LEWISBURG — The Bucknell University Environmental Center’s Green Screens film series began Tuesday night with the screening of a film that used time-lapse photography to demonstrate changes to glaciers attributed to climate change.

“Chasing Ice” followed photographer James Balog as he documented melting glaciers over a period of three years for the National Geographic Society. Degradation of Iceland’s Solheim Glacier was illustrated using the time lapse technique, as an area the size of lower Manhattan broke away and fell into the sea.

The vivid imagery was interspersed with lectures and news footage that featured Balog, as he described the retreat of the glaciers as the place were climate change is most evident.

“Glacier National Park, Montana will be known as ‘glacier-less national park,’ by the middle of the century because all of the glaciers will be gone,” Balog said in the film.

A discussion among some of the more than 200 people who attended the film followed, led by Bucknell University Associate Professor of Geography Duane Griffin and Geology Professor Craig Kochel.

Griffin said the time-lapse photography used in the film was effective in demonstrating the global scale of the degradation. Similarly, archived still photos can be used as well.

“There have also been projects to take old photography, from the turn of the last century, go back and identify those photo points exactly, then re-photograph them and compare them,” Griffin said, recalling an advisor who recorded vegetation changes that way. “He was seeing these meadows in the west being invaded by pine trees and other things, which was another aspect of climate change, but one that was happening in the 1970s and 1980s.”

It was the glaciers, Griffin said, which really illustrate the ravages of climate change.

Kochel, who recently returned from observing glacial changes in New Zealand, said the film hit him on many different levels.

“What these guys are doing is remarkable, because they are actually capturing it in a way that you can see things happen,” Kochel said. “If you go back to your favorite glacier, you can see things changing, but it is very difficult to document.”

An audience member asked for a prediction of how high sea levels will rise if the Greenland ice sheet melts. Griffin said a commonly accepted figure is an increase of 21 feet by 2100, resulting in problems for residents of low-lying areas with little high ground, such as Florida.

However, Griffin said global warming would likely continue, resulting in ocean levels perhaps 40 feet higher than where they are now, and enormous changes to major food producing areas of the world, such as the Mekong River delta and portions of Bangladesh will result.

Griffin said a recent tour of the Alps and a portion of France with Bucknell students taking a climate change course was eye opening.

“About half the students were skeptical as to whether climate change was real,” he said. “But if you go up into the Alps and see where there glaciers were in the Ice Age…you could see them going away.

“We went down to the Mediterranean and saw a beach that just a year before had been a beach, and now it wasn’t. There were picnic tables sticking out of the water and little barrier dune system had been breached…Several hundred yards of France was lost in that one event…it was very convincing,” Griffin added.

“These things are happening, and if you go to the right places, you can see them,” he concluded.