OSU scientist studies the effects of global warming

Global warming has been a hot topic this summer. But it’s not just because of movies by ex-vice-presidents.

On Ohio State University’s campus, there’s a giant freezer, kept at minus 30 degrees Fahrenheit. The freezer contains several racks. They hold rows of silver canisters about three feet long and four inches in diameter. Inside the canisters is glacial ice from the tops of mountains.

Professor of Geological Sciences Lonnie Thompson uses the ice to study global climate change.

In this week’s issue of the journal, Proceedings of the National Academy of Sciences, Thompson and his team published a paper compiling 30 years of ice studies.

They’ve drilled for ice from mountains in the tropics, having gone to places like the Himalayas, Mt. Kilimanjaro in Tanzania, and the mountains of Peru.

This week’s paper argues the evidence from ice around the world paints a consistent picture of rising global temperatures and abrupt, dramatic impacts. Thompson hopes that this paper will provide a global story on climate change for policy-makers.

“What they want to see is the big picture, the composite of what’s happening globally. And to me, that’s what this paper does. And it does it for a part of the world where we have very few records, and certainly none with the time resolution that the ice core provides,” Thompson said.

The ice cores record everything from temperatures and greenhouse gases to other forces that affect climate, like volcanic eruptions. The paper highlights annual records that go back 400 years, and other records that go back as far as 2000 years. Thompson says that some ice cores can trace back 650,000 years.

He says these records consistently indicate the last 50 years show a warming trend unique to the Earth’s climate history.

Perhaps the most dramatic indicator of global warming is the melting of the ice itself. Melting ice in Peru has uncovered perfectly preserved plants dating back 5000 years. This means that the temperatures there are now the warmest they’ve been in those 5000 years. Thompson believes the glaciers on Mt. Kilimanjaro will disappear within 10 years.

The scientists say that what is even more important is the fact that records show precipitation to be at around average levels. This discredits the argument that less snowfall is the cause of retreating glaciers. University of California Berkeley Professor, John Harte, is a leading expert on climate change. Earlier this week, he gave a public lecture at OSU entitled Why The Skeptics Are Wrong.

Harte studies how ecosystems interact with changes in climate. For the past 16 years, he’s been doing an experiment in a high-altitude meadow in Colorado. Using electric heaters, he gently warms patches of land by just a few degrees. This simulates conditions that would exist in 50 years, when carbon dioxide concentrations would’ve doubled.

“What we’re finding is that in fact these warmer ecosystems do release greenhouse gases to the atmosphere, particularly carbon dioxide,” said Harte.

He says this release of carbon dioxide will further warm the earth, exacerbating the problem. This is an example of a positive feedback, where warming causes even more warming.

But, there is a small minority of scientists who dispute the dangers of positive feedbacks and global warming. One doubting scientist is Professor of Meteorology at the Massachusetts Institute of Technology, Richard Lindzen. Although he agrees with the basic facts of global warming, he does not believe it’s a cause for alarm. Lindzen warns against merely citing consensus as a reason for the dangers of climate change. He also says the Earth is more stable than climate models predict.

“So far we’re finding that nature is better designed than the models. That in the models, whatever CO2 does, the main greenhouse gases, which are water vapor and clouds, act to make it much, much worse. As you know, I mean, any well designed piece of equipment has negative feedbacks that try and resist change,” Lindzen said. Harte, on the other hand, counters every relevant paper published in a refereed scientific journal show positive feedbacks are by far the dominating factor. Along with the majority of scientists, Harte believes global warming is a serious problem.

“Science of global warming is really firm, convincing, sound, and while there are remaining uncertainties, the major criticisms by scientific skeptics that the science is shoddy just don’t stand up to scrutiny,” said Harte.

More than 150 people listened to Harte’s public lecture. He carried the optimistic message that solutions to global warming are feasible.

OSU Geology Professor Ellen Mosley-Thompson is Thompson’s partner in studying ice cores and climate change. She’s wary of stressing doomsday scenarios for global warming. But, like most scientists, she believes immediate action is critical.

“The sooner we delay, then either the greater the action we’ll have to take, or the greater the likelihood of even worse consequences,” Mosley-Thompson said.

Last week, the National Academy of Sciences issued a report supporting an earlier study from 1998 that the Earth is the hottest it has been for the last 400 years.