced — when it’s clear what that job is and how we can solve it — the world can work together to accomplish it,” Thompson said.

Funding from the National Science Foundation has supported much of the research and scientists quoted in this story.

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